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Sample records for short period seismic

  1. Short-Period Surface Wave Based Seismic Event Relocation

    Science.gov (United States)

    White-Gaynor, A.; Cleveland, M.; Nyblade, A.; Kintner, J. A.; Homman, K.; Ammon, C. J.

    2017-12-01

    Accurate and precise seismic event locations are essential for a broad range of geophysical investigations. Superior location accuracy generally requires calibration with ground truth information, but superb relative location precision is often achievable independently. In explosion seismology, low-yield explosion monitoring relies on near-source observations, which results in a limited number of observations that challenges our ability to estimate any locations. Incorporating more distant observations means relying on data with lower signal-to-noise ratios. For small, shallow events, the short-period (roughly 1/2 to 8 s period) fundamental-mode and higher-mode Rayleigh waves (including Rg) are often the most stable and visible portion of the waveform at local distances. Cleveland and Ammon [2013] have shown that teleseismic surface waves are valuable observations for constructing precise, relative event relocations. We extend the teleseismic surface wave relocation method, and apply them to near-source distances using Rg observations from the Bighorn Arche Seismic Experiment (BASE) and the Earth Scope USArray Transportable Array (TA) seismic stations. Specifically, we present relocation results using short-period fundamental- and higher-mode Rayleigh waves (Rg) in a double-difference relative event relocation for 45 delay-fired mine blasts and 21 borehole chemical explosions. Our preliminary efforts are to explore the sensitivity of the short-period surface waves to local geologic structure, source depth, explosion magnitude (yield), and explosion characteristics (single-shot vs. distributed source, etc.). Our results show that Rg and the first few higher-mode Rayleigh wave observations can be used to constrain the relative locations of shallow low-yield events.

  2. New serial time codes for seismic short period and long period data acquisition systems

    International Nuclear Information System (INIS)

    Kolvankar, V.G.; Rao, D.S.

    1988-01-01

    This paper discusses a new time code for time indexing multichannel short period (1 to 25 hz) seismic event data recorded on a single track of magnetic tape in digital format and discusses its usefulness in contrast to Vela time code used in continuous analog multichannel data recording system on multitrack instrumentation tape deck. This paper also discusses another time code, used for time indexing of seismic long period (DC to 2.5 seconds) multichannel data recorded on a single track of magnetic tape in digital format. The time code decoding and display system developed to provide quick access to any desired portion of the tape in both data recording and repro duce system is also discussed. (author). 7 figs

  3. Toward 2D Seismic Wavefield Monitoring: Seismic Gradiometry for Long-Period Seismogram and Short-Period Seismogram Envelope applied to the Hi-net Array

    Science.gov (United States)

    Maeda, T.; Nishida, K.; Takagi, R.; Obara, K.

    2015-12-01

    The high-sensitive seismograph network Japan (Hi-net) operated by National Research Institute for Earth Science and Disaster Prevention (NIED) has about 800 stations with average separation of 20 km. We can observe long-period seismic wave propagation as a 2D wavefield with station separations shorter than wavelength. In contrast, short-period waves are quite incoherent at stations, however, their envelope shapes resemble at neighbor stations. Therefore, we may be able to extract seismic wave energy propagation by seismogram envelope analysis. We attempted to characterize seismic waveform at long-period and its envelope at short-period as 2D wavefield by applying seismic gradiometry. We applied the seismic gradiometry to a synthetic long-period (20-50s) dataset prepared by numerical simulation in realistic 3D medium at the Hi-net station layout. Wave amplitude and its spatial derivatives are estimated by using data at nearby stations. The slowness vector, the radiation pattern and the geometrical spreading are extracted from estimated velocity, displacement and its spatial derivatives. For short-periods at shorter than 1 s, seismogram envelope shows temporal and spatial broadening through scattering by medium heterogeneity. It is expected that envelope shape may be coherent among nearby stations. Based on this idea, we applied the same method to the time-integration of seismogram envelope to estimate its spatial derivatives. Together with seismogram envelope, we succeeded in estimating the slowness vector from the seismogram envelope as well as long-period waveforms by synthetic test, without using phase information. Our preliminarily results show that the seismic gradiometry suits the Hi-net to extract wave propagation characteristics both at long and short periods. This method is appealing that it can estimate waves at homogeneous grid to monitor seismic wave as a wavefield. It is promising to obtain phase velocity variation from direct waves, and to grasp wave

  4. Observations of short period seismic scattered waves by small seismic arrays

    Directory of Open Access Journals (Sweden)

    M. Simini

    1997-06-01

    Full Text Available The most recent observations of well correlated seismic phases in the high frequency coda of local earthquakes recorded throughout the world are reported. In particular the main results, obtained on two active volcanoes, Teide and Deception, using small array are described. The ZLC (Zero Lag Cross-correlation method and polarization analysis have been applied to the data in order to distinguish the main phases in the recorded seismograms and their azimuths and apparent velocities. The results obtained at the Teide volcano demonstrate that the uncorrelated part of the seismograms may be produced by multiple scattering from randomly distributed heterogeneity, while the well correlated part, showing SH type polarization or the possible presence of Rayleigh surface waves, may be generated by single scattering by strong scatterers. At the Deception Volcano strong scattering, strongly focused in a precise direction, is deduced from the data. In that case, all the coda radiation is composed of surface waves.

  5. Seismic Site Effects from the Seafloor Motion Recorded by the Short-period Ocean Bottom Seismometers

    Science.gov (United States)

    Lin, J. Y.; Cheng, W. B.; Chin, S. J.; Hsu, S. K.; Dong, J. J.

    2014-12-01

    For decades, it has been mentioned that submarine slope failures are spatially linked to the presence of gas hydrates/gas-charged sediments. When triggered by earthquakes, oversteepen and instable sediments may prompt breakouts of the slopes containing gas hydrates and cause submarine landslides and tsunamis. Widely distributed BSRs have been observed in the area offshore of southwestern Taiwan where the active accretionary complex meets with the passive China continental margin. In the region, large or small scale landslides were also reported based on seismic interpretations. In order to clarify the link between earthquake, landslide and the presence of gas hydrate, we evaluate the response of seafloor sediments in regard to passive dynamic loads. Horizontal-to-vertical (H/V) spectral ratios are used to characterize the local sediment response. Ambient noise as well as distant earthquakes are used as generators of the passive dynamic loads. Based on this study, we aim to characterize the site in terms of its physical properties and the local site effect produced by shallow marine sediments. The results show that the maximum H/V ratios appeared in the range of 5-10 Hz, where the horizontal amplitudes increased by an order of magnitude relative to the vertical amplitude. The stations located in the northwestern part of study area were characterized by another relatively small peak at proximately 2 Hz, which may indicates the presence of a discontinuity of sediments. For most stations, the H/V ratios estimated based on the earthquake (i.e. strong input signal) and noise (background, micro-seismic noise) records were characterized by different pattern. No distinct peak is observed for the H/V pattern calculated during earthquakes. This phenomenon may suggest that no clear sedimentary boundary exist when a stronger motion applies. Estimating H/V spectral ratios of data recorded by the seven short period OBSs (Ocean Bottom Seismometer) deployed in the southwest Taiwan

  6. On the use of volumetric strain meters to infer additional characteristics of short-period seismic radiation

    Science.gov (United States)

    Borcherdt, R.D.; Johnston, M.J.S.; Glassmoyer, G.

    1989-01-01

    Volumetric strain meters (Sacks-Evertson design) are installed at 15 sites along the San Andreas fault system, to monitor long-term strain changes for earthquake prediction. Deployment of portable broadband, high-resolution digital recorders (GEOS) at several of the sites extends the detection band for volumetric strain to periods shorter than 5 ?? 10-2 sec and permits the simultaneous observation of seismic radiation fields using conventional short-period pendulum seismometers. Recordings of local and regional earthquakes indicate that dilatometers respond to P energy but not direct shear energy and that straingrams can be used to resolve superimposed reflect P and S waves for inference of wave characteristics not permitted by either sensor alone. Simultaneous measurements of incident P- and S-wave amplitudes are used to introduce a technique for single-station estimates of wave field inhomogeneity, free-surface reflection coefficients and local material P velocity. -from Authors

  7. Waveform correlation and coherence of short-period seismic noise within Gauribidanur array with implications for event detection

    International Nuclear Information System (INIS)

    Bhadauria, Y.S.; Arora, S.K.

    1995-01-01

    In continuation with our effort to model the short-period micro seismic noise at the seismic array at Gauribidanur (GBA), we have examined in detail time-correlation and spectral coherence of the noise field within the array space. This has implications of maximum possible improvement in signal-to-noise ratio (SNR) relevant to event detection. The basis of this study is about a hundred representative wide-band noise samples collected from GBA throughout the year 1992. Both time-structured correlation as well as coherence of the noise waveforms are found to be practically independent of the inter element distances within the array, and they exhibit strong temporal and spectral stability. It turns out that the noise is largely incoherent at frequencies ranging upwards from 2 Hz; the coherency coefficient tends to increase in the lower frequency range attaining a maximum of 0.6 close to 0.5 Hz. While the maximum absolute cross-correlation also diminishes with increasing frequency, the zero-lag cross-correlation is found to be insensitive to frequency filtering regardless of the pass band. An extremely small value of -0.01 of the zero-lag correlation and a comparatively higher year-round average estimate at 0.15 of the maximum absolute time-lagged correlation yields an SNR improvement varying between a probable high of 4.1 and a low of 2.3 for the full 20-element array. 19 refs., 6 figs

  8. Long Period Seismic Waves

    Science.gov (United States)

    1976-08-01

    Geoffsica, TPHM. No. 5 , p. 161. Vargas, Freddy (To he published in 1976) 1 .-DTSCRP1TNACTON DE EVENTO«; NATHDALE«; Y ARTTFTCT ALES. 2.- CALCULO DEL...seismic risk, bv de - fininn relative weiqht of maximum MM intensity at a pivon distance ponulation density, area feolupy and attenuation of intensity wit...Population densitv, area peolopv and attenuation of intensitv with distance, is presented topether with a map anplvinp theorv to Bo- livia. ^«^a

  9. High-Precision Locations and the Stress Field from Instrumental Seismicity, Moment Tensors, and Short-Period Mechanisms through the Mina Deflection, Central Walker Lane

    Science.gov (United States)

    Ruhl, C. J.; Smith, K. D.

    2012-12-01

    well as available and developed short-period focal mechanisms are compiled to evaluate the stress field to assess mechanisms of slip accommodation. Based on the complex distribution of fault orientations, the stress field varies locally northward from the SWL throughout the MD; however, in many cases, fault plane alignments can be isolated from high-precision locations, providing better constraints on stress and slip orientations.

  10. Multichannel long period seismic data acquisition system

    International Nuclear Information System (INIS)

    Kolvankar, V.G.; Rao, D.S.

    1990-01-01

    This paper discusses the specifications and performance of an eight channel long period seismic digital data acquisition system, which is developed and installed at Seismic Array Station, Gauribidanur, Karnataka State. The paper describes how these data in an unedited form are recorded on a single track of magnetic tape inter-mittantly, which has resulted in recording of 50 days data on a single tapespool. A time indexing technique which enables quick access to any desired portion of a recorded tape is also discussed. Typical examples of long period seismic event signals recorded by this system are also illustrated. Various advantages, the system provides over the analog multichannel instrumentation tape recording system, operating at Seismic Array Station for th e last two decades, are also discussed. (author). 7 figs

  11. Seismic isolation of two dimensional periodic foundations

    International Nuclear Information System (INIS)

    Yan, Y.; Mo, Y. L.; Laskar, A.; Cheng, Z.; Shi, Z.; Menq, F.; Tang, Y.

    2014-01-01

    Phononic crystal is now used to control acoustic waves. When the crystal goes to a larger scale, it is called periodic structure. The band gaps of the periodic structure can be reduced to range from 0.5 Hz to 50 Hz. Therefore, the periodic structure has potential applications in seismic wave reflection. In civil engineering, the periodic structure can be served as the foundation of upper structure. This type of foundation consisting of periodic structure is called periodic foundation. When the frequency of seismic waves falls into the band gaps of the periodic foundation, the seismic wave can be blocked. Field experiments of a scaled two dimensional (2D) periodic foundation with an upper structure were conducted to verify the band gap effects. Test results showed the 2D periodic foundation can effectively reduce the response of the upper structure for excitations with frequencies within the frequency band gaps. When the experimental and the finite element analysis results are compared, they agree well with each other, indicating that 2D periodic foundation is a feasible way of reducing seismic vibrations.

  12. Three dimensional periodic foundations for base seismic isolation

    International Nuclear Information System (INIS)

    Yan, Y; Mo, Y L; Cheng, Z; Shi, Z; Menq, F; Tang, Y

    2015-01-01

    Based on the concept of phononic crystals, periodic foundations made of periodic materials are investigated in this paper. The periodic foundations can provide low frequency band gaps, which cover the main frequency ranges of seismic waves. Therefore, the periodic foundations are able to protect the upper structures during earthquake events. In this paper, the basic theory of three dimensional periodic foundations is studied and the finite element method was used to conduct the sensitivity study. A simplified three-dimensional periodic foundation with a superstructure was tested in the field and the feasibility of three dimensional periodic foundations was proved. The test results showed that the response of the upper structure with the three dimensional periodic foundation was reduced under excitation waves with the main frequency falling in the attenuation zones. The finite element analysis results are consistent with the experimental data, indicating that three dimensional periodic foundations are a feasible way of reducing seismic vibrations. (paper)

  13. Southern hemisphere searches for short period pulsars

    International Nuclear Information System (INIS)

    Manchester, R.N.

    1984-01-01

    Two searches of the southern sky for short period pulsars are briefly described. The first, made using the 64-m telescope at Parkes, is sensitive to pulsars with periods greater than about 10 ms and the second, made using the Molonglo radio telescope, has sensitivity down to periods of about 1.5 ms. Four pulsars were found in the Parkes survey and none in the Molonglo survey, although analysis of the latter is as yet incomplete. 10 references, 1 figure, 2 tables

  14. Models for seismic wave propagation in periodically layered porous media

    NARCIS (Netherlands)

    Kudarova, A.; Van Dalen, K.N.; Drijkoningen, G.G.

    2014-01-01

    Several models are discussed for seismic wave propagation in periodically layered poroelastic media where layers represent mesoscopic-scale heterogeneities that are larger than the pore and grain sizes but smaller than the wavelength. The layers behave according to Biot’s theory. Wave propagation

  15. Field Optimization for short Period Undulators

    CERN Document Server

    Peiffer, P; Rossmanith, R; Schoerling, D

    2011-01-01

    Undulators dedicated to low energy electron beams, like Laser Wakefield Accelerators, require very short period lengths to achieve X-ray emission. However, at these short period length (LambdaU ~ 5 mm) it becomes difficult to reach magnetic field amplitudes that lead to a K parameter of >1, which is generally desired. Room temperature permanent magnets and even superconductive undulators using Nb-Ti as conductor material have proven insufficient to achieve the desired field amplitudes. The superconductor Nb$_{3}$Sn has the theoretical potential to achieve the desired fields. However, up to now it is limited by several technological challenges to much lower field values than theoretically predicted. An alternative idea for higher fields is to manufacture the poles of the undulator body from Holmium instead of iron or to use Nb-Ti wires with a higher superconductor/copper ratio. The advantages and challenges of the different options are compared in this contribution.

  16. Short period tidal variations of earth rotation

    Science.gov (United States)

    Yoder, C. F.; Williams, J. G.; Parke, M. E.; Dickey, J. O.

    1981-01-01

    It is explained that the tidal deformation of the earth's polar moment of inertia by the moon and sun cause periodic variations in rotation. The short period oscillations give rise to a meter-sized, diurnal signature in the lunar laser ranging data obtained at McDonald Observatory. A solution is given for the scale parameter k/C at fortnightly and monthly tidal frequencies. The results are compared with those obtained by other investigators and with a theoretical estimate which includes the effect of oceans and a decoupled fluid core.

  17. Development of Seismic Isolation Systems Using Periodic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Yiqun [Univ. of Houston, Houston, TX (United States); Mo, Yi-Lung [Univ. of Houston, Houston, TX (United States); Menq, Farn-Yuh [Univ. of Texas, Austin, TX (United States); Stokoe, II, Kenneth H. [Univ. of Texas, Austin, TX (United States); Perkins, Judy [Prairie View A & M University, Prairie View, TX (United States); Tang, Yu [Argonne National Lab. (ANL), Argonne, IL (United States)

    2014-12-10

    Advanced fast nuclear power plants and small modular fast reactors are composed of thin-walled structures such as pipes; as a result, they do not have sufficient inherent strength to resist seismic loads. Seismic isolation, therefore, is an effective solution for mitigating earthquake hazards for these types of structures. Base isolation, on which numerous studies have been conducted, is a well-defined structure protection system against earthquakes. In conventional isolators, such as high-damping rubber bearings, lead-rubber bearings, and friction pendulum bearings, large relative displacements occur between upper structures and foundations. Only isolation in a horizontal direction is provided; these features are not desirable for the piping systems. The concept of periodic materials, based on the theory of solid-state physics, can be applied to earthquake engineering. The periodic material is a material that possesses distinct characteristics that prevent waves with certain frequencies from being transmitted through it; therefore, this material can be used in structural foundations to block unwanted seismic waves with certain frequencies. The frequency band of periodic material that can filter out waves is called the band gap, and the structural foundation made of periodic material is referred to as the periodic foundation. The design of a nuclear power plant, therefore, can be unified around the desirable feature of a periodic foundation, while the continuous maintenance of the structure is not needed. In this research project, three different types of periodic foundations were studied: one-dimensional, two-dimensional, and three-dimensional. The basic theories of periodic foundations are introduced first to find the band gaps; then the finite element methods are used, to perform parametric analysis, and obtain attenuation zones; finally, experimental programs are conducted, and the test data are analyzed to verify the theory. This procedure shows that the

  18. Seismic Regionalization of Michoacan, Mexico and Recurrence Periods for Earthquakes

    Science.gov (United States)

    Magaña García, N.; Figueroa-Soto, Á.; Garduño-Monroy, V. H.; Zúñiga, R.

    2017-12-01

    Michoacán is one of the states with the highest occurrence of earthquakes in Mexico and it is a limit of convergence triggered by the subduction of Cocos plate over the North American plate, located in the zone of the Pacific Ocean of our country, in addition to the existence of active faults inside of the state like the Morelia-Acambay Fault System (MAFS).It is important to make a combination of seismic, paleosismological and geological studies to have good planning and development of urban complexes to mitigate disasters if destructive earthquakes appear. With statistical seismology it is possible to characterize the degree of seismic activity as well as to estimate the recurrence periods for earthquakes. For this work, seismicity catalog of Michoacán was compiled and homogenized in time and magnitude. This information was obtained from world and national agencies (SSN, CMT, etc), some data published by Mendoza and Martínez-López (2016) and starting from the seismic catalog homogenized by F. R. Zúñiga (Personal communication). From the analysis of the different focal mechanisms reported in the literature and geological studies, the seismic regionalization of the state of Michoacán complemented the one presented by Vázquez-Rosas (2012) and the recurrence periods for earthquakes within the four different seismotectonic regions. In addition, stable periods were determined for the b value of the Gutenberg-Richter (1944) using the Maximum Curvature and EMR (Entire Magnitude Range Method, 2005) techniques, which allowed us to determine recurrence periods: years for earthquakes upper to 7.5 for the subduction zone (A zone) with EMR technique and years with MAXC technique for the same years for earthquakes upper to 5 for B1 zone with EMR technique and years with MAXC technique; years for earthquakes upper to 7.0 for B2 zone with EMR technique and years with MAXC technique; and the last one, the Morelia-Acambay Fault Sistem zone (C zone) years for earthquakes

  19. Preferred Hosts for Short-Period Exoplanets

    Science.gov (United States)

    Kohler, Susanna

    2015-12-01

    In an effort to learn more about how planets form around their host stars, a team of scientists has analyzed the population of Kepler-discovered exoplanet candidates, looking for trends in where theyre found.Planetary OccurrenceSince its launch in 2009, Kepler has found thousands of candidate exoplanets around a variety of star types. Especially intriguing is the large population of super-Earths and mini-Neptunes planets with masses between that of Earth and Neptune that have short orbital periods. How did they come to exist so close to their host star? Did they form in situ, or migrate inwards, or some combination of both processes?To constrain these formation mechanisms, a team of scientists led by Gijs Mulders (University of Arizona and NASAs NExSS coalition) analyzed the population of Kepler planet candidates that have orbital periods between 2 and 50 days.Mulders and collaborators used statistical reconstructions to find the average number of planets, within this orbital range, around each star in the Kepler field. They then determined how this planet occurrence rate changed for different spectral types and therefore the masses of the host stars: do low-mass M-dwarf stars host more or fewer planets than higher-mass, main-sequence F, G, or K stars?Challenging ModelsAuthors estimates for the occurrence rate for short-period planets of different radii around M-dwarfs (purple) and around F, G, and K-type stars (blue). [Mulders et al. 2015]The team found that M dwarfs, compared to F, G, or K stars, host about half as many large planets with orbital periods of P 50 days. But, surprisingly, they host significantly more small planets, racking up an average of 3.5 times the number of planets in the size range of 12.8 Earth-radii.Could it be that M dwarfs have a lower total mass of planets, but that mass is distributed into more, smaller planets? Apparently not: the authors show that the mass of heavy elements trapped in short-orbital-period planets is higher for M

  20. A short period undulator for MAX

    International Nuclear Information System (INIS)

    Ahola, H.; Meinander, T.

    1992-01-01

    A hybrid undulator for generation of high brilliance synchrotron radiation in the photon energy range of 60--600 eV at the 550 MeV electron storage ring MAX in Lund, Sweden has been designed and built at the Technical Research Centre of Finland in close collaboration with MAX-lab of Lund University. At the rather modest electron energy of MAX this photon energy range can be reached only by an undulator featuring a fairly short period and the smallest possible magnetic gap. Even then, higher harmonics (up to the 13th) of the radiation spectrum must be utilized. An optimization of the magnetic design resulted in a hybrid configuration of NdFeB magnets and soft iron poles with a period of 24 mm and a minimum magnetic gap of 7--10 mm. A variable-gap vacuum chamber allows reduction of the vacuum gap from a maximum of 20 mm, needed for injection, down to 6 mm during stored beam operation. A special design of this chamber permits a magnetic gap between pole tips that is only 1 mm larger than the vacuum gap. Adequate field uniformity was ensured by calibration of magnets to equal strength at their true operating point and verification of the homogeneity of their magnetization. Magnetic measurements included Hall probe scans of the undulator field and flip coil evaluations of the field integral

  1. Theoretical study of nitride short period superlattices

    Science.gov (United States)

    Gorczyca, I.; Suski, T.; Christensen, N. E.; Svane, A.

    2018-02-01

    Discussion of band gap behavior based on first principles calculations of electronic band structures for various short period nitride superlattices is presented. Binary superlattices, as InN/GaN and GaN/AlN as well as superlattices containing alloys, as InGaN/GaN, GaN/AlGaN, and GaN/InAlN are considered. Taking into account different crystallographic directions of growth (polar, semipolar and nonpolar) and different strain conditions (free-standing and pseudomorphic) all the factors influencing the band gap engineering are analyzed. Dependence on internal strain and lattice geometry is considered, but the main attention is devoted to the influence of the internal electric field and the hybridization of well and barrier wave functions. The contributions of these two important factors to band gap behavior are illustrated and estimated quantitatively. It appears that there are two interesting ranges of layer thicknesses; in one (few atomic monolayers in barriers and wells) the influence of the wave function hybridization is dominant, whereas in the other (layers thicker than roughly five to six monolayers) dependence of electric field on the band gaps is more important. The band gap behavior in superlattices is compared with the band gap dependence on composition in the corresponding ternary and quaternary alloys. It is shown that for superlattices it is possible to exceed by far the range of band gap values, which can be realized in ternary alloys. The calculated values of the band gaps are compared with the photoluminescence emission energies, when the corresponding data are available. Finally, similarities and differences between nitride and oxide polar superlattices are pointed out by comparison of wurtzite GaN/AlN and ZnO/MgO.

  2. Estimating of seismic return periods in Laguna Verde Nuclear Power Plant

    International Nuclear Information System (INIS)

    Flores R, J.H.

    1993-01-01

    The study of seismic risk in the site of Laguna Verde Nuclear Power Plant and surroundings was made considering the different periods of seismic return and the probability of occurrence in distinct time intervals (50, 75, 100, 125, 150 years) starting with the distribution of first type of extreme values of Gumbel (G1), the value used for the assessment of lifetime of lump was 50 years, and the rest of the periods are used to evaluate temporary nuclear cemeteries, it is to say for reducing the radioactivity of burned fuel assemblies. The seismic data belongs to the seismicity catalog (1920-1982) elaborated around the site, which average magnitude was 5 in the Richter Scale and are considered as shallow and are located in the Continental crust of North American shelf, and are induced by the pressure of the cocos shelf, being 36 % of the seismic movements of intermediate value and two seismic movements of deep value. (Author)

  3. On the short periods oscillation in relativistic stars

    International Nuclear Information System (INIS)

    Aquilano, R.; Morales, S.; Navone, H.; Sevilla, D.; Zorzi, A.

    2009-01-01

    We expand the study of neutron and strange matter stars with general relativistic formalism. We analyze the correlation with the observational data short periods oscillations in these stars, and we intend to discriminate between them.

  4. Origin of very-short orbital-period binary systems

    International Nuclear Information System (INIS)

    Miyaji, S.

    1983-01-01

    Recent observations of four close binaries have established that there is a group of very-short orbital-period (VSOP) binaries whose orbital periods are less than 60 minutes. The VSOP binaries consist of both X-ray close binaries and cataclysmic variables. Their orbital periods are too short to have a main-sequence companion. However, four binaries, none of which belongs to any globular cluster, are too abundant to be explained by the capturing mechanism of a white dwarf. Therefore it seemed to be worthwhile to present an evolutionary scenario from an original binary system which can be applied for all VSOP binaries. (Auth.)

  5. Swedish National Seismic Network (SNSN). A short report on recorded earthquakes during the fourth quarter of the year 2010

    Energy Technology Data Exchange (ETDEWEB)

    Boedvarsson, Reynir (Uppsala Univ. (Sweden), Dept. of Earth Sciences)

    2011-01-15

    According to an agreement with Swedish Nuclear Fuel and Waste Management Company (SKB) and Uppsala Univ., the Dept. of Earth Sciences has continued to carry out observations of seismic events at seismic stations within the Swedish National Seismic Network (SNSN). This short report gives brief information about the recorded seismicity during October through December 2010. The Swedish National Seismic Network consists of 62 stations. During October through December, 2,241 events were located whereof 158 are estimated as real earthquakes, 1,457 are estimated as explosions, 444 are induced earthquakes in the vicinity of the mines in Kiruna and Malmberget and 182 events are still considered as uncertain but these are most likely explosions and are mainly located outside the network. One earthquake had a magnitude above M{sub L} = 2.0 during the period. In November one earthquake was located 13 km SW of Haernoesand with a magnitude of M{sub L} = 2.1. The largest earthquake in October had a magnitude of M{sub L} = 1.7 and was located 12 km NE of Eksjoe and in December an earthquake with a magnitude of M{sub L} = 1.8 was located 19 km north of Motala

  6. Crosshole investigations - short and medium range seismic tomography

    International Nuclear Information System (INIS)

    Cosma, C.

    1987-02-01

    Seismic tomographic tests were conducted as a part of the Crosshole Investigations program of the Stripa Project. The aim has been to study if it is possible to detect by seismic tomography major fracture zones and determine their dimensions and orientation. The analysis was based on both compressional (P) and transversal (S) waves. The Young's modulus has been also calculated for a sub-set of measurements as a cross check for the P and S wave velocities. The experimental data was collected at the crosshole site in the Stripa mine during 1984-1985. A down-the-hole impact source was used together with triaxial detectors and a digital seismograph. Five tomographic sections were obtained. The number of records per section was appr. 250. Measurements were done down to 200 m depth in all boreholes. The main conclusion is that it is possible to detect major fracture zones by seismic tomography. Their position and orientation can also be estimated. (orig./HP)

  7. How Do Earth-Sized, Short-Period Planets Form?

    Science.gov (United States)

    Kohler, Susanna

    2017-08-01

    Matching theory to observation often requires creative detective work. In a new study, scientists have used a clever test to reveal clues about the birth of speedy, Earth-sized planets.Former Hot Jupiters?Artists impression of a hot Jupiter with an evaporating atmosphere. [NASA/Ames/JPL-Caltech]Among the many different types of exoplanets weve observed, one unusual category is that of ultra-short-period planets. These roughly Earth-sized planets speed around their host stars at incredible rates, with periods of less than a day.How do planets in this odd category form? One popular theory is that they were previously hot Jupiters, especially massive gas giants orbiting very close to their host stars. The close orbit caused the planets atmospheres to be stripped away, leaving behind only their dense cores.In a new study, a team of astronomers led by Joshua Winn (Princeton University) has found a clever way to test this theory.Planetary radius vs. orbital period for the authors three statistical samples (colored markers) and the broader sample of stars in the California Kepler Survey. [Winn et al. 2017]Testing MetallicitiesStars hosting hot Jupiters have an interesting quirk: they typically have metallicities that are significantly higher than an average planet-hosting star. It is speculated that this is because planets are born from the same materials as their host stars, and hot Jupiters require the presence of more metals to be able to form.Regardless of the cause of this trend, if ultra-short-period planets are in fact the solid cores of former hot Jupiters, then the two categories of planets should have hosts with the same metallicity distributions. The ultra-short-period-planet hosts should therefore also be weighted to higher metallicities than average planet-hosting stars.To test this, the authors make spectroscopic measurements and gather data for a sample of stellar hosts split into three categories:64 ultra-short-period planets (orbital period shorter than a

  8. Design issues for cryogenic cooling of short period superconducting undulators

    International Nuclear Information System (INIS)

    Green, M.A.; Dietderich, D.R.; Marks, S.; Prestemon, S.O.; Schlueter, R.D.

    2003-01-01

    Superconducting insertion devices, which produce periodic magnetic fields, have been built and installed in a number of synchrotron-light source storage-rings. For the most part, these devices have been wigglers, which have relatively long period lengths. This report concerns itself with the special cryogenic issues associated with short period undulators. The motivation for considering the incorporation of superconducting technology in insertion device designs is to achieve higher magnetic fields than can be achieved with more conventional permanent magnet technology. Since the peak field decreases sharply with increased magnet gap to period ratio, the cryogenic design of the magnet system is crucial. In particular, the insulation required for a warm vacuum bore device is impractical for short period undulators. This report describes the issues that are related to a cold bore (∼4 K) and an intermediate temperature bore (30 to 70 K) designs. The criteria for the use of small cryocoolers for cooling a short period undulator are presented. The problems associated with connecting small coolers to an undulator at 4.2 K are discussed

  9. Response of phytoplankton assemblages isolated for short periods ...

    African Journals Online (AJOL)

    The response of phytoplankton assemblages isolated in enclosures for short periods of time was examined in hyper-eutrophic Lake Chivero (Harare, Zimbabwe), to determine the factors that influenced the structure of the phytoplankton community, after noticing a marked decline in the dominance of Microcystis aeruginosa ...

  10. Magnetospheric Truncation, Tidal Inspiral, and the Creation of Short-period and Ultra-short-period Planets

    International Nuclear Information System (INIS)

    Lee, Eve J.; Chiang, Eugene

    2017-01-01

    Sub-Neptunes around FGKM dwarfs are evenly distributed in log orbital period down to ∼10 days, but dwindle in number at shorter periods. Both the break at ∼10 days and the slope of the occurrence rate down to ∼1 day can be attributed to the truncation of protoplanetary disks by their host star magnetospheres at corotation. We demonstrate this by deriving planet occurrence rate profiles from empirical distributions of pre-main-sequence stellar rotation periods. Observed profiles are better reproduced when planets are distributed randomly in disks—as might be expected if planets formed in situ—rather than piled up near disk edges, as would be the case if they migrated in by disk torques. Planets can be brought from disk edges to ultra-short (<1 day) periods by asynchronous equilibrium tides raised on their stars. Tidal migration can account for how ultra-short-period planets are more widely spaced than their longer-period counterparts. Our picture provides a starting point for understanding why the sub-Neptune population drops at ∼10 days regardless of whether the host star is of type FGK or early M. We predict planet occurrence rates around A stars to also break at short periods, but at ∼1 day instead of ∼10 days because A stars rotate faster than stars with lower masses (this prediction presumes that the planetesimal building blocks of planets can drift inside the dust sublimation radius).

  11. Magnetospheric Truncation, Tidal Inspiral, and the Creation of Short-period and Ultra-short-period Planets

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eve J.; Chiang, Eugene, E-mail: evelee@berkeley.edu [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)

    2017-06-10

    Sub-Neptunes around FGKM dwarfs are evenly distributed in log orbital period down to ∼10 days, but dwindle in number at shorter periods. Both the break at ∼10 days and the slope of the occurrence rate down to ∼1 day can be attributed to the truncation of protoplanetary disks by their host star magnetospheres at corotation. We demonstrate this by deriving planet occurrence rate profiles from empirical distributions of pre-main-sequence stellar rotation periods. Observed profiles are better reproduced when planets are distributed randomly in disks—as might be expected if planets formed in situ—rather than piled up near disk edges, as would be the case if they migrated in by disk torques. Planets can be brought from disk edges to ultra-short (<1 day) periods by asynchronous equilibrium tides raised on their stars. Tidal migration can account for how ultra-short-period planets are more widely spaced than their longer-period counterparts. Our picture provides a starting point for understanding why the sub-Neptune population drops at ∼10 days regardless of whether the host star is of type FGK or early M. We predict planet occurrence rates around A stars to also break at short periods, but at ∼1 day instead of ∼10 days because A stars rotate faster than stars with lower masses (this prediction presumes that the planetesimal building blocks of planets can drift inside the dust sublimation radius).

  12. Planetary perturbations and the origins of short-period comets

    International Nuclear Information System (INIS)

    Quinn, T.; Tremaine, S.; Duncan, M.

    1990-01-01

    To investigate the dynamical plausibility of possible sources for the short-period comets, a representative sample of comet orbits in the field of the sun and the giant planets was integrated, with the aim to determine whether the distribution of orbits from a proposed source that reach observable perihelia (q less than 2.5 AU) matches the observed distribution of short-period orbits. It is found that the majority of the short-period comets, those with orbital period P less than 20 yr (the Jupiter family), cannot arise from isotropic orbits with perihelia near Jupiter's orbit, because the resulting observable comet orbits have the wrong distribution in period, inclination, and argument of perihelion. The simulations also show that Jupiter-family comets cannot arise from isotropic orbits with perihelia in the Uranus-Neptune region. On the other hand, a source of low-inclination Neptune-crossing orbits yields a distribution of observable Jupiter-family comets that is consistent with the data in all respects. These results imply that the Jupiter-family comets arise from a disk source in the outer solar system rather than from the Oort comet cloud. 30 refs

  13. CLATHRATE HYDRATES FORMATION IN SHORT-PERIOD COMETS

    International Nuclear Information System (INIS)

    Marboeuf, Ulysse; Mousis, Olivier; Petit, Jean-Marc; Schmitt, Bernard

    2010-01-01

    The initial composition of current models of cometary nuclei is only based on two forms of ice: crystalline ice for long-period comets and amorphous ice for short-period comets. A third form of ice, i.e., clathrate hydrate, could exist within the short-period cometary nuclei, but the area of formation of this crystalline structure in these objects has never been studied. Here, we show that the thermodynamic conditions in the interior of short-period comets allow the existence of clathrate hydrates in Halley-type comets. We show that their existence is viable in the Jupiter family comets only when the equilibrium pressure of CO clathrate hydrate is at least 1 order of magnitude lower than the usually assumed theoretical value. We calculate that the amount of volatiles that could be trapped in the clathrate hydrate layer may be orders of magnitude greater than the daily amount of gas released at the surface of the nucleus at perihelion. The formation and the destruction of the clathrate hydrate cages could then explain the diversity of composition of volatiles observed in comets, as well as some pre-perihelion outbursts. We finally show that the potential clathrate hydrate layer in comet 67P/Churyumov-Gerasimenko would, unfortunately, be deep inside the nucleus, out of reach of the Rosetta lander. However, such a clathrate hydrate layer would show up by the gas composition of the coma.

  14. Origin of the pulse-like signature of shallow long-period volcano seismicity

    Science.gov (United States)

    Chouet, Bernard A.; Dawson, Phillip B.

    2016-01-01

    Short-duration, pulse-like long-period (LP) events are a characteristic type of seismicity accompanying eruptive activity at Mount Etna in Italy in 2004 and 2008 and at Turrialba Volcano in Costa Rica and Ubinas Volcano in Peru in 2009. We use the discrete wave number method to compute the free surface response in the near field of a rectangular tensile crack embedded in a homogeneous elastic half space and to gain insights into the origin of the LP pulses. Two source models are considered, including (1) a vertical fluid-driven crack and (2) a unilateral tensile rupture growing at a fixed sub-Rayleigh velocity with constant opening on a vertical crack. We apply cross correlation to the synthetics and data to demonstrate that a fluid-driven crack provides a natural explanation for these data with realistic source sizes and fluid properties. Our modeling points to shallow sources (signatures are representative of the Rayleigh pulse sampled at epicentral distances >∼1 km. While a slow-rupture failure provides another potential model for these events, the synthetics and resulting fits to the data are not optimal in this model compared to a fluid-driven source. We infer that pulse-like LP signatures are parts of the continuum of responses produced by shallow fluid-driven sources in volcanoes.

  15. Could ionospheric variations be precursors of a seismic event? A short discussion

    Energy Technology Data Exchange (ETDEWEB)

    Kouris, S.S. [Thessaloniki Univ., Thessaloniki (Greece). Dept. of Electrical and Computer Engineering; Spalla, P. [Consiglio Nazionale delle Ricerche, Istituto di Ricerca Onde Elettromagnetiche, Florence (Italy); Zolesi, B. [Istituto Nazionale di Geofisica e Vulcanologia, Rome (Italy)

    2001-04-01

    A short review of published papers on the perturbations in the ionosphere due to seismogenic effects is reported. The method to correlate different classes of phenomena as ionospheric variations and subsequent seismic events is discussed. Even if the theoretical attempts to understand or to explain the electromagnetic phenomena in the ionosphere, as precursors of earthquakes are not satisfactory, the reported results encourage further investigations.

  16. Scenario for a Short-Term Probabilistic Seismic Hazard Assessment (PSHA in Chiayi, Taiwan

    Directory of Open Access Journals (Sweden)

    Chung-Han Chan

    2013-01-01

    Full Text Available Using seismic activity and the Meishan earthquake sequence that occurred from 1904 to 1906, a scenario for short-term probabilistic seismic hazards in the Chiayi region of Taiwan is assessed. The long-term earthquake occurrence rate in Taiwan was evaluated using a smoothing kernel. The highest seismicity rate was calculated around the Chiayi region. To consider earthquake interactions, the rate-and-state friction model was introduced to estimate the seismicity rate evolution due to the Coulomb stress change. As imparted by the 1904 Touliu earthquake, stress changes near the 1906 Meishan and Yangshuigang epicenters was higher than the magnitude of tidal triggering. With regard to the impact of the Meishan earthquake, the region close to the Yangshuigang earthquake epicenter had a +0.75 bar stress increase. The results indicated significant interaction between the three damage events. Considering the path and site effect using ground motion prediction equations, a probabilistic seismic hazard in the form of a hazard evolution and a hazard map was assessed. A significant elevation in hazards following the three earthquakes in the sequence was determined. The results illustrate a possible scenario for seismic hazards in the Chiayi region which may take place repeatly in the future. Such scenario provides essential information on earthquake preparation, devastation estimations, emergency sheltering, utility restoration, and structure reconstruction.

  17. Seismic Performance of High-Ductile Fiber-Reinforced Concrete Short Columns

    Directory of Open Access Journals (Sweden)

    Mingke Deng

    2018-01-01

    Full Text Available This study mainly aims to investigate the effectiveness of high-ductile fiber-reinforced concrete (HDC as a means to enhance the seismic performance of short columns. Six HDC short columns and one reinforced concrete (RC short column were designed and tested under lateral cyclic loading. The influence of the material type (concrete or HDC, axial load, stirrup ratio, and shear span ratio on crack patterns, hysteresis behavior, shear strength, deformation capacity, energy dissipation, and stiffness degradation was presented and discussed, respectively. The test results show that the RC short column failed in brittle shear with poor energy dissipation, while using HDC to replace concrete can effectively improve the seismic behavior of the short columns. Compared with the RC short column, the shear strength of HDC specimens was improved by 12.6–30.2%, and the drift ratio and the energy dissipation increases were 56.9–88.5% and 237.7–336.7%, respectively, at the ultimate displacement. Additionally, the prediction model of the shear strength for RC columns based on GB50010-2010 (Chinese code can be safely adopted to evaluate the shear strength of HDC short columns.

  18. Risk management considerations for seismic upgrading of an older facility for short-term residue stabilization

    International Nuclear Information System (INIS)

    Additon, S.L.; Peregoy, W.L.; Foppe, T.L.

    1999-01-01

    Building 707 and its addition, Building 707A, were selected, after the production mission of Rocky Flats was terminated a few years ago, to stabilize many of the plutonium residues remaining at the site by 2002. The facility had undergone substantial safety improvements to its safety systems and conduct of operations for resumption of plutonium operations in the early 1990s and appeared ideally suited for this new mission to support accelerated Site closure. During development of a new authorization basis, a seismic evaluation was performed. This evaluation addressed an unanalyzed expansion joint and suspect connection details for the precast concrete tilt-up construction and concluded that the seismic capacity of the facility is less than half of that determined by previous analysis. Further, potential seismic interaction was identified between a collapsing Building 707 and the seismically upgraded Building 707A, possibly causing the partial collapse of the latter. Both the operating contractor and the Department of Energy sought a sound technical basis for deciding how to proceed. This paper addresses the risks of the as-is facility and possible benefits of upgrades to support a decision on whether to upgrade the seismic capacity of Building 707, accept the risk of the as-is facility for its short remaining mission, or relocate critical stabilization missions. The paper also addresses the Department of Energy's policy on natural phenomena

  19. Estimation of seismic return periods in the Laguna Verde nuclear plant

    International Nuclear Information System (INIS)

    Flores R, J.H.

    1992-01-01

    The study of seismic risk in the area of the Laguna Verde Nucleo electric plant (PNLV) and its surroundings, one carries out estimating the different return periods and the occurrence probability in different intervals of time (5, 75, 100, 125, 150 years starting from the distribution of first type of Gumbel (G1) of extreme values (Burton, 1986), the value that was used to evaluate the useful life of the PNLV was of 50 years, the other periods will be occupy to evaluate 'temporal' nuclear cemeteries, that is to say for diminish the radioactive activity of the fuel assemblies already burned in the reactor pool or in a near place to the place. The seismic data that were used for the analysis were of the seismic catalog that it was elaborated from (1920-1982), around the place whose seismic half magnitude was of 5 grades Richter and a depth 65 km, these earthquakes are classified as shallow earthquakes, which are located in the continental plaque of North-America, these they are induced by the efforts of push of the plaque of Cocos, existing 36% of intermediate and 2 of deep earthquakes. (Author)

  20. Properties of Repetitive Long-Period Seismicity at Villarrica Volcano, Chile

    Science.gov (United States)

    Richardson, J.; Waite, G. P.; Palma, J.; Johnson, J. B.

    2011-12-01

    Villarrica Volcano, Chile hosts a persistent lava lake and is characterized by degassing and long-period seismicity. In order to better understand the relationship between outgassing and seismicity, we recorded broadband seismic and acoustic data along with high-rate SO2 emission data. We used both a densely-spaced linear array deployed on the northern flank of Villarrica, during the austral summer of 2011, and a wider aperture array of stations distributed around the volcano that was active in the austral summer of 2010. Both deployments consisted of three-component broadband stations and were augmented with broadband infrasound sensors. Of particular interests are repetitive, ~1 Hz seismic and coincident infrasound signals that occurred approximately every 2 minutes. Because these events are typically very low amplitude, we used a matched filter approach to identify them. We windowed several high-amplitude records of these events from broadband seismic stations near the vent. The record section of each event served as a template to compare with the entire dataset by cross-correlation. This approach identified ~20,000 nearly identical events during the ~7 day deployment of the linear array, which were otherwise difficult to identify in the raw records. Assuming that all of the events that we identified have identical source mechanisms and depths, we stack the large suite of events to produce low-noise records and particle motions at receivers farther than 5 km from the vent. We find that the records from stations near the edifice are dominated by tangential particle motion, suggesting the influence of near-field components. Correlation of these data with broadband acoustic data collected at the summit suggest that these repeatable seismic processes are linked to acoustic emissions, probably due to gas bubbles bursting at the magma free surface, as no eruptive products besides gas were being emitted by the volcano during the instrument deployment. The acoustic

  1. An Ensemble Approach for Improved Short-to-Intermediate-Term Seismic Potential Evaluation

    Science.gov (United States)

    Yu, Huaizhong; Zhu, Qingyong; Zhou, Faren; Tian, Lei; Zhang, Yongxian

    2017-06-01

    Pattern informatics (PI), load/unload response ratio (LURR), state vector (SV), and accelerating moment release (AMR) are four previously unrelated subjects, which are sensitive, in varying ways, to the earthquake's source. Previous studies have indicated that the spatial extent of the stress perturbation caused by an earthquake scales with the moment of the event, allowing us to combine these methods for seismic hazard evaluation. The long-range earthquake forecasting method PI is applied to search for the seismic hotspots and identify the areas where large earthquake could be expected. And the LURR and SV methods are adopted to assess short-to-intermediate-term seismic potential in each of the critical regions derived from the PI hotspots, while the AMR method is used to provide us with asymptotic estimates of time and magnitude of the potential earthquakes. This new approach, by combining the LURR, SV and AMR methods with the choice of identified area of PI hotspots, is devised to augment current techniques for seismic hazard estimation. Using the approach, we tested the strong earthquakes occurred in Yunnan-Sichuan region, China between January 1, 2013 and December 31, 2014. We found that most of the large earthquakes, especially the earthquakes with magnitude greater than 6.0 occurred in the seismic hazard regions predicted. Similar results have been obtained in the prediction of annual earthquake tendency in Chinese mainland in 2014 and 2015. The studies evidenced that the ensemble approach could be a useful tool to detect short-to-intermediate-term precursory information of future large earthquakes.

  2. Periodization of Carbohydrate Intake: Short-Term Effect on Performance

    Directory of Open Access Journals (Sweden)

    Laurie-Anne Marquet

    2016-11-01

    Full Text Available Background: “Sleep-low” consists of a sequential periodization of carbohydrate (CHO availability—low glycogen recovery after “train high” glycogen-depleting interval training, followed by an overnight-fast and light intensity training (“train low” the following day. This strategy leads to an upregulation of several exercise-responsive signaling proteins, but the chronic effect on performance has received less attention. We investigated the effects of short-term exposure to this strategy on endurance performance. Methods: Following training familiarization, 11 trained cyclists were divided into two groups for a one-week intervention—one group implemented three cycles of periodized CHO intake to achieve the sleep-low strategy over six training sessions (SL, CHO intake: 6 g·kg−1·day−1, whereas the control group consumed an even distribution of CHO over the day (CON. Tests were a 2 h submaximal ride and a 20 km time trial. Results: SL improved their performance (mean: +3.2%; p < 0.05 compared to CON. The improvement was associated with a change in pacing strategy with higher power output during the second part of the test. No change in substrate utilization was observed after the training period for either group. Conclusion: Implementing the “sleep-low” strategy for one week improved performance by the same magnitude previously seen in a three-week intervention, without any significant changes in selected markers of metabolism.

  3. Periodization of Carbohydrate Intake: Short-Term Effect on Performance

    Science.gov (United States)

    Marquet, Laurie-Anne; Hausswirth, Christophe; Molle, Odeline; Hawley, John A.; Burke, Louise M.; Tiollier, Eve; Brisswalter, Jeanick

    2016-01-01

    Background: “Sleep-low” consists of a sequential periodization of carbohydrate (CHO) availability—low glycogen recovery after “train high” glycogen-depleting interval training, followed by an overnight-fast and light intensity training (“train low”) the following day. This strategy leads to an upregulation of several exercise-responsive signaling proteins, but the chronic effect on performance has received less attention. We investigated the effects of short-term exposure to this strategy on endurance performance. Methods: Following training familiarization, 11 trained cyclists were divided into two groups for a one-week intervention—one group implemented three cycles of periodized CHO intake to achieve the sleep-low strategy over six training sessions (SL, CHO intake: 6 g·kg−1·day−1), whereas the control group consumed an even distribution of CHO over the day (CON). Tests were a 2 h submaximal ride and a 20 km time trial. Results: SL improved their performance (mean: +3.2%; p < 0.05) compared to CON. The improvement was associated with a change in pacing strategy with higher power output during the second part of the test. No change in substrate utilization was observed after the training period for either group. Conclusion: Implementing the “sleep-low” strategy for one week improved performance by the same magnitude previously seen in a three-week intervention, without any significant changes in selected markers of metabolism. PMID:27897989

  4. Surface electron structure of short-period semiconductor superlattice

    International Nuclear Information System (INIS)

    Bartos, I.; Czech Academy Science, Prague,; Strasser, T.; Schattke, W.

    2004-01-01

    Full text: Semiconductor superlattices represent man-made crystals with unique physical properties. By means of the directed layer-by-layer molecular epitaxy growth their electric properties can be tailored (band structure engineering). Longer translational periodicity in the growth direction is responsible for opening of new electron energy gaps (minigaps) with surface states and resonances localized at superlattice surfaces. Similarly as for the electron structure of the bulk, a procedure enabling to modify the surface electron structure of superlattices is desirable. Short-period superlattice (GaAs) 2 (AlAs) 2 with unreconstructed (100) surface is investigated in detail. Theoretical description in terms of full eigenfunctions of individual components has to be used. The changes of electron surface state energies governed by the termination of a periodic crystalline potential, predicted on simple models, are confirmed for this system. Large surface state shifts are found in the lowest minigap of the superlattice when this is terminated in four different topmost layer configurations. The changes should be observable in angle resolved photoelectron spectroscopy as demonstrated in calculations based on the one step model of photoemission. Surface state in the center of the two dimensional Brillouin zone moves from the bottom of the minigap (for the superlattice terminated by two bilayers of GaAs) to its top (for the superlattice terminated by two bilayers of AlAs) where it becomes a resonance. No surface state/resonance is found for a termination with one bilayer of AlAs. The surface state bands behave similarly in the corresponding gaps of the k-resolved section of the electron band structure. The molecular beam epitaxy, which enables to terminate the superlattice growth with atomic layer precision, provides a way of tuning the superlattice surface electron structure by purely geometrical means. The work was supported by the Grant Agency of the Academy of Sciences

  5. Localization of short-range acoustic and seismic wideband sources: Algorithms and experiments

    Science.gov (United States)

    Stafsudd, J. Z.; Asgari, S.; Hudson, R.; Yao, K.; Taciroglu, E.

    2008-04-01

    We consider the determination of the location (source localization) of a disturbance source which emits acoustic and/or seismic signals. We devise an enhanced approximate maximum-likelihood (AML) algorithm to process data collected at acoustic sensors (microphones) belonging to an array of, non-collocated but otherwise identical, sensors. The approximate maximum-likelihood algorithm exploits the time-delay-of-arrival of acoustic signals at different sensors, and yields the source location. For processing the seismic signals, we investigate two distinct algorithms, both of which process data collected at a single measurement station comprising a triaxial accelerometer, to determine direction-of-arrival. The direction-of-arrivals determined at each sensor station are then combined using a weighted least-squares approach for source localization. The first of the direction-of-arrival estimation algorithms is based on the spectral decomposition of the covariance matrix, while the second is based on surface wave analysis. Both of the seismic source localization algorithms have their roots in seismology; and covariance matrix analysis had been successfully employed in applications where the source and the sensors (array) are typically separated by planetary distances (i.e., hundreds to thousands of kilometers). Here, we focus on very-short distances (e.g., less than one hundred meters) instead, with an outlook to applications in multi-modal surveillance, including target detection, tracking, and zone intrusion. We demonstrate the utility of the aforementioned algorithms through a series of open-field tests wherein we successfully localize wideband acoustic and/or seismic sources. We also investigate a basic strategy for fusion of results yielded by acoustic and seismic arrays.

  6. Non-periodic homogenization of 3-D elastic media for the seismic wave equation

    Science.gov (United States)

    Cupillard, Paul; Capdeville, Yann

    2018-05-01

    Because seismic waves have a limited frequency spectrum, the velocity structure of the Earth that can be extracted from seismic records has a limited resolution. As a consequence, one obtains smooth images from waveform inversion, although the Earth holds discontinuities and small scales of various natures. Within the last decade, the non-periodic homogenization method shed light on how seismic waves interact with small geological heterogeneities and `see' upscaled properties. This theory enables us to compute long-wave equivalent density and elastic coefficients of any media, with no constraint on the size, the shape and the contrast of the heterogeneities. In particular, the homogenization leads to the apparent, structure-induced anisotropy. In this paper, we implement this method in 3-D and show 3-D tests for the very first time. The non-periodic homogenization relies on an asymptotic expansion of the displacement and the stress involved in the elastic wave equation. Limiting ourselves to the order 0, we show that the practical computation of an upscaled elastic tensor basically requires (i) to solve an elastostatic problem and (ii) to low-pass filter the strain and the stress associated with the obtained solution. The elastostatic problem consists in finding the displacements due to local unit strains acting in all directions within the medium to upscale. This is solved using a parallel, highly optimized finite-element code. As for the filtering, we rely on the finite-element quadrature to perform the convolution in the space domain. We end up with an efficient numerical tool that we apply on various 3-D models to test the accuracy and the benefit of the homogenization. In the case of a finely layered model, our method agrees with results derived from Backus. In a more challenging model composed by a million of small cubes, waveforms computed in the homogenized medium fit reference waveforms very well. Both direct phases and complex diffracted waves are

  7. Note on nonlinear seismic response of reinforced concrete structures with low initial periods

    International Nuclear Information System (INIS)

    Sozen, M.A.

    1985-01-01

    This note was prepared to illustrate by specific examples an opinion on the seismic response of reinforced concrete structures with low initial periods. The object is to point out what the writer considers to be important in relation to the behavior of such structures at levels of ground shaking higher than indicated by design criteria. Structures of concern are assumed to have low initial periods. A structure with a low initial period is assumed to have both of two attributes: (a) its flexural stiffness is high so that its total overall lateral deformation is not dominated by flexural deformation and (b) its calculated period is below the one at which the calculated response spectrum may be idealized to change from the nearly-constant acceleration to the nearly-constant velocity response range

  8. Ocular discomfort responses after short periods of contact lens wear.

    Science.gov (United States)

    Papas, Eric; Tilia, Daniel; McNally, John; de la Jara, Percy Lazon

    2015-06-01

    To investigate if contact lens-related discomfort is a function of the time of day at which lenses are worn. This was a randomized, crossover, open-label clinical trial where subjective responses, with and without contact lenses, were assessed every 2 hours during five stages (A to E). Each stage began at the time when subjects would normally have inserted their contact lenses (T0). During stage A, no lenses were worn, whereas in stage B, lenses were worn continuously for 12 hours. In stages C to E, lenses were worn for only 4 hours. Contact lenses were inserted at T0 for stage C, but for stages D and E, lenses were not inserted until T0 + 4 and T0 + 8 hours, respectively. Mixed linear models were used for statistical analysis. In the absence of contact lenses, ocular comfort and dryness remained reasonably constant throughout the observation period. Ocular comfort and dryness decreased during 12 hours of continuous lens wear and became significantly worse from the 8-hour time onward compared with insertion (p 0.05) to the first 4 hours of continuous contact lens wear. Comparing the scores of each of these stages with the no-lens response at the corresponding time showed no significant differences for comfort (p > 0.23) or dryness (p > 0.37). Short periods of wear can be experienced at any time of day without significant change in ocular discomfort and dryness. This suggests that subjective responses at the end of the day are determined by the length of time lenses are in contact with the eye, rather than the time of day at which lenses are worn.

  9. Re-assessment of seismic loads in conjunction with periodic safety review

    International Nuclear Information System (INIS)

    Jonczyk, Josef

    2002-01-01

    The objective of this paper is the fundamental consideration of a safeguard-aim-oriented approach for use in the re-assessment of seismic events with regard to the periodic safety review (PSR) of nuclear power plants (NPP). The re-assessment aspects of site-specific design earthquakes (DEQ), specially the procedure for seismic hazard analysis, will not, however, be considered in detail here. The proposed assessment concept clearly presents a general approach for safety assessments. The approach is based on a successive screening review of components that are considered sufficiently earthquake-resistant. In this respect, the principle of maximum practical application of the design documentation has been considered in the re-assessment process. On the other hand, the safeguard-aim-oriented evaluation will also be applied with regard to whether the requirements of the safety regulations are fulfilled with respect to the safety goals. The review in conjunction with PSR does not, however, attempt to perform this under all technical aspects. Moreover, it is possible to make extensive use of experimental knowledge and engineering judgement with regard to the structural capacity behaviour in case of a seismic event. Compared with design procedures, however, this proposed approach differs from the one applied in licensing procedures, in which such assessment freedom will not usually be exhausted. (author)

  10. Short-Period Binary Stars: Observations, Analyses, and Results

    CERN Document Server

    Milone, Eugene F; Hobill, David W

    2008-01-01

    Short-period binaries run the gamut from widely separated stars to black-hole pairs; in between are systems that include neutron stars and white dwarfs, and partially evolved systems such as tidally distorted and over-contact systems. These objects represent stages of evolution of binary stars, and their degrees of separation provide critical clues to how their evolutionary paths differ from that of single stars. The widest and least distorted systems provide astronomers with the essential precise data needed to study all stars: mass and radius. The interactions of binary star components, on the other hand, provide a natural laboratory to observe how the matter in these stars behaves under different and often varying physical conditions. Thus, cataclysmic variables with and without overpoweringly strong magnetic fields, and stars with densities from that found in the Sun to the degenerate matter of white dwarfs and the ultra-compact states of neutron stars and black holes are all discussed. The extensive inde...

  11. The rise and fall of periodic 'drumbeat' seismicity at Tungurahua volcano, Ecuador

    Science.gov (United States)

    Bell, Andrew F.; Hernandez, Stephen; Gaunt, H. Elizabeth; Mothes, Patricia; Ruiz, Mario; Sierra, Daniel; Aguaiza, Santiago

    2017-10-01

    Highly periodic 'drumbeat' long period (LP) earthquakes have been described from several andesitic and dacitic volcanoes, commonly accompanying incremental ascent and effusion of viscous magma. However, the processes controlling the occurrence and characteristics of drumbeat, and LP earthquakes more generally, remain contested. Here we use new quantitative tools to describe the emergence, evolution, and degradation of drumbeat LP seismicity at the andesitic Tungurahua volcano, Ecuador, in April 2015. The signals were recorded during an episode of minor explosive activity and ash emission, without lava effusion, and are the first to be reported at Tungurahua during the ongoing 17 yrs of eruption. Following four days of high levels of continuous and 'pulsed' tremor, highly-periodic LP earthquakes first appear on 10 April. Over the next four days, inter-event times and event amplitudes evolve through a series of step-wise transitions between stable behaviors, each involving a decrease in the degree of periodicity. Families of similar waveforms persist before, during, and after drumbeat activity, but the activity levels of different families change coincidentally with transitions in event rate, amplitude, and periodicity. A complex micro-seismicity 'initiation' sequence shows pulse-like and stepwise changes in inter-event times and amplitudes in the hours preceding the onset of drumbeat activity that indicate a partial de-coupling between event size and rate. The observations increase the phenomenology of drumbeat LP earthquakes, and suggest that at Tungurahua they result from gas flux and rapid depressurization controlled by shear failure of the margins of the ascending magma column.

  12. Studies of short and long memory in mining-induced seismic processes

    Science.gov (United States)

    Węglarczyk, Stanisław; Lasocki, Stanisław

    2009-09-01

    Memory of a stochastic process implies its predictability, understood as a possibility to gain information on the future above the random guess level. Here we search for memory in the mining-induced seismic process (MIS), that is, a process induced or triggered by mining operations. Long memory is investigated by means of the Hurst rescaled range analysis, and the autocorrelation function estimate is used to test for short memory. Both methods are complemented with result uncertainty analyses based on different resampling techniques. The analyzed data comprise event series from Rudna copper mine in Poland. The studies show that the interevent time and interevent distance processes have both long and short memory. MIS occurrences and locations are internally interrelated. Internal relations among the sizes of MIS events are apparently weaker than those of other two studied parameterizations and are limited to long term interactions.

  13. The analysis and interpretation of very-long-period seismic signals on volcanoes

    Science.gov (United States)

    Sindija, Dinko; Neuberg, Jurgen; Smith, Patrick

    2017-04-01

    The study of very long period (VLP) seismic signals became possible with the widespread use of broadband instruments. VLP seismic signals are caused by transients of pressure in the volcanic edifice and have periods ranging from several seconds to several minutes. For the VLP events recorded in March 2012 and 2014 at Soufriere Hills Volcano, Montserrat, we model the ground displacement using several source time functions: a step function using Richards growth equation, Küpper wavelet, and a damped sine wave to which an instrument response is then applied. This way we get a synthetic velocity seismogram which is directly comparable to the data. After the full vector field of ground displacement is determined, we model the source mechanism to determine the relationship between the source mechanism and the observed VLP waveforms. Emphasis of the research is on how different VLP waveforms are related to the volcano environment and the instrumentation used and on the processing steps in this low frequency band to get most out of broadband instruments.

  14. Analysis and modelization of short-duration windows of seismic signals

    International Nuclear Information System (INIS)

    Berriani, B.; Lacoume, J.L.; Martin, N.; Cliet, C.; Dubesset, M.

    1987-01-01

    The spectral analysis of a seismic arrival is of a great interest, but unfortunately the common Fourier analysis is unserviceable on short-time windows. So, in order to obtain the spectral characteristics of the dominant components of a seismic signal on a short-time interval, the authors study parametric methods. At first, the autoregressive methods are able to localize a small number of non-stationary pure frequencies. But the amplitude determination is impossible with these methods. So, they develop a combination of AR and Capon's methods. In the Capon's method, the amplitude is conserved for a given frequency, at the very time when the contribution of the other frequencies is minimized. Finally, to characterize completely the different pure-frequency dominant components of the signal and to be able to reconstruct the signal and to be able to reconstruct the signal with these elements, the authors need also the phase and the attenuation; for that, they use the Prony's method where the signal is represented by a sum of damped sinusoids. This last method is used to modelize an offset VSP. It is shown that, using four frequencies and their attributes (amplitude, phase, attenuation), it is possible to modelize quasi-exactly the section. When reconstructing the signal, if one (or more) frequency is eliminated, an efficient filtering can be applied. The AR methods, and Prony's in particular, are efficient tools for signal component decomposition and information compression

  15. The first orbital parameters and period variation of the short-period eclipsing binary AQ Boo

    Science.gov (United States)

    Wang, Shuai; Zhang, Liyun; Pi, Qingfeng; Han, Xianming L.; Zhang, Xiliang; Lu, Hongpeng; Wang, Daimei; Li, TongAn

    2016-10-01

    We obtained the first VRI CCD light curves of the short-period contact eclipsing binary AQ Boo, which was observed on March 22 and April 19 in 2014 at Xinglong station of National Astronomical Observatories, and on January 20, 21 and February 28 in 2015 at Kunming station of Yunnan Observatories of Chinese Academy of Sciences, China. Using our six newly obtained minima and the minima that other authors obtained previously, we revised the ephemeris of AQ Boo. By fitting the O-C (observed minus calculated) values of the minima, the orbital period of AQ Boo shows a decreasing tendency P˙ = - 1.47(0.17) ×10-7 days/year. We interpret the phenomenon by mass transfer from the secondary (more massive) component to the primary (less massive) one. By using the updated Wilson & Devinney program, we also derived the photometric orbital parameters of AQ Boo for the first time. We conclude that AQ Boo is a near contact binary with a low contact factor of 14.43%, and will become an over-contact system as the mass transfer continues.

  16. Precessional Periods of Long and Short Foucault Pendulums

    Science.gov (United States)

    Soga, Michitoshi

    1978-01-01

    Derives the precessional period of a Foucault pendulum without using small oscillation amplitudes. Shows that if the path of the pendulum passes through the origin, the periods for differing amplitudes are essentially the same. (GA)

  17. Location of long-period events below Kilauea Volcano using seismic amplitudes and accurate relative relocation

    Science.gov (United States)

    Battaglia, J.; Got, J.-L.; Okubo, P.

    2003-01-01

    We present methods for improving the location of long-period (LP) events, deep and shallow, recorded below Kilauea Volcano by the permanent seismic network. LP events might be of particular interest to understanding eruptive processes as their source mechanism is assumed to directly involve fluid transport. However, it is usually difficult or impossible to locate their source using traditional arrival time methods because of emergent wave arrivals. At Kilauea, similar LP waveform signatures suggest the existence of LP multiplets. The waveform similarity suggests spatially close sources, while catalog solutions using arrival time estimates are widely scattered beneath Kilauea's summit caldera. In order to improve estimates of absolute LP location, we use the distribution of seismic amplitudes corrected for station site effects. The decay of the amplitude as a function of hypocentral distance is used for inferring LP location. In a second stage, we use the similarity of the events to calculate their relative positions. The analysis of the entire LP seismicity recorded between January 1997 and December 1999 suggests that a very large part of the LP event population, both deep and shallow, is generated by a small number of compact sources. Deep events are systematically composed of a weak high-frequency onset followed by a low-frequency wave train. Aligning the low-frequency wave trains does not lead to aligning the onsets indicating the two parts of the signal are dissociated. This observation favors an interpretation in terms of triggering and resonance of a magmatic conduit. Instead of defining fault planes, the precise relocation of similar LP events, based on the alignment of the high-energy low-frequency wave trains, defines limited size volumes. Copyright 2003 by the American Geophysical Union.

  18. Long period seismic source characterization at Popocatépetl volcano, Mexico

    Science.gov (United States)

    Arciniega-Ceballos, Alejandra; Dawson, Phillip; Chouet, Bernard A.

    2012-01-01

    The seismicity of Popocatépetl is dominated by long-period and very-long period signals associated with hydrothermal processes and magmatic degassing. We model the source mechanism of repetitive long-period signals in the 0.4–2 s band from a 15-station broadband network by stacking long-period events with similar waveforms to improve the signal-to-noise ratio. The data are well fitted by a point source located within the summit crater ~250 m below the crater floor and ~200 m from the inferred magma conduit. The inferred source includes a volumetric component that can be modeled as resonance of a horizontal steam-filled crack and a vertical single force component. The long-period events are thought to be related to the interaction between the magmatic system and a perched hydrothermal system. Repetitive injection of fluid into the horizontal fracture and subsequent sudden discharge when a critical pressure threshold is met provides a non-destructive source process.

  19. Short periodic oscillations of the dwarf nova VW Hydri

    International Nuclear Information System (INIS)

    Haefner, R.; Schoembs, R.

    1977-01-01

    A coherent oscillation of approximately 88 s period and 0.m005 amplitude was detected during the decline stage at the end of the long eruption of VW Hyi in December 1975. The period changed erratically between 86 and 90 s during eight nights. There are indications that the amplitude depends on the phase of the orbital revolution. The new period favours models in which such oscillations are caused by the orbital motion of inhomogeneities in the disc. (orig.) [de

  20. Search for Long Period Solar Normal Modes in Ambient Seismic Noise

    Science.gov (United States)

    Caton, R.; Pavlis, G. L.

    2016-12-01

    We search for evidence of solar free oscillations (normal modes) in long period seismic data through multitaper spectral analysis of array stacks. This analysis is similar to that of Thomson & Vernon (2015), who used data from the most quiet single stations of the global seismic network. Our approach is to use stacks of large arrays of noisier stations to reduce noise. Arrays have the added advantage of permitting the use of nonparametic statistics (jackknife errors) to provide objective error estimates. We used data from the Transportable Array, the broadband borehole array at Pinyon Flat, and the 3D broadband array in Homestake Mine in Lead, SD. The Homestake Mine array has 15 STS-2 sensors deployed in the mine that are extremely quiet at long periods due to stable temperatures and stable piers anchored to hard rock. The length of time series used ranged from 50 days to 85 days. We processed the data by low-pass filtering with a corner frequency of 10 mHz, followed by an autoregressive prewhitening filter and median stack. We elected to use the median instead of the mean in order to get a more robust stack. We then used G. Prieto's mtspec library to compute multitaper spectrum estimates on the data. We produce delete-one jackknife error estimates of the uncertainty at each frequency by computing median stacks of all data with one station removed. The results from the TA data show tentative evidence for several lines between 290 μHz and 400 μHz, including a recurring line near 379 μHz. This 379 μHz line is near the Earth mode 0T2 and the solar mode 5g5, suggesting that 5g5 could be coupling into the Earth mode. Current results suggest more statistically significant lines may be present in Pinyon Flat data, but additional processing of the data is underway to confirm this observation.

  1. Studying Short-Period Comets and Long-Period Comets Detected by WISE/NEOWISE

    Science.gov (United States)

    Kramer, Emily A.; Fernández, Yanga R.; Bauer, James M.; Stevenson, Rachel; Mainzer, Amy K.; Grav, Tommy; Masiero, Joseph; Walker, Russell G.; Lisse, Carey M.

    2014-11-01

    The Wide-field Infrared Survey Explorer (WISE) mission surveyed the sky in four infrared wavelength bands (3.4, 4.6, 12 and 22-micron) between January 2010 and February 2011 [1, 2]. During the mission, WISE serendipitously observed 160 comets, including 21 newly discovered objects. About 89 of the comets observed by WISE displayed a significant dust tail in the 12 and 22-micron (thermal emission) bands, showing a wide range of activity levels and dust morphology. Since the observed objects are a mix of both long-period comets (LPCs) and short-period comets (SPCs), differences in their activity can be used to better understand the thermal evolution that each of these populations has undergone. For the comets that displayed a significant dust tail, we have estimated the sizes and ages of the particles using dynamical models based on the Finson-Probstein method [3, 4]. For a selection of 40 comets, we have then compared these models to the data using a novel tail-fitting method that allows the best-fit model to be chosen analytically rather than subjectively. For comets that were observed multiple times by WISE, the dust tail particle properties were estimated separately, and then compared. We find that the dust tails of both LPCs and SPCs are primarily comprised of ~mm to cm sized particles, which were the result of emission that occurred several months to several years prior to the observations. The LPCs nearly all have strong dust emission close to the comet's perihelion distance, and the SPCs mostly have strong dust emission close to perihelion, but some have strong dust emission well before perihelion. Acknowledgments: This publication makes use of data products from (1) WISE, which is a joint project of UCLA and JPL/Caltech, funded by NASA; and (2) NEOWISE, which is a project of JPL/Caltech, funded by the Planetary Science Division of NASA. EK was supported by a NASA Earth and Space Sciences Fellowship. RS gratefully acknowledges support from the NASA

  2. Seismicity in the Vicinity of Yucca Mountain, Nevada, for the Period October 1, 2004 to September 30, 2006

    International Nuclear Information System (INIS)

    Smith, Ken

    2007-01-01

    This report describes earthquake activity within approximately 65 km of Yucca Mountain site during the October 1, 2004 to September 30, 2006 time period (FY05-06). The FY05-06 earthquake activity will be compared with the historical and more recent period of seismic activity in the Yucca Mountain region. The relationship between the distribution of seismicity and active faults, historical patterns of activity, and rates of earthquakes (number of events and their magnitudes) are important components in the assessment of the seismic hazard for the Yucca Mountain site. Since October 1992 the University of Nevada has compiled a catalog of earthquakes in the Yucca Mountain area. Seismicity reports have identified notable earthquake activity, provided interpretations of the seismotectonics of the region, and documented changes in the character of earthquake activity based on nearly 30 years of site-characterization monitoring. Data from stations in the seismic network in the vicinity of Yucca Mountain is collected and managed at the Nevada Seismological Laboratory (NSL) at the University of Nevada Reno (UNR). Earthquake events are systematically identified and cataloged under Implementing Procedures developed in compliance with the Nevada System of Higher Education (NSHE) Quality Assurance Program. The earthquake catalog for FY05-06 in the Yucca Mountain region submitted to the Yucca Mountain Technical Data Management System (TDMS) forms the basis of this report

  3. Short-Period RF Undulator for a SASE Nanometer source

    International Nuclear Information System (INIS)

    Hirshfield, Jay L.

    2011-01-01

    Analysis is described towards development of a RF undulator with a period < 1 cm, an undulator parameter K of the order of unity, and a gap greater than 2.25 mm. The application for the undulator is for a SASE source to produce 1 nm wavelength radiation using a low energy electron beam in the range 1-2 GeV. Particle orbit calculations in a conventional standing-wave resonator configuration show that the presence of a co-propagating component of RF field can cause deleterious motion for the undulating electrons that can seriously degrade their radiation spectrum. To obviate this problem, resonator designs were devised in which only the counter-propagating field components interact with the particles. Two resonator configurations with the same undulator parameter K = 0.4 have been devised and are described in this report.

  4. Beamline front end for in-vacuum short period undulator at the photon factory storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Miyauchi, Hiroshi, E-mail: hiroshi.miyauchi@kek.jp [Accelerator Laboratory, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Department of Accelerator Science, School of High Energy Accelerator Science, SOKENDAI (The Graduate University for Advanced Studies), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Tahara, Toshihiro, E-mail: ttahara@post.kek.jp; Asaoka, Seiji, E-mail: seiji.asaoka@kek.jp [Accelerator Laboratory, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2016-07-27

    The straight-section upgrade project of the Photon Factory created four new short straight sections capable of housing in-vacuum short period undulators. The first to fourth short period undulators SGU#17, SGU#03, SGU#01 and SGU#15 were installed at the 2.5-GeV Photon Factory storage ring in 2005, 2006, 2009 and 2013, respectively. The beamline front end for SGU#15 is described in this paper.

  5. Detection of very long period solar free oscillations in ambient seismic array noise

    Science.gov (United States)

    Caton, R.; Pavlis, G. L.; Thomson, D. J.; Vernon, F.

    2017-12-01

    For nearly two decades long-period seismologists have been aware that the Earth's free oscillations are in a constant state of excitement, even in the absence of large earthquakes. This phenomenon is now called the "Earth's hum," and much research has been done to determine what generates this hum. Here we examine a hypothesis first put forward by Thomson et al. in 2007 that a portion of the hum's energy comes from the sun. They hypothesized that solar free oscillations couple into the solid Earth, likely through electromagnetic processes, and produce signals that are observable in the frequency domain. If this is true, then at least some measurement of helioseismic oscillations may be possible using relatively cheap, ground-based instruments rather than spacecraft. In this project we attempt to improve upon previous studies by producing spectra from seismic arrays, rather than a single station. We use data from two arrays: The Homestake Mine 3D array in Lead, SD, and the Pinyon Flats array, which has seismometers in boreholes drilled into bedrock. Both have exceptionally low noise levels at ultra long periods and show easily visible earth tides on horizontal component data filtered to below the microseism band. In the Homestake data, below 500 μHz we have found evidence of what we suggest may be closely spaced solar g-mode lines. Such modes are produced by a density inversion at the top of the solar core. There is no sign of these modes in the Pinyon Flats data, but we find this is likely due to the signal-to-noise ratio of those data, which is significantly lower than Homestake. Significance tests of bands below 500 μHz indicate with probability levels as high as 40σ that these lines are not the result of random processes. Critical examination of our processing steps for sources of bias indicate that the observed line structure is not a processing artifact.

  6. Long-period and short-period variations of ionospheric parameters studied from complex observations performed on Cuba

    Energy Technology Data Exchange (ETDEWEB)

    Laso, B; Lobachevskii, L A; Potapova, N I; Freizon, I A; Shapiro, B S

    1980-09-01

    Cuban data from 1978 are used to study long-period (i.e., diurnal) variations of Doppler shift on a 3000 km path at frequencies of 10 and 15 MHz these variations are related to variations of parameters on the ionospheric path. Short-period variations were also studied on the basis of Doppler shift data and vertical sounding data in the 0.000111-0.00113 Hz frequency range. The relation between the observed variations and internal gravity waves are discussed.

  7. Estimation of seismic return periods in the Laguna Verde nuclear plant; Estimacion de periodos de retorno sismico en la PNLV

    Energy Technology Data Exchange (ETDEWEB)

    Flores R, J.H

    1992-01-15

    The study of seismic risk in the area of the Laguna Verde Nucleo electric plant (PNLV) and its surroundings, one carries out estimating the different return periods and the occurrence probability in different intervals of time (5, 75, 100, 125, 150 years starting from the distribution of first type of Gumbel (G1) of extreme values (Burton, 1986), the value that was used to evaluate the useful life of the PNLV was of 50 years, the other periods will be occupy to evaluate 'temporal' nuclear cemeteries, that is to say for diminish the radioactive activity of the fuel assemblies already burned in the reactor pool or in a near place to the place. The seismic data that were used for the analysis were of the seismic catalog that it was elaborated from (1920-1982), around the place whose seismic half magnitude was of 5 grades Richter and a depth 65 km, these earthquakes are classified as shallow earthquakes, which are located in the continental plaque of North-America, these they are induced by the efforts of push of the plaque of Cocos, existing 36% of intermediate and 2 of deep earthquakes. (Author)

  8. Estimation of seismic return periods in the Laguna Verde nuclear plant; Estimacion de periodos de retorno sismico en la PNLV

    Energy Technology Data Exchange (ETDEWEB)

    Flores R, J H

    1992-01-15

    The study of seismic risk in the area of the Laguna Verde Nucleo electric plant (PNLV) and its surroundings, one carries out estimating the different return periods and the occurrence probability in different intervals of time (5, 75, 100, 125, 150 years starting from the distribution of first type of Gumbel (G1) of extreme values (Burton, 1986), the value that was used to evaluate the useful life of the PNLV was of 50 years, the other periods will be occupy to evaluate 'temporal' nuclear cemeteries, that is to say for diminish the radioactive activity of the fuel assemblies already burned in the reactor pool or in a near place to the place. The seismic data that were used for the analysis were of the seismic catalog that it was elaborated from (1920-1982), around the place whose seismic half magnitude was of 5 grades Richter and a depth 65 km, these earthquakes are classified as shallow earthquakes, which are located in the continental plaque of North-America, these they are induced by the efforts of push of the plaque of Cocos, existing 36% of intermediate and 2 of deep earthquakes. (Author)

  9. Layering of Structure in the North American Upper Mantle: Combining Short Period Constraints and Full Waveform Tomography

    Science.gov (United States)

    Roy, C.; Calo, M.; Bodin, T.; Romanowicz, B. A.

    2016-12-01

    Recent receiver function (RF) studies of the north American craton suggest the presence of layering within the cratonic lithosphere with significant lateral variations in the depth. However, the location and character of these discontinuities depends on assumptions made on a background 3D velocity model. On the other hand, the implementation of the Spectral Element Method (SEM) for the computation of the seismic wavefield in 3D structures is allowing improved resolution of volumetric structure in full waveform tomography. The corresponding computations are however very heavy and limit our ability to attain short enough periods to resolve short scale features such as the existence and lateral variations of discontinuities. In order to overcome these limitations, we have developed a methodology that combines full waveform inversion tomography and information provided by short period seismic observables. In a first step we constructed a 3D discontinuous radially anisotropic starting model combining 1D models calculated using RF and L and R wave dispersion data in a Bayesian framework using trans-dimensional MCMC inversion at a collection of 30 stations across the north American continent (Calò et al., 2016). This model was then interpolated and smoothed using a procedure based on residual homogenization (Capdeville et al. 2013) and serves as input model for full waveform tomography using a three-component waveform dataset previously collected (Yuan et al., 2014). The homogenization is necessary to avoid meshing problems and heavy SEM computations. In a second step, several iterations of the full waveform inversion are performed until convergence, using a regional SEM code for forward computations (RegSEM, Cupillard et al., 2012). Results of the inversion are volumetric velocity perturbations around the homogenized starting model, which are then added to the discontinuous 3D starting model. The final result is a multiscale discontinuous model containing both short and

  10. Analysis of short time-space range seismicity patterns in Italy

    Directory of Open Access Journals (Sweden)

    M. Imotof

    1997-06-01

    Full Text Available In our paper we analyze the data base obtained from the observations of the Italian Seismological Network from 1975 to 1994 by using a simple algotithm to determine the rate of occurrence of seismic events condi- tioned by the occurrence of previous events after a period of quiescence. The number of observed pairs of earthquakes depends on several parameters: the magnitude threshold of the two events, the spatial and tempo- ral ranges of the quiescence period preceding the first (non aftershock event, the time elapsed between the first and the second events and the spatial dimension of the alarm area. The Akaike information criterion was adopted to assess the optimal set of space-time parameters used in the definition of non-aftershock (events not related to a stronger previous one. In Central Italy, the rate of M ³3.8 earthquakes preceded by at least one M ~ 3.3 foreshock within 14.1 km and 2 days is 30%, while the rate of M ~ 3.3 earthquakes followed by a M ~ 3.8 mainshock in the same space time range is 7%. We observed that the probability that an earthquake of magnitude MI will be followed by an earthquake of magnitude M2 (success rate fits the law log À = a+b (Mi -M2 with b approximately equal to l. By computing the success rate for given values of magnitude threshold of the first and the second events over a dense grid of spatial coordinates, we obtained maps of this feature over the investigated area. The results of this process document variations larger than a factor of five in the success rate over the Italian territory.

  11. The effect of short recovery period investment on least-cost generation system expansion

    International Nuclear Information System (INIS)

    Yiqun He; David, A.K.; Fernando, P.N.

    1995-01-01

    The effect of the short recovery period of private investment on least-cost generation system expansion is analysed, and a trade-off method for generation system expansion, which gives consideration to both the least-cost strategy and the short recovery period of private investment, is presented. First, the optimal mix of generation units under a standard recovery period for all units is established, and then the surcharge, due to the difference between the short recovery period and the standard recovery period, is calculated and shared between all units. The former is an optimization to make best use of natural resources, and the latter is a trade-off method to spread the surcharge throughout the system. (Author)

  12. A survey for very short-period planets in the Kepler data

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Brian; Stark, Christopher C.; Chambers, John [Carnegie Institution for Science, 5241 Broad Branch Road NW, Washington, DC 20015 (United States); Adams, Elisabeth R. [Planetary Science Institute, 1700 East Fort Lowell, Suite 106, Tucson, AZ 85719 (United States); Deming, Drake, E-mail: bjackson@dtm.ciw.edu [Department of Astronomy, University of Maryland at College Park, College Park, MD 20742 (United States)

    2013-12-20

    We conducted a search for very short-period transiting objects in the publicly available Kepler data set. Our preliminary survey has revealed four planetary candidates, all with orbital periods less than 12 hr. We have analyzed the data for these candidates using photometric models that include transit light curves, ellipsoidal variations, and secondary eclipses to constrain the candidates' radii, masses, and effective temperatures. Even with masses of only a few Earth masses, the candidates' short periods mean that they may induce stellar radial velocity signals (a few m s{sup –1}) detectable by currently operating facilities. The origins of such short-period planets are unclear, but we discuss the possibility that they may be the remnants of disrupted hot Jupiters. Whatever their origins, if confirmed as planets, these candidates would be among the shortest-period planets ever discovered. Such planets would be particularly amenable to discovery by the planned TESS mission.

  13. A survey for very short-period planets in the Kepler data

    International Nuclear Information System (INIS)

    Jackson, Brian; Stark, Christopher C.; Chambers, John; Adams, Elisabeth R.; Deming, Drake

    2013-01-01

    We conducted a search for very short-period transiting objects in the publicly available Kepler data set. Our preliminary survey has revealed four planetary candidates, all with orbital periods less than 12 hr. We have analyzed the data for these candidates using photometric models that include transit light curves, ellipsoidal variations, and secondary eclipses to constrain the candidates' radii, masses, and effective temperatures. Even with masses of only a few Earth masses, the candidates' short periods mean that they may induce stellar radial velocity signals (a few m s –1 ) detectable by currently operating facilities. The origins of such short-period planets are unclear, but we discuss the possibility that they may be the remnants of disrupted hot Jupiters. Whatever their origins, if confirmed as planets, these candidates would be among the shortest-period planets ever discovered. Such planets would be particularly amenable to discovery by the planned TESS mission.

  14. Staggered and short-period solutions of the saturable discrete nonlinear Schrodinger equation

    DEFF Research Database (Denmark)

    Khare, A.; Rasmussen, K.O.; Samuelsen, Mogens Rugholm

    2009-01-01

    We point out that the nonlinear Schrodinger lattice with a saturable nonlinearity also admits staggered periodic aswell as localized pulse-like solutions. Further, the same model also admits solutions with a short period. We examine the stability of these solutions and find that the staggered as ...

  15. Spectra of short-period pulsars according to the hypothesis of the two types of pulsars

    International Nuclear Information System (INIS)

    Malov, I.F.

    1985-01-01

    The lack of low-frequency turnovers in the spectra of PSR 0531+21 and 1937+21 may be expl ned if the generation of radio emission in these pulsars occurs near the light cylinder. Differences of high frequency cut-offs and spectral inoices for long-period pulsars and short-period ones are discussed

  16. A Search for Exoplanets in Short-Period Binary Star Systems

    Directory of Open Access Journals (Sweden)

    Ronald Kaitchuck

    2012-03-01

    Full Text Available This paper reports the progress of a search for exoplanets with S-type orbits in short-period binary star systems. The selected targets have stellar orbital periods of just a few days. These systems are eclipsing binaries so that exoplanet transits, if planets exist, will be highly likely. We report the results for seven binary star systems.

  17. Short interval overnight laser scanning suggest sub-circadian periodicity of tree turgor

    DEFF Research Database (Denmark)

    Zlinszky, Andras; Barfod, Anders

    2018-01-01

    in amplitude and 2-6hour periodicity. Sub-circadian process dynamics of plants were so far not in focus of research, but here we compare the findings with other published cases of short-term periodicity in leaf turgor, sap flow and especially trunk diameter. Several authors have noted overnight variations...

  18. Short interval overnight laser scanning suggests sub-circadian periodicity of tree turgor

    DEFF Research Database (Denmark)

    Zlinszky, Andras; Barfod, Anders

    2018-01-01

    in amplitude and 2-6hour periodicity. Sub-circadian process dynamics of plants were so far not in focus of research, but here we compare the findings with other published cases of short-term periodicity in leaf turgor, sap flow and especially trunk diameter. Several authors have noted overnight variations...

  19. New insights of seismic disturbances due to wind turbines - long and short term measurements in SW Germany

    Science.gov (United States)

    Zieger, Toni; Ritter, Joachim

    2017-04-01

    Within the scope of the project "TremAc", we present new insights of ground motion disturbances due to wind turbines (WTs) in the vicinity of the town of Landau, SW Germany. The main goal of this project, which is funded by the German Federal Ministry for Economic Affairs and Energy, is the detection of influences from WTs on human health and buildings in an interdisciplinary way. The interaction between WTs, humans, infrastructure (incl.seismic stations) becomes more and more an important role with the increase of installed WTs. We present averaged one hour long PSD-spectra in a frequency range from 0.5 Hz to 7 Hz depending on the wind speed before and after the installation of characteristic WTs, especially for seismic borehole stations, during one month measurements. The results show a clear increase of the ground motion and a related disturbance of the seismic recordings. The station threshold for signal detection below 2 Hz is reduced after the installation of a new wind farm in the area around Landau. This effect occurs even up to distances to the WTs of more than 5 kilometers. The increasing noise level depends also clearly on wind speed, which indicate also the WT origin related with the signals. Using short-term measurements during few hours, we are able to determine the maximum of the PSD values for different discrete frequencies as function of distance to the next WT and to fit a power-law decay curve proportional to 1/rb to the data. In this way we can differentiate between near- and far-field effects of the seismic wave propagation of WTs. A clear frequency dependent decay can be observed, for which high frequencies are more attenuated than lower frequencies, probably due to scattering processes. The new results will help for a better understanding of WTs as a seismic noise source and their interaction with nearby seismic stations and other infrastructure. Seismic data were provided by "Erdbebendienst Südwest", "Federal Institute for Geosciences and

  20. Lithospheric layering in the North American craton revealed by including Short Period Constraints in Full Waveform Tomography

    Science.gov (United States)

    Roy, C.; Calo, M.; Bodin, T.; Romanowicz, B. A.

    2017-12-01

    Recent receiver function studies of the North American craton suggest the presence of significant layering within the cratonic lithosphere, with significant lateral variations in the depth of the velocity discontinuities. These structural boundaries have been confirmed recently using a transdimensional Markov Chain Monte Carlo approach (TMCMC), inverting surface wave dispersion data and converted phases simultaneously (Calò et al., 2016; Roy and Romanowicz 2017). The lateral resolution of upper mantle structure can be improved with a high density of broadband seismic stations, or with a sparse network using full waveform inversion based on numerical wavefield computation methods such as the Spectral Element Method (SEM). However, inverting for discontinuities with strong topography such as MLDS's or LAB, presents challenges in an inversion framework, both computationally, due to the short periods required, and from the point of view of stability of the inversion. To overcome these limitations, and to improve resolution of layering in the upper mantle, we are developing a methodology that combines full waveform inversion tomography and information provided by short period seismic observables. We have extended the 30 1D radially anisotropic shear velocity profiles of Calò et al. 2016 to several other stations, for which we used a recent shear velocity model (Clouzet et al., 2017) as constraint in the modeling. These 1D profiles, including both isotropic and anisotropic discontinuities in the upper mantle (above 300 km depth) are then used to build a 3D starting model for the full waveform tomographic inversion. This model is built after 1) homogenization of the layered 1D models and 2) interpolation between the 1D smooth profiles and the model of Clouzet et al. 2017, resulting in a smooth 3D starting model. Waveforms used in the inversion are filtered at periods longer than 30s. We use the SEM code "RegSEM" for forward computations and a quasi-Newton inversion

  1. Coherent Phonon Dynamics in Short-Period InAs/GaSb Superlattices

    OpenAIRE

    Noe, G. T.; Haugan, H. J.; Brown, G. J.; Sanders, G. D.; Stanton, C. J.; Kono, J.

    2011-01-01

    We have performed ultrafast pump-probe spectroscopy studies on a series of InAs/GaSb-based short-period superlattice (SL) samples with periods ranging from 46 \\AA to 71 \\AA. We observe two types of oscillations in the differential reflectivity with fast ($\\sim$ 1- 2 ps) and slow ($\\sim$ 24 ps) periods. The period of the fast oscillations changes with the SL period and can be explained as coherent acoustic phonons generated from carriers photoexcited within the SL. This mode provides an accura...

  2. Seismic Activity in Medieval Jeroným Mine, West Bohemia, During Period 2006-2009

    Czech Academy of Sciences Publication Activity Database

    Kaláb, Zdeněk; Lednická, Markéta; Knejzlík, Jaromír; Hrubešová, E.

    2010-01-01

    Roč. 5, č. 2 (2010), s. 67-77 ISSN 1896-3145. [Ochrona środowiska w górnictwie podziemnym, odkrywkowym i otworowym. Zawiercie, 19.05.2010-21.05.2010] R&D Projects: GA ČR GA105/09/0089 Institutional research plan: CEZ:AV0Z30860518 Keywords : medieval Jeroným mine * seismic load * numerical modelling of underground spaces Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  3. Effects of age, gender, and stimulus presentation period on visual short-term memory.

    Science.gov (United States)

    Kunimi, Mitsunobu

    2016-01-01

    This study focused on age-related changes in visual short-term memory using visual stimuli that did not allow verbal encoding. Experiment 1 examined the effects of age and the length of the stimulus presentation period on visual short-term memory function. Experiment 2 examined the effects of age, gender, and the length of the stimulus presentation period on visual short-term memory function. The worst memory performance and the largest performance difference between the age groups were observed in the shortest stimulus presentation period conditions. The performance difference between the age groups became smaller as the stimulus presentation period became longer; however, it did not completely disappear. Although gender did not have a significant effect on d' regardless of the presentation period in the young group, a significant gender-based difference was observed for stimulus presentation periods of 500 ms and 1,000 ms in the older group. This study indicates that the decline in visual short-term memory observed in the older group is due to the interaction of several factors.

  4. A new seismic station in Romania the Bucovina seismic array

    International Nuclear Information System (INIS)

    Grigore, Adrian; Grecu, Bogdan; Ionescu, Constantin; Ghica, Daniela; Popa, Mihaela; Rizescu, Mihaela

    2002-01-01

    Recently, a new seismic monitoring station, the Bucovina Seismic Array, has been established in the northern part of Romania, in a joint effort of the Air Force Technical Applications Center, USA, and the National Institute for Earth Physics, Romania. The array consists of 10 seismic sensors (9 short-period and one broad band) located in boreholes and distributed in a 5 x 5 km area. On July 24, 2002 the official Opening Ceremony of Bucovina Seismic Array took place in the area near the city of Campulung Moldovenesc in the presence of Romanian Prime Minister, Adrian Nastase. Starting with this date, the new seismic monitoring system became fully operational by continuous recording and transmitting data in real-time to the National Data Center of Romania, in Bucharest and to the National Data Center of USA, in Florida. Bucovina Seismic Array, added to the present Seismic Network, will provide much better seismic monitoring coverage of Romania's territory, on-scale recording for weak-to-strong events, and will contribute to advanced seismological studies on seismic hazard and risk, local effects and microzonation, seismic source physics, Earth structure. (authors)

  5. Short-period AM CVn systems as optical, X-ray and gravitational-wave sources

    NARCIS (Netherlands)

    Nelemans, G.; Yungelson, L.; Portegies Zwart, S.F.

    2004-01-01

    We model the population of AM CVn systems in the Galaxy and discuss the detectability of these systems with optical, X-ray and gravitational-wave detectors. We concentrate on the short-period (P < 1500 s) systems, some of which are expected to be in a phase of direct-impact accretion. Using a

  6. Evaluation of short-period rainfall estimates from Kalpana-1 satellite

    Indian Academy of Sciences (India)

    The INSAT Multispectral Rainfall Algorithm (IMSRA) technique for rainfall estimation, has recently been developed to meet the shortcomings of the Global Precipitation Index (GPI) technique of rainfall estimation from the data of geostationary satellites; especially for accurate short period rainfall estimates. This study ...

  7. Seismicity patterns during a period of inflation at Sierra Negra volcano, Galápagos Ocean Island Chain

    Science.gov (United States)

    Davidge, Lindsey; Ebinger, Cynthia; Ruiz, Mario; Tepp, Gabrielle; Amelung, Falk; Geist, Dennis; Coté, Dustin; Anzieta, Juan

    2017-03-01

    Basaltic shield volcanoes of the western Galápagos islands are among the most rapidly deforming volcanoes worldwide, but little was known of the internal structure and brittle deformation processes accompanying inflation and deflation cycles. A 15-station broadband seismic array was deployed on and surrounding Sierra Negra volcano, Galápagos from July 2009 through June 2011 to characterize seismic strain patterns during an inter-eruption inflation period and to evaluate single and layered magma chamber models for ocean island volcanoes. We compare precise earthquake locations determined from a 3D velocity model and from a double difference cluster method. Using first-motion of P-arrivals, we determine focal mechanisms for 8 of the largest earthquakes (ML ≤ 1.5) located within the array. Most of the 2382 earthquakes detected by the array occurred beneath the broad (∼9 km-wide) Sierra Negra caldera, at depths from surface to about 8 km below sea level. Although outside our array, frequent and larger magnitude (ML ≤ 3.4) earthquakes occurred at Alcedo and Fernandina volcano, and in a spatial cluster beneath the shallow marine platform between Fernandina and Sierra Negra volcanoes. The time-space relations and focal mechanism solutions from a 4-day long period of intense seismicity June 4-9, 2010 along the southeastern flank of Sierra Negra suggests that the upward-migrating earthquake swarm occurred during a small volume intrusion at depths 5-8 km subsurface, but there was no detectable signal in InSAR data to further constrain geometry and volume. Focal mechanisms of earthquakes beneath the steep intra-caldera faults and along the ring fault system are reverse and strike-slip. These new seismicity data integrated with tomographic, geodetic, and petrological models indicate a stratified magmatic plumbing system: a shallow sill beneath the large caldera that is supplied by magma from a large volume deeper feeding system. The large amplitude inter

  8. PLANET HUNTERS: ASSESSING THE KEPLER INVENTORY OF SHORT-PERIOD PLANETS

    International Nuclear Information System (INIS)

    Schwamb, Megan E.; Lintott, Chris J.; Lynn, Stuart; Smith, Arfon M.; Simpson, Robert J.; Fischer, Debra A.; Giguere, Matthew J.; Brewer, John M.; Parrish, Michael; Schawinski, Kevin

    2012-01-01

    We present the results from a search of data from the first 33.5 days of the Kepler science mission (Quarter 1) for exoplanet transits by the Planet Hunters citizen science project. Planet Hunters enlists members of the general public to visually identify transits in the publicly released Kepler light curves via the World Wide Web. Over 24,000 volunteers reviewed the Kepler Quarter 1 data set. We examine the abundance of ≥2 R ⊕ planets on short-period ( ⊕ Planet Hunters ≥85% efficient at identifying transit signals for planets with periods less than 15 days for the Kepler sample of target stars. Our high efficiency rate for simulated transits along with recovery of the majority of Kepler ≥4 R ⊕ planets suggests that the Kepler inventory of ≥4 R ⊕ short-period planets is nearly complete.

  9. Stress modulation of earthquakes: A study of long and short period stress perturbations and the crustal response

    Science.gov (United States)

    Johnson, Christopher W.

    laboratory to explore the causal relationship between low-amplitude stress changes and dynamically triggered events. Interestingly, observations of dynamically triggered M≥5.5 earthquakes are absent in the seismic records [Johnson et al., 2015; Parsons and Velasco, 2011], which invokes questions regarding whether or not large magnitude events can be dynamically triggered. Emerging results in the literature indicate undocumented M≥5.5 events at near to intermediate distances are dynamically triggered during the passage of surface waves but are undetected by automated networks [Fan and Shearer, 2016]. This raises new questions about the amplitude and duration of dynamic stressing for large magnitude events. I used 35-years of global seismicity and find that large event rate increases only occur following a delay from the transient load, suggesting aseismic processes are associated with large magnitude triggered events. To extend this finding I investigated three cases of large magnitude delayed dynamic triggering following the M8.6 2012 Indian Ocean earthquake [Pollitz et al., 2012] by producing microseismicity catalogs and modeling the transient stresses. The results indicate immediate triggering of microseismic events that hours later culminate into a large magnitude event and support the notion that large magnitude events are triggerable by transient loading, but seismic and aseismic processes (e.g. induced creep or fluid mobilization) are contributing to the nucleation process. Open questions remain concerning the source of a nucleation delay period following a stress perturbation that require both geodetic and seismic observations to constrain the source of delayed dynamic triggering and possibly provide insight into a precursory nucleation phase. Induced seismicity has gained much attention in the past 5 years as earthquake rates in regions of low tectonic strain accumulation accelerate to unprecedented levels [Ellsworth, 2013]. The source of the seismicity is

  10. Ultra-short period X-ray mirrors: Production and investigation

    International Nuclear Information System (INIS)

    Bibishkin, M.S.; Chkhalo, N.I.; Fraerman, A.A.; Pestov, A.E.; Prokhorov, K.A.; Salashchenko, N.N.; Vainer, Yu.A.

    2005-01-01

    Technological problems that deal with manufacturing of highly effective ultra-short (d=0.7-3.2 nm) period X-ray multilayer mirrors (MLM) are discussed in the article. In an example of Cr/Sc and W/B 4 C MLM it is experimentally shown, that the problem of periodicity and selectivity for multilayer dispersive X-ray elements has been generally solved by now. However, the problem of short-period MLM reflectivity increase related to existing of transitive borders between layers in structures remains rather urgent. The new technique of tungsten deposition using the RF source in order to decrease roughness in borders is discussed and tested. The results of measurements on wavelengths of 0.154, 0.834 and 1.759 nm are given. The RbAP crystals ordinary used in experiments and short-period W/B 4 C MLM produced are compared. The specular and non-specular characteristics of scattering on the 0.154 nm wavelengths are also measured in order to study transitive borders structures

  11. Shallow degassing events as a trigger for very-long-period seismicity at Kīlauea Volcano, Hawai‘i

    Science.gov (United States)

    Patrick, Matthew; Wilson, David; Fee, David; Orr, Tim R.; Swanson, Donald A.

    2011-01-01

    The first eruptive activity at Kīlauea Volcano’s summit in 25 years began in March 2008 with the opening of a 35-m-wide vent in Halema‘uma‘u crater. The new activity has produced prominent very-long-period (VLP) signals corresponding with two new behaviors: episodic tremor bursts and small explosive events, both of which represent degassing events from the top of the lava column. Previous work has shown that VLP seismicity has long been present at Kīlauea’s summit, and is sourced approximately 1 km below Halema‘uma‘u. By integrating video observations, infrasound and seismic data, we show that the onset of the large VLP signals occurs within several seconds of the onset of the degassing events. This timing indicates that the VLP is caused by forces—sourced at or very near the lava free surface due to degassing—transmitted down the magma column and coupling to the surrounding rock at 1 km depth.

  12. Proposed Risk-Informed Seismic Hazard Periodic Reevaluation Methodology for Complying with DOE Order 420.1C

    Energy Technology Data Exchange (ETDEWEB)

    Kammerer, Annie [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-03-01

    methodology, there is potential for general applicability to other facilities across the DOE complex. As such, both a general methodology and a specific approach intended for INL are described in this document. The general methodology proposed in this white paper is referred to as the “seismic hazard periodic review methodology,” or SHPRM. It presents a graded approach for SDC-3, SDC-4 and SDC-5 facilities that can be applied in any risk-informed regulatory environment once risk-objectives appropriate for the framework are developed. While the methodology was developed for seismic hazard considerations, it can also be directly applied to other types of natural hazards.

  13. Proposed Risk-Informed Seismic Hazard Periodic Reevaluation Methodology for Complying with DOE Order 420.1C

    Energy Technology Data Exchange (ETDEWEB)

    Kammerer, Annie [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-10-01

    methodology, there is potential for general applicability to other facilities across the DOE complex. As such, both a general methodology and a specific approach intended for INL are described in this document. The general methodology proposed in this white paper is referred to as the “seismic hazard periodic review methodology,” or SHPRM. It presents a graded approach for SDC-3, SDC-4 and SDC-5 facilities that can be applied in any risk-informed regulatory environment by once risk-objectives appropriate for the framework are developed. While the methodology was developed for seismic hazard considerations, it can also be directly applied to other types of natural hazards.

  14. Complexity analyses show two distinct types of nonlinear dynamics in short heart period variability recordings

    Science.gov (United States)

    Porta, Alberto; Bari, Vlasta; Marchi, Andrea; De Maria, Beatrice; Cysarz, Dirk; Van Leeuwen, Peter; Takahashi, Anielle C. M.; Catai, Aparecida M.; Gnecchi-Ruscone, Tomaso

    2015-01-01

    Two diverse complexity metrics quantifying time irreversibility and local prediction, in connection with a surrogate data approach, were utilized to detect nonlinear dynamics in short heart period (HP) variability series recorded in fetuses, as a function of the gestational period, and in healthy humans, as a function of the magnitude of the orthostatic challenge. The metrics indicated the presence of two distinct types of nonlinear HP dynamics characterized by diverse ranges of time scales. These findings stress the need to render more specific the analysis of nonlinear components of HP dynamics by accounting for different temporal scales. PMID:25806002

  15. Design of a short-period superconducting undulator at KEK-PF

    Energy Technology Data Exchange (ETDEWEB)

    Ohmi, K.; Ikeda, N.; Ishii, S.

    1998-06-01

    A short-period undulator using a superconducting magnet is proposed. This undulator has been designed to install in the KEK-Photon Factory 2.5-GeV or 6.5-GeV storage ring. The idea of a staggered wiggler, developed in Stanford university, is used in this undulator. The target of the period and K value of the undulator are set to be 1 cm and 1, respectively. We can obtain monochromatic photons with an energy of {approx} 5keV or {approx} 40 keV by using the undulator. (author)

  16. A superconducting short period undulator for a harmonic generation FEL experiment

    International Nuclear Information System (INIS)

    Ingold, G.; Solomon, L.; Ben-Zvi, I.; Krinsky, S.; Li, D.; Lynch, D.; Sheehan, J.; Woodle, M.; Qiu, X.Z.; Yu, L.H.

    1993-01-01

    A three stage superconducting (SC) undulator for a high gain harmonic generation (HGE) FEL experiment in the infrared is under construction at the NSLS in collaboration with Grumman Corporation. A novel undulator technology suitable for short period (6-40mm) undulators will be employed for all three stages, the modulator, the dispersive section and the radiator. The undulator triples the frequency of a 10.4μm CO 2 seed laser. So far a 27 period (one third of the final radiator) prototype radiator has been designed, built and tested

  17. Short-rotation woody-crops program. Quarterly progress report for period ending May 31, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Cushman, J.H.; Ranney, J.W.

    1982-04-01

    Progress of twenty projects in the Short Rotation Woody Crops Program is summarized for the period March 1 through May 31, 1981. Individual quarterly reports included from each of the projects discuss accomplishments within specific project objectives and identify recent papers and publications resulting from the research. The major project activities are species screening and genetic selection, stand establishment and cultural treatment, and harvest, collection, transportation, and storage.

  18. Short-rotation woody-crops program. Quarterly progress report for period ending August 31, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Cushman, J.H.; Ranney, J.W.

    1982-04-01

    Progress of twenty-one projects in the Short Rotation Woody Crops Program is summarized for the period June 1 through August 31, 1981. Individual quarterly reports included from each of the projects discuss accomplishments within specific project objectives and identify recent papers and publications resulting from the research. The major program activities are species screening and genetic selection, stand establishment and cultural treatment, and harvest, collection, transportation, and storage.

  19. Magnetoresistance calculations for a two-dimensional electron gas with unilateral short-period strong modulation

    Czech Academy of Sciences Publication Activity Database

    Výborný, Karel; Smrčka, Ludvík

    2002-01-01

    Roč. 66, č. 20 (2002), s. 205318-1 - 205318-8 ISSN 0163-1829 R&D Projects: GA ČR GA202/01/0754 Institutional research plan: CEZ:AV0Z1010914 Keywords : magnetoresistance * short-period superlattices * two-dimensional electron gas Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.327, year: 2002

  20. Hydrostatic pressure and strain effects in short period InN/GaN superlattices

    DEFF Research Database (Denmark)

    Gorczyca, I.; Suski, T.; Christensen, Niels Egede

    2012-01-01

    The electronic structures of short-period pseudomorphically grown superlattices (SLs) of the form mInN/nGaN are calculated and the band gap variation with the well and the barrier thicknesses is discussed including hydrostatic pressure effects. The calculated band gap shows a strong dependence...... strongly on the strain conditions and SL geometry, but weakly on the applied external hydrostatic pressure....

  1. Short-period strain (0.1-105 s): Near-source strain field for an earthquake (M L 3.2) near San Juan Bautista, California

    Science.gov (United States)

    Johnston, M. J. S.; Borcherdt, R. D.; Linde, A. T.

    1986-10-01

    Measurements of dilational earth strain in the frequency band 25-10-5 Hz have been made on a deep borehole strainmeter installed near the San Andreas fault. These data are used to determine seismic radiation fields during nuclear explosions, teleseisms, local earthquakes, and ground noise during seismically quiet times. Strains of less than 10-10 on these instruments can be clearly resolved at short periods (< 10 s) and are recorded with wide dynamic range digital recorders. This permits measurement of the static and dynamic strain variations in the near field of local earthquakes. Noise spectra for earth strain referenced to 1 (strain)2/Hz show that strain resolution decreases at about 10 dB per decade of frequency from -150 dB at 10-4 Hz to -223 dB at 10 Hz. Exact expressions are derived to relate the volumetric strain and displacement field for a homogeneous P wave in a general viscoelastic solid as observed on colocated dilatometers and seismometers. A rare near-field recording of strain and seismic velocity was obtained on May 26, 1984, from an earthquake (ML 3.2) at a hypocentral distance of 3.2 km near the San Andreas fault at San Juan Bautista, California. While the data indicate no precursory strain release at the 5 × 10-11 strain level, a coseismic strain release of 1.86 nanostrain was observed. This change in strain is consistent with that calculated from a simple dislocation model of the event. Ground displacement spectra, determined from the downhole strain data and instrument-corrected surface seismic data, suggest that source parameters estimated from surface recordings may be contaminated by amplification effects in near-surface low-velocity materials.

  2. Observation of short period fluctuation of CygX-1 with balloon

    International Nuclear Information System (INIS)

    Nakagawa, Michio; Sakurai, Takahisa; Uchida, Masayoshi

    1977-01-01

    CygX-1 presents very complex short period fluctuation of X-ray, therefore the hard X-ray was especially observed in 1972 and 1973 with large balloons, and the data were analyzed. This short period fluctuation and energy spectra of CygX-1 in the normal and flare time bands were compared. The observing apparatuses consisted of the 3 in diameter NaI detector and a high pressure proportional counter. The observing method is to turn the gondora alternately to the directions of source (ON) and background (OFF). As for the data analysis, the events at ON and OFF in the observation data in 1972 and 1973 were plotted for time interval. The background component is in agreement with Poisson's distribution, but source component is not. This difference for Poisson's distribution means the behavior of CygX-1. The power spectrum was analyzed, and the strong power density was observed at 5.4 x 10 -2 Hz in ON, but such power density was not observed in OFF. Accordingly this is presumed to be caused by CygX-1. The events for time interval in flare time are shown. The rise of about 2.9 σ exists at 80 msec. The count rates were compared for photon energy in the normal and flare times. The short period fluctuation of hard X-ray from CygX-1 deviates from Poisson's distribution and is different in the normal and flare times. (Nakai, Y.)

  3. Importance of historical seismicity in the evaluation of large return period hazards

    International Nuclear Information System (INIS)

    Oliveira, C.S.

    1983-01-01

    This paper reports the results from an historical investigation on earthquake activity in Portugal based on data collected from original sources. A detailed revision of earthquake catalogues in what concerns date of occurrence, isosseismal maps, epicentral location, magnitude and duration of vibration was made for most of the 260 events identified in the period 1000 to 1900. Introducing this new piece of information which exhibits a much higher degree of quality into standard hazard models, uncertainties on final estimates for the zones of large return periods, RP, (RP > 200 years) are greatly reduced

  4. Anomalous short period geomagnetic variations at two stations in Sri Lanka

    International Nuclear Information System (INIS)

    Kunaratnam, K.

    1986-08-01

    An analysis of the rates of change in the geomagnetic field components in the period range 20-600 sec recorded at Kondavil and Hikkaduwa, two stations in the equatorial electrojet belt near the northern and south western coasts respectively of Sri Lanka, shows anomalous variations. The results confirm induced current concentration in the Palk Strait and deflection of induced currents around the southerncoast of Sri Lanka postulated by earlier workers from observations of SSC and Bay events at Indian stations and from analogue and numerical model studies. At Kondavil, which is situated close to the geomagnetic equator, no appreciable difference in the night-time and day-time values of ΔZ/ΔH and ΔD/ΔH ratios was noticed while at Hikkaduwa, a station situated under the edge of the equatorial electrojet belt, a day-time enhancement of ΔZ/ΔH ratios was found at all periods in the observed range. An enhancement of the H component at Colombo over that at Hikkaduwa was also found at short periods, the enhancement being greater at day-time. The day-time enhancement in the ΔZ/ΔH ratios at Hikkaduwa and in the ratio of the H components at Colombo and Hikkaduwa could be due to the effect of the equatorial electrojet on the short period variations. (author)

  5. Survival of a planet in short-period Neptunian desert under effect of photoevaporation

    Science.gov (United States)

    Ionov, Dmitry E.; Pavlyuchenkov, Yaroslav N.; Shematovich, Valery I.

    2018-06-01

    Despite the identification of a great number of Jupiter-like and Earth-like planets at close-in orbits, the number of `hot Neptunes' - the planets with 0.6-18 times of Neptune mass and orbital periods less than 3 d - turned out to be very small. The corresponding region in the mass-period distribution was assigned as the `short-period Neptunian desert'. The common explanation of this fact is that the gaseous planet with few Neptune masses would not survive in the vicinity of host star due to intensive atmosphere outflow induced by heating from stellar radiation. To check this hypothesis, we performed numerical simulations of atmosphere dynamics for a hot Neptune. We adopt the previously developed self-consistent 1D model of hydrogen-helium atmosphere with suprathermal electrons accounted. The mass-loss rates as a function of orbital distances and stellar ages are presented. We conclude that the desert of short-period Neptunes could not be entirely explained by evaporation of planet atmosphere caused by the radiation from a host star. For the less massive Neptune-like planet, the estimated upper limits of the mass-loss may be consistent with the photoevaporation scenario, while the heavier Neptune-like planets could not lose the significant mass through this mechanism. We also found the significant differences between our numerical results and widely used approximate estimates of the mass-loss.

  6. Multi-band photometric study of the short-period eclipsing binary GR Boo

    Science.gov (United States)

    Wang, Daimei; Zhang, Liyun; Han, Xianming L.; Lu, Hongpeng

    2017-05-01

    We present BVRI light curves with complete phase coverage for the short-period (p = 0.377day) eclipsing binary star GR Boo. We carried out the observations using the SARA 90 cm telescope located at Kitt Peak National Observatory. We obtained six new light curve minimum times. By fitting all of the available O-C minimum times, we obtained an updated ephemeris that shows the orbital period of GR Boo is decreasing at a rate of P˙ = - 2.36 ×10-7 days/year. This decrease in its period can be explained by either mass transfer from the more massive component to the less massive one, or angular momentum exchange due to magnetic activities. We also obtained a set of revised orbital parameters using the Wilson & Devinney program. And finally, we concluded that GR Boo is a contact binary with a dark spot.

  7. Short-period oscillations in photoemission from thin films of Cr(100)

    Science.gov (United States)

    Vyalikh, Denis V.; Zahn, Peter; Richter, Manuel; Dedkov, Yu. S.; Molodtsov, S. L.

    2005-07-01

    Angle-resolved photoemission (PE) study of thin films of Cr grown on Fe(100) reveals thickness-dependent short-period oscillations of the PE intensity close to the Fermi energy at k‖˜0 . The oscillations are assigned to quantum-well states (QWS) caused by the nesting between the Fermi-surface sheets around the Γ and the X points in the Brillouin zone of antiferromagnetic Cr. The experimental data are confirmed by density-functional calculations applying a screened Korringa-Kohn-Rostoker Green’s function method. The period of the experimentally observed QWS oscillations amounts to about 2.6 monolayers and is larger than the fundamental 2-monolayer period of antiferromagnetic coupling in Cr.

  8. THE SHORT ROTATION PERIOD OF HI’IAKA, HAUMEA’S LARGEST SATELLITE

    Energy Technology Data Exchange (ETDEWEB)

    Hastings, Danielle M.; Margot, Jean-Luc [University of California, Los Angeles, Department of Earth, Planetary, and Space Sciences, 595 Charles Young Drive East, Los Angeles, CA 90095 (United States); Ragozzine, Darin [Florida Institute of Technology, Department of Physics and Space Sciences, 150 West University Boulevard, Melbourne, FL 32901 (United States); Fabrycky, Daniel C. [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Burkhart, Luke D.; Holman, Matthew [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Fuentes, Cesar [Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Santiago (Chile); Brown, Michael E., E-mail: dhastings@g.ucla.edu [California Institute of Technology, Division of Geological and Planetary Sciences, MC 150-21, Pasadena, CA 91125 (United States)

    2016-12-01

    Hi’iaka is the larger outer satellite of the dwarf planet Haumea. Using relative photometry from the Hubble Space Telescope and Magellan and a phase dispersion minimization analysis, we have identified the rotation period of Hi’iaka to be ∼9.8 hr (double peaked). This is ∼120 times faster than its orbital period, creating new questions about the formation of this system and possible tidal evolution. The rapid rotation suggests that Hi’iaka could have a significant obliquity and spin precession that could be visible in light curves within a few years. We then turn to an investigation of what we learn about the (currently unclear) formation of the Haumea system and family based on this unexpectedly rapid rotation rate. We explore the importance of the initial semimajor axis and rotation period in tidal evolution theory and find that they strongly influence the time required to despin to synchronous rotation, relevant to understanding a wide variety of satellite and binary systems. We find that despinning tides do not necessarily lead to synchronous spin periods for Hi’iaka, even if it formed near the Roche limit. Therefore, the short rotation period of Hi’iaka does not rule out significant tidal evolution. Hi’iaka’s spin period is also consistent with formation near its current location and spin-up due to Haumea-centric impactors.

  9. QUASI-PERIODIC OSCILLATIONS AND BROADBAND VARIABILITY IN SHORT MAGNETAR BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Huppenkothen, Daniela; Watts, Anna L.; Uttley, Phil; Van der Horst, Alexander J.; Van der Klis, Michiel [Astronomical Institute ' ' Anton Pannekoek' ' , University of Amsterdam, Postbus 94249, 1090-GE Amsterdam (Netherlands); Kouveliotou, Chryssa [Office of Science and Technology, ZP12, NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States); Goegues, Ersin [Sabanc Latin-Small-Letter-Dotless-I University, Orhanl Latin-Small-Letter-Dotless-I -Tuzla, Istanbul 34956 (Turkey); Granot, Jonathan [The Open University of Israel, 1 University Road, P.O. Box 808, Ra' anana 43537 (Israel); Vaughan, Simon [X-Ray and Observational Astronomy Group, University of Leicester, Leicester LE1 7RH (United Kingdom); Finger, Mark H., E-mail: D.Huppenkothen@uva.nl [Universities Space Research Association, Huntsville, AL 35805 (United States)

    2013-05-01

    The discovery of quasi-periodic oscillations (QPOs) in magnetar giant flares has opened up prospects for neutron star asteroseismology. However, with only three giant flares ever recorded, and only two with data of sufficient quality to search for QPOs, such analysis is seriously data limited. We set out a procedure for doing QPO searches in the far more numerous, short, less energetic magnetar bursts. The short, transient nature of these bursts requires the implementation of sophisticated statistical techniques to make reliable inferences. Using Bayesian statistics, we model the periodogram as a combination of red noise at low frequencies and white noise at high frequencies, which we show is a conservative approach to the problem. We use empirical models to make inferences about the potential signature of periodic and QPOs at these frequencies. We compare our method with previously used techniques and find that although it is on the whole more conservative, it is also more reliable in ruling out false positives. We illustrate our Bayesian method by applying it to a sample of 27 bursts from the magnetar SGR J0501+4516 observed by the Fermi Gamma-ray Burst Monitor, and we find no evidence for the presence of QPOs in any of the bursts in the unbinned spectra, but do find a candidate detection in the binned spectra of one burst. However, whether this signal is due to a genuine quasi-periodic process, or can be attributed to unmodeled effects in the noise is at this point a matter of interpretation.

  10. Absence of a Metallicity Effect for Ultra-short-period Planets

    International Nuclear Information System (INIS)

    Winn, Joshua N.; Sanchis-Ojeda, Roberto; Isaacson, Howard; Marcy, Geoffrey W.; Rogers, Leslie; Petigura, Erik A.; Howard, Andrew W.; Schlaufman, Kevin C.; Cargile, Phillip; Hebb, Leslie

    2017-01-01

    Ultra-short-period (USP) planets are a newly recognized class of planets with periods shorter than one day and radii smaller than about 2  R ⊕ . It has been proposed that USP planets are the solid cores of hot Jupiters that have lost their gaseous envelopes due to photo-evaporation or Roche lobe overflow. We test this hypothesis by asking whether USP planets are associated with metal-rich stars, as has long been observed for hot Jupiters. We find the metallicity distributions of USP-planet and hot-Jupiter hosts to be significantly different ( p = 3 × 10 −4 ) based on Keck spectroscopy of Kepler stars. Evidently, the sample of USP planets is not dominated by the evaporated cores of hot Jupiters. The metallicity distribution of stars with USP planets is indistinguishable from that of stars with short-period planets with sizes between 2 and 4  R ⊕ . Thus, it remains possible that the USP planets are the solid cores of formerly gaseous planets that are smaller than Neptune.

  11. Absence of a Metallicity Effect for Ultra-short-period Planets

    Energy Technology Data Exchange (ETDEWEB)

    Winn, Joshua N. [Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08540 (United States); Sanchis-Ojeda, Roberto; Isaacson, Howard; Marcy, Geoffrey W. [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Rogers, Leslie [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Petigura, Erik A.; Howard, Andrew W. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Schlaufman, Kevin C. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Cargile, Phillip [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Hebb, Leslie [Hobart and William Smith Colleges, Geneva, NY 14456 (United States)

    2017-08-01

    Ultra-short-period (USP) planets are a newly recognized class of planets with periods shorter than one day and radii smaller than about 2  R {sub ⊕}. It has been proposed that USP planets are the solid cores of hot Jupiters that have lost their gaseous envelopes due to photo-evaporation or Roche lobe overflow. We test this hypothesis by asking whether USP planets are associated with metal-rich stars, as has long been observed for hot Jupiters. We find the metallicity distributions of USP-planet and hot-Jupiter hosts to be significantly different ( p = 3 × 10{sup −4}) based on Keck spectroscopy of Kepler stars. Evidently, the sample of USP planets is not dominated by the evaporated cores of hot Jupiters. The metallicity distribution of stars with USP planets is indistinguishable from that of stars with short-period planets with sizes between 2 and 4  R {sub ⊕}. Thus, it remains possible that the USP planets are the solid cores of formerly gaseous planets that are smaller than Neptune.

  12. Time lag between deformation and seismicity along monogenetic volcanic unrest periods: The case of El Hierro Island (Canary Islands)

    Science.gov (United States)

    Lamolda, Héctor; Felpeto, Alicia; Bethencourt, Abelardo

    2017-07-01

    Between 2011 and 2014 there were at least seven episodes of magmatic intrusion in El Hierro Island, but only the first one led to a submarine eruption in 2011-2012. In order to study the relationship between GPS deformation and seismicity during these episodes, we compare the temporal evolution of the deformation with the cumulative seismic energy released. In some of the episodes both deformation and seismicity evolve in a very similar way, but in others a time lag appears between them, in which the deformation precedes the seismicity. Furthermore, a linear correlation between decimal logarithm of intruded magma volume and decimal logarithm of total seismic energy released along the different episodes has been observed. Therefore, if a future magmatic intrusion in El Hierro Island follows this behavior with a proper time lag, we could have an a priori estimate on the order of magnitude the seismic energy released would reach.

  13. Epitaxial nanowire formation in metamorphic GaAs/GaPAs short-period superlattices

    Science.gov (United States)

    Zheng, Nan; Ahrenkiel, S. Phillip

    2017-07-01

    Metamorphic growth presents routes to novel nanomaterials with unique properties that may be suitable for a range of applications. We discuss self-assembled, epitaxial nanowires formed during metalorganic chemical vapor deposition of metamorphic GaAs/GaPAs short-period superlattices. The heterostructures incorporate strain-engineered GaPAs compositional grades on 6°-B miscut GaAs substrates. Lateral diffusion within the SPS into vertically aligned, three-dimensional columns results in nanowires extending along A directions with a lateral period of 70-90 nm. The microstructure is probed by transmission electron microscopy to confirm the presence of coherent GaAs nanowires within GaPAs barriers. The compositional profile is inferred from analysis of {200} dark-field image contrast and lattice images.

  14. Role of short periodic orbits in quantum maps with continuous openings

    Science.gov (United States)

    Prado, Carlos A.; Carlo, Gabriel G.; Benito, R. M.; Borondo, F.

    2018-04-01

    We apply a recently developed semiclassical theory of short periodic orbits to the continuously open quantum tribaker map. In this paradigmatic system the trajectories are partially bounced back according to continuous reflectivity functions. This is relevant in many situations that include optical microresonators and more complicated boundary conditions. In a perturbative regime, the shortest periodic orbits belonging to the classical repeller of the open map—a cantor set given by a region of exactly zero reflectivity—prove to be extremely robust in supporting a set of long-lived resonances of the continuously open quantum maps. Moreover, for steplike functions a significant reduction in the number needed is obtained, similarly to the completely open situation. This happens despite a strong change in the spectral properties when compared to the discontinuous reflectivity case. In order to give a more realistic interpretation of these results we compare with a Fresnel-type reflectivity function.

  15. Cooperative learning combined with short periods of lecturing: A good alternative in teaching biochemistry.

    Science.gov (United States)

    Fernández-Santander, Ana

    2008-01-01

    The informal activities of cooperative learning and short periods of lecturing has been combined and used in the university teaching of biochemistry as part of the first year course of Optics and Optometry in the academic years 2004-2005 and 2005-2006. The lessons were previously elaborated by the teacher and included all that is necessary to understand the topic (text, figures, graphics, diagrams, pictures, etc.). Additionally, a questionnaire was prepared for every chapter. All lessons contained three parts: objectives, approach and development, and the assessment of the topic. Team work, responsibility, and communication skills were some of the abilities developed with this new methodology. Students worked collaboratively in small groups of two or three following the teacher's instructions with short periods of lecturing that clarified misunderstood concepts. Homework was minimized. On comparing this combined methodology with the traditional one (only lecture), students were found to exhibit a higher satisfaction with the new method. They were more involved in the learning process and had a better attitude toward the subject. The use of this new methodology showed a significant increase in the mean score of the students' academic results. The rate of students who failed the subject was significantly inferior in comparison with those who failed in the previous years when only lecturing was applied. This combined methodology helped the teacher to observe the apprenticeship process of students better and to act as a facilitator in the process of building students' knowledge. Copyright © 2008 International Union of Biochemistry and Molecular Biology, Inc.

  16. Determination of circulation and short period fluctuation in Ilha Grande Bay (RJ, Brazil

    Directory of Open Access Journals (Sweden)

    Yoshimine Ikeda

    1980-06-01

    Full Text Available A mesosoale study was made of the Ilha Grande area. The local circulation described through -progressive vector diagrams showed a clochwise bottom circulation determined in June 1976, while in the upper 10 m the direction of the flow entering the Ilha Grande Bay was towards the center in the west and towards the Marambaia sandbank in the east side of the Bay. Short periods and amplitude fluctuations were evaluted using power spectral analysis, Fourier and Maximum Entropy Method, which showed that in the upper 10 m predominant periods decrease from 1.1h (A = 6.3cm sec-1 (position = 3C to 1.0h (A = 7.4 cm sec-1 (position = 2D and increase to 5.8h (A = 6.8 cm., sec-1 (position = ID, while at the bottom layer the predominant period increases from 0.4 h (A = 5.0 cm sec-1 (position = 3G to 6.4h (A = 7.0 cm sec-1 (position = 2G and to 4.4h (A = 7.9 cm sec-1 (position = 1G . From the original data it has been possible to determine an "intense pulsation" between 30-70 cm sec-1 in the upper 10 m with about 1.0h period and 10-20 min duration in all the stations.

  17. THE FREQUENCY OF LOW-MASS EXOPLANETS. III. TOWARD η+ AT SHORT PERIODS

    International Nuclear Information System (INIS)

    Wittenmyer, Robert A.; Tinney, C. G.; Bailey, J.; Horner, J.; Butler, R. P.; O'Toole, Simon J.; Jones, H. R. A.; Carter, B. D.

    2011-01-01

    Determining the occurrence rate of 'super-Earth' planets (m sin i + ) is a critically important step on the path toward determining the frequency of Earth-like planets (η + ), and hence the uniqueness of our solar system. Current radial-velocity surveys, achieving precisions of 1 m s -1 , are now able to detect super-Earths and provide meaningful estimates of their occurrence rate. We present an analysis of 67 solar-type stars from the Anglo-Australian Planet Search specifically targeted for very high precision observations. When corrected for incompleteness, we find that the planet occurrence rate increases sharply with decreasing planetary mass. Our results are consistent with those from other surveys: in periods shorter than 50 days, we find that 3.0% of stars host a giant (msin i > 100 M + ) planet, and that 17.4% of stars host a planet with msin i + . The preponderance of low-mass planets in short-period orbits is in conflict with formation simulations in which the majority of super-Earths reside at larger orbital distances. This work gives a hint as to the size of η + , but to make meaningful predictions on the frequency of terrestrial planets in longer, potentially habitable orbits, low-mass terrestrial planet searches at periods of 100-200 days must be made an urgent priority for ground-based Doppler planet searches in the years ahead.

  18. SOHO/SWAN OBSERVATIONS OF SHORT-PERIOD SPACECRAFT TARGET COMETS

    International Nuclear Information System (INIS)

    Combi, M. R.; Lee, Y.; Patel, T. S.; Maekinen, J. T. T.; Bertaux, J.-L.; Quemerais, E.

    2011-01-01

    SWAN, the Solar Wind ANisotropies all-sky hydrogen Lyα camera on the Solar and Heliospheric Observatory spacecraft that makes all-sky images of interplanetary neutral hydrogen, has an ongoing campaign to make special observations of comets, both short- and long-period ones, in addition to the serendipitous observations of comets as part of the all-sky monitoring program. We report here on a study of several short-period comets that were detected by SWAN: 21P/Giacobini-Zinner (1998 and 2005 apparitions), 19P/Borrelly (2001 apparition), 81P/Wild 2 (1997 apparition), and 103P/Hartley 2 (1997 apparition). SWAN observes comets over long continuous stretches of their visible apparitions and therefore provides excellent temporal coverage of the water production. For some of the observations we are also able to analyze an entire sequence of images over many days to several weeks/months using our time-resolved model and extract daily average water production rates over continuous periods of several days to months. The short-term (outburst) and long-term behavior can be correlated with other observations. The overall long-term variation is examined in light of seasonal effects seen in the pre- to post-perihelion differences. For 21P/Giacobini-Zinner and 81P/Wild 2 the activity variations over each apparition were more continuously monitored but nonetheless consistent with previous observations. For 19P/Borrelly we found a very steep variation of water production rates, again consistent with some previous observations, and a variation over six months around perihelion that was reasonably consistent with the spin-axis model of Schleicher et al. and the illumination of the main active areas. During the 1997-1998 apparition of 103P/Hartley 2, the target comet of the EPOXI mission (the Deep Impact extended mission), we found a variation with heliocentric distance (∼r -3.6 ) that was almost as steep as 19P/Borrelly and, given the small measured radius near aphelion, this places

  19. How long-term dynamics of sediment subduction controls short-term dynamics of seismicity

    Science.gov (United States)

    Brizzi, S.; van Zelst, I.; van Dinther, Y.; Funiciello, F.; Corbi, F.

    2017-12-01

    Most of the world's greatest earthquakes occur along the subduction megathrust. Weak and porous sediments have been suggested to homogenize the plate interface and thereby promote lateral rupture propagation and great earthquakes. However, the importance of sediment thickness, let alone their physical role, is not yet unequivocally established. Based on a multivariate statistical analysis of a global database of 62 subduction segments, we confirm that sediment thickness is one of the key parameters controlling the maximum magnitude a megathrust can generate. Moreover, Monte Carlo simulations highlighted that the occurrence of great earthquakes on sediment-rich subduction segments is very unlikely (p-value≪0.05) related to pure chance. To understand how sediments in the subduction channel regulate earthquake size, this study extends and demystifies multivariate, spatiotemporally limited data through numerical modeling. We use the 2D Seismo-Thermo-Mechanical modeling approach to simulate both the long- and short-term dynamics of subduction and related seismogenesis (van Dinther et al., JGR, 2013). These models solve for the conservation of mass, momentum and energy using a visco-elasto-plastic rheology with rate-dependent friction. Results show that subducted sediments have a strong influence on the long-term evolution of the convergent margin. Increasing the sediment thickness on the incoming plate from 0 to 6 km causes a decrease of slab dip from 23° to 10°. This, in addition to increased radiogenic heating, extends isotherms, thereby widening the seismogenic portion of the megathrust from 80 to 150 km. Consequently, over tens of thousands of years, we observe that the maximum moment magnitude of megathrust earthquakes increases from 8.2 to 9.2 for these shallower and warmer interfaces. In addition, we observe more and larger splay faults, which could enhance vertical seafloor displacements. These results highlight the primary role of subducted sediments in

  20. Burar seismic station: evaluation of seismic performance

    International Nuclear Information System (INIS)

    Ghica, Daniela; Popa, Mihaela

    2005-01-01

    A new seismic monitoring system, the Bucovina Seismic Array (BURAR), has been established since July 2002, in the Northern part of Romania, in a joint effort of the Air Force Technical Applications Center, USA, and the National Institute for Earth Physics (NIEP), Romania. The small-aperture array consists of 10 seismic sensors (9 vertical short-period and one three-component broad band) located in boreholes and distributed in a 5 x 5 km 2 area. At present, the seismic data are continuously recorded by the BURAR and transmitted in real-time to the Romanian National Data Center in Bucharest and National Data Center of the USA, in Florida. Based on the BURAR seismic information gathered at the National Data Center, NIEP (ROM N DC), in the August 2002 - December 2004 time interval, analysis and statistical assessments were performed. Following the preliminary processing of the data, several observations on the global performance of the BURAR system were emphasized. Data investigation showed an excellent efficiency of the BURAR system particularly in detecting teleseismic and regional events. Also, a statistical analysis for the BURAR detection capability of the local Vrancea events was performed in terms of depth and magnitude for the year 2004. The high signal detection capability of the BURAR resulted, generally, in improving the location solutions for the Vrancea seismic events. The location solution accuracy is enhanced when adding BURAR recordings, especially in the case of low magnitude events (recorded by few stations). The location accuracy is increased, both in terms of constraining hypocenter depth and epicentral coordinates. Our analysis certifies the importance of the BURAR system in NIEP efforts to elaborate seismic bulletins. Furthermore, the specific procedures for array data processing (beam forming, f-k analysis) increase significantly the signal-to-noise ratio by summing up the coherent signals from the array components, and ensure a better accuracy

  1. Ultra-short-period WC/SiC multilayer coatings for x-ray applications

    International Nuclear Information System (INIS)

    Fernández-Perea, Mónica; Pivovaroff, Mike J.; Soufli, Regina; Alameda, Jennifer; Mirkarimi, Paul; Descalle, Marie-Anne; Baker, Sherry L.; McCarville, Tom; Ziock, Klaus; Hornback, Donald; Romaine, Suzanne; Bruni, Ric; Zhong, Zhong; Honkimäki, Veijo; Ziegler, Eric; Christensen, Finn E.; Jakobsen, Anders C.

    2013-01-01

    Multilayer coatings enhance x-ray mirror performance at incidence angles steeper than the critical angle, allowing for improved flux, design flexibility and facilitating alignment. In an attempt to extend the use of multilayer coatings to photon energies higher than previously achieved, we have developed multilayers with ultra-short periods between 1 and 2 nm based on the material system WC/SiC. This material system was selected because it possesses very sharp and stable interfaces. In this article, we show highlights from a series of experiments performed in order to characterize the stress, microstructure and morphology of the multilayer films, as well as their reflective performance at photon energies from 8 to 384 keV

  2. The Colorado Ultraviolet Transit Experiment (CUTE): Observing Mass Loss on Short-Period Exoplanets

    Science.gov (United States)

    Egan, Arika; Fleming, Brian; France, Kevin

    2018-06-01

    The Colorado Ultraviolet Transit Experiment (CUTE) is an NUV spectrograph packaged into a 6U CubeSat, designed to characterize the interaction between exoplanetary atmospheres and their host stars. CUTE will conduct a transit spectroscopy survey, gathering data over multiple transits on more than 12 short-period exoplanets with a range of masses and radii. The instrument will characterize the spectral properties of the transit light curves to atomic and molecular absorption features predicted to exist in the upper atmospheres of these planets, including Mg I, Mg II, Fe II, and OH. The shape and evolution of these spectral light curves will be used to quantify mass loss rates, the stellar drives of that mass loss, and the possible existence of exoplanetary magnetic fiends. This poster presents the science motivation for CUTE, planned observation and data analysis methods, and expected results.

  3. THE VERY SHORT PERIOD M DWARF BINARY SDSS J001641-000925

    Energy Technology Data Exchange (ETDEWEB)

    Davenport, James R. A.; Becker, Andrew C.; Hawley, Suzanne L.; Gunning, Heather C.; Munshi, Ferah A.; Albright, Meagan [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); West, Andrew A. [Astronomy Department, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States); Bochanski, John J. [Astronomy and Astrophysics Department, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Holtzman, Jon [Department of Astronomy, New Mexico State University, Box 30001, Las Cruces, NM 88003 (United States); Hilton, Eric J., E-mail: jrad@astro.washington.edu [Department of Geology and Geophysics and Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)

    2013-02-10

    We present follow-up observations and analysis of the recently discovered short period low-mass eclipsing binary, SDSS J001641-000925. With an orbital period of 0.19856 days, this system has one of the shortest known periods for an M dwarf binary system. Medium-resolution spectroscopy and multi-band photometry for the system are presented. Markov Chain Monte Carlo modeling of the light curves and radial velocities yields estimated masses for the stars of M {sub 1} = 0.54 {+-} 0.07 M {sub Sun} and M {sub 2} = 0.34 {+-} 0.04 M {sub Sun }, and radii of R {sub 1} = 0.68 {+-} 0.03 R {sub Sun} and R {sub 2} = 0.58 {+-} 0.03 R {sub Sun }, respectively. This solution places both components above the critical Roche overfill limit, providing strong evidence that SDSS J001641-000925 is the first verified M-dwarf contact binary system. Within the follow-up spectroscopy we find signatures of non-solid body rotation velocities, which we interpret as evidence for mass transfer or loss within the system. In addition, our photometry samples the system over nine years, and we find strong evidence for period decay at the rate of P-dot {approx} 8 s yr{sup -1}. Both of these signatures raise the intriguing possibility that the system is in over-contact, and actively losing angular momentum, likely through mass loss. This places SDSS J001641-000925 as not just the first M-dwarf over-contact binary, but one of the few systems of any spectral type known to be actively undergoing coalescence. Further study of SDSS J001641-000925 is ongoing to verify the nature of the system, which may prove to be a unique astrophysical laboratory.

  4. Short-term Periodization Models: Effects on Strength and Speed-strength Performance.

    Science.gov (United States)

    Hartmann, Hagen; Wirth, Klaus; Keiner, Michael; Mickel, Christoph; Sander, Andre; Szilvas, Elena

    2015-10-01

    Dividing training objectives into consecutive phases to gain morphological adaptations (hypertrophy phase) and neural adaptations (strength and power phases) is called strength-power periodization (SPP). These phases differ in program variables (volume, intensity, and exercise choice or type) and use stepwise intensity progression and concomitant decreasing volume, converging to peak intensity (peaking phase). Undulating periodization strategies rotate these program variables in a bi-weekly, weekly, or daily fashion. The following review addresses the effects of different short-term periodization models on strength and speed-strength both with subjects of different performance levels and with competitive athletes from different sports who use a particular periodization model during off-season, pre-season, and in-season conditioning. In most periodization studies, it is obvious that the strength endurance sessions are characterized by repetition zones (12-15 repetitions) that induce muscle hypertrophy in persons with a low performance level. Strictly speaking, when examining subjects with a low training level, many periodization studies include mainly hypertrophy sessions interspersed with heavy strength/power sessions. Studies have demonstrated equal or statistically significant higher gains in maximal strength for daily undulating periodization compared with SPP in subjects with a low to moderate performance level. The relatively short intervention period and the lack of concomitant sports conditioning call into question the practical value of these findings for competitive athletes. Possibly owing to differences in mesocycle length, conditioning programs, and program variables, competitive athletes either maintained or improved strength and/or speed-strength performance by integrating daily undulating periodization and SPP during off-season, pre-season and in-season conditioning. In high-performance sports, high-repetition strength training (>15) should be

  5. Seismic hazard map of the western hemisphere

    Science.gov (United States)

    Shedlock, K.M.; Tanner, J.G.

    1999-01-01

    Vulnerability to natural disasters increases with urbanization and development of associated support systems (reservoirs, power plants, etc.). Catastrophic earthquakes account for 60% of worldwide casualties associated with natural disasters. Economic damage from earthquakes is increasing, even in technologically advanced countries with some level of seismic zonation, as shown by the 1989 Loma Prieta, CA ($6 billion), 1994 Northridge, CA ($ 25 billion), and 1995 Kobe, Japan (> $ 100 billion) earthquakes. The growth of megacities in seismically active regions around the world often includes the construction of seismically unsafe buildings and infrastructures, due to an insufficient knowledge of existing seismic hazard. Minimization of the loss of life, property damage, and social and economic disruption due to earthquakes depends on reliable estimates of seismic hazard. National, state, and local governments, decision makers, engineers, planners, emergency response organizations, builders, universities, and the general public require seismic hazard estimates for land use planning, improved building design and construction (including adoption of building construction codes), emergency response preparedness plans, economic forecasts, housing and employment decisions, and many more types of risk mitigation. The seismic hazard map of the Americas is the concatenation of various national and regional maps, involving a suite of approaches. The combined maps and documentation provide a useful global seismic hazard framework and serve as a resource for any national or regional agency for further detailed studies applicable to their needs. This seismic hazard map depicts Peak Ground Acceleration (PGA) with a 10% chance of exceedance in 50 years for the western hemisphere. PGA, a short-period ground motion parameter that is proportional to force, is the most commonly mapped ground motion parameter because current building codes that include seismic provisions specify the

  6. Seismic hazard map of the western hemisphere

    Directory of Open Access Journals (Sweden)

    J. G. Tanner

    1999-06-01

    Full Text Available Vulnerability to natural disasters increases with urbanization and development of associated support systems (reservoirs, power plants, etc.. Catastrophic earthquakes account for 60% of worldwide casualties associated with natural disasters. Economic damage from earthquakes is increasing, even in technologically advanced countries with some level of seismic zonation, as shown by the 1989 Loma Prieta, CA ($ 6 billion, 1994 Northridge, CA ($ 25 billion, and 1995 Kobe, Japan (> $ 100 billion earthquakes. The growth of megacities in seismically active regions around the world often includes the construction of seismically unsafe buildings and infrastructures, due to an insufficient knowledge of existing seismic hazard. Minimization of the loss of life, property damage, and social and economic disruption due to earthquakes depends on reliable estimates of seismic hazard. National, state, and local governments, decision makers, engineers, planners, emergency response organizations, builders, universities, and the general public require seismic hazard estimates for land use planning, improved building design and construction (including adoption of building construction codes, emergency response preparedness plans, economic forecasts, housing and employment decisions, and many more types of risk mitigation. The seismic hazard map of the Americas is the concatenation of various national and regional maps, involving a suite of approaches. The combined maps and documentation provide a useful global seismic hazard framework and serve as a resource for any national or regional agency for further detailed studies applicable to their needs. This seismic hazard map depicts Peak Ground Acceleration (PGA with a 10% chance of exceedance in 50 years for the western hemisphere. PGA, a short-period ground motion parameter that is proportional to force, is the most commonly mapped ground motion parameter because current building codes that include seismic provisions

  7. Born dry in the photoevaporation desert: Kepler's ultra-short-period planets formed water-poor

    Science.gov (United States)

    Lopez, Eric D.

    2017-11-01

    Recent surveys have uncovered an exciting new population of ultra-short-period (USP) planets with orbital periods less than a day. These planets typically have radii ≲1.5 R⊕, indicating that they likely have rocky compositions. This stands in contrast to the overall distribution of planets out to ∼100 d, which is dominated by low-density sub-Neptunes above 2 R⊕, which must have gaseous envelopes to explain their size. However, on the USP orbits, planets are bombarded by intense levels of photoionizing radiation and consequently gaseous sub-Neptunes are extremely vulnerable to losing their envelopes to atmospheric photoevaporation. Using models of planet evolution, I show that the rocky USP planets can easily be produced as the evaporated remnants of sub-Neptunes with H/He envelopes and that we can therefore understand the observed dearth of USP sub-Neptunes as a natural consequence of photoevaporation. Critically however, planets on USP orbits could often retain their envelopes if they are formed with very high-metallicity water-dominated envelopes. Such water-rich planets would commonly be ≳2 R⊕ today, which is inconsistent with the observed evaporation desert, indicating that most USP planets likely formed from water-poor material within the snow-line. Finally, I examine the special case of 55 Cancri e and its possible composition in the light of recent observations, and discuss the prospects for further characterizing this population with future observations.

  8. Raman analysis of phonon modes in a short period AlN/GaN superlattice

    Science.gov (United States)

    Sarkar, Ketaki; Datta, Debopam; Gosztola, David J.; Shi, Fengyuan; Nicholls, Alan; Stroscio, Michael A.; Dutta, Mitra

    2018-03-01

    AlN/GaN-based optoelectronic devices have been the subject of intense research underlying the commercialization of efficient devices. Areas of considerable interest are the study of their lattice dynamics, phonon transport, and electron-phonon interactions specific to the interface of these heterostructures which results in additional optical phonon modes known as interface phonon modes. In this study, the framework of the dielectric continuum model (DCM) has been used to compare and analyze the optical phonon modes obtained from experimental Raman scattering measurements on AlN/GaN short-period superlattices. We have observed the localized E2(high), A1(LO) and the E1(TO) modes in superlattice measurements at frequencies shifted from their bulk values. To the best of our knowledge, the nanostructures used in these studies are among the smallest yielding useful Raman signatures for the interface modes. In addition, we have also identified an additional spread of interface phonon modes in the TO range resulting from the superlattice periodicity. The Raman signature contribution from the underlying AlxGa1-xN ternary has also been observed and analyzed. A temperature calibration was done based on Stokes/anti-Stokes ratio of A1(LO) using Raman spectroscopy in a broad operating temperature range. Good agreement between the experimental results and theoretically calculated calibration plot predicted using Bose-Einstein statistics was obtained.

  9. Use of 7Be to document soil erosion associated with a short period of extreme rainfall

    International Nuclear Information System (INIS)

    Sepulveda, A.; Schuller, P.; Walling, D.E.; Castillo, A.

    2008-01-01

    Intensification and expansion of agricultural production since the 1970s have increased soil erosion problems in south-central Chile. Quantitative information on soil loss is needed for erosion risk assessment and to establish the effectiveness of improved land management practices. Since information from traditional sources, such as erosion plots, is limited, attention has been directed to the use of environmental radionuclides for documenting erosion rates. Cs-137 has been successfully utilised for this purpose, but only provides information on medium-term erosion rates. There is also a need to document event-related soil erosion. This paper outlines the basis for using 7 Be measurements to document short-term erosion and reports its successful use for quantifying the erosion that occurred within an arable field, as a result of a period of heavy rainfall (400 mm in 27 days) occurring in May 2005. The study field had been under a no-till, no-burning system for 18 years, but immediately prior to the period of heavy rainfall the harvest residues were burnt. The erosion recorded therefore reflected both the extreme nature of the rainfall and the effects of the burning in increasing surface runoff and erosion. The sampled area corresponded to that used previously by the authors to document the medium-term erosion rates associated with both conventional tillage and the subsequent switch to a no-till system. Comparisons between the erosion documented for the period of heavy rainfall in 2005 with these medium-term erosion rates permits some tentative conclusions regarding the importance of extreme events and the impact of burning in increasing the erosion associated with the no-till system

  10. Towards a Fundamental Understanding of Short Period Eclipsing Binary Systems Using Kepler Data

    Science.gov (United States)

    Prsa, Andrej

    Kepler's ultra-high precision photometry is revolutionizing stellar astrophysics. We are seeing intrinsic phenomena on an unprecedented scale, and interpreting them is both a challenge and an exciting privilege. Eclipsing binary stars are of particular significance for stellar astrophysics because precise modeling leads to fundamental parameters of the orbiting components: masses, radii, temperatures and luminosities to better than 1-2%. On top of that, eclipsing binaries are ideal physical laboratories for studying other physical phenomena, such as asteroseismic properties, chromospheric activity, proximity effects, mass transfer in close binaries, etc. Because of the eclipses, the basic geometry is well constrained, but a follow-up spectroscopy is required to get the dynamical masses and the absolute scale of the system. A conjunction of Kepler photometry and ground- based spectroscopy is a treasure trove for eclipsing binary star astrophysics. This proposal focuses on a carefully selected set of 100 short period eclipsing binary stars. The fundamental goal of the project is to study the intrinsic astrophysical effects typical of short period binaries in great detail, utilizing Kepler photometry and follow-up spectroscopy to devise a robust and consistent set of modeling results. The complementing spectroscopy is being secured from 3 approved and fully funded programs: the NOAO 4-m echelle spectroscopy at Kitt Peak (30 nights; PI Prsa), the 10- m Hobby-Eberly Telescope high-resolution spectroscopy (PI Mahadevan), and the 2.5-m Sloan Digital Sky Survey III spectroscopy (PI Mahadevan). The targets are prioritized by the projected scientific yield. Short period detached binaries host low-mass (K- and M- type) components for which the mass-radius relationship is sparsely populated and still poorly understood, as the radii appear up to 20% larger than predicted by the population models. We demonstrate the spectroscopic detection viability in the secondary

  11. The Very Short Period M Dwarf Binary SDSS J001641-000925

    Science.gov (United States)

    Davenport, James R. A.; Becker, Andrew C.; West, Andrew A.; Bochanski, John J.; Hawley, Suzanne L.; Holtzman, Jon; Gunning, Heather C.; Hilton, Eric J.; Munshi, Ferah A.; Albright, Meagan

    2013-02-01

    We present follow-up observations and analysis of the recently discovered short period low-mass eclipsing binary, SDSS J001641-000925. With an orbital period of 0.19856 days, this system has one of the shortest known periods for an M dwarf binary system. Medium-resolution spectroscopy and multi-band photometry for the system are presented. Markov Chain Monte Carlo modeling of the light curves and radial velocities yields estimated masses for the stars of M 1 = 0.54 ± 0.07 M ⊙ and M 2 = 0.34 ± 0.04 M ⊙, and radii of R 1 = 0.68 ± 0.03 R ⊙ and R 2 = 0.58 ± 0.03 R ⊙, respectively. This solution places both components above the critical Roche overfill limit, providing strong evidence that SDSS J001641-000925 is the first verified M-dwarf contact binary system. Within the follow-up spectroscopy we find signatures of non-solid body rotation velocities, which we interpret as evidence for mass transfer or loss within the system. In addition, our photometry samples the system over nine years, and we find strong evidence for period decay at the rate of \\dot{P}\\sim 8 s yr-1. Both of these signatures raise the intriguing possibility that the system is in over-contact, and actively losing angular momentum, likely through mass loss. This places SDSS J001641-000925 as not just the first M-dwarf over-contact binary, but one of the few systems of any spectral type known to be actively undergoing coalescence. Further study of SDSS J001641-000925 is ongoing to verify the nature of the system, which may prove to be a unique astrophysical laboratory. Based on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. Support for the design and construction of the Magellan Echellette Spectrograph was received from the Observatories of the Carnegie Institution of Washington, the

  12. Estimating return periods of extreme values from relatively short time series of winds

    Science.gov (United States)

    Jonasson, Kristjan; Agustsson, Halfdan; Rognvaldsson, Olafur; Arfeuille, Gilles

    2013-04-01

    An important factor for determining the prospect of individual wind farm sites is the frequency of extreme winds at hub height. Here, extreme winds are defined as the value of the highest 10 minutes averaged wind speed with a 50 year return period, i.e. annual exceeding probability of 2% (Rodrigo, 2010). A frequently applied method to estimate winds in the lowest few hundred meters above ground is to extrapolate observed 10-meter winds logarithmically to higher altitudes. Recent study by Drechsel et al. (2012) showed however that this methodology is not as accurate as interpolating simulated results from the global ECMWF numerical weather prediction (NWP) model to the desired height. Observations of persistent low level jets near Colima in SW-Mexico also show that the logarithmic approach can give highly inaccurate results for some regions (Arfeuille et al., 2012). To address these shortcomings of limited, and/or poorly representative, observations and extrapolations of winds one can use NWP models to dynamically scale down relatively coarse resolution atmospheric analysis. In the case of limited computing resources one has typically to make a compromise between spatial resolution and the duration of the simulated period, both of which can limit the quality of the wind farm siting. A common method to estimate maximum winds is to fit an extreme value distribution (e.g. Gumbel, gev or Pareto) to the maximum values of each year of available data, or the tail of these values. If data are only available for a short period, e.g. 10 or 15 years, then this will give a rather inaccurate estimate. It is possible to deal with this problem by utilizing monthly or weekly maxima, but this introduces new problems: seasonal variation, autocorrelation of neighboring values, and increased discrepancy between data and fitted distribution. We introduce a new method to estimate return periods of extreme values of winds at hub height from relatively short time series of winds, simulated

  13. Long-period amplification in deep alluvial basins and consequences for site-specific probabilistic seismic-hazard: the case of Castelleone in the Po Plain (Northern Italy)

    Science.gov (United States)

    Barani, S.; Mascandola, C.; Massa, M.; Spallarossa, D.

    2017-12-01

    The recent Emilia seismic sequence (Northern Italy) occurred at the end of the first half of 2012 with main shock of Mw6.1 highlighted the importance of studying site effects in the Po Plain, the larger and deeper sedimentary basin in Italy. As has long been known, long-period amplification related to deep sedimentary basins can significantly affect the characteristics of the ground-motion induced by strong earthquakes. It follows that the effects of deep sedimentary deposits on ground shaking require special attention during the definition of the design seismic action. The work presented here analyzes the impact of deep-soil discontinuities on ground-motion amplification, with particular focus on long-period probabilistic seismic-hazard assessment. The study focuses on the site of Castelleone, where a seismic station of the Italian National Seismic Network has been recording since 2009. Our study includes both experimental and numerical site response analyses. Specifically, extensive active and passive geophysical measurements were carried out in order to define a detailed shear-wave velocity (VS) model to be used in the numerical analyses. These latter are needed to assess the site-specific ground-motion hazard. Besides classical seismic refraction profiles and multichannel analysis of surface waves, we analyzed ambient vibration measurements in both single and array configurations. The VS profile was determined via joint inversion of the experimental phase-velocity dispersion curve with the ellipticity curve derived from horizontal-to-vertical spectral ratios. The profile shows two main discontinuities at depths of around 160 and 1350 m, respectively. The probabilistic site-specific hazard was assessed in terms of both spectral acceleration and displacement. A partially non-ergodic approach was adopted. We have found that the spectral acceleration hazard is barely sensitive to long-period (up to 10 s) amplification related to the deeper discontinuity whereas the

  14. Textured dysprosium and gadolinium poles for high-field, short-period hybrid undulators

    International Nuclear Information System (INIS)

    Murokh, Alex; Solovyov, Vyacheslav; Agustsson, Ron; O'Shea, Finn H.; Chubar, Oleg; Chen, Yung; Grandsaert, Thomas

    2014-01-01

    We discuss the feasibility of enhancement of the gap field in a short-period hybrid undulator by using pole inserts with the saturation inductance B s , over that of iron, 2 T. Dysprosium metal, with the saturation inductance of 3.4 T below 90 K, and Gadolinium with B s =2.7 T, appear as good candidates as the optimized pole material. However, due to the high magnetic anisotropy of Dy, such a high level of magnetization can only be realized when the external field lies in the basal plane. This implies that the pole has to be single-crystalline or highly textured. Considering that growing large, >10mm, Dy single crystals is difficult, we propose secondary recrystallization as a method to induce the required texture in thin Dy and Gd foils. The textured foils can be stacked to produce pole inserts of the desired geometry and orientation. Results of small-scale processing and magnetic measurements of thin (20–60 μ) foils provide evidence that the required texture quality can be achieved by a relatively simple sequence of heat-treatments and cold rolling. The advantage of textured Dy and Gd poles is demonstrated in a several period test undulator. -- Highlights: • Textured rare-earth materials for use as undulator pole materials. • We measure the development of texture in Dy and Gd. • We compare the rare-earth materials with high saturation steel in undulators. • Thin sheets of Dy and Gd materials perform similar to single crystals

  15. Observation of a Short Period Quasi-periodic Pulsation in Solar X-Ray, Microwave, and EUV Emissions

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Pankaj; Cho, Kyung-Suk [Korea Astronomy and Space Science Institute (KASI), Daejeon, 305-348 (Korea, Republic of); Nakariakov, Valery M., E-mail: pankaj@kasi.re.kr [Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, CV4 7AL (United Kingdom)

    2017-02-10

    This paper presents the multiwavelength analysis of a 13 s quasi-periodic pulsation (QPP) observed in hard X-ray (12–300 keV) and microwave (4.9–34 GHz) emissions during a C-class flare that occurred on 2015 September 21. Atmospheric Image Assembly (AIA) 304 and 171 Å images show an emerging loop/flux tube (L1) moving radially outward, which interacts with the preexisting structures within the active region (AR). The QPP was observed during the expansion of and rising motion of L1. The Nobeyama Radioheliograph microwave images in 17/34 GHz channels reveal a single radio source that was co-spatial with a neighboring loop (L2). In addition, using AIA 304 Å images, we detected intensity oscillations in the legs of L2 with a period of about 26 s. A similar oscillation period was observed in the GOES soft X-ray flux derivative. This oscillation period seems to increase with time. We suggest that the observed QPP is most likely generated by the interaction between L2 and L3 observed in the AIA hot channels (131 and 94 Å). The merging speed of loops L2 and L3 was ∼35 km s{sup −1}. L1 was destroyed possibly by its interaction with preexisting structures in the AR, and produced a cool jet with the speed of ∼106–118 km s{sup −1} associated with a narrow CME (∼770 km s{sup −1}). Another mechanism of the QPP in terms of a sausage oscillation of the loop (L2) is also possible.

  16. A neutral network based technique for short-term forecasting of anomalous load periods

    Energy Technology Data Exchange (ETDEWEB)

    Sforna, M [ENEL, s.p.a, Italian Power Company (Italy); Lamedica, R; Prudenzi, A [Rome Univ. ` La Sapienza` , Rome (Italy); Caciotta, M; Orsolini Cencelli, V [Rome Univ. III, Rome (Italy)

    1995-01-01

    The paper illustrates a part of the research activity conducted by authors in the field of electric Short Term Load Forecasting (STLF) based on Artificial Neural Network (ANN) architectures. Previous experiences with basic ANN architectures have shown that, even though these architecture provide results comparable with those obtained by human operators for most normal days, they evidence some accuracy deficiencies when applied to `anomalous` load conditions occurring during holidays and long weekends. For these periods a specific procedure based upon a combined (unsupervised/supervised) approach has been proposed. The unsupervised stage provides a preventive classification of the historical load data by means of a Kohonen`s Self Organizing Map (SOM). The supervised stage, performing the proper forecasting activity, is obtained by using a multi-layer percept ron with a back propagation learning algorithm similar to the ones above mentioned. The unconventional use of information deriving from the classification stage permits the proposed procedure to obtain a relevant enhancement of the forecast accuracy for anomalous load situations.

  17. Ontogeny of sensorimotor gating and short-term memory processing throughout the adolescent period in rats

    Directory of Open Access Journals (Sweden)

    Anja A. Goepfrich

    2017-06-01

    Full Text Available Adolescence and puberty are highly susceptible developmental periods during which the neuronal organization and maturation of the brain is completed. The endocannabinoid (eCB system, which is well known to modulate cognitive processing, undergoes profound and transient developmental changes during adolescence. With the present study we were aiming to examine the ontogeny of cognitive skills throughout adolescence in male rats and clarify the potential modulatory role of CB1 receptor signalling. Cognitive skills were assessed repeatedly every 10th day in rats throughout adolescence. All animals were tested for object recognition memory and prepulse inhibition of the acoustic startle reflex. Although cognitive performance in short-term memory as well as sensorimotor gating abilities were decreased during puberty compared to adulthood, both tasks were found to show different developmental trajectories throughout adolescence. A low dose of the CB1 receptor antagonist/inverse agonist SR141716 was found to improve recognition memory specifically in pubertal animals while not affecting behavioral performance at other ages tested. The present findings demonstrate that the developmental trajectory of cognitive abilities does not occur linearly for all cognitive processes and is strongly influenced by pubertal maturation. Developmental alterations within the eCB system at puberty onset may be involved in these changes in cognitive processing.

  18. Planet X as the source of the periodic and steady-state flux of short period comets

    International Nuclear Information System (INIS)

    Matese, J.J.; Whitmire, D.P.

    1986-01-01

    The cratering and fossil records suggest that impacts on the earth have been modulated with a period of roughly 30 Myr. In the Planet X model, this modulation is the result of the interaction of Planet X with a primordial disk of planetesimals lying beyond the orbit of Neptune. In this paper, observational and theoretical evidence supporting the existence of Planet X and the planetesimal disk is briefly reviewed, and the constraints on the orbit parameters of Planet X and the disk parameters which must be satisfied to ensure consistency with observational limits are discussed

  19. Magneto-transport studies of InAs/GaSb short period superlattices

    International Nuclear Information System (INIS)

    Broadley, Victoria Jane

    2002-01-01

    This thesis studies the transport properties of short period semiconducting InAs/GaSb superlattices in the presence of strong electric and magnetic fields applied parallel to the growth axis. Electrical transport parallel to the growth axis occurs through the superlattice miniband, which have widths varying from three to 30meV. Resonant scattering between confined Landau levels and Stark levels is observed at low temperatures (4.2K). In addition LO-phonon assisted scattering between Landau levels is observed in both type-I GaAs/AIAs and type-ll inAs/GaSb superlattices, which are enhanced in the type-ll system due to the strong interband coupling. K·p band structure calculations show that the interband coupling causes the superlattice miniband energy dispersion to be strongly dependent on the in-plane wavevector and the applied magnetic field. For large applied electric fields, where the miniband is split into discrete Stark levels, strong stark-cyclotron resonance (SCR) features are observed, which occur when the Landau level separation equals to the stark level separation. These resonances are enhanced when compared to SCR in type-I superlattices due to the suppression of miniband conduction in higher lying Landau levels. At low electric fields electrical transport through the superlattice miniband yields characteristic miniband transport features, which are modelled using the Esaki-Tsu miniband transport model. Strong electron - LO-phonon scattering is also observed in InAs/GaSb superlattices, where we report the first observation of miniband transport assisted via the emission of LO-phonons between stark levels in adjacent wells. Below 50K thermally activated behaviour is reported and at high magnetic fields (in the quantum limit) complete localisation of carriers is observed. In this regime LO-phonon delocalised transport in also observed. (author)

  20. Nitrogen fertilization and yield formation of potato during a short growing period

    Directory of Open Access Journals (Sweden)

    L. MUSTONEN

    2008-12-01

    Full Text Available The effects various rates of nitrogen application on accumulation of dry matter and nitrogen in potato (Solanum tuberosum L. were studied during a short growing period of 140–180 days, at MTT Agrifood Research Finland in 2000–2001. The treatments were 0, 60 and 120 kg N ha-1 and the potato cultivars tested were Van Gogh and Nicola. Four successive harvests were made during the course of the experiment to monitor changes in the accumulation of dry matter and nitrogen over the season. Applications of nitrogen substantially increased haulm dry matter accumulation and to an even greater extent their nitrogen contents. The highest dry matter values were generally registered at 120 kg N ha-1. Dry matter and nitrogen content of haulms started to decline during the later part of season and most nitrogen was relocated to tubers. The results suggest that an application of only 60 kg N ha-1 was sufficient to promote rapid canopy development and there were only small reductions in dry matter and nitrogen accumulation until late in the season when the canopy started to senesce as nitrogen supply diminished. Tuber yield, plant dry matter and nitrogen accumulation at maturity were related to crop nitrogen supply. Although application of the high rate, 120 N kg ha-1, resulted in a significant increase in dry matter accumulation, this was not reflected in the profit because the higher nitrogen application reduced dry matter content of tubers by 2.6% in 2000 and by 1.1% in 2001 relative to the use of 60 kg N ha-1. Apparent fertilizer nitrogen recovery values on a whole plant basis ranged from 53 to 75%. The proportion of fertilizer recovered in tubers clearly declined with increase in nitrogen supply.;

  1. The Conceptual Model of Calculating the Return Period of the Costs for Creation of the Enterprise’s Economic Security Service in the Short-Term Period

    Directory of Open Access Journals (Sweden)

    Melikhova Tetiana O.

    2018-03-01

    Full Text Available Determination of the return period of the costs, advanced for the creation of economic security service of enterprise during a year, involves consideration of interaction of the conditional money flow, accumulated for a certain number of months, and the constant costs. The main component of the constant costs are the annual depreciation deductions. The return period is considered as gross, net, valid, and specified. The gross (net, valid, and specified return period is the time, wherein the gross conditional money flow, equal to the advanced costs, will be accumulated. The gross return period, taking account of the effect of time factor, is proposed to be defined as the ratio of annual depreciation deductions increased by the annual compounding coefficient to the conditional average monthly gross money flow, increased by the average monthly inflation index. As for the short-term period, a relationship between the gross, net, valid, and specified return periods of the costs, advanced to the creation of the economic security service, has been identified. The net (valid, specified return period is equal to the gross period adjusted to the coefficient of excess of the gross conditional money flow, accumulated in the gross period, over the net (valid, specified conditional cash flow.

  2. Tidally distorted exoplanets: Density corrections for short-period hot-Jupiters based solely on observable parameters

    Energy Technology Data Exchange (ETDEWEB)

    Burton, J. R.; Watson, C. A.; Fitzsimmons, A.; Moulds, V. [Astrophysics Research Centre, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Pollacco, D.; Wheatley, P. J. [Department of Physics and Astronomy, University of Warwick, Coventry CV4 7AL (United Kingdom); Littlefair, S. P., E-mail: jburton04@qub.ac.uk [Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH (United Kingdom)

    2014-07-10

    The close proximity of short-period hot-Jupiters to their parent star means they are subject to extreme tidal forces. This has a profound effect on their structure and, as a result, density measurements that assume that the planet is spherical can be incorrect. We have simulated the tidally distorted surface for 34 known short-period hot-Jupiters, assuming surfaces of constant gravitational equipotential for the planet, and the resulting densities have been calculated based only on observed parameters of the exoplanet systems. Comparing these results to the density values, assuming the planets are spherical, shows that there is an appreciable change in the measured density for planets with very short periods (typically less than two days). For one of the shortest-period systems, WASP-19b, we determine a decrease in bulk density of 12% from the spherical case and, for the majority of systems in this study, this value is in the range of 1%-5%. On the other hand, we also find cases where the distortion is negligible (relative to the measurement errors on the planetary parameters) even in the cases of some very short period systems, depending on the mass ratio and planetary radius. For high-density gas planets requiring apparently anomalously large core masses, density corrections due to tidal deformation could become important for the shortest-period systems.

  3. A non-accelerating foreshock sequence followed by a short period of quiescence for a large inland earthquake

    Science.gov (United States)

    Doi, I.; Kawakata, H.

    2012-12-01

    Laboratory experiments [e.g. Scholz, 1968; Lockner et al., 1992] and field observations [e.g. Dodge et al., 1996; Helmstetter and Sornette, 2003; Bouchon et al., 2011] have elucidated part of foreshock behavior and mechanism, but we cannot identify foreshocks while they are occurring. Recently, in Japan, a dense seismic network, Hi-net (High Sensitivity Seismograph Network), provides continuous waveform records for regional seismic events. The data from this network enable us to analyze small foreshocks which occur on long period time scales prior to a major event. We have an opportunity to grasp the more detailed pattern of foreshock generation. Using continuous waveforms recorded at a seismic station located in close proximity to the epicenter of the 2008 Iwate-Miyagi inland earthquake, we conducted a detailed investigation of its foreshocks. In addition to the two officially recognized foreshocks, calculation of cross-correlation coefficients between the continuous waveform record and one of the previously recognized foreshocks revealed that 20 micro foreshocks occurred within the same general area. Our analysis also shows that all of these foreshocks occurred within the same general area relative to the main event. Over the two week period leading up to the Iwate-Miyagi earthquake, such foreshocks only occurred during the last 45 minutes, specifically over a 35 minute period followed by a 10 minute period of quiescence just before the mainshock. We found no evidence of acceleration of this foreshock sequence. Rock fracturing experiments using a constant loading rate or creep tests have consistently shown that the occurrence rate of small fracturing events (acoustic emissions; AEs) increases before the main rupture [Scholz, 1968]. This accelerative pattern of preceding events was recognized in case of the 1999 Izmit earthquake [Bouchon et al., 2011]. Large earthquakes however need not be accompanied by acceleration of foreshocks if a given fault's host rock

  4. The Banat seismic network: Evolution and performance

    International Nuclear Information System (INIS)

    Oros, E.

    2002-01-01

    In the Banat Seismic Region, with its important seismogenic zones (Banat and Danube), operates today the Banat Seismic Network. This network has four short period seismic stations telemetered at the Timisoara Seismological Observatory (since 1995): Siria, Banloc, Buzias and Timisoara. The stations are equipped with short-period S13 seismometers (1 second). The data recorded by the short-period stations are telemetered to Timisoara where they are digitized at 50 samples per second, with 16 bit resolution. At Timisoara works SAPS, an automated system for data acquisition and processing, which performs real-time event detection (based on Allen algorithm), discrimination between local and teleseismic events, automatic P and S waves picking, location and magnitude determination for local events and teleseisms, 'feeding' of an Automatic Data Request Manager with phases, locations and waveforms, sending of earthquake information (as phases and location), by e-mail to Bucharest. The beginning of the seismological observations in Banat is in the 1880's (Timisoara Meteorological Observatory). The first seismograph was installed in Timisoara in 1901, and its systematic observations began in 1902. The World War I interrupted its work. In 1942 Prof. I. Curea founded the Seismic Station Timisoara, and since 1967 until today this station worked into a special building. After 1972 two stations with high amplification were installed in Retezat Mts (Gura Zlata) and on Nera Valey (Susara), as a consequence of the research results. Since 1982 Buzias station began to work completing the Banat Seismic Network. Therefore, the network could detect and locate any local seismic event with M > 2.2. Moreover, up to 20 km distance from each station any seismic event could be detected over M = 0.5. The paper also presents the quality of the locations versus different local seismic sources. (author)

  5. Impact of high temperature and short period annealing on SnS films deposited by E-beam evaporation

    International Nuclear Information System (INIS)

    Gedi, Sreedevi; Reddy, Vasudeva Reddy Minnam; Kang, Jeong-yoon; Jeon, Chan-Wook

    2017-01-01

    Highlights: • Preparation SnS films using electron beam evaporation at room temperature. • SnS films were annealed at a high temperaure for different short period of times. • The films showed highly oriented (111) planes with orthorhombic crystal structure. • Surface morphology showed bigger and faceted grains embedded in orthorombic. • The TEM confirmed that big orthorombic slabs had single-crystalline nature. - Abstract: Thin films of SnS were deposited on Mo-substrate using electron beam evaporation at room temperature. As-deposited SnS films were annealed at a constant high temperaure of 860 K for different short period of times, 1 min, 3 min, and 5 min. The impact of heat treatment period on the physical properties of SnS films was investigated using appropriate characterization tools. XRD analysis revealed that the films were highly oriented along (111) plane with orthorhombic crystal structure. Surface morphology of as-deposited SnS films showed an identical leaf texture where as the annealed films showed large orthorombic slab shape grains in adidition to the leaf shape grains, which indicates the significance of short period annealing at high temperature. The transmission electron microscopy confirmed that those large orthorombic slabs had single-crystalline nature. The results emphasized that the short period annealing treatment at high temperature stimulated the growth of film towards the single crystallinity.

  6. Impact of high temperature and short period annealing on SnS films deposited by E-beam evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Gedi, Sreedevi; Reddy, Vasudeva Reddy Minnam; Kang, Jeong-yoon; Jeon, Chan-Wook, E-mail: cwjeon@ynu.ac.kr

    2017-04-30

    Highlights: • Preparation SnS films using electron beam evaporation at room temperature. • SnS films were annealed at a high temperaure for different short period of times. • The films showed highly oriented (111) planes with orthorhombic crystal structure. • Surface morphology showed bigger and faceted grains embedded in orthorombic. • The TEM confirmed that big orthorombic slabs had single-crystalline nature. - Abstract: Thin films of SnS were deposited on Mo-substrate using electron beam evaporation at room temperature. As-deposited SnS films were annealed at a constant high temperaure of 860 K for different short period of times, 1 min, 3 min, and 5 min. The impact of heat treatment period on the physical properties of SnS films was investigated using appropriate characterization tools. XRD analysis revealed that the films were highly oriented along (111) plane with orthorhombic crystal structure. Surface morphology of as-deposited SnS films showed an identical leaf texture where as the annealed films showed large orthorombic slab shape grains in adidition to the leaf shape grains, which indicates the significance of short period annealing at high temperature. The transmission electron microscopy confirmed that those large orthorombic slabs had single-crystalline nature. The results emphasized that the short period annealing treatment at high temperature stimulated the growth of film towards the single crystallinity.

  7. Correlations, spectral composition and interaction character of seismic and atmospheric geophysical fields in the 1-4 hours period range

    International Nuclear Information System (INIS)

    Petrova, L.N.

    1995-01-01

    Results of analysis of synchronized observations of seismic oscillations ans near-surface atmosphere pressure variations are presented. Similar spectra structure and high levels of coherency coefficients point out the existence of correlational links between them. The conclusion on the necessity of the investigation of the links is made. H hypothesis on possible gravity mechanism of induceing the oscillations in the analyzed geophysical fields is proposed. 5 refs., 2 tabs

  8. Adding seismic broadband analysis to characterize Andean backarc seismicity in Argentina

    Science.gov (United States)

    Alvarado, P.; Giuliano, A.; Beck, S.; Zandt, G.

    2007-05-01

    Characterization of the highly seismically active Andean backarc is crucial for assessment of earthquake hazards in western Argentina. Moderate-to-large crustal earthquakes have caused several deaths, damage and drastic economic consequences in Argentinean history. We have studied the Andean backarc crust between 30°S and 36°S using seismic broadband data available from a previous ("the CHARGE") IRIS-PASSCAL experiment. We collected more than 12 terabytes of continuous seismic data from 22 broadband instruments deployed across Chile and Argentina during 1.5 years. Using free software we modeled full regional broadband waveforms and obtained seismic moment tensor inversions of crustal earthquakes testing for the best focal depth for each event. We also mapped differences in the Andean backarc crustal structure and found a clear correlation with different types of crustal seismicity (i.e. focal depths, focal mechanisms, magnitudes and frequencies of occurrence) and previously mapped terrane boundaries. We now plan to use the same methodology to study other regions in Argentina using near-real time broadband data available from the national seismic (INPRES) network and global seismic networks operating in the region. We will re-design the national seismic network to optimize short-period and broadband seismic station coverage for different network purposes. This work is an international effort that involves researchers and students from universities and national government agencies with the goal of providing more information about earthquake hazards in western Argentina.

  9. A short period of high-intensity interval training improves skeletal muscle mitochondrial function and pulmonary oxygen uptake kinetics

    DEFF Research Database (Denmark)

    Christensen, Peter Møller; Jacobs, Robert A; Bonne, Thomas Christian

    2016-01-01

    The aim of the present study was to examine whether improvements in pulmonary V̇O2 kinetics following a short period of high-intensity training (HIT) would be associated with improved skeletal muscle mitochondrial function. Ten untrained male volunteers (age: 26 ± 2; mean ± SD) performed six HIT...

  10. Capability of simultaneous Rayleigh LiDAR and O2 airglow measurements in exploring the short period wave characteristics

    Science.gov (United States)

    Taori, Alok; Raghunath, Karnam; Jayaraman, Achuthan

    We use combination of simultaneous measurements made with Rayleigh lidar and O2 airglow monitoring to improve lidar investigation capability to cover a higher altitude range. We feed instantaneous O2 airglow temperatures instead the model values at the top altitude for subsequent integration method of temperature retrieval using Rayleigh lidar back scattered signals. Using this method, errors in the lidar temperature estimates converges at higher altitudes indicating better altitude coverage compared to regular methods where model temperatures are used instead of real-time measurements. This improvement enables the measurements of short period waves at upper mesospheric altitudes (~90 km). With two case studies, we show that above 60 km the few short period wave amplitude drastically increases while, some of the short period wave show either damping or saturation. We claim that by using such combined measurements, a significant and cost effective progress can be made in the understanding of short period wave processes which are important for the coupling across the different atmospheric regions.

  11. Long-period seismicity reveals magma pathways above a laterally propagating dyke during the 2014-15 Bárðarbunga rifting event, Iceland

    Science.gov (United States)

    Woods, Jennifer; Donaldson, Clare; White, Robert S.; Caudron, Corentin; Brandsdóttir, Bryndís; Hudson, Thomas S.; Ágústsdóttir, Thorbjörg

    2018-05-01

    The 2014-15 Bárðarbunga-Holuhraun rifting event comprised the best-monitored dyke intrusion to date and the largest eruption in Iceland in 230 years. A huge variety of seismicity was produced, including over 30,000 volcano-tectonic earthquakes (VTs) associated with the dyke propagation at ∼6 km depth below sea level, and large-magnitude earthquakes accompanying the collapse of Bárðarbunga caldera. We here study the long-period seismicity associated with the rifting event. We systematically detect and locate both long-period events (LPs) and tremor during the dyke propagation phase and the first week of the eruption. We identify clusters of highly similar, repetitive LPs, which have a peak frequency of ∼1 Hz and clear P and S phases followed by a long-duration coda. The source mechanisms are remarkably consistent between clusters and also fundamentally different to those of the VTs. We accurately locate LP clusters near each of three ice cauldrons (depressions formed by basal melting) that were observed on the surface of Dyngjujökull glacier above the path of the dyke. Most events are in the vicinity of the northernmost cauldron, at shallower depth than the VTs associated with lateral dyke propagation. At the two northerly cauldrons, periods of shallow seismic tremor following the clusters of LPs are also observed. Given that the LPs occur at ∼4 km depth and in swarms during times of dyke-stalling, we infer that they result from excitation of magmatic fluid-filled cavities and indicate magma ascent. We suggest that the tremor is the climax of the vertical melt movement, arising from either rapid, repeated excitation of the same LP cavities, or sub-glacial eruption processes. This long-period seismicity therefore represents magma pathways between the depth of the dyke-VT earthquakes and the surface. Notably, we do not detect tremor associated with each cauldron, despite melt reaching the base of the overlying ice cap, a concern for hazard monitoring.

  12. National Seismic Station

    International Nuclear Information System (INIS)

    Stokes, P.A.

    1982-06-01

    The National Seismic Station was developed to meet the needs of regional or worldwide seismic monitoring of underground nuclear explosions to verify compliance with a nuclear test ban treaty. The Station acquires broadband seismic data and transmits it via satellite to a data center. It is capable of unattended operation for periods of at least a year, and will detect any tampering that could result in the transmission of unauthentic seismic data

  13. Development of Speech Fluency over a Short Period of Time: Effects of Pedagogic Intervention

    Science.gov (United States)

    Tavakoli, Parvaneh; Campbell, Colin; McCormack, Joan

    2016-01-01

    This study investigates the effects of a short-term pedagogic intervention on development of second language (L2) fluency among learners studying English for academic purposes at a UK university. It also examines the interaction between development of fluency and complexity and accuracy. Through a pretest and posttest design, data were collected…

  14. Short (

    NARCIS (Netherlands)

    Telleman, Gerdien; den Hartog, Laurens

    2013-01-01

    Aim: This systematic review assessed the implant survival rate of short (<10 mm) dental implants installed in partially edentulous patients. A case report of a short implant in the posterior region have been added. Materials and methods: A search was conducted in the electronic databases of MEDLINE

  15. Multi-point ground-based ULF magnetic field observations in Europe during seismic active periods in 2004 and 2005

    Directory of Open Access Journals (Sweden)

    G. Prattes

    2008-05-01

    Full Text Available We present the results of ground-based Ultra Low Frequency (ULF magnetic field measurements observed from June to August 2004 during the Bovec earthquake on 12 July 2004. Further we give information about the seismic activity in the local observatory region for an extended time span 2004 and 2005. ULF magnetic field data are provided by the South European Geomagnetic Array (SEGMA where the experience and heritage from the CHInese MAGnetometer (CHIMAG fluxgate magnetometer comes to application. The intensities of the horizontal H and vertical Z magnetic field and the polarization ratio R of the vertical and horizontal magnetic field intensity are analyzed taking into consideration three SEGMA observatories located at different close distances and directions from the earthquake epicenter. We observed a significant increase of high polarization ratios during strong seismic activity at the observatory nearest to the Bovec earthquake epicenter. Apart from indirect ionospheric effects electromagnetic noise could be emitted in the lithosphere due to tectonic effects in the earthquake focus region causing anomalies of the vertical magnetic field intensity. Assuming that the measured vertical magnetic field intensities are of lithospheric origin, we roughly estimate the amplitude of electromagnetic noise in the Earths crust considering an average electrical conductivity of <σ>=10−3 S/m and a certain distance of the observatory to the earthquake epicenter.

  16. Response to long-period seismic waves recorded by broadband seismometer and pore pressure sensor at IODP Site C0002, Nankai Trough

    Science.gov (United States)

    Kitada, K.; Araki, E.; Kimura, T.; Saffer, D. M.

    2013-12-01

    Long term in situ monitoring of seismic activity, slow slip event, and pore fluid behavior around mega earthquake zone is important for understanding the processes of earthquake generation and strain accumulation. In order to characterize the response to long-period seismic waves, we compared waveforms and hydroseismograms recorded by broadband seismometer and pore pressure transducers, respectively, which were installed at IODP Site C0002 in the Nankai Trough Kumano Basin. The borehole monitoring system sensor array at Site C0002 is designed to collect multiparameter observations covering a dynamic range of events, including local microearthquakes, low frequency earthquakes, and large-scale earthquakes similar to the Tonankai earthquake. The suite of sensors for the downhole portion of the observatory includes a broadband seismometer (CMG3TBD, Guralp Systems Ltd.) with sampling rate of 100Hz at the depth of 907mbsf, and four pressure ports connected to pressure gauges located at 948mbsf, 917mbsf, 766mbsf, and at the seafloor. The sampling rate of the data logger was set to 1Hz after successful connection to the DONET seafloor cable network for real-time monitoring on 24 Jan 2013. Since then, we processed 12 earthquakes between a moment magnitude of 6.5 to 8.3. In addition to the comparison of long-period surface waves waveform and pressure data, we compared the records with theoretical strain seismograms. The latter were calculated by normal mode summation using the earth model PREM of Dziewonski and Anderson (1981). A Butterworth bandpass filter was applied to the records with cut-off frequencies of 0.003 and 0.1 Hz. Our initial results indicate that the hydroseismograms correspond well with the vertical rather than the horizontal (radial and transverse) components in seismic data. The observed hydroseismogram have a good correlation with the predicted volumetric strain seismogram, especially for the Okhotsk (2013/05/24 14:17UT, Mw8.3, 632km depth), the Chishima

  17. Evaluation of induced seismicity forecast models in the Induced Seismicity Test Bench

    Science.gov (United States)

    Király, Eszter; Gischig, Valentin; Zechar, Jeremy; Doetsch, Joseph; Karvounis, Dimitrios; Wiemer, Stefan

    2016-04-01

    Induced earthquakes often accompany fluid injection, and the seismic hazard they pose threatens various underground engineering projects. Models to monitor and control induced seismic hazard with traffic light systems should be probabilistic, forward-looking, and updated as new data arrive. Here, we propose an Induced Seismicity Test Bench to test and rank such models. We apply the test bench to data from the Basel 2006 and Soultz-sous-Forêts 2004 geothermal stimulation projects, and we assess forecasts from two models that incorporate a different mix of physical understanding and stochastic representation of the induced sequences: Shapiro in Space (SiS) and Hydraulics and Seismics (HySei). SiS is based on three pillars: the seismicity rate is computed with help of the seismogenic index and a simple exponential decay of the seismicity; the magnitude distribution follows the Gutenberg-Richter relation; and seismicity is distributed in space based on smoothing seismicity during the learning period with 3D Gaussian kernels. The HySei model describes seismicity triggered by pressure diffusion with irreversible permeability enhancement. Our results show that neither model is fully superior to the other. HySei forecasts the seismicity rate well, but is only mediocre at forecasting the spatial distribution. On the other hand, SiS forecasts the spatial distribution well but not the seismicity rate. The shut-in phase is a difficult moment for both models in both reservoirs: the models tend to underpredict the seismicity rate around, and shortly after, shut-in. Ensemble models that combine HySei's rate forecast with SiS's spatial forecast outperform each individual model.

  18. Romanian seismic network

    International Nuclear Information System (INIS)

    Ionescu, Constantin; Rizescu, Mihaela; Popa, Mihaela; Grigore, Adrian

    2000-01-01

    The research in the field of seismology in Romania is mainly carried out by the National Institute for Earth Physics (NIEP). The NIEP activities are mainly concerned with the fundamental research financed by research contracts from public sources and the maintenance and operation of the Romanian seismic network. A three stage seismic network is now operating under NIEP, designed mainly to monitor the Vrancea seismic region in a magnitude range from microearthquakes to strong events: - network of 18 short-period seismometers (S13); - Teledyne Geotech Instruments (Texas); - network of 7 stations with local digital recording (PCM-5000) on magnetic tape, made up of, S13 geophone (T=2 s) on vertical component and SH1 geophone (T=5 s) on horizontal components; - network of 28 SMA-1 accelerometers and 30 digital accelerometers (Kinemetrics - K2) installed in the free field conditions in the framework of the joint German-Romanian cooperation program (CRC); the K2 instruments cover a magnitude range from 1.4 to 8.0. Since 1994, MLR (Muntele Rosu) station has become part of the GEOFON network and was provided with high performance broad band instruments. At Bucharest and Timisoara data centers, an automated and networked seismological system performs the on-line digital acquisition and processing of the telemetered data. Automatic processing includes discrimination between local and distant seismic events, earthquake location and magnitude computation, and source parameter determination for local earthquakes. The results are rapidly distributed via Internet, to several seismological services in Europe and USA, to be used in the association/confirmation procedures. Plans for new developments of the network include the upgrade from analog to digital telemetry and new stations for monitoring local seismicity. (authors)

  19. Nature of short-period microtremors on the cliff-like ground. part 6; Gakechi kinbo no tanshuki bido. 6

    Energy Technology Data Exchange (ETDEWEB)

    Maiguma, T; Kimura, Y [Waseda University, Tokyo (Japan). School of Science and Engineering; Yasui, [Toda Corp., Tokyo, (Japan)

    1997-10-22

    Short-period microtremors were observed on the cliff-like ground to discuss vibration characteristics of the ground. It is known that damage of an earthquake becomes especially serious in the vicinity of the cliff-like ground with steep slopes. The present investigation has performed observations on short-period microtremors in two cliff-like grounds, one with a height of about 17 m and an inclination angle of about 55 degrees, and another with a height of 11 m and an inclination angle of about 60 degrees. The areas of the investigation are the Musashino tableland of the Pleistocene era covered by the Kanto loam bed, and the Oritate area (a farm land) with the cliff-like ground which has been formed as a result of erosion of a river terrace consisted of a gravel bed. The observation was carried out with nine moving coil type vibration converters having a natural period of one second installed for horizontal movements and seven converters installed for vertical movements. The result of the investigation revealed that, at the Musashino tableland, no noticeable influence of the cliff-like ground was recognized in the short-period microtremors; at the Oritate area, the spectra of the horizontal movements vary largely with vibrating directions; and the cliff effect can be seen in microtremors with frequencies from 5 Hz to 9 Hz. 5 refs., 9 figs.

  20. Seismicity in the Vicinity of Yucca Mountain, Nevada, for the Period October 1, 2002, to September 30, 2003

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Ken; von Seggern, David

    2007-12-04

    Earthquake activity in the Yucca Mountain from October 1, 2002 through September 30, 2003 (FY03) is assessed and compared with previous activity in the region. FY03 is the first reporting year since the 1992 M 5.6 Little Skull Mountain earthquake with no earthquakes greater than M 3.0 within 65 km of Yucca Mountain. In addition, FY03 includes the fewest number of earthquakes greater than M 2.0 in any reporting year since the LSM event. With 3075 earthquakes in the catalog, FY03 represents the second largest number of earthquakes (second to FY02) since FY96 when digital seismic network operations began. The largest event during FY03 was M 2.78 in eastern NTS and there were only 8 earthquakes greater than M 2.0.

  1. Seismicity in the Vicinity of Yucca Mountain, Nevada, for the Period October 1, 2002, to September 30, 2003

    International Nuclear Information System (INIS)

    Smith, Ken; von Seggern, David

    2007-01-01

    Earthquake activity in the Yucca Mountain from October 1, 2002 through September 30, 2003 (FY03) is assessed and compared with previous activity in the region. FY03 is the first reporting year since the 1992 M 5.6 Little Skull Mountain earthquake with no earthquakes greater than M 3.0 within 65 km of Yucca Mountain. In addition, FY03 includes the fewest number of earthquakes greater than M 2.0 in any reporting year since the LSM event. With 3075 earthquakes in the catalog, FY03 represents the second largest number of earthquakes (second to FY02) since FY96 when digital seismic network operations began. The largest event during FY03 was M 2.78 in eastern NTS and there were only 8 earthquakes greater than M 2.0

  2. Closeout of IE Bulletin 79-12: short-period scrams at boiling-water reactors. Final report

    International Nuclear Information System (INIS)

    DeBevac, C.J.; Holland, R.A.

    1985-03-01

    IE Circular 77-07 was issued on April 14, 1977 because of the occurrence of short period scram events at Dresden Unit 2 on December 28, 1976 and at Monticello on February 23, 1977. The circular advised BWR plants to revise their control rod withdrawal sequences and operating procedures to reduce the likelihood of future short period scrams. However, similar events continued to occur. These included events at Oyster Creek on December 14, 1978; at Browns Ferry Unit 1 on January 18, 1979; and at Hatch Unit 1 on January 31, 1979. As a result of these events, IE Bulletin 79-12 was issued on May 31, 1979. This bulletin required a written response from licensees of GE-designed BWRs regarding specific actions listed in the bulletin. All of the licensees responded in a satisfactory manner. No similar events have been reported since IE Bulletin 79-12 was issued

  3. A high-average power tapered FEL amplifier at submillimeter frequencies using sheet electron beams and short-period wigglers

    International Nuclear Information System (INIS)

    Bidwell, S.W.; Radack, D.J.; Antonsen, T.M. Jr.; Booske, J.H.; Carmel, Y.; Destler, W.W.; Granatstein, V.L.; Levush, B.; Latham, P.E.; Zhang, Z.X.

    1990-01-01

    A high-average-power FEL amplifier operating at submillimeter frequencies is under development at the University of Maryland. Program goals are to produce a CW, ∼1 MW, FEL amplifier source at frequencies between 280 GHz and 560 GHz. To this end, a high-gain, high-efficiency, tapered FEL amplifier using a sheet electron beam and a short-period (superconducting) wiggler has been chosen. Development of this amplifier is progressing in three stages: (1) beam propagation through a long length (∼1 m) of short period (λ ω = 1 cm) wiggler, (2) demonstration of a proof-of-principle amplifier experiment at 98 GHz, and (3) designs of a superconducting tapered FEL amplifier meeting the ultimate design goal specifications. 17 refs., 1 fig., 1 tab

  4. Kinetic Monte Carlo simulation of phase-precipitation versus instability behavior in short period FeCr superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez-Martínez, F.J. [UCAM, Universidad Católica de Murcia, Campus de los Jerónimos, 30107 Guadalupe (Murcia) (Spain); Castejón-Mochón, J.F., E-mail: jfcastejon@ucam.edu [UCAM, Universidad Católica de Murcia, Campus de los Jerónimos, 30107 Guadalupe (Murcia) (Spain); Castrillo, P.; Berenguer-Vidal, R. [UCAM, Universidad Católica de Murcia, Campus de los Jerónimos, 30107 Guadalupe (Murcia) (Spain); Dopico, I.; Martin-Bragado, I. [IMDEA Materials Institute, Eric Kandel 2, 28906 Getafe (Madrid) (Spain)

    2017-02-15

    The structural evolution of FeCr superlattices has been studied using a quasi-atomistic Object Kinetic Monte Carlo model. Superlattices with different spatial periods have been simulated for anneal durations from few hours to several months at 500 °C. Relatively-long period superlattices stabilize into Fe-rich and Cr-rich layers with compositions close to those of bulk α and α′ phases. In contrast, superlattices with very short periods (4, 5, 6 nm) are observed to undergo instability and, for long annealing times, evolve into three-dimensionally decomposed regions, in qualitative agreement to recent experimental observations. The instability onset is delayed as the spatial period increases, and it occurs via interface roughness. This evolution can be explained as a minimization of the free-energy associated to the α/α′ interfaces. A comprehensive description of the evolution dynamics of FeCr-based structures is obtained with our model.

  5. Physiological Responses of Bambara Groundnut (Vigna subterranea L. Verdc) to Short Periods of Water Stress During Different Developmental Stages

    OpenAIRE

    R. Vurayai; V. Emongor and B. Moseki

    2011-01-01

    The study was conducted to evaluate the responses of bambara groundnut (Vigna subterranea L. Verdc) to short periods of water stress imposed at different growth stages, and the recuperative ability of the species from drought stress. A major problem associated with Bambara groundnut production is its very low yields due to intra-seasonal and inter-seasonal variability in rainfall in semi-arid regions. The response pattern of physiological processes to water stress imposed at different growth ...

  6. Short Term Strategies for a Dynamic Multi-Period Routing Problem

    NARCIS (Netherlands)

    Angelelli, E.; Bianchessi, N.; Mansini, R.; Speranza, M. G.

    2009-01-01

    We consider a Dynamic Multi-Period Routing Problem (DMPRP) faced by a company which deals with on-line pick-up requests and has to serve them by a fleet of uncapacitated vehicles over a finite time horizon. When a request is issued, a deadline of a given number of days d ≤ 2 is associated to it: if

  7. Attenuation of short-period P, PcP, ScP, and pP waves in the earth's mantle

    International Nuclear Information System (INIS)

    Bock, G.; Clements, J.R.

    1982-01-01

    The parameter t* (ratio of body wave travel time to the average quality factor Q) was estimated under various assumptions of the nature of the earthquake sources for short-period P, PcP, and ScP phases originating from earthquakes in the Fiji-Tonga region and recorded at the Warramunga Seismic Array at Tennant Creek (Northern Territory, Australia). Spectral ratios were calculated for the amplitudes of PcP to P and of pP to P. The data reveal a laterally varying Q structure in the Fiji-Tonga region. The high-Q lithosphere descending beneath the Tonga Island arc is overlain above 350 km depth by a wedgelike zone of high attenuation with an average Q/sub α/ between 120 and 200 at short periods. The upper mantle farther to the west of the Tonga island arc is less attenuating, with Q/sub α/, between 370 and 560. Q/sub α/ is about 500 in the upper mantle on the oceanic side of the subduction zone. The t* estimates of this study are much smaller than estimates from the free oscillation model SL8. This can be partly explained by regional variations of Q in the upper mantle. If no lateral Q variations occur in the lower mantle, a frequency-dependent Q can make the PcP and ScP observations consistent with model SL8. Adopting the absorption band model to describe the frequency dependence of Q, the parameter tau 2 , the cut-off period of the high-frequency end of the absorption band, was determined. For different source models with finite corner frequencies, the average tau 2 for the mantle is between 0.01 and 0.10 s (corresponding to frequencies between 16 and 1.6 Hz) as derived from the PcP data, and between 0.06 and 0.12 s (2.7 and 1.3 Hz), as derived from the ScP data

  8. Short communication: study of immune parameters in three Greek dairy sheep breeds during the periparturient period.

    Science.gov (United States)

    Theodorou, G; Fragou, S; Chronopoulou, R; Kominakis, A; Rogdakis, E; Politis, I

    2007-12-01

    The objective of the present study was to evaluate whether immunosuppression occurs in 3 different Greek dairy sheep breeds during the periparturient period. A total of 33 ewes from 3 breeds [i.e., the low-producing Boutsiko breed (n = 11), which is highly adaptable to harsh environments; the high-producing but environmentally fragile Chios breed (n = 11); and an intermediate synthetic breed (50% Boutsiko, 25% Arta, and 25% Chios, n = 11)] were used. Blood samples were collected at 18 and 2 d before parturition and at 15 d after parturition. Total cell-associated and membrane-bound urokinase plasminogen activator (U-PA) activity, free U-PA binding sites on cellular membranes, and superoxide anion (SA) production by activated phagocytes were determined. Results indicated that all immune parameters measured remained constant during the periparturient period for the Boutsiko breed. In contrast, there were reductions in total cell-associated and membrane-bound U-PA activity by both monocytes-macrophages and neutrophils and in SA production by monocytes-macrophages at d 2 before parturition for the Chios breed. In the synthetic breed, there were reductions in total cell-associated and membrane-bound U-PA activity by monocytes-macrophages and in SA production by both monocytes-macrophages and neutrophils at d 15 after parturition. Thus, mild immunosuppression during the periparturient period was observed in the 2 breeds with the highest milk production.

  9. A large outbreak of Listeria monocytogenes infection with short incubation period in a tertiary care hospital.

    Science.gov (United States)

    Johnsen, Bjørn Odd; Lingaas, Egil; Torfoss, Dag; Strøm, Erik H; Nordøy, Ingvild

    2010-12-01

    Listeria monocytogenes is a foodborne pathogen with a high mortality rate. We report a large, nosocomial outbreak of Listeria monocytogenes infection. Patients with L. monocytogenes isolated from a sterile site, or from faeces when diarrhoea and fever were present, were included. Clinical data were collected from the patient records. The incubation period was calculated as the time between exposure and start of symptoms. Seventeen patients (11 women, median age 64 years) were infected of whom 15 patients were at increased risk for listeriosis. Eleven patients received empiric antibiotic treatment, eight of them with cephalosporins. Three patients died with a resulting mortality rate of 18%. The source of the outbreak was a Camembert cheese made from pasteurised milk containing up to 360 million colony forming units per portion. The median incubation period was 3-4 days. The incubation period in this outbreak was significantly shorter than previously reported, a fact that may be due to the high number of ingested bacteria. Furthermore, food restrictions in hospitals seem warranted, as do treatment with antibiotics effective against L. monocytogenes in at-risk populations. Copyright © 2010 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

  10. Propagation of short-period gravity waves at high-latitudes during the MaCWAVE winter campaign

    Directory of Open Access Journals (Sweden)

    K. Nielsen

    2006-07-01

    Full Text Available As part of the MaCWAVE (Mountain and Convective Waves Ascending Vertically winter campaign an all-sky monochromatic CCD imager has been used to investigate the properties of short-period mesospheric gravity waves at high northern latitudes. Sequential measurements of several nightglow emissions were made from Esrange, Sweden, during a limited period from 27–31 January 2003. Coincident wind measurements over the altitude range (~80–100 km using two meteor radar systems located at Esrange and Andenes have been used to perform a novel investigation of the intrinsic properties of five distinct wave events observed during this period. Additional lidar and MSIS model temperature data have been used to investigate their nature (i.e. freely propagating or ducted. Four of these extensive wave events were found to be freely propagating with potential source regions to the north of Scandinavia. No evidence was found for strong orographic forcing by short-period waves in the airglow emission layers. The fifth event was most unusual exhibiting an extensive, but much smaller and variable wavelength pattern that appeared to be embedded in the background wind field. Coincident wind measurements indicated the presence of a strong shear suggesting this event was probably due to a large-scale Kelvin-Helmholtz instability.

  11. Non-radial oscillations of rotating stars and their relevance to the short-period oscillations of cataclysmic variables

    International Nuclear Information System (INIS)

    Papaloizou, J.; Pringle, J.E.

    1978-01-01

    The usual hypothesis, that the short-period coherent oscillations seen in cataclysmic variables are attributable to g modes in a slowly rotating white dwarf, is considered. It is shown that this hypothesis is untenable for three main reasons: (i) the observed periods are too short for reasonable white dwarf models, (ii) the observed variability of the oscillations is too rapid and (iii) the expected rotation of the white dwarf, due to accretion, invalidates the slow rotation assumption on which standard g-mode theory is based. The low-frequency spectrum of a rotating pulsating star is investigated taking the effects of rotation fully into account. In this case there are two sets of low-frequency modes, the g modes, and modes similar to Rossby waves in the Earth's atmosphere and oceans, which are designated r modes. Typical periods for such modes are 1/m times the rotation period of the white dwarfs outer layers (m is the aximuthal wavenumber). It is concluded that non-radial oscillations of rotating white dwarfs can account for the properties of the oscillations seen in dwarf novae. Application of these results to other systems is also discussed. (author)

  12. France's seismic zoning

    International Nuclear Information System (INIS)

    Mohammadioun, B.

    1997-01-01

    In order to assess the seismic hazard in France in relation to nuclear plant siting, the CEA, EDF and the BRGM (Mine and Geology Bureau) have carried out a collaboration which resulted in a seismic-tectonic map of France and a data base on seismic history (SIRENE). These studies were completed with a seismic-tectonic zoning, taking into account a very long period of time, that enabled a probabilistic evaluation of the seismic hazard in France, and that may be related to adjacent country hazard maps

  13. Short time scale laws in self-potentialsignals from two different seismically active Mediterranean areas(the Southern Apennine chainand Crete Island

    Directory of Open Access Journals (Sweden)

    M. Macchiato

    2001-06-01

    Full Text Available Self-potential time series are investigated to characterise self-potential time scales. The data analysed were recorded in stations located in two active seismic areas of the Mediterranean region, the Southern Apennine chain (Giuliano and Crete Island (Heraklion, where in past and recent years many destructive seismic events have taken place. The seismological and geological settings, combined with a low level of cultural noise, allow us to consider these areas ideal outdoor laboratories to study the time dynamics of geophysical parameters of electrical nature. At the same time, the different seismological features of such areas make an inter-comparison between the geoelectrical variability observed at the two sites interesting. Fractal analysis tools, able to detect scale laws and quantify persistence features, are used to better understand the background variability properties of the self-potential signals. As results from our analysis, antipersistence seems to be a ubiquitous feature on short time scales (minutes regardless of environmental conditions. On such scales, the accumulation of random fluctuations is not particularly efficient and significant variations mostly occur as sudden jumps.

  14. Seismic testing

    International Nuclear Information System (INIS)

    Sollogoub, Pierre

    2001-01-01

    This lecture deals with: qualification methods for seismic testing; objectives of seismic testing; seismic testing standards including examples; main content of standard; testing means; and some important elements of seismic testing

  15. First Kepler results on compact pulsators - V. Slowly pulsating subdwarf B stars in short-period binaries

    DEFF Research Database (Denmark)

    Kawaler, Stephen D.; Reed, Michael D.; Østensen, Roy H.

    2010-01-01

    of sdB stars with a close M-dwarf companion with orbital periods of less than half a day. Because the orbital period is so short, the stars should be in synchronous rotation, and if so, the rotation period should imprint itself on the multiplet structure of the pulsations. However, we do not find clear......The survey phase of the Kepler Mission includes a number of hot subdwarf B (sdB) stars to search for non-radial pulsations. We present our analysis of two sdB stars that are found to be g-mode pulsators of the V1093 Her class. These two stars also display the distinct irradiation effect typical...... evidence for such rotational splitting. Though the stars do show some frequency spacings that are consistent with synchronous rotation, they also display multiplets with splittings that are much smaller. Longer-duration time series photometry will be needed to determine if those small splittings...

  16. Compensatory growth response of rainbow trout Oncorhynchus mykiss Walbaum following short starvation periods

    Science.gov (United States)

    Azodi, Maryam; Ebrahimi, Eisa; Farhadian, Omidvar; Mahboobi-Soofiani, Nasrollah; Morshedi, Vahid

    2015-07-01

    This sixty-day study was performed to determine the effects of short-term starvation and re-feeding cycles on growth, feeding performances and body composition of rainbow trout ( Oncorhynchus mykiss). Three hundred trout fingerlings with an average initial weight of 17.5±0.06 g were randomly distributed in 15 circular fiberglass tanks. The fish were exposed to 5 different feeding regimes; control: continuously fed twice daily to apparent satiation; T1: starved for 1 day and re-fed for 2 days; T2: starved for 1 day and re-fed for 4 days; T3: starved for 3 days and re-fed for 12 days; T4: starved for 4 days and re-fed for 16 days. At the end of the experiment, growth performance, feed utilization, whole body ash and moisture contents were not significantly ( P>0.05) different among the treatments. However, whole body protein content in T3 was significantly higher than other treatments ( Ptrout culture.

  17. Short-period atmospheric gravity waves - A study of their statistical properties and source mechanisms

    Science.gov (United States)

    Gedzelman, S. D.

    1983-01-01

    Gravity waves for the one year period beginning 19 October 1976 around Palisades, New York, are investigated to determine their statistical properties and sources. The waves have typical periods of 10 min, pressure amplitudes of 3 Pa and velocities of 30 m/s. In general, the largest, amplitude waves occur during late fall and early winter when the upper tropospheric winds directly overhead are fastest and the static stability of the lower troposphere is greatest. Mean wave amplitudes correlate highly with the product of the mean maximum wind speed and the mean low level stratification directly aloft. A distinct diurnal variation of wave amplitudes with the largest waves occurring in the pre-dawn hours is also observed as a result of the increased static stability then. The majority of waves are generated by shear instability; however, a number of waves are generated by distant sources such as nuclear detonations or large thunderstorms. The waves with distant sources can be distinguished on the basis of their generally much higher coherency across the grid and velocities that depart markedly from the wind velocity at any point in the sounding.

  18. Non-thyroid cancer in Northern Ukraine in the post-Chernobyl period: Short report.

    Science.gov (United States)

    Hatch, M; Ostroumova, E; Brenner, A; Federenko, Z; Gorokh, Y; Zvinchuk, O; Shpak, V; Tereschenko, V; Tronko, M; Mabuchi, K

    2015-06-01

    The Chernobyl nuclear power plant accident in Ukraine in 1986 led to widespread radioactive releases into the environment - primarily of radioiodines and cesium - heavily affecting the northern portions of the country, with settlement-averaged thyroid doses estimated to range from 10 mGy to more than 10 Gy. The increased risk of thyroid cancer among exposed children and adolescents is well established but the impact of radioactive contamination on the risk of other types of cancer is much less certain. To provide data on a public health issue of major importance, we have analyzed the incidence of non-thyroid cancers during the post-Chernobyl period in a well-defined cohort of 13,203 individuals who were <18 years of age at the time of the accident. The report is based on standardized incidence ratio (SIR) analysis of 43 non-thyroid cancers identified through linkage with the National Cancer Registry of Ukraine for the period 1998 through 2009. We compared the observed and expected number of cases in three cancer groupings: all solid cancers excluding thyroid, leukemia, and lymphoma. Our analyses found no evidence of a statistically significant elevation in cancer risks in this cohort exposed at radiosensitive ages, although the cancer trends, particularly for leukemia (SIR=1.92, 95% confidence interval: 0.69; 4.13), should continue to be monitored. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Short period sound speed oscillation measured by intensive XBT survey and its role on GNSS/acoustic positioning

    Science.gov (United States)

    Kido, M.; Matsui, R.; Imano, M.; Honsho, C.

    2017-12-01

    In the GNSS/acoustic measurement, sound speed in ocean plays a key role of accuracy of final positioning. We have shown than longer period sound speed undulation can be properly estimated from GNSS-A analysis itself in our previous work. In this work, we have carried out intensive XBT measurement to get temporal variation of sound speed in short period to be compared with GNSS-A derived one. In the individual temperature profile obtained by intensive XBT measurements (10 minutes interval up to 12 times of cast), clear vertical oscillation up to 20 m of amplitude in the shallow part were observed. These can be interpreted as gravitational internal wave with short-period and hence short wavelength anomaly. Kido et al. (2007) proposed that horizontal variation of the ocean structure can be considered employing five or more transponders at once if the structure is expressed by two quantities, i.e., horizontal gradient in x/y directions. However, this hypothesis requires that the variation must has a large spatial scale (> 2-5km) so that the horizontal variation can be regarded as linear within the extent of acoustic path to seafloor transponders. Therefore the wavelength of the above observed internal wave is getting important. The observed period of internal wave was 30-60 minute. However its wavelength cannot be directly measured. It must be estimate based on density profile of water column. In the comparison between sound speed change and positioning, the delay of their phases were 90 degree, which indicates that most steep horizontal slope of internal wave correspond to largest apparent positioning shift.

  20. Tailoring of the electrical and thermal properties using ultra-short period non-symmetric superlattices

    Directory of Open Access Journals (Sweden)

    Paulina Komar

    2016-10-01

    Full Text Available Thermoelectric modules based on half-Heusler compounds offer a cheap and clean way to create eco-friendly electrical energy from waste heat. Here we study the impact of the period composition on the electrical and thermal properties in non-symmetric superlattices, where the ratio of components varies according to (TiNiSnn:(HfNiSn6−n, and 0 ⩽ n ⩽ 6 unit cells. The thermal conductivity (κ showed a strong dependence on the material content achieving a minimum value for n = 3, whereas the highest value of the figure of merit ZT was achieved for n = 4. The measured κ can be well modeled using non-symmetric strain relaxation applied to the model of the series of thermal resistances.

  1. A Population of planetary systems characterized by short-period, Earth-sized planets

    Science.gov (United States)

    Steffen, Jason H.; Coughlin, Jeffrey L.

    2016-01-01

    We analyze data from the Quarter 1–17 Data Release 24 (Q1–Q17 DR24) planet candidate catalog from NASA’s Kepler mission, specifically comparing systems with single transiting planets to systems with multiple transiting planets, and identify a population of exoplanets with a necessarily distinct system architecture. Such an architecture likely indicates a different branch in their evolutionary past relative to the typical Kepler system. The key feature of these planetary systems is an isolated, Earth-sized planet with a roughly 1-d orbital period. We estimate that at least 24 of the 144 systems we examined (≳17%) are members of this population. Accounting for detection efficiency, such planetary systems occur with a frequency similar to the hot Jupiters. PMID:27790984

  2. A Population of planetary systems characterized by short-period, Earth-sized planets.

    Science.gov (United States)

    Steffen, Jason H; Coughlin, Jeffrey L

    2016-10-25

    We analyze data from the Quarter 1-17 Data Release 24 (Q1-Q17 DR24) planet candidate catalog from NASA's Kepler mission, specifically comparing systems with single transiting planets to systems with multiple transiting planets, and identify a population of exoplanets with a necessarily distinct system architecture. Such an architecture likely indicates a different branch in their evolutionary past relative to the typical Kepler system. The key feature of these planetary systems is an isolated, Earth-sized planet with a roughly 1-d orbital period. We estimate that at least 24 of the 144 systems we examined ([Formula: see text]17%) are members of this population. Accounting for detection efficiency, such planetary systems occur with a frequency similar to the hot Jupiters.

  3. Biomass production of dense direct-seeded lodgepole pine (Pinus contorta) at short rotation periods

    Energy Technology Data Exchange (ETDEWEB)

    Backlund, I.; Bergsten, U.

    2012-07-01

    Lodgepole pine (Pinus contorta) is a fast-growing species that is suitable for producing woody biomass in Nordic countries. Direct seeding of this species is cheaper than planting and creates dense, stable stands. The objective of this study was to quantify the stem volume and biomass production of direct seeded lodgepole pine stands grown under different site conditions with different stem densities, at an age that would permit extensive harvesting of biomass. A circle-plot inventory was performed in 16 of the oldest direct seeded lodgepole pine stands in mid-northern Sweden. Stemwood production of almost 200 m{sup 3}/ha was achieved on average on the best sites, rising to about 300 m{sup 3}/ha for the best circle-plots within 30 years of direct seeding despite the fact that pre-commercial thinning was made once or twice. This corresponds to 100 and 140 tons of dry weight biomass/ha, respectively. Higher stand stem densities ({>=}3000 st/ha) yielded more biomass with only slight reductions in diameter at breast height. The development of stem volume with respect to dominant height in direct seeded stands was becoming comparable to that in planted stands with similar spacing. It therefore seems that there is an unutilized potential for cost-effectively growing lodgepole pine in dense stands for biomass production after direct seeding. It may be possible to devise regimes for short(er) rotation forestry that would yield substantial amount of inexpensive biomass for biorefineries within a few decades. (orig.)

  4. The Unconstrained Event Bulletin (UEB) for the IMS Seismic Network Spaning the Period May 15-28, 2010: a New Resource for Algorithm Development and Testing

    Science.gov (United States)

    Brogan, R.; Young, C. J.; Ballard, S.

    2017-12-01

    A major problem with developing new data processing algorithms for seismic event monitoring is the lack of standard, high-quality "ground-truth" data sets to test against. The unfortunate effect of this is that new algorithms are often developed and tested with new data sets, making comparison of algorithms difficult and subjective. In an effort towards resolving this problem, we have developed the Unconstrained Event Bulletin (UEB), a ground-truth data set from the International Monitoring System (IMS) primary and auxiliary seismic networks for a two-week period in May 2010. All UEB analysis was performed by the same expert, who has more than 30 years of experience analyzing seismic data for nuclear explosion monitoring. We used the most complete International Data Centre (IDC) analyst-review event bulletin (the Late Event Bulletin or LEB) as a starting point for this analysis. To make the UEB more complete, we relaxed the minimum event definite criteria to the level of a pair of P-type and an S-type phases at a single station and using azimuth/slowness as defining. To add even more events that our analyst recognized and didn't want to omit, in rare cases, events were constructed using only 1 P-phase. Perhaps most importantly, on average our analyst spent more than 60 hours per day of data, far more than was possible in the production of the LEB. The result of all this was that while the LEB had 2,101 LEB events for the 2-week time period, we ended up with 11,435 events in the UEB, an increase of over 400%. New events are located all over the world and include both earthquakes and manmade events such as mining explosions. Our intent is to make our UEB data set openly available for all researchers to use for testing detection, correlation, and location algorithms, thus making it much easier to objectively compare different research efforts. Acknowledgement: Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and

  5. BVRI Photometric Study of the Short Period, Solar Type, Semi-Detached Binary, NSVS 10083189

    Science.gov (United States)

    Samec, Ronald G.; Caton, Daniel B.; Olsen, Amber; Faulkner, Danny R.; Hill, Robert L.

    2017-06-01

    Precision BVRcIc light curves of NSVS 5066754 were taken on 11 nights in February through April 2015 at Dark Sky Observatory in North Carolina with the 0.81-m reflector of Appalachian State University and on 1 night on the SARA 1-m reflector at Kitt Peak National Observatory in remote mode. It is an ~ F8V eclipsing binary with a period of 0.4542238 (2) d.Seven times of minimum light were calculated, for 5 primary and 2 secondary eclipses from our present observations:HJD I = 2457067.75453±0.0003, 2457088.64907±0.0001, 2457089.55708±0.0001, 2457098.64163±0.0004, 24557113.63117±0.0002HJD II = 2457066.61874±0.0008, 2457067.52329±0.0017.In addition, seven observations at minima were introduced as low weighted times of minimum light taken from archived NSVS Data.The following decreasing quadratic ephemeris was determined from all available times of minimum light in this study covering some 15 years:JD Hel MinI = 2457089.55665±0.00054d + 0.4542179±0. 0000006 X E -0.00000000049±0.00000000005 × E2We note that this result has a strong level of confidence. This again gives evidence that the components are coming into contact possibly due to magnetic braking as indicated by dark spot activity on the binary.We initially modeled the B,V,R,I curves simultaneously with the Wilson-Devinney program in a shallow contact configuration (mode 3) as indicated by our Binary Maker 3 fits. This led to a near but non-contact configuration. Next, the general Mode 2 was used to give clues regarding the configuration. During this investigation, the primary component came into contact while the secondary star remained detached. Next, a solution was determined in a semidetached, mode 4 state (larger component filling its critical lobe and the secondary under filing. This may indicate that NSVS 10083189 is coming into contact for the first time. The mode and the period change corroborate.Our semi-detached, near contact solution, gave a mass ratio of 0.58, with component temperatures of

  6. Short and long periodic atmospheric variations between 25 and 200 km

    Science.gov (United States)

    Justus, C. G.; Woodrum, A.

    1973-01-01

    Previously collected data on atmospheric pressure, density, temperature and winds between 25 and 200 km from sources including Meteorological Rocket Network data, ROBIN falling sphere data, grenade release and pitot tube data, meteor winds, chemical release winds, satellite data, and others were analyzed by a daily difference method and results on the distribution statistics, magnitude, and spatial structure of gravity wave and planetary wave atmospheric variations are presented. Time structure of the gravity wave variations were determined by the analysis of residuals from harmonic analysis of time series data. Planetary wave contributions in the 25-85 km range were discovered and found to have significant height and latitudinal variation. Long period planetary waves, and seasonal variations were also computed by harmonic analysis. Revised height variations of the gravity wave contributions in the 25 to 85 km height range were computed. An engineering method and design values for gravity wave magnitudes and wave lengths are given to be used for such tasks as evaluating the effects on the dynamical heating, stability and control of spacecraft such as the space shuttle vehicle in launch or reentry trajectories.

  7. Probability Estimates of Solar Proton Doses During Periods of Low Sunspot Number for Short Duration Missions

    Science.gov (United States)

    Atwell, William; Tylka, Allan J.; Dietrich, William F.; Rojdev, Kristina; Matzkind, Courtney

    2016-01-01

    In an earlier paper presented at ICES in 2015, we investigated solar particle event (SPE) radiation exposures (absorbed dose) to small, thinly-shielded spacecraft during a period when the monthly smoothed sunspot number (SSN) was less than 30. Although such months are generally considered "solar-quiet", SPEs observed during these months even include Ground Level Events, the most energetic type of SPE. In this paper, we add to previous study those SPEs that occurred in 1973-2015 when the SSN was greater than 30 but less than 50. Based on the observable energy range of the solar protons, we classify the event as GLEs, sub-GLEs, and sub-sub-GLEs, all of which are potential contributors to the radiation hazard. We use the spectra of these events to construct a probabilistic model of the absorbed dose due to solar protons when SSN < 50 at various confidence levels for various depths of shielding and for various mission durations. We provide plots and tables of solar proton-induced absorbed dose as functions of confidence level, shielding thickness, and mission-duration that will be useful to system designers.

  8. Magnetic field topology of the cool, active, short-period binary system σ2 Coronae Borealis

    Science.gov (United States)

    Rosén, L.; Kochukhov, O.; Alecian, E.; Neiner, C.; Morin, J.; Wade, G. A.; BinaMIcS Collaboration

    2018-06-01

    Aims: The goal of this work is to study the cool, active binary star σ2 CrB, focussing on its magnetic field. The two F9-G0 components of this system are tidally locked and in a close orbit, increasing the chance of interaction between their magnetospheres. Methods: We used Stokes IV data from the twin spectropolarimeters Narval at the TBL and ESPaDOnS at the CFHT. The least-squares deconvolution multi-line technique was used to increase the signal-to-noise ratio of the data. We then applied a new binary Zeeman-Doppler imaging code to reconstruct simultaneously the magnetic topology and brightness distribution of both components of σ2 CrB. This analysis was carried out for two observational epochs in 2014 and 2017. Results: A previously unconfirmed magnetic field of the primary star has been securely detected. At the same time, the polarisation signatures of the secondary appear to have a systematically larger amplitude than that of the primary. This corresponds to a stronger magnetic field, for which the magnetic energy of the secondary exceeds that of the primary by a factor of 3.3-5.7. While the magnetic energy is similar for the secondary star in the two epochs, the magnetic energy is about twice as high in 2017 for the primary. The magnetic field topology of the two stars in the earlier epoch (2014) is very different. The fractions of energy in the dipole and quadrupole components of the secondary are similar and thereafter decrease with increasing harmonic angular degree ℓ. At the same time, for the primary the fraction of energy in the dipole component is low and the maximum energy contribution comes from ℓ = 4. However, in the 2017 epoch both stars have similar field topologies and a systematically decreasing energy with increasing ℓ. In the earlier epoch, the magnetic field at the visible pole appears to be of opposite polarity for the primary and secondary, suggesting linked magnetospheres. The apparent rotational periods of both σ2 Cr

  9. Interfacial electronic charge transfer and density of states in short period Cu/Cr multilayers; TOPICAL

    International Nuclear Information System (INIS)

    Barbee, T W; Bello, A F; Klepeis, J E; Van Buuren, T

    1999-01-01

    Nanometer period metallic multilayers are ideal structures to investigate electronic phenomena at interfaces between metal films since interfacial atoms comprise a large atomic fraction of the samples. The Cu/Cr binary pair is especially suited to study the interfaces in metals since these elements are mutually insoluble, thus eliminating mixing effects and compound formation and the lattice mismatch is very small. This allows the fabrication of high structural quality Cu/Cr multilayers that have a structure which can be approximated in calculations based on idealized atomic arrangements. The electronic structure of the Cu and the Cr layers in several samples of thin Cu/Cr multilayers were studied using x-ray absorption spectroscopy (XAS). Total electron yield was measured and used to study the white lines at the Cu L(sub 2) and L(sub 3) absorption edges. The white lines at the Cu absorption edges are strongly related to the unoccupied d-orbitals and are used to calculate the amount of charge transfer between the Cr and Cu atoms in interfaces. Analysis of the Cu white lines show a charge transfer of 0.026 electrons/interfacial Cu atom to the interfacial Cr atoms. In the Cu XAS spectra we also observe a van Hove singularity between the L(sub 2) and L(sub 3) absorption edges as expected from the structural analysis. The absorption spectra are compared to partial density of states obtained from a full-potential linear muffin-tin orbital calculation. The calculations support the presence of charge transfer and indicate that it is localized to the first two interfacial layers in both Cu and Cr

  10. Influence of temperature of the short-period heat treatment on mechanical properties of the NiTi alloy

    Directory of Open Access Journals (Sweden)

    Jaroslav Čapek

    2014-01-01

    Full Text Available The equiatomic alloy of nickel and titanium, known as nitinol, possesses unique properties such as superelasticity, pseudoplasticity, shape memory, while maintaining good corrosion resistance and sufficient biocompatibility. Therefore it is used for production of various devices including surgery implants. Heat treatment of nickel-rich NiTi alloys can result in precipitation of nickel-rich phases, which strongly influence tensile and fatigue behaviour of the material.In this work we have studied influence of short-period heat treatment on tensile behaviour and fatigue life of the NiTi (50.9 at. % Ni wire intended for fabrication of surgery stents.

  11. Magnetic Activity and Period Variation Studies of the Short-period Eclipsing Binaries. II. V1101 Her, AD Phe, and NSV 455 (J011636.15-394955.7)

    Science.gov (United States)

    Pi, Qing-feng; Zhang, Li-yun; Bi, Shao-lan; Han, Xianming L.; Wang, Dai-mei; Lu, Hong-peng

    2017-12-01

    In this paper, we present new BVRI light curves of short-period contact eclipsing binaries V1101 Her and AD Phe from our observations carried out from 2014 to 2015 using the SARA KP and SARA CT telescopes. There is an eclipsing binary located at α(2000) = 01h16m36.ˢ15 and δ(2000) = -39°49‧55.″7 in the field of view of AD Phe. We derived an updated ephemeris and found there a cyclic variation overlaying a continuous period increase (V1101 Her) and decrease (AD Phe). This kind of cyclic variation may be attributed to the light time effect via the presence of the third body or magnetic activity cycle. The orbital period increase suggests that V1101 Her is undergoing a mass-transfer from the primary to the secondary component (dM 1/dt = 2.64(±0.11) × 10-6 M ⊙ yr-1) with the third body (P 3 = 13.9(±1.9) years), or 2.81(±0.07) × 10-6 M ⊙ yr-1 for an increase andmagnetic cycle (12.4(±0.5) years). The long-term period decrease suggests that AD Phe is undergoing a mass-transfer from the secondary component to the primary component at a rate of -8.04(±0.09) × 10-8 M ⊙ yr-1 for a period decrease and the third body (P 3 = 56.2(±0.8) years), or -7.11(±0.04) × 10-8 M ⊙ yr-1 for a decrease and magnetic cycle (50.3(±0.5) years). We determined their orbital and geometrical parameters. For AD Phe, we simultaneously analyzed our BVRI light curves and the spectroscopic observations obtained by Duerbeck & Rucinski. The spectral type of V1101 Her was classified as G0 ± 2V by LAMOST stellar spectra survey. The asymmetry of the R-band light curve of AD Phe obtained by McFarlane & Hilditch in 1987 is explained by a cool spot on the primary component.

  12. Interfacial intermixing in InAs/GaSb short-period-superlattices grown by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Luna, E.; Satpati, B.; Trampert, A.; Rodriguez, J. B.; Baranov, A. N.; Tournie, E.

    2010-01-01

    The unique properties of the noncommon-atom InAs/GaSb short-period-superlattices (SPSL) strongly depend on the interface structure. These interfaces are characterized using transmission electron microscopy (TEM). The compositional sharpness is obtained from the comparison of the experimental contrast in g 002 two-beam dark-field TEM images with simulated intensity profiles, which are calculated assuming that the element distribution profiles are described by sigmoidal functions. The interfacial intermixing, defined by the chemical width, is obtained for SPSL with different periods and layer thicknesses, even in the extreme case of nominally less than 3 ML thick InAs layers. Nominal 1 ML InSb layers intentionally inserted are also identified.

  13. Design response spectra-compliant real and synthetic GMS for seismic analysis of seismically isolated nuclear reactor containment building

    Directory of Open Access Journals (Sweden)

    Ahmer Ali

    2017-06-01

    Full Text Available Due to the severe impacts of recent earthquakes, the use of seismic isolation is paramount for the safety of nuclear structures. The diversity observed in seismic events demands ongoing research to analyze the devastating attributes involved, and hence to enhance the sustainability of base-isolated nuclear power plants. This study reports the seismic performance of a seismically-isolated nuclear reactor containment building (NRCB under strong short-period ground motions (SPGMs and long-period ground motions (LPGMs. The United States Nuclear Regulatory Commission-based design response spectrum for the seismic design of nuclear power plants is stipulated as the reference spectrum for ground motion selection. Within the period range(s of interest, the spectral matching of selected records with the target spectrum is ensured using the spectral-compatibility approach. NRC-compliant SPGMs and LPGMs from the mega-thrust Tohoku earthquake are used to obtain the structural response of the base-isolated NRCB. To account for the lack of earthquakes in low-to-moderate seismicity zones and the gap in the artificial synthesis of long-period records, wavelet-decomposition based autoregressive moving average modeling for artificial generation of real ground motions is performed. Based on analysis results from real and simulated SPGMs versus LPGMs, the performance of NRCBs is discussed with suggestions for future research and seismic provisions.

  14. Design response spectra-compliant real and synthetic GMS for seismic analysis of seismically isolated nuclear reactor containment building

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Ahmer [ENVICO Consultants Co. Ltd., Seoul (Korea, Republic of); Abu-Hayah, Nadin; Kim, Doo Kie [Civil and Environmental Engineering, Kunsan National University, Gunsan (Korea, Republic of); Cho, Sung Gook [Innose Tech Co., Ltd., Incheon (Korea, Republic of)

    2017-06-15

    Due to the severe impacts of recent earthquakes, the use of seismic isolation is paramount for the safety of nuclear structures. The diversity observed in seismic events demands ongoing research to analyze the devastating attributes involved, and hence to enhance the sustainability of base-isolated nuclear power plants. This study reports the seismic performance of a seismically-isolated nuclear reactor containment building (NRCB) under strong short-period ground motions (SPGMs) and long-period ground motions (LPGMs). The United States Nuclear Regulatory Commission-based design response spectrum for the seismic design of nuclear power plants is stipulated as the reference spectrum for ground motion selection. Within the period range(s) of interest, the spectral matching of selected records with the target spectrum is ensured using the spectral-compatibility approach. NRC-compliant SPGMs and LPGMs from the mega-thrust Tohoku earthquake are used to obtain the structural response of the base-isolated NRCB. To account for the lack of earthquakes in low-to-moderate seismicity zones and the gap in the artificial synthesis of long-period records, wavelet-decomposition based autoregressive moving average modeling for artificial generation of real ground motions is performed. Based on analysis results from real and simulated SPGMs versus LPGMs, the performance of NRCBs is discussed with suggestions for future research and seismic provisions.

  15. Short-period volcanic gas precursors to phreatic eruptions: Insights from Poás Volcano, Costa Rica

    Science.gov (United States)

    de Moor, Maarten; Aiuppa, Alessandro; Pacheco, Javier; Avard, Geoffroy; Kern, Christoph; Liuzzo, Marco; Martinez, Maria; Giudice, Gaetano; Fischer, Tobias P.

    2016-01-01

    Volcanic eruptions involving interaction with water are amongst the most violent and unpredictable geologic phenomena on Earth. Phreatic eruptions are exceptionally difficult to forecast by traditional geophysical techniques. Here we report on short-term precursory variations in gas emissions related to phreatic blasts at Poás volcano, Costa Rica, as measured with an in situ multiple gas analyzer that was deployed at the edge of the erupting lake. Gas emitted from this hyper-acid crater lake approaches magmatic values of SO2/CO2 1–6 days prior to eruption. The SO2 flux derived from magmatic degassing through the lake is measureable by differential optical absorption spectrometry (sporadic campaign measurements), which allows us to constrain lake gas output and input for the major gas species during eruptive and non-eruptive periods. We can further calculate power supply to the hydrothermal system using volatile mass balance and thermodynamics, which indicates that the magmatic heat flux into the shallow hydrothermal system increases from ∼27 MW during quiescence to ∼59 MW during periods of phreatic events. These transient pulses of gas and heat from the deeper magmatic system generate both phreatic eruptions and the observed short-term changes in gas composition, because at high gas flux scrubbing of sulfur by the hydrothermal system is both kinetically and thermodynamically inhibited whereas CO2gas is always essentially inert in hyperacid conditions. Thus, the SO2/CO2 of lake emissions approaches magmatic values as gas and power supply to the sub-limnic hydrothermal system increase, vaporizing fluids and priming the hydrothermal system for eruption. Our results suggest that high-frequency real-time gas monitoring could provide useful short-term eruptive precursors at volcanoes prone to phreatic explosions.

  16. Micromachined silicon seismic accelerometer development

    Energy Technology Data Exchange (ETDEWEB)

    Barron, C.C.; Fleming, J.G.; Montague, S. [and others

    1996-08-01

    Batch-fabricated silicon seismic transducers could revolutionize the discipline of seismic monitoring by providing inexpensive, easily deployable sensor arrays. Our ultimate goal is to fabricate seismic sensors with sensitivity and noise performance comparable to short-period seismometers in common use. We expect several phases of development will be required to accomplish that level of performance. Traditional silicon micromachining techniques are not ideally suited to the simultaneous fabrication of a large proof mass and soft suspension, such as one needs to achieve the extreme sensitivities required for seismic measurements. We have therefore developed a novel {open_quotes}mold{close_quotes} micromachining technology that promises to make larger proof masses (in the 1-10 mg range) possible. We have successfully integrated this micromolding capability with our surface-micromachining process, which enables the formation of soft suspension springs. Our calculations indicate that devices made in this new integrated technology will resolve down to at least sub-{mu}G signals, and may even approach the 10{sup -10} G/{radical}Hz acceleration levels found in the low-earth-noise model.

  17. CSI 2264: CHARACTERIZING YOUNG STARS IN NGC 2264 WITH SHORT-DURATION PERIODIC FLUX DIPS IN THEIR LIGHT CURVES

    Energy Technology Data Exchange (ETDEWEB)

    Stauffer, John; Cody, Ann Marie; Rebull, Luisa; Plavchan, Peter; Carey, Sean [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); McGinnis, Pauline; Alencar, Silvia H. P. [Departamento de Física—ICEx—UFMG, Av. Antônio Carlos, 6627, 30270-901, Belo Horizonte, MG (Brazil); Hillenbrand, Lynne A.; Carpenter, John [Astronomy Department, California Institute of Technology, Pasadena, CA 91125 (United States); Turner, Neal J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Terebey, Susan [Department of Physics and Astronomy, 5151 State University Drive, California State University at Los Angeles, Los Angeles, CA 90032 (United States); Morales-Calderón, María [Centro de Astrobiología, Dpto. de Astrofísica, INTA-CSIC, PO BOX 78, E-28691, ESAC Campus, Villanueva de la Cañada, Madrid (Spain); Bouvier, Jerome; Venuti, Laura [Université de Grenoble, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG), F-38000 Grenoble (France); CNRS, IPAG, F-38000 Grenoble (France); Hartmann, Lee; Calvet, Nuria [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48105 (United States); Micela, Giusi; Flaccomio, Ettore [INAF—Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, I-90134, Palermo (Italy); Song, Inseok [Department of Physics and Astronomy, The University of Georgia, Athens, GA 30602–2451 (United States); Gutermuth, Rob, E-mail: stauffer@ipac.caltech.edu [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); and others

    2015-04-15

    We identify nine young stellar objects (YSOs) in the NGC 2264 star-forming region with optical CoRoT light curves exhibiting short-duration, shallow periodic flux dips. All of these stars have infrared excesses that are consistent with their having inner disk walls near the Keplerian co-rotation radius. The repeating photometric dips have FWHMs generally less than 1 day, depths almost always less than 15%, and periods (3 < P < 11 days) consistent with dust near the Keplerian co-rotation period. The flux dips vary considerably in their depth from epoch to epoch, but usually persist for several weeks and, in two cases, were present in data collected in successive years. For several of these stars, we also measure the photospheric rotation period and find that the rotation and dip periods are the same, as predicted by standard “disk-locking” models. We attribute these flux dips to clumps of material in or near the inner disk wall, passing through our line of sight to the stellar photosphere. In some cases, these dips are also present in simultaneous Spitzer IRAC light curves at 3.6 and 4.5 microns. We characterize the properties of these dips, and compare the stars with light curves exhibiting this behavior to other classes of YSOs in NGC 2264. A number of physical mechanisms could locally increase the dust scale height near the inner disk wall, and we discuss several of those mechanisms; the most plausible mechanisms are either a disk warp due to interaction with the stellar magnetic field or dust entrained in funnel-flow accretion columns arising near the inner disk wall.

  18. CSI 2264: CHARACTERIZING YOUNG STARS IN NGC 2264 WITH SHORT-DURATION PERIODIC FLUX DIPS IN THEIR LIGHT CURVES

    International Nuclear Information System (INIS)

    Stauffer, John; Cody, Ann Marie; Rebull, Luisa; Plavchan, Peter; Carey, Sean; McGinnis, Pauline; Alencar, Silvia H. P.; Hillenbrand, Lynne A.; Carpenter, John; Turner, Neal J.; Terebey, Susan; Morales-Calderón, María; Bouvier, Jerome; Venuti, Laura; Hartmann, Lee; Calvet, Nuria; Micela, Giusi; Flaccomio, Ettore; Song, Inseok; Gutermuth, Rob

    2015-01-01

    We identify nine young stellar objects (YSOs) in the NGC 2264 star-forming region with optical CoRoT light curves exhibiting short-duration, shallow periodic flux dips. All of these stars have infrared excesses that are consistent with their having inner disk walls near the Keplerian co-rotation radius. The repeating photometric dips have FWHMs generally less than 1 day, depths almost always less than 15%, and periods (3 < P < 11 days) consistent with dust near the Keplerian co-rotation period. The flux dips vary considerably in their depth from epoch to epoch, but usually persist for several weeks and, in two cases, were present in data collected in successive years. For several of these stars, we also measure the photospheric rotation period and find that the rotation and dip periods are the same, as predicted by standard “disk-locking” models. We attribute these flux dips to clumps of material in or near the inner disk wall, passing through our line of sight to the stellar photosphere. In some cases, these dips are also present in simultaneous Spitzer IRAC light curves at 3.6 and 4.5 microns. We characterize the properties of these dips, and compare the stars with light curves exhibiting this behavior to other classes of YSOs in NGC 2264. A number of physical mechanisms could locally increase the dust scale height near the inner disk wall, and we discuss several of those mechanisms; the most plausible mechanisms are either a disk warp due to interaction with the stellar magnetic field or dust entrained in funnel-flow accretion columns arising near the inner disk wall

  19. PHOTOMETRIC STUDIES OF THREE NEGLECTED SHORT-PERIOD CONTACT BINARIES GN BOOTIS, BL LEONIS, AND V1918 CYGNI

    International Nuclear Information System (INIS)

    Yang, Y.-G.; Dai, H.-F.; Qian, S.-B.

    2013-01-01

    We present new photometry for three short-period contact binaries, GN Boo, BL Leo, and V1918 Cyg, observed from 2008 December to 2012 April using several small telescopes in China. Photometric models were deduced from new observations using the updated Wilson-Devinney Code. The results show that GN Boo and BL Leo are W-type contact binaries, while V1918 Cyg is an A-type one. The mass ratios and fill-out factors are q = 0.320(± 0.002) and f = 5.8(± 0.1)% for GN Boo, q = 0.476(± 0.005) and f = 21.3(± 1.1)% for BL Leo, q = 0.264(± 0.002), and f = 49.7(± 0.7)% for V1918 Cyg, respectively. From the (O – C) curves, it is discovered that the orbital periods of three binaries have varied in a complicated way, i.e., cyclic oscillation for GN Boo, long-term period decrease for BL Leo, and both for V1918 Cyg. The cyclic variations for GN Boo and V1918 Cyg may probably be attributed to the magnetic activity of the primary component or light-time effect due to the third body. Meanwhile, the secular period decreases for BL Leo and V1918 Cyg may result from mass transfer from the primary to the secondary, accompanying the mass and angular momentum loss from the central system. Finally, GN Boo, BL Leo, and V1918 Cyg will evolve into deep contact binaries. Additionally, a statistical study of 37 contact binaries with decreasing periods is given. We obtained the relations of q – f and q – dln P/dt, and preliminarily determined the mass loss rate of dln M/dt from the binary system.

  20. Martian seismicity

    International Nuclear Information System (INIS)

    Goins, N.R.; Lazarewicz, A.R.

    1979-01-01

    During the Viking mission to Mars, the seismometer on Lander II collected approximately 0.24 Earth years of observations data, excluding periods of time dominated by wind-induced Lander vibration. The ''quiet-time'' data set contains no confirmed seismic events. A proper assessment of the significance of this fact requires quantitative estimates of the expected detection rate of the Viking seismometer. The first step is to calculate the minimum magnitude event detectable at a given distance, including the effects of geometric spreading, anelastic attenuation, seismic signal duration, seismometer frequency response, and possible poor ground coupling. Assuming various numerical quantities and a Martian seismic activity comparable to that of intraplate earthquakes, the appropriate integral gives an expected annual detection rate of 10 events, nearly all of which are local. Thus only two to three events would be expected in the observational period presently on hand and the lack of observed events is not in gross contradiction to reasonable expectations. Given the same assumptions, a seismometer 20 times more sensitive than the present instrument would be expected to detect about 120 events annually

  1. PG 0308 + 096 and PG 1026 + 002 - Two new short period binary stars resulting from common-envelope evolution

    Science.gov (United States)

    Saffer, Rex A.; Wade, Richard A.; Liebert, James; Green, Richard F.; Sion, Edward M.; Bechtold, J.; Foss, Diana; Kidder, K.

    1993-01-01

    Ultraviolet spectroscopy, optical spectroscopy, and spectrophotometry have been used to study the excess UV stars PG 0308 + 096 and PG 1026 + 002. Both objects are short-period binary systems, each containing a DA white dwarf star and a dM star. Orbital periods of approximately 0.284 day for PG 0308 + 096, and aproximately 0.597 day for PG 1026, have been found by spectroscopic analysis of the H-alpha emission line. Ly-alpha and Balmer line profile fitting were used to estimate the mass of white dwarf stars; mass estimates for the dM stars are based on their spectral types. The orbital inclinations are derived from these masses, the periods, and amplitudes of the H-alpha radial velocity curves. The equivalent width of the H-alpha emission line, in each binary system, varies with the orbital phase in such a manner as to imply that it arises, in large part at least, from the hemisphere of the M star that faces the white dwarf star.

  2. Exercise during Short-Term and Long-Term Continuous Exposure to Hypoxia Exacerbates Sleep-Related Periodic Breathing

    Science.gov (United States)

    Tellez, Helio Fernandez; Morrison, Shawnda A.; Neyt, Xavier; Mairesse, Olivier; Piacentini, Maria Francesca; Macdonald-Nethercott, Eoin; Pangerc, Andrej; Dolenc-Groselj, Leja; Eiken, Ola; Pattyn, Nathalie; Mekjavic, Igor B.; Meeusen, Romain

    2016-01-01

    Study Objectives: Exposure to hypoxia elevates chemosensitivity, which can lead to periodic breathing. Exercise impacts gas exchange, altering chemosensitivity; however, interactions between sleep, exercise and chronic hypoxic exposure have not been examined. This study investigated whether exercise exacerbates sleep-related periodic breathing in hypoxia. Methods: Two experimental phases. Short-Term Phase: a laboratory controlled, group-design study in which 16 active, healthy men (age: 25 ± 3 y, height: 1.79 ± 0.06 m, mass: 74 ± 8 kg) were confined to a normobaric hypoxic environment (FIO2 = 0.139 ± 0.003, 4,000 m) for 10 days, after random assignment to a sedentary (control, CON) or cycle-exercise group (EX). Long-Term Phase: conducted at the Concordia Antarctic Research Station (3,800 m equivalent at the Equator) where 14 men (age: 36 ± 9 y, height: 1.77 ± 0.09 m, mass: 75 ± 10 kg) lived for 12–14 months, continuously confined. Participants were stratified post hoc based on self-reported physical activity levels. We quantified apnea-hypopnea index (AHI) and physical activity variables. Results: Short-Term Phase: mean AHI scores were significantly elevated in the EX group compared to CON (Night1 = CON: 39 ± 51, EX: 91 ± 59; Night10 = CON: 32 ± 32, EX: 92 ± 48; P = 0.046). Long-Term Phase: AHI was correlated to mean exercise time (R2 = 0.4857; P = 0.008) and the coefficient of variation in night oxyhemoglobin saturation (SpO2; R2 = 0.3062; P = 0.049). Conclusions: Data indicate that exercise (physical activity) per se affects night SpO2 concentrations and AHI after a minimum of two bouts of moderate-intensity hypoxic exercise, while habitual physical activity in hypobaric hypoxic confinement affects breathing during sleep, up to 13+ months' duration Citation: Tellez HF, Morrison SA, Neyt X, Mairesse O, Piacentini MF, Macdonald-Nethercott E, Pangerc A, Dolenc-Groselj L, Eiken O, Pattyn N, Mekjavic IB, Meeusen R. Exercise during short-term and long

  3. A passive method for the determination of the equilibrium factor between radon gas and its short period progeny

    International Nuclear Information System (INIS)

    Lopez, Fabio O.; Canoba, Analia C.

    2001-01-01

    Due to the radiological importance of 222 Rn gas and its progeny of short period it is extremely necessary to count with an adequate methodology for the determination of its concentration in the different atmospheres in which human activity is developed. In this work a method was developed to determine the concentration of 222 Rn gas and the equilibrium factor between the concentration of the gas and its descendants, by means of a single device that has two Makrofol passive tracks detector. This device is completely passive and integrating, conditions that make it very appropriate to be used in any atmospheres in which human activity is developed, for example in houses, schools, places of work, underground mines, etc. (author)

  4. Short-range order in alloys of nickel with the elements of group VIII of the periodic table

    International Nuclear Information System (INIS)

    Khwaja, F.A.

    1981-08-01

    Experimental measurements of the diffuse X-ray scattering intensity were performed on alloys of Ni with Rh and Os. The atomic short-range order (SRO) parameters αsub(i) and the size-effect parameters βsub(i) were calculated from these measurements. It is established that SRO and size-effect exist in Ni-Rh and Ni-Os alloys analogously as in a few other alloys of Ni with the elements of group VIII of the periodic table. The experimental data was interpreted theoretically by calculating the interaction energies from the pseudo-potentials and the effective valencies of the individual components of the systems studied. It was found that theoretically calculated values of the interaction energies for these alloys are inconsistent with the experimentally determined sign of the SRO parameter. (author)

  5. Quasi-periodic oscillations in short recurring bursts of the soft gamma repeater J1550–5418

    Energy Technology Data Exchange (ETDEWEB)

    Huppenkothen, D.; D' Angelo, C.; Watts, A. L.; Heil, L.; Van der Klis, M.; Van der Horst, A. J. [Astronomical Institute " Anton Pannekoek," University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands); Kouveliotou, C. [Astrophysics Office, ZP 12, NASA-Marshall Space Flight Center, Huntsville, AL 35812 (United States); Baring, M. G. [Department of Physics and Astronomy, Rice University, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Göğüş, E.; Kaneko, Y. [SabancıUniversity, Orhanlı-Tuzla, İstanbul 34956 (Turkey); Granot, J. [Department of Natural Sciences, The Open University of Israel, 1 University Road, P.O. Box 808, Ra' anana 43537 (Israel); Lin, L. [François Arago Centre, APC, 10 rue Alice Domon et Léonie Duquet, F-75205 Paris (France); Von Kienlin, A. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); Younes, G., E-mail: D.Huppenkothen@uva.nl [NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States)

    2014-06-01

    The discovery of quasi-periodic oscillations (QPOs) in magnetar giant flares has opened up prospects for neutron star asteroseismology. The scarcity of giant flares makes a search for QPOs in the shorter, far more numerous bursts from soft gamma repeaters (SGRs) desirable. In Huppenkothen et al., we developed a Bayesian method for searching for QPOs in short magnetar bursts, taking into account the effects of the complicated burst structure, and have shown its feasibility on a small sample of bursts. Here we apply the same method to a much larger sample from a burst storm of 286 bursts from SGR J1550–5418. We report a candidate signal at 260 Hz in a search of the individual bursts, which is fairly broad. We also find two QPOs at ∼93 Hz, and one at 127 Hz, when averaging periodograms from a number of bursts in individual triggers, at frequencies close to QPOs previously observed in magnetar giant flares. Finally, for the first time, we explore the overall burst variability in the sample and report a weak anti-correlation between the power-law index of the broadband model characterizing aperiodic burst variability and the burst duration: shorter bursts have steeper power-law indices than longer bursts. This indicates that longer bursts vary over a broader range of timescales and are not simply longer versions of the short bursts.

  6. A random field model for the estimation of seismic hazard. Final report for the period 1 January 1990 - 31 December 1990

    International Nuclear Information System (INIS)

    Yucemen, S.

    1991-02-01

    The general theory of stationary random functions is utilized to assess the seismic hazard associated with a linearly extending seismic source. The past earthquake occurrence data associated with a portion of the North Anatolian fault are used to demonstrate the implementation of the proposed model. 18 refs, figs and tabs

  7. A random field model for the estimation of seismic hazard. Final report for the period 1 January 1990 - 31 December 1990

    Energy Technology Data Exchange (ETDEWEB)

    Yucemen, S [Middle East Technical Univ., Ankara (Turkey). Dept. of Statistics

    1991-02-01

    The general theory of stationary random functions is utilized to assess the seismic hazard associated with a linearly extending seismic source. The past earthquake occurrence data associated with a portion of the North Anatolian fault are used to demonstrate the implementation of the proposed model. 18 refs, figs and tabs.

  8. Genome variability of foot-and-mouth disease virus during the short period of the 2010 epidemic in Japan.

    Science.gov (United States)

    Nishi, Tatsuya; Yamada, Manabu; Fukai, Katsuhiko; Shimada, Nobuaki; Morioka, Kazuki; Yoshida, Kazuo; Sakamoto, Kenichi; Kanno, Toru; Yamakawa, Makoto

    2017-02-01

    Foot-and-mouth disease virus (FMDV) is highly contagious and has a high mutation rate, leading to extensive genetic variation. To investigate how FMDV genetically evolves over a short period of an epidemic after initial introduction into an FMD-free area, whole L-fragment sequences of 104 FMDVs isolated from the 2010 epidemic in Japan, which continued for less than three months were determined and phylogenetically and comparatively analyzed. Phylogenetic analysis of whole L-fragment sequences showed that these isolates were classified into a single group, indicating that FMDV was introduced into Japan in the epidemic via a single introduction. Nucleotide sequences of 104 virus isolates showed more than 99.56% pairwise identity rates without any genetic deletion or insertion, although no sequences were completely identical with each other. These results indicate that genetic substitutions of FMDV occurred gradually and constantly during the epidemic and generation of an extensive mutant virus could have been prevented by rapid eradication strategy. From comparative analysis of variability of each FMDV protein coding region, VP4 and 2C regions showed the highest average identity rates and invariant rates, and were confirmed as highly conserved. In contrast, the protein coding regions VP2 and VP1 were confirmed to be highly variable regions with the lowest average identity rates and invariant rates, respectively. Our data demonstrate the importance of rapid eradication strategy in an FMD epidemic and provide valuable information on the genome variability of FMDV during the short period of an epidemic. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  9. Propagation of Regional Seismic Phases in Western Europe

    Science.gov (United States)

    1991-03-08

    and Southeastern France recorded at short period stations of the LDG (Laboratoire de Detection Geophysique , France) and IGG (Istituto Geofisico di...here were provided by the L.D.G. (Laboratoire de Geophysique ). The french seismic network consists of 27 stations with the same features : the

  10. Seismic activity in northeastern Brazill-new perspectives

    Science.gov (United States)

    Ferreira, J. M.; Do Nascimento, A. F.; Vilar, C. S.; Bezerra, F. H.; Assumpcao, M.; Berrocal, J.; Fuck, R. A.

    2007-05-01

    Northeastern Brazil is the most seismic active region in the country. Some earthquakes with magnitude above 5.0 and intensity VII MM associated with swam-like seismic activity lasting for many years are a serious social concern. Since the 1980's macroseismic and instrumental surveys have been carried out in this region and they are an important data archive which allows the composition of a reliable catalogue of seismic activity for this region. Among the many scientific results it was possible to identify the main seismogenic areas, obtain reliable hypocentres and focal mechanisms. As a consequence, it was possible also to analyse the relationship between seismicity and geological features. It was also possible to determined maximum horizontal stress direction for the region. An important induced seismic activity case has also been reported in the area as being a classical example of pore pressure diffusion triggering mechanism. The majority of the results were obtained using analogic data. Recently, a new research project is being conducted and will allow us to provide a regional scale monitoring with 6 broad-band stations and a new portable six station digital seismic network equipped with short- period sensors. Thus, with the continuous seismic activity in the area we trust that the results of this project will increase the present knowledge of seismic activity in northeastern Brazil.

  11. Real-time monitoring and massive inversion of source parameters of very long period seismic signals: An application to Stromboli Volcano, Italy

    Science.gov (United States)

    Auger, E.; D'Auria, L.; Martini, M.; Chouet, B.; Dawson, P.

    2006-01-01

    We present a comprehensive processing tool for the real-time analysis of the source mechanism of very long period (VLP) seismic data based on waveform inversions performed in the frequency domain for a point source. A search for the source providing the best-fitting solution is conducted over a three-dimensional grid of assumed source locations, in which the Green's functions associated with each point source are calculated by finite differences using the reciprocal relation between source and receiver. Tests performed on 62 nodes of a Linux cluster indicate that the waveform inversion and search for the best-fitting signal over 100,000 point sources require roughly 30 s of processing time for a 2-min-long record. The procedure is applied to post-processing of a data archive and to continuous automatic inversion of real-time data at Stromboli, providing insights into different modes of degassing at this volcano. Copyright 2006 by the American Geophysical Union.

  12. Study of short-period RS Canum Venaticorum and W Ursae Majoris binary systems: The global nature of Hα

    International Nuclear Information System (INIS)

    Barden, S.C.

    1985-01-01

    I present the rotation versus emission characteristics of the Hα line for several short-period (P -5 ) and the Rossby number (the ratio between the rotational period and the convective time scale) is seen for those components showing emission. Such a correlation suggests that the Hα line is a good diagnostic for the study of the magnetic-related activity in late-type stellar systems. Plotting the L/sub Halpha//L/sub bol/ against a measure of the tidal amplitude of Scharlemann shows that the activity of the W UMa secondary components may be shut off by the tidal forces of the primaries. The shut-off appears in those components having a tidal amplitude > or approx. =0.02. It is, however, unclear whether the tidal damping of the differential rotation is the sole mechanism responsible for the shut-off of the Hα emission, as the activity damping may also be attributable to the contact nature of the W UMa systems

  13. Performance of a reactor containing denitrifying immobilized biomass in removing ethanol and aromatic hydrocarbons (BTEX) in a short operating period

    International Nuclear Information System (INIS)

    Gusmao, Valquiria Ribeiro; Chinalia, Fabio Alexandre; Sakamoto, Isabel Kimiko; Varesche, Maria Bernadete Amancio

    2007-01-01

    A horizontal-flow anaerobic immobilized biomass reactor (HAIB) containing denitrifying biomass was evaluated with respect to its ability to remove, separately and in a short operating period (30 days), organic matter, nitrate, and the hydrocarbons benzene (41.4 mg L -1 ), toluene (27.8 mg L -1 ), ethylbenzene (31.1 mg L -1 ), o-xylene (28.5 mg L -1 ), m-xylene (28.4 mg L -1 ) and p-xylene (32.1 mg L -1 ). The purified culture, which was grown in the presence of the specific hydrocarbon, was used as the source of cells to be immobilized in the polyurethane foam. After 30 days of operation, the foam was removed and a new immobilized biomass was grown in the presence of another hydrocarbon. The average hydrocarbon removal efficiency attained was 97%. The organic matter, especially ethanol, was removed with an average efficiency of 83% at a mean influent concentration of 1185.0 mg L -1 . A concomitant removal of 97% of nitrate was observed for a mean influent concentration of 423.4 mg L -1 . The independent removal of each hydrocarbon demonstrated that these contaminants can be biodegraded separately, without the need for a compound to be the primary substrate for the degradation of another. This study proposes the application of the system for treatment of areas contaminated with these compounds, with substitution and formation of a biofilm in a 30-day period

  14. The Discovery and Mass Measurement of a New Ultra-short-period Planet: K2-131b

    Science.gov (United States)

    Dai, Fei; Winn, Joshua N.; Gandolfi, Davide; Wang, Sharon X.; Teske, Johanna K.; Burt, Jennifer; Albrecht, Simon; Barragán, Oscar; Cochran, William D.; Endl, Michael; Fridlund, Malcolm; Hatzes, Artie P.; Hirano, Teruyuki; Hirsch, Lea A.; Johnson, Marshall C.; Justesen, Anders Bo; Livingston, John; Persson, Carina M.; Prieto-Arranz, Jorge; Vanderburg, Andrew; Alonso, Roi; Antoniciello, Giuliano; Arriagada, Pamela; Butler, R. P.; Cabrera, Juan; Crane, Jeffrey D.; Cusano, Felice; Csizmadia, Szilárd; Deeg, Hans; Dieterich, Sergio B.; Eigmüller, Philipp; Erikson, Anders; Everett, Mark E.; Fukui, Akihiko; Grziwa, Sascha; Guenther, Eike W.; Henry, Gregory W.; Howell, Steve B.; Johnson, John Asher; Korth, Judith; Kuzuhara, Masayuki; Narita, Norio; Nespral, David; Nowak, Grzegorz; Palle, Enric; Pätzold, Martin; Rauer, Heike; Montañés Rodríguez, Pilar; Shectman, Stephen A.; Smith, Alexis M. S.; Thompson, Ian B.; Van Eylen, Vincent; Williamson, Michael W.; Wittenmyer, Robert A.

    2017-12-01

    We report the discovery of a new ultra-short-period planet and summarize the properties of all such planets for which the mass and radius have been measured. The new planet, K2-131b, was discovered in K2 Campaign 10. It has a radius of {1.81}-0.12+0.16 {R}\\oplus and orbits a G dwarf with a period of 8.9 hr. Radial velocities obtained with Magellan/PFS and TNG/HARPS-N show evidence for stellar activity along with orbital motion. We determined the planetary mass using two different methods: (1) the “floating chunk offset” method, based only on changes in velocity observed on the same night; and (2) a Gaussian process regression based on both the radial velocity and photometric time series. The results are consistent and lead to a mass measurement of 6.5+/- 1.6 {M}\\oplus and a mean density of {6.0}-2.7+3.0 g cm-3.

  15. Seismic Structure of Perth Basin (Australia) and surroundings from Passive Seismic Deployments

    Science.gov (United States)

    Issa, N.; Saygin, E.; Lumley, D. E.; Hoskin, T. E.

    2016-12-01

    We image the subsurface structure of Perth Basin, Western Australia and surroundings by using ambient seismic noise data from 14 seismic stations recently deployed by University of Western Australia (UWA) and other available permanent stations from Geoscience Australia seismic network and the Australian Seismometers in Schools program. Each of these 14 UWA seismic stations comprises a broadband sensor and a high fidelity 3-component 10 Hz geophone, recording in tandem at 250 Hz and 1000 Hz. The other stations used in this study are equipped with short period and broadband sensors. In addition, one shallow borehole station is operated with eight 3 component geophones at depths of between 2 and 44 m. The network is deployed to characterize natural seismicity in the basin and to try and identify any microseismic activity across Darling Fault Zone (DFZ), bounding the basin to the east. The DFZ stretches to approximately 1000 km north-south in Western Australia, and is one of the longest fault zones on the earth with a limited number of detected earthquakes. We use seismic noise cross- and auto-correlation methods to map seismic velocity perturbations across the basin and the transition from DFZ to the basin. Retrieved Green's functions are stable and show clear dispersed waveforms. Travel times of the surface wave Green's functions from noise cross-correlations are inverted with a two-step probabilistic framework to map the absolute shear wave velocities as a function of depth. The single station auto-correlations from the seismic noise yields P wave reflectivity under each station, marking the major discontinuities. Resulting images show the shear velocity perturbations across the region. We also quantify the variation of ambient seismic noise at different depths in the near surface using the geophones in the shallow borehole array.

  16. MARVELS-1b: A SHORT-PERIOD, BROWN DWARF DESERT CANDIDATE FROM THE SDSS-III MARVELS PLANET SEARCH

    International Nuclear Information System (INIS)

    Lee, Brian L.; Ge Jian; Fleming, Scott W.; Mahadevan, Suvrath; Sivarani, Thirupathi; Stassun, Keivan G.; Gary, Bruce; Pepper, Joshua; Gaudi, B. Scott; Eastman, Jason D.; Siverd, Robert J.; Barnes, Rory; Laws, Chris; Wisniewski, John P.; Wright, Jason; Ghezzi, Luan; Ogando, Ricardo L. C.; Maia, Marcio A. G.; Da Costa, Luiz Nicolaci; Porto de Mello, G. F.

    2011-01-01

    We present a new short-period brown dwarf (BD) candidate around the star TYC 1240-00945-1. This candidate was discovered in the first year of the Multi-object APO Radial Velocity Exoplanets Large-area Survey (MARVELS), which is part of the Sloan Digital Sky Survey (SDSS) III, and we designate the BD as MARVELS-1b. MARVELS uses the technique of dispersed fixed-delay interferometery to simultaneously obtain radial velocity (RV) measurements for 60 objects per field using a single, custom-built instrument that is fiber fed from the SDSS 2.5 m telescope. From our 20 RV measurements spread over a ∼370 day time baseline, we derive a Keplerian orbital fit with semi-amplitude K = 2.533 ± 0.025 km s -1 , period P = 5.8953 ± 0.0004 days, and eccentricity consistent with circular. Independent follow-up RV data confirm the orbit. Adopting a mass of 1.37 ± 0.11 M sun for the slightly evolved F9 host star, we infer that the companion has a minimum mass of 28.0 ± 1.5 M Jup , a semimajor axis 0.071 ± 0.002 AU assuming an edge-on orbit, and is probably tidally synchronized. We find no evidence for coherent intrinsic variability of the host star at the period of the companion at levels greater than a few millimagnitudes. The companion has an a priori transit probability of ∼14%. Although we find no evidence for transits, we cannot definitively rule them out for companion radii ∼ Jup .

  17. Background noise model development for seismic stations of KMA

    Science.gov (United States)

    Jeon, Youngsoo

    2010-05-01

    The background noise recorded at seismometer is exist at any seismic signal due to the natural phenomena of the medium which the signal passed through. Reducing the seismic noise is very important to improve the data quality in seismic studies. But, the most important aspect of reducing seismic noise is to find the appropriate place before installing the seismometer. For this reason, NIMR(National Institution of Meteorological Researches) starts to develop a model of standard background noise for the broadband seismic stations of the KMA(Korea Meteorological Administration) using a continuous data set obtained from 13 broadband stations during the period of 2007 and 2008. We also developed the model using short period seismic data from 10 stations at the year of 2009. The method of Mcmara and Buland(2004) is applied to analyse background noise of Korean Peninsula. The fact that borehole seismometer records show low noise level at frequency range greater than 1 Hz compared with that of records at the surface indicate that the cultural noise of inland Korean Peninsula should be considered to process the seismic data set. Reducing Double Frequency peak also should be regarded because the Korean Peninsula surrounded by the seas from eastern, western and southern part. The development of KMA background model shows that the Peterson model(1993) is not applicable to fit the background noise signal generated from Korean Peninsula.

  18. Training Load, Physical Performance, Biochemical Markers, and Psychological Stress During A Short Preparatory Period in Brazilian Elite Male Volleyball Players.

    Science.gov (United States)

    Horta, Thiago A G; Bara Filho, Maurício G; Coimbra, Danilo R; Miranda, R; Werneck, Francisco Z

    2017-12-11

    The aim of this study was to assess the relationship between training load (TL) and physical performance, biochemical markers, and psychological stress during a short preparatory period (PP) in Brazilian elite male volleyball players. Twelve volleyball players from a team competing in the Brazilian Men's Volleyball Super League were enrolled (26.9 ± 4.6 years). Countermovement Jump (CMJ), Creatine Kinase (CK), Testosterone (T), Cortisol (Cr), T/Cr ratio, and Recovery and Stress Questionnaire for Athletes (RESTQ-Sport) were collected at baseline, after 2, 4, and 6 week. TL was quantified daily using the Rating of Perceived Exertion (RPE). Differences were noted between Total Weekly TL (TWTL) (F3,33 = 50.907; p = 0.0001), CK (F3,33 = 16.157; p = 0.0001), and T (F3,33 = 3.283; p = 0.03). No differences were seen in CMJ (F3,33 = 1.821; p = 0.16), Cr (F3,33 = 2.409; p = 0.08), or T/Cr ratio (F3,33 = 1.527; p = 0.23). The RESTQ-Sport demonstrated differences between moments in Social Stress (F3,33 = 2.297; p = 0.04; Eta = 0.25), Success (F3,33 = 4.350; p = 0.01; Eta = 0.19), General Well-being (F3,33 = 4.465; p = 0.01; Eta = 0.36), and Injury (F3,33 = 2.792; p = 0.05; Eta = 0.62). The results showed a significant correlations of small to moderate magnitude between TWTL and CK (r = 0.32; p = 0.05). In conclusion, a short PP in volleyball leads to increased TL, CK level, and psychological stress. TL was related with the increase of CK, suggesting muscle damage without increased of physical performance.

  19. OGS improvements in 2012 in running the Northeastern Italy Seismic Network: the Ferrara VBB borehole seismic station

    Science.gov (United States)

    Pesaresi, Damiano; Romanelli, Marco; Barnaba, Carla; Bragato, Pier Luigi; Durì, Giorgio

    2013-04-01

    The Centro di Ricerche Sismologiche (CRS, Seismological Research Center) of the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS, Italian National Institute for Oceanography and Experimental Geophysics) in Udine (Italy) after the strong earthquake of magnitude M=6.4 occurred in 1976 in the Italian Friuli-Venezia Giulia region, started to operate the Northeastern Italy Seismic Network: it currently consists of 17 very sensitive broad band and 18 simpler short period seismic stations, all telemetered to and acquired in real time at the OGS-CRS data center in Udine. Real time data exchange agreements in place with other Italian, Slovenian, Austrian and Swiss seismological institutes lead to a total number of about 100 seismic stations acquired in real time, which makes the OGS the reference institute for seismic monitoring of Northeastern Italy. The southwestern edge of the OGS seismic network stands on the Po alluvial basin: earthquake localization and characterization in this area is affected by the presence of soft alluvial deposits. OGS ha already experience in running a local seismic network in high noise conditions making use of borehole installations in the case of the micro-seismicity monitoring of a local gas storage site for a private company. Following the ML=5.9 earthquake that struck the Emilia region around Ferrara in Northern Italy on May 20, 2012 at 02:03:53 UTC, a cooperation of Istituto Nazionale di Geofisica e Vulcanologia, OGS, the Comune di Ferrara and the University of Ferrara lead to the reinstallation of a previously existing very broad band (VBB) borehole seismic station in Ferrara. The aim of the OGS intervention was on one hand to extend its real time seismic monitoring capabilities toward South-West, including Ferrara and its surroundings, and on the other hand to evaluate the seismic response at the site. We will describe improvements in running the Northeastern Italy Seismic Network, including details of the Ferrara VBB

  20. Seismic Creep, USA Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Seismic creep is the constant or periodic movement on a fault as contrasted with the sudden rupture associated with an earthquake. It is a usually slow deformation...

  1. Nature of short-period microtremors on the cliff-like ground. 3; Gakechi kinbo no tanshuki bido . 3

    Energy Technology Data Exchange (ETDEWEB)

    Maiguma, T; Matsuzawa, H [Saitama University, Saitama (Japan). Faculty of Engineering

    1996-05-01

    Vibration characteristics were investigated of the ground in the vicinity of a cliff-like sharp slope. Short-period microtremors were observed in the vicinity of an artificially made cliff-like test ground, height 8m and inclination 90{degree}, and a natural cliff, height approximately 9m and inclination approximately 35{degree}. The artificial cliff was reinforced by a virtually vertical retaining wall of concrete, and the ground was prepared for testing with a belt approximately 20m wide and 50m long along the cliff face. All the vibration components were simultaneously measured at measuring spots that were located 5-40m apart from the cliff end and orientated perpendicular to the cliff face. It was then found that in case of artificial cliff there is a conspicuous 3.1Hz prevalent ground vibration in the component squarely meeting the cliff face, that the prevalent ground vibration is not particularly great near the cliff end because the retaining wall and the ground are artificially prepared, that there is no influence of the cliff-like ground in the ground vibration parallel to or vertical along the cliff face, and that in case of natural ground there are no vibration characteristic proper to a cliff-like ground in any of the vibration components. 3 refs., 7 figs.

  2. Evidence of negative electrorefraction in type-II GaAs/GaAlAs short-period superlattice

    International Nuclear Information System (INIS)

    Shchukin, V A; Ledentsov, N N; Karachinsky, L Ya; Novikov, I I; Egorov, A Yu; Blokhin, S A; Maximov, M V; Gordeev, N Yu; Kulagina, M M; Ustinov, V M

    2015-01-01

    A type-II GaAs/GaAlAs short-period superlattice (SPSL) used as an electro-optic medium for the spectral range 820–850 nm is studied in a vertical microcavity geometry. SPSL is sandwiched between two GaAlAs distributed Bragg reflectors. Optical power reflectance (OR) spectra are measured as a function of applied reverse bias at different tilt angles and temperatures. All spectra reveal a blue shift of the reflectivity dip upon applied voltage which evidences a negative electrorefraction of the electro-optic medium. The shift enhances up to ∼0.6 nm once the exciton resonance is brought close to the wavelength of the reflectivity dip. As opposed to those modulators based on quantum–confined Stark effect, no increased absorption is observed at an applied bias, because the integrated intensity of the reflectivity dip in the OR spectra is virtually constant. This indicates a low absorption loss with applied bias and consequently a high potential for the increased dynamic range of the related modulator. (paper)

  3. Nature of short-period microtremors on the cliff-like ground. Part 4; Gakechi kinbo no tanshuki bido. 4

    Energy Technology Data Exchange (ETDEWEB)

    Maiguma, T; Yoshiike, T [Waseda University, Tokyo (Japan). School of Science and Engineering

    1996-10-01

    Microtremors were measured on the cliff-like ground with a height about 10 m, to examine the vibration characteristics. Test field-1 near Akabane, Kita-ku, Tokyo is located in a part of Musashino plateau covered with Kanto loam on its surface, and has relatively sound ground. Test field-2 at Machida is located in the western part of Tama hills, and also has Kanto loam on its surface. For the cliff-like ground with inclined angle 70{degree} at Akabane, remarkably predominant frequency 3.2 Hz was observed for the microtremors in the direction perpendicular to the cliff surface. However, this predominant vibration did not become larger due to the damping effects of the reinforcement walls near the end of cliff and the large trees on the cliff. Influence of the cliff-like ground was scarcely observed in the microtremors spectrum in both the directions parallel and vertical to the cliff-surface. From the observation of microtremors with short period on the cliff-like ground with inclined angle around 32{degree} at Machida, influence of cliff-like ground was not observed in the microtremors spectrum in all of the vibrating directions perpendicular, parallel and vertical to the cliff surface. 3 refs., 10 figs.

  4. Optical properties of spontaneous lateral composition modulation in AlAs/InAs short-period superlattices

    International Nuclear Information System (INIS)

    Francoeur, S.; Zhang, Yong; Norman, A. G.; Alsina, F.; Mascarenhas, A.; Reno, J. L.; Jones, E. D.; Lee, S. R.; Follstaedt, D. M.

    2000-01-01

    The effect of lateral composition modulation, spontaneously generated during the epitaxial growth of an AlAs/InAs short-period superlattice, on the electronic band structure is investigated using phototransmission and photoluminescence spectroscopy. Compared with uniform layers of identical average composition, the presence of the composition modulation considerably reduces the band-gap energy and produces strongly polarized emission and absorption spectra. We demonstrate that the dominant polarization direction can selectively be aligned along the [1(bar sign)10] or [010] crystallographic directions. In compressively strained samples, the use of (001) InP substrates slightly miscut toward (111)A or (101) resulted in modulation directions along [110] or [100], respectively, and dominant polarization directions along a direction orthogonal to the respective composition modulation. Band-gap reductions as high as 350 and 310 meV are obtained for samples with composition modulation along [110] and [100], respectively. Ratios of polarized intensities up to 26 are observed in transmission spectra. (c) 2000 American Institute of Physics

  5. The persistent signature of tropical cyclones in ambient seismic noise

    KAUST Repository

    Gualtieri, Lucia; Camargo, Suzana J.; Pascale, Salvatore; Pons, Flavio M.E.; Ekströ m, Gö ran

    2017-01-01

    The spectrum of ambient seismic noise shows strong signals associated with tropical cyclones, yet a detailed understanding of these signals and the relationship between them and the storms is currently lacking. Through the analysis of more than a decade of seismic data recorded at several stations located in and adjacent to the northwest Pacific Ocean, here we show that there is a persistent and frequency-dependent signature of tropical cyclones in ambient seismic noise that depends on characteristics of the storm and on the detailed location of the station relative to the storm. An adaptive statistical model shows that the spectral amplitude of ambient seismic noise, and notably of the short-period secondary microseisms, has a strong relationship with tropical cyclone intensity and can be employed to extract information on the tropical cyclones.

  6. The persistent signature of tropical cyclones in ambient seismic noise

    KAUST Repository

    Gualtieri, Lucia

    2017-12-28

    The spectrum of ambient seismic noise shows strong signals associated with tropical cyclones, yet a detailed understanding of these signals and the relationship between them and the storms is currently lacking. Through the analysis of more than a decade of seismic data recorded at several stations located in and adjacent to the northwest Pacific Ocean, here we show that there is a persistent and frequency-dependent signature of tropical cyclones in ambient seismic noise that depends on characteristics of the storm and on the detailed location of the station relative to the storm. An adaptive statistical model shows that the spectral amplitude of ambient seismic noise, and notably of the short-period secondary microseisms, has a strong relationship with tropical cyclone intensity and can be employed to extract information on the tropical cyclones.

  7. Seismic assessment of a site using the time series method

    International Nuclear Information System (INIS)

    Krutzik, N.J.; Rotaru, I.; Bobei, M.; Mingiuc, C.; Serban, V.; Androne, M.

    2001-01-01

    1. To increase the safety of a NPP located on a seismic site, the seismic acceleration level to which the NPP should be qualified must be as representative as possible for that site, with a conservative degree of safety but not too exaggerated. 2. The consideration of the seismic events affecting the site as independent events and the use of statistic methods to define some safety levels with very low annual occurrence probabilities (10 -4 ) may lead to some exaggerations of the seismic safety level. 3. The use of some very high values for the seismic accelerations imposed by the seismic safety levels required by the hazard analysis may lead to very expensive technical solutions that can make the plant operation more difficult and increase the maintenance costs. 4. The consideration of seismic events as a time series with dependence among the events produced may lead to a more representative assessment of a NPP site seismic activity and consequently to a prognosis on the seismic level values to which the NPP would be ensured throughout its life-span. That prognosis should consider the actual seismic activity (including small earthquakes in real time) of the focuses that affect the plant site. The method is useful for two purposes: a) research, i.e. homogenizing the history data basis by the generation of earthquakes during periods lacking information and correlation of the information with the existing information. The aim is to perform the hazard analysis using a homogeneous data set in order to determine the seismic design data for a site; b) operation, i.e. the performance of a prognosis on the seismic activity on a certain site and consideration of preventive measures to minimize the possible effects of an earthquake. 5. The paper proposes the application of Autoregressive Time Series to issue a prognosis on the seismic activity of a focus and presents the analysis on Vrancea focus that affects Cernavoda NPP site by this method. 6. The paper also presents the

  8. Seismic and Geodetic Monitoring of the Nicoya, Costa Rica, Seismic Gap

    Science.gov (United States)

    Protti, M.; Gonzalez, V.; Schwartz, S.; Dixon, T.; Kato, T.; Kaneda, Y.; Simila, G.; Sampson, D.

    2007-05-01

    The Nicoya segment of the Middle America Trench has been recognized as a mature seismic gap with potential to generate a large earthquake in the near future (it ruptured with large earthquakes in 1853, 1900 and 1950). Low level of background seismicity and fast crustal deformation of the forearc are indicatives of strong coupling along the plate interface. Given its high seismic potential, the available data and especially the fact that the Nicoya peninsula extends over large part of the rupture area, this gap was selected as one of the two sites for a MARGINS-SEIZE experiment. With the goal of documenting the evolution of loading and stress release along this seismic gap, an international effort involving several institutions from Costa Rica, the United States and Japan is being carried out for over a decade in the region. This effort involves the installation of temporary and permanent seismic and geodetic networks. The seismic network includes short period, broad band and strong motion instruments. The seismic monitoring has provided valuable information on the geometry and characteristics of the plate interface. The geodetic network includes temporary and permanent GPS stations as well as surface and borehole tiltmeters. The geodetic networks have helped quantify the extend and degree of coupling. A continuously recording, three- station GPS network on the Nicoya Peninsula, Costa Rica, recorded what we believe is the first slow slip event observed along the plate interface of the Costa Rica subduction zone. We will present results from these monitoring networks. Collaborative international efforts are focused on expanding these seismic and geodetic networks to provide improved resolution of future creep events, to enhanced understanding of the mechanical behavior of the Nicoya subduction segment of the Middle American Trench and possibly capture the next large earthquake and its potential precursor deformation.

  9. Seismic hazard map of North and Central America and the Caribbean

    Directory of Open Access Journals (Sweden)

    K. M. Shedlock

    1999-06-01

    Full Text Available Minimization of the loss of life, property damage, and social and economic disruption due to earthquakes depends on reliable estimates of seismic hazard. National, state, and local governments, decision makers, engineers, planners, emergency response organizations, builders, universities, and the general public require seismic hazard estimates for land use planning, improved building design and construction (including adoption of building construction codes, emergency response preparedness plans, economic forecasts, housing and employment decisions, and many more types of risk mitigation. The seismic hazard map of North and Central America and the Caribbean is the concatenation of various national and regional maps, involving a suite of approaches. The combined maps and documentation provide a useful regional seismic hazard framework and serve as a resource for any national or regional agency for further detailed studies applicable to their needs. This seismic hazard map depicts Peak Ground Acceleration (PGA with a 10% chance of exceedance in 50 years. PGA, a short-period ground motion parameter that is proportional to force, is the most commonly mapped ground motion parameter because current building codes that include seismic provisions specify the horizontal force a building should be able to withstand during an earthquake. This seismic hazard map of North and Central America and the Caribbean depicts the likely level of short-period ground motion from earthquakes in a fifty-year window. Short-period ground motions effect short-period structures (e.g., one-to-two story buildings. The highest seismic hazard values in the region generally occur in areas that have been, or are likely to be, the sites of the largest plate boundary earthquakes.

  10. Production of well-matured compost from night-soil sludge by an extremely short period of thermophilic composting.

    Science.gov (United States)

    Nakasaki, Kiyohiko; Ohtaki, Akihito; Takemoto, Minoru; Fujiwara, Shunrokuro

    2011-03-01

    The effect of various operational conditions on the decomposition of organic material during the composting of night-soil treatment sludge was quantitatively examined. The optimum composting conditions were found to be a temperature of ca. 60°C and an initial pH value of 8. Rapid decomposition of organic matter ceased by the sixth day of composting under these optimum conditions, and the final value of the cumulative emission of carbon (E(C)), which represents the degree of organic matter decomposition, was less than 40%, indicating that the sludge contained only a small amount of easily degradable organic material. A plant growth assay using Komatsuna (Brassica campestris L. var. rapiferafroug) in a 1/5000a standard cultivation pot was then conducted for the compost at various degrees of organic matter decomposition: the raw composting material, the final compost obtained on day 6, and the 2 intermediate compost products (i.e., E(C)=10% and 20%). It was found that the larger the E(C), the greater the yield of Komatsuna growth. It was also found that 6 days of composting is sufficient to promote Komatsuna growth at the standard loading level, which is equivalent to a 1.5 g N/pot, since the promotion effect was as high as that obtained using chemical fertilizer. It can therefore be concluded that well-matured compost could be obtained in a short period of time (i.e., as early as 6 days), when night-soil sludge is composted under optimum conditions. Copyright © 2010 Elsevier Ltd. All rights reserved.

  11. InN/GaN short-period superlattices as ordered InGaN ternary alloys

    International Nuclear Information System (INIS)

    Kusakabe, Kazuhide; Imai, Daichi; Wang, Ke; Yoshikawa, Akihiko

    2016-01-01

    Coherent (InN) 1 /(GaN) n short-period superlattices (SPSs) were successfully grown through dynamic atomic layer epitaxy (D-ALEp) mode by RF-plasma molecular beam epitaxy (MBE), where GaN layer thicknesses n were thinned down to 4 monolayer (ML). After this achievement, we demonstrated quasi-ternary InGaN behavior in their photoluminescence (PL) spectra for the first time. It was found interestingly that GaN layer thickness of n = 4 ML was the criterion both for structural control and continuum-band formation. Although highly lattice-mismatched InN/GaN interfaces easily introduce relaxation in (InN) 1 /(GaN) 4 SPSs during growth depending on the dynamic surface stoichiometry condition, this problem was overcome by precise control/removal of fluid-like residual In/Ga metals on the growth front with in-situ monitoring method. The (InN) 1 /(GaN) n SPSs with n ≥ 7 ML showed a constant PL peak energy around 3.2 eV at 12 K, reflecting discrete electron/hole wavefunctions. On the other hand, the (InN) 1 /(GaN) 4 SPSs indicated the red-shifted PL peak at 2.93 eV at 12 K, which was attributed to the continuum-band state with increasing in the overlap of electrons/hole wavefunctions. This result is concluded that the (InN) 1 /(GaN) 4 SPSs can be considered as ordered InGaN alloys. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Broadband analysis of landslides seismic signal : example of the Oso-Steelhead landslide and other recent events

    Science.gov (United States)

    Hibert, C.; Stark, C. P.; Ekstrom, G.

    2014-12-01

    Landslide failures on the scale of mountains are spectacular, dangerous, and spontaneous, making direct observations hard to obtain. Measurement of their dynamic properties during runout is a high research priority, but a logistical and technical challenge. Seismology has begun to help in several important ways. Taking advantage of broadband seismic stations, recent advances now allow: (i) the seismic detection and location of large landslides in near-real-time, even for events in very remote areas that may have remain undetected, such as the 2014 Mt La Perouse supraglacial failure in Alaska; (ii) inversion of long-period waves generated by large landslides to yield an estimate of the forces imparted by the bulk accelerating mass; (iii) inference of the landslide mass, its center-of-mass velocity over time, and its trajectory.Key questions persist, such as: What can the short-period seismic data tell us about the high-frequency impacts taking place within the granular flow and along its boundaries with the underlying bedrock? And how does this seismicity relate to the bulk acceleration of the landslide and the long-period seismicity generated by it?Our recent work on the joint analysis of short- and long-period seismic signals generated by past and recent events, such as the Bingham Canyon Mine and the Oso-Steelhead landslides, provides new insights to tackle these issues. Qualitative comparison between short-period signal features and kinematic parameters inferred from long-period surface wave inversion helps to refine interpretation of the source dynamics and to understand the different mechanisms for the origin of the short-period wave radiation. Our new results also suggest that quantitative relationships can be derived from this joint analysis, in particular between the short-period seismic signal envelope and the inferred momentum of the center-of-mass. In the future, these quantitative relationships may help to constrain and calibrate parameters used in

  13. Seismic activity maps for the Armenian Highlands

    Energy Technology Data Exchange (ETDEWEB)

    Karapetyan, N.K.; Manukyan, Zh.O.

    1976-01-01

    Seismic activity maps for the periods 1952 to 1967 and 1952 to 1968 were compiled for the Armenian Highlands in order to study the spatial distribution of earthquake recurrence and to construct maps in isolines of seismic activity. Diagrams are presented illustrating such seismic activity maps for the indicated periods. 4 references, 3 figures, 1 table.

  14. Simulation of channeling and radiation of 855 MeV electrons and positrons in a small-amplitude short-period bent crystal

    Energy Technology Data Exchange (ETDEWEB)

    Korol, Andrei V., E-mail: korol@mbnexplorer.com [MBN Research Center, Altenhöferallee 3, 60438 Frankfurt am Main (Germany); Bezchastnov, Victor G. [A.F. Ioffe Physical-Technical Institute, Politechnicheskaya Str. 26, 194021 St. Petersburg (Russian Federation); Peter the Great St. Petersburg Polytechnic University, Politechnicheskaya 29, 195251 St. Petersburg (Russian Federation); Sushko, Gennady B.; Solov’yov, Andrey V. [MBN Research Center, Altenhöferallee 3, 60438 Frankfurt am Main (Germany)

    2016-11-15

    Channeling and radiation are studied for the relativistic electrons and positrons passing through a Si crystal periodically bent with a small amplitude and a short period. Comprehensive analysis of the channeling process for various bending amplitudes is presented on the grounds of numerical simulations. The features of the channeling are highlighted and elucidated within an analytically developed continuous potential approximation. The radiation spectra are computed and discussed.

  15. POSITION AND CHARACTER (Ɖ OR X) OF ENERGY STATES IN SHORT-PERIOD (GaAs)m(AlAs)n SUPERLATTICES

    OpenAIRE

    Nagle , J.; Garriga , M.; Stolz , W.; Isu , T.; Ploog , K.

    1987-01-01

    We have grown a series of (GaAs)m(AlAs)n short period superlattices by molecular beam epitaxy including samples with m=n and m≠n. Low temperature photoluminescence, excitation spectroscopy and ellipsometry measurements have been performed to determine the positions and origins of the different electronic states.

  16. Precursory groundwater level changes in the period of activation of the weak intraplate seismic activity on the NE margin of the Bohemian Massif (central Europe) in 2005

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Vladimír; Kašpárek, L.; Kopylova, Galina N.; Lyubushin, Alexei A.; Skalský, Lumír

    2009-01-01

    Roč. 53, č. 2 (2009), s. 215-238 ISSN 0039-3169 R&D Projects: GA ČR GA205/09/1244; GA ČR(CZ) GD205/05/H020 Institutional research plan: CEZ:AV0Z30460519; CEZ:AV0Z30120515 Keywords : seismic activity * earthquake precursors * groundwater Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.000, year: 2009

  17. Intensity Based Seismic Hazard Map of Republic of Macedonia

    Science.gov (United States)

    Dojcinovski, Dragi; Dimiskovska, Biserka; Stojmanovska, Marta

    2016-04-01

    The territory of the Republic of Macedonia and the border terrains are among the most seismically active parts of the Balkan Peninsula belonging to the Mediterranean-Trans-Asian seismic belt. The seismological data on the R. Macedonia from the past 16 centuries point to occurrence of very strong catastrophic earthquakes. The hypocenters of the occurred earthquakes are located above the Mohorovicic discontinuity, most frequently, at a depth of 10-20 km. Accurate short -term prognosis of earthquake occurrence, i.e., simultaneous prognosis of time, place and intensity of their occurrence is still not possible. The present methods of seismic zoning have advanced to such an extent that it is with a great probability that they enable efficient protection against earthquake effects. The seismic hazard maps of the Republic of Macedonia are the result of analysis and synthesis of data from seismological, seismotectonic and other corresponding investigations necessary for definition of the expected level of seismic hazard for certain time periods. These should be amended, from time to time, with new data and scientific knowledge. The elaboration of this map does not completely solve all issues related to earthquakes, but it provides basic empirical data necessary for updating the existing regulations for construction of engineering structures in seismically active areas regulated by legal regulations and technical norms whose constituent part is the seismic hazard map. The map has been elaborated based on complex seismological and geophysical investigations of the considered area and synthesis of the results from these investigations. There were two phases of elaboration of the map. In the first phase, the map of focal zones characterized by maximum magnitudes of possible earthquakes has been elaborated. In the second phase, the intensities of expected earthquakes have been computed according to the MCS scale. The map is prognostic, i.e., it provides assessment of the

  18. The association between short periods of everyday life activities and affective states: a replication study using ambulatory assessment

    Directory of Open Access Journals (Sweden)

    Thomas eBossmann

    2013-04-01

    Full Text Available Regularly conducted exercise programs effectively influence affective states. Studies suggest that this is also true for short bouts of physical activity of ten minutes or less. Accordingly, everyday life activities of short duration might be used to regulate affective states. However, this association has rarely been studied in reference to unstructured activities in ongoing real-life situations. The current study examined the influence of various everyday life activities on three dimensions of mood (valence, calmness, energetic arousal in a predominantly inactive sample. Ambulatory Assessment (AA was used to investigate the association between actual physical activity (aPA and affective states during the course of one day. Seventy-seven students ages 19 - 30 participated in the study. aPA was assessed with accelerometers, and affective state assessments were conducted hourly using an e-diary with a six-item mood scale that was specially designed for AA. Multilevel analyses indicated that the mood dimensions energetic arousal (p = .001 and valence (p = .005 were positively influenced by the intensity of the activity carried out in the ten minutes prior to the assessment. As their activity increased, the participants’ positive feelings and energetic arousal increased. However, the students’ calmness was not affected by their activity levels. The findings highlight the importance of integrating short activity intervals of 10 minutes or less into everyday life routines to improve affective states.

  19. Seismic Ecology

    Science.gov (United States)

    Seleznev, V. S.; Soloviev, V. M.; Emanov, A. F.

    The paper is devoted to researches of influence of seismic actions for industrial and civil buildings and people. The seismic actions bring influence directly on the people (vibration actions, force shocks at earthquakes) or indirectly through various build- ings and the constructions and can be strong (be felt by people) and weak (be fixed by sensing devices). The great number of work is devoted to influence of violent seismic actions (first of all of earthquakes) on people and various constructions. This work is devoted to study weak, but long seismic actions on various buildings and people. There is a need to take into account seismic oscillations, acting on the territory, at construction of various buildings on urbanized territories. Essential influence, except for violent earthquakes, man-caused seismic actions: the explosions, seismic noise, emitted by plant facilities and moving transport, radiation from high-rise buildings and constructions under action of a wind, etc. can exert. Materials on increase of man- caused seismicity in a number of regions in Russia, which earlier were not seismic, are presented in the paper. Along with maps of seismic microzoning maps to be built indicating a variation of amplitude spectra of seismic noise within day, months, years. The presence of an information about amplitudes and frequencies of oscillations from possible earthquakes and man-caused oscillations in concrete regions allows carry- ing out soundly designing and construction of industrial and civil housing projects. The construction of buildings even in not seismically dangerous regions, which have one from resonance frequencies coincident on magnitude to frequency of oscillations, emitted in this place by man-caused objects, can end in failure of these buildings and heaviest consequences for the people. The practical examples of detail of engineering- seismological investigation of large industrial and civil housing projects of Siberia territory (hydro power

  20. The relative kicking frequency of infants born full-term and preterm during learning and short-term and long-term memory periods of the mobile paradigm.

    Science.gov (United States)

    Heathcock, Jill C; Bhat, Anjana N; Lobo, Michele A; Galloway, James C

    2005-01-01

    Infants born preterm differ in their spontaneous kicking, as well as their learning and memory abilities in the mobile paradigm, compared with infants born full-term. In the mobile paradigm, a supine infant's ankle is tethered to a mobile so that leg kicks cause a proportional amount of mobile movement. The purpose of this study was to investigate the relative kicking frequency of the tethered (right) and nontethered (left) legs in these 2 groups of infants. Ten infants born full-term and 10 infants born preterm (infants participated in the study. The relative kicking frequencies of the tethered and nontethered legs were analyzed during learning and short-term and long-term memory periods of the mobile paradigm. Infants born full-term showed an increase in the relative kicking frequency of the tethered leg during the learning period and the short-term memory period but not for the long-term memory period. Infants born preterm did not show a change in kicking pattern for learning or memory periods, and consistently kicked both legs in relatively equal amounts. Infants born full-term adapted their baseline kicking frequencies in a task-specific manner to move the mobile and then retained this adaptation for the short-term memory period. In contrast, infants born preterm showed no adaptation, suggesting a lack of purposeful leg control. This lack of control may reflect a general decrease in the ability of infants born preterm to use their limb movements to interact with their environment. As such, the mobile paradigm may be clinically useful in the early assessment and intervention of infants born preterm and at risk for future impairment.

  1. Response of Aspergillus niger Inoculated on Tomatoes Exposed to Vapor Phase Mustard Essential Oil for Short or Long Periods and Sensory Evaluation of Treated Tomatoes

    Directory of Open Access Journals (Sweden)

    Ana Elena Aguilar-González

    2017-01-01

    Full Text Available The inhibitory effect of mustard essential oil (EO in vapor phase against Aspergillus niger was evaluated in vitro and in vivo (in tomatoes. Mold response in tomatoes exposed for short or long periods to selected concentrations of mustard EO was also evaluated. Furthermore, a sensory evaluation was also performed among treated tomatoes and compared with nontreated ones. Minimum inhibitory concentration (MIC for the studied EO was determined by the inverted Petri dish method. MIC for the in vitro and in vivo tests for mustard EO was of 3.08 μL/Lair. In vitro and in vivo results demonstrate the effectiveness of vapors of mustard EO against A. niger. The studied EO contains highly volatile organic compounds with strong inhibitory effects, even when applied for short periods, and can consequently be considered a good alternative to traditional synthetic antimicrobials without detriment of selected sensory attributes.

  2. X-RAY AND EUV OBSERVATIONS OF SIMULTANEOUS SHORT AND LONG PERIOD OSCILLATIONS IN HOT CORONAL ARCADE LOOPS

    International Nuclear Information System (INIS)

    Kumar, Pankaj; Cho, Kyung-Suk; Nakariakov, Valery M.

    2015-01-01

    We report decaying quasi-periodic intensity oscillations in the X-ray (6–12 keV) and extreme-ultraviolet (EUV) channels (131, 94, 1600, 304 Å) observed by the Fermi Gamma-ray Burst Monitor and Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA), respectively, during a C-class flare. The estimated periods of oscillation and decay time in the X-ray channel (6–12 keV) were about 202 and 154 s, respectively. A similar oscillation period was detected at the footpoint of the arcade loops in the AIA 1600 and 304 Å channels. Simultaneously, AIA hot channels (94 and 131 Å) reveal propagating EUV disturbances bouncing back and forth between the footpoints of the arcade loops. The period of the oscillation and decay time were about 409 and 1121 s, respectively. The characteristic phase speed of the wave is about 560 km s −1 for about 115 Mm of loop length, which is roughly consistent with the sound speed at the temperature about 10–16 MK (480–608 km s −1 ). These EUV oscillations are consistent with the Solar and Heliospheric Observatory/Solar Ultraviolet Measurement of Emitted Radiation Doppler-shift oscillations interpreted as the global standing slow magnetoacoustic wave excited by a flare. The flare occurred at one of the footpoints of the arcade loops, where the magnetic topology was a 3D fan-spine with a null-point. Repetitive reconnection at this footpoint could have caused the periodic acceleration of non-thermal electrons that propagated to the opposite footpoint along the arcade and that are precipitating there, causing the observed 202 s periodicity. Other possible interpretations, e.g., the second harmonics of the slow mode, are also discussed

  3. X-RAY AND EUV OBSERVATIONS OF SIMULTANEOUS SHORT AND LONG PERIOD OSCILLATIONS IN HOT CORONAL ARCADE LOOPS

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Pankaj; Cho, Kyung-Suk [Korea Astronomy and Space Science Institute (KASI), Daejeon, 305-348 (Korea, Republic of); Nakariakov, Valery M., E-mail: pankaj@kasi.re.kr [Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, CV4 7AL (United Kingdom)

    2015-05-01

    We report decaying quasi-periodic intensity oscillations in the X-ray (6–12 keV) and extreme-ultraviolet (EUV) channels (131, 94, 1600, 304 Å) observed by the Fermi Gamma-ray Burst Monitor and Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA), respectively, during a C-class flare. The estimated periods of oscillation and decay time in the X-ray channel (6–12 keV) were about 202 and 154 s, respectively. A similar oscillation period was detected at the footpoint of the arcade loops in the AIA 1600 and 304 Å channels. Simultaneously, AIA hot channels (94 and 131 Å) reveal propagating EUV disturbances bouncing back and forth between the footpoints of the arcade loops. The period of the oscillation and decay time were about 409 and 1121 s, respectively. The characteristic phase speed of the wave is about 560 km s{sup −1} for about 115 Mm of loop length, which is roughly consistent with the sound speed at the temperature about 10–16 MK (480–608 km s{sup −1}). These EUV oscillations are consistent with the Solar and Heliospheric Observatory/Solar Ultraviolet Measurement of Emitted Radiation Doppler-shift oscillations interpreted as the global standing slow magnetoacoustic wave excited by a flare. The flare occurred at one of the footpoints of the arcade loops, where the magnetic topology was a 3D fan-spine with a null-point. Repetitive reconnection at this footpoint could have caused the periodic acceleration of non-thermal electrons that propagated to the opposite footpoint along the arcade and that are precipitating there, causing the observed 202 s periodicity. Other possible interpretations, e.g., the second harmonics of the slow mode, are also discussed.

  4. CSI 2264: Characterizing Young Stars In NGC 2264 With Short-Duration Periodic Flux Dips in Their Light Curves

    Science.gov (United States)

    2015-04-01

    excess presumably due to circumstellar Table 1 Basic Information for YSOs with Short Duration Flux Dips Mon IDa 2MASS ID CoRoTb CoRoTc SpTd Hα EWd FR4.5e...reported in Venuti et al. (2014); the JHKs data are from the on line 2MASS all-sky point source catalog; the IRAC data are from Sung et al. (2009), or...little additional reddening as inferred from their mean 2MASS photometry. One exception is Mon-6975, whose IR colors of H − Ks = 0.42, J −H = 0.90

  5. Short communication: Effect of heat stress on markers of autophagy in the mammary gland during the dry period.

    Science.gov (United States)

    Wohlgemuth, S E; Ramirez-Lee, Y; Tao, S; Monteiro, A P A; Ahmed, B M; Dahl, G E

    2016-06-01

    Heat stress (HT) during the dry period compromises mammary gland (MG) growth, thus negatively affecting subsequent milk yield. Cooling during the late dry period, when mammary tissue proliferates, is a common management practice. However, it neglects MG involution during the early dry period, a process that is accomplished by both apoptosis and autophagy. Our objective was to evaluate the effect of HT on MG autophagy during the early dry period. Holstein cows were dried off ~45d before expected calving and randomly assigned to 1 of 2 treatments: HT or cooling (CL). All cows were housed in the same free stall barn during the dry period, but only the stall area for CL cows was equipped with soakers and fans. Rectal temperature and respiration rate were measured daily during the dry period. Mammary gland biopsies were collected from each cow 3d before dry-off and on d 3, 7, 14, and 22±2 after dry-off. Autophagy in the MG was determined by measuring protein expression of 2 autophagic markers, autophagy-related protein 7 and microtubule-associated protein light chain 3 (LC3). The average temperature-humidity index during the dry period was 77.7, which indicated that HT and CL cows were exposed to significant heat stress. However, the cooling system effectively alleviated heat strain in CL cows by decreasing the rectal temperature (39.0 vs. 39.4°C) and respiration rate (47.3 vs. 71.2 breaths per minute) relative to HT cows. Protein expression of autophagy-related protein 7, a marker for early autophagosome formation, did not change within or between groups. In contrast, protein expression of LC3-II, a marker of autophagosomes, and its precursor LC3-I showed a dynamic expression pattern in MG from CL cows during the early dry period. Relative to HT cows, MG from CL cows displayed higher expression of LC3-I and LC3-II on d 7 and lower expression of LC3-II on d 14 and 22 after dry-off. Collectively, our data provide a possible mechanistic explanation for the impairment of

  6. Seismic hazard assessment of Iran

    Directory of Open Access Journals (Sweden)

    M. Ghafory-Ashtiany

    1999-06-01

    Full Text Available The development of the new seismic hazard map of Iran is based on probabilistic seismic hazard computation using the historical earthquakes data, geology, tectonics, fault activity and seismic source models in Iran. These maps have been prepared to indicate the earthquake hazard of Iran in the form of iso-acceleration contour lines, and seismic hazard zoning, by using current probabilistic procedures. They display the probabilistic estimates of Peak Ground Acceleration (PGA for the return periods of 75 and 475 years. The maps have been divided into intervals of 0.25 degrees in both latitudinal and longitudinal directions to calculate the peak ground acceleration values at each grid point and draw the seismic hazard curves. The results presented in this study will provide the basis for the preparation of seismic risk maps, the estimation of earthquake insurance premiums, and the preliminary site evaluation of critical facilities.

  7. RADIAL VELOCITY PLANETS DE-ALIASED: A NEW, SHORT PERIOD FOR SUPER-EARTH 55 Cnc e

    International Nuclear Information System (INIS)

    Dawson, Rebekah I.; Fabrycky, Daniel C.

    2010-01-01

    Radial velocity measurements of stellar reflex motion have revealed many extrasolar planets, but gaps in the observations produce aliases, spurious frequencies that are frequently confused with the planets' orbital frequencies. In the case of Gl 581 d, the distinction between an alias and the true frequency was the distinction between a frozen, dead planet and a planet possibly hospitable to life. To improve the characterization of planetary systems, we describe how aliases originate and present a new approach for distinguishing between orbital frequencies and their aliases. Our approach harnesses features in the spectral window function to compare the amplitude and phase of predicted aliases with peaks present in the data. We apply it to confirm prior alias distinctions for the planets GJ 876 d and HD 75898 b. We find that the true periods of Gl 581 d and HD 73526 b/c remain ambiguous. We revise the periods of HD 156668 b and 55 Cnc e, which were afflicted by daily aliases. For HD 156668 b, the correct period is 1.2699 days and the minimum mass is (3.1 ± 0.4) M + . For 55 Cnc e, the correct period is 0.7365 days-the shortest of any known planet-and the minimum mass is (8.3 ± 0.3) M + . This revision produces a significantly improved five-planet Keplerian fit for 55 Cnc, and a self-consistent dynamical fit describes the data just as well. As radial velocity techniques push to ever-smaller planets, often found in systems of multiple planets, distinguishing true periods from aliases will become increasingly important.

  8. Processing of seismic signals from a seismometer network

    International Nuclear Information System (INIS)

    Key, F.A.; Warburton, P.J.

    1983-08-01

    A description is given of the Seismometer Network Analysis Computer (SNAC) which processes short period data from a network of seismometers (UKNET). The nine stations of the network are distributed throughout the UK and their outputs are transmitted to a control laboratory (Blacknest) where SNAC monitors the data for seismic signals. The computer gives an estimate of the source location of the detected signals and stores the waveforms. The detection logic is designed to maintain high sensitivity without excessive ''false alarms''. It is demonstrated that the system is able to detect seismic signals at an amplitude level consistent with a network of single stations and, within the limitations of signal onset time measurements made by machine, can locate the source of the seismic disturbance. (author)

  9. Forecast demand and supply of energy in the short period. Its forecast and sensitivity analysis until the 2004 fiscal year

    International Nuclear Information System (INIS)

    Yamashita, Yukari; Suehiro, Shigeru; Yanagisawa, Akira; Imaeda, Toshiya; Komiyama, Ryouichi

    2004-01-01

    The object of this report is forecast demand and supply of energy in the 2003 and 2004 fiscal year, which correspond to a business recovery period. A macroeconomics model and an energy supply model are calculated by changing actual GNP, crude oil rate and the rerunning period of nuclear power plants. The calculation results are compared with the reference case. In the first chapter, forecast Japanese economy until the 2004 fiscal year is explained. In the second chapter, the results of energy demand and supply in the first chapter are investigated by the home supply and consumption of primary energy (the reference case) and each energy resources. The sensitivity analytical results of actual GNP, consumer price index, home supply of the primary energy, energy expenditure, sales account of electric power, city gas and fuel by five cases such as reference, increase and decrease of oil cost and increase and decrease of economic growth are investigated. The effects of fast rerunning period of nuclear power plant and atmosphere temperature on these above demands of energies are indicated in the third chapter. (S.Y.)

  10. THE ACS LCID PROJECT. I. SHORT-PERIOD VARIABLES IN THE ISOLATED DWARF SPHEROIDAL GALAXIES CETUS AND TUCANA

    International Nuclear Information System (INIS)

    Bernard, Edouard J.; Monelli, Matteo; Gallart, Carme

    2009-01-01

    We present the first study of the variable star populations in the isolated dwarf spheroidal galaxies (dSphs) Cetus and Tucana. Based on Hubble Space Telescope images obtained with the Advanced Camera for Surveys in the F475W and F814W bands, we identified 180 and 371 variables in Cetus and Tucana, respectively. The vast majority are RR Lyrae stars. In Cetus, we also found three anomalous Cepheids (ACs), four candidate binaries and one candidate long-period variable (LPV), while six ACs and seven LPV candidates were found in Tucana. Of the RR Lyrae stars, 147 were identified as fundamental mode (RRab) and only eight as first-overtone mode (RRc) in Cetus, with mean periods of 0.614 and 0.363 day, respectively. In Tucana, we found 216 RRab and 82 RRc giving mean periods of 0.604 and 0.353 day. These values place both galaxies in the so-called Oosterhoff Gap, as is generally the case for dSph. We calculated the distance modulus to both galaxies using different approaches based on the properties of RRab and RRc, namely, the luminosity-metallicity and period-luminosity-metallicity relations, and found values in excellent agreement with previous estimates using independent methods: (m - M) 0,Cet = 24.46 ± 0.12 and (m - M) 0,Tuc = 24.74 ± 0.12, corresponding to 780 ± 40 kpc and 890 ± 50 kpc. We also found numerous RR Lyrae variables pulsating in both modes simultaneously (RRd): 17 in Cetus and 60 in Tucana. Tucana is, after Fornax, the second dSph in which such a large fraction of RRd (∼17%) has been observed. We provide the photometry and pulsation parameters for all the variables, and compare the latter with values from the literature for well studied dSph of the Local Group and Galactic globular clusters. The parallel WFPC2 fields were also searched for variables, as they lie well within the tidal radius of Cetus, and at its limit in the case of Tucana. No variables were found in the latter, while 15 were discovered in the outer field of Cetus (11 RRab, three RRc

  11. A Conceptual Model for Calculating the Return of Costs Invested in the Creation of an Economic Security Service, During a Short-Term Period

    Directory of Open Access Journals (Sweden)

    Melikhova Tetiana O.

    2018-02-01

    Full Text Available The article is aimed at suggesting methods for calculating the short-term period of return of costs invested in creation of an economic security service. The article considers approaches to calculation of the period of return of costs, advanced at the level of enterprise, which build the methodical basis for definition of such period. At the level of structural subdivisions of enterprise, which do not produce products, it is suggested to use conditional money flow as a source of financing advanced costs. The calculation of the short-term return on investment at the enterprise level provides for: allocation of expenses for the permanent and the replacement parts during the year; determination of the production of money flow and the money flow accumulated during the year. Annual depreciation payments are the basis of fixed costs. Methods of determination of the gross, net, valid, and specified periods of return of costs, advanced during the year for introduction of an economic security service at enterprise, have been suggested.

  12. Exercise following a short immobilization period is detrimental to tendon properties and joint mechanics in a rat rotator cuff injury model.

    Science.gov (United States)

    Peltz, Cathryn D; Sarver, Joseph J; Dourte, Leann M; Würgler-Hauri, Carola C; Williams, Gerald R; Soslowsky, Louis J

    2010-07-01

    Rotator cuff tears are a common clinical problem that can result in pain and disability. Previous studies in a rat model showed enhanced tendon to bone healing with postoperative immobilization. The objective of this study was to determine the effect of postimmobilization activity level on insertion site properties and joint mechanics in a rat model. Our hypothesis was that exercise following a short period of immobilization will cause detrimental changes in insertion site properties compared to cage activity following the same period of immobilization, but that passive shoulder mechanics will not be affected. We detached and repaired the supraspinatus tendon of 22 Sprague-Dawley rats, and the injured shoulder was immobilized postoperatively for 2 weeks. Following immobilization, rats were prescribed cage activity or exercise for 12 weeks. Passive shoulder mechanics were determined, and following euthanasia, tendon cross-sectional area and mechanical properties were measured. Exercise following immobilization resulted in significant decreases compared to cage activity in range of motion, tendon stiffness, modulus, percent relaxation, and several parameters from both a structurally based elastic model and a quasi-linear viscoelastic model. Therefore, we conclude that after a short period of immobilization, increased activity is detrimental to both tendon mechanical properties and shoulder joint mechanics, presumably due to increased scar production. (c) 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc

  13. Task-irrelevant distractors in the delay period interfere selectively with visual short-term memory for spatial locations.

    Science.gov (United States)

    Marini, Francesco; Scott, Jerry; Aron, Adam R; Ester, Edward F

    2017-07-01

    Visual short-term memory (VSTM) enables the representation of information in a readily accessible state. VSTM is typically conceptualized as a form of "active" storage that is resistant to interference or disruption, yet several recent studies have shown that under some circumstances task-irrelevant distractors may indeed disrupt performance. Here, we investigated how task-irrelevant visual distractors affected VSTM by asking whether distractors induce a general loss of remembered information or selectively interfere with memory representations. In a VSTM task, participants recalled the spatial location of a target visual stimulus after a delay in which distractors were presented on 75% of trials. Notably, the distractor's eccentricity always matched the eccentricity of the target, while in the critical conditions the distractor's angular position was shifted either clockwise or counterclockwise relative to the target. We then computed estimates of recall error for both eccentricity and polar angle. A general interference model would predict an effect of distractors on both polar angle and eccentricity errors, while a selective interference model would predict effects of distractors on angle but not on eccentricity errors. Results showed that for stimulus angle there was an increase in the magnitude and variability of recall errors. However, distractors had no effect on estimates of stimulus eccentricity. Our results suggest that distractors selectively interfere with VSTM for spatial locations.

  14. Analisis Parameter Gap Dalam Tahapan Dekonvolusi Prediktif Guna Mereduksi Short Period Multiple dan Meningkatkan S/N Ratio pada Pengolahan Data Seismik Refleksi 2D Marine

    Directory of Open Access Journals (Sweden)

    Bella Chintia

    2017-05-01

    Full Text Available Penelitian ini bertujuan untuk menentukan nilai gap terbaik dari salah satu parameter gap yang digunakan untuk mereduksi short-period multiple dengan metode dekonvolusi prediktif. Variasi Nilai gap yang digunakan adalah 4, 8, 12, 16, 20, 24, 28, dan 64 ms. Berdasarkan hasil penelitian, diketahui bahwa gap 12 merupakan gap terbaik. Nilai gap 12 menghasilkan sp gather, penampang stack dan NTG (Near Trace Gather yang lebih tajam dibandingkan dengan gap lainnya. Selain itu, dari spectrum analysis didapatkan sp gather dan penampang stack yang menunjukkan bahwa frekuensi terletak pada rentang nilai 10 - 80 Hz, dan nilai spectrum amplitude seismik yang terkecil berkisar -21 s.d 0 dB.

  15. OGS improvements in 2012 in running the North-eastern Italy Seismic Network: the Ferrara VBB borehole seismic station

    Science.gov (United States)

    Pesaresi, D.; Romanelli, M.; Barnaba, C.; Bragato, P. L.; Durì, G.

    2014-07-01

    The Centro di Ricerche Sismologiche (CRS, Seismological Research Centre) of the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS, Italian National Institute for Oceanography and Experimental Geophysics) in Udine (Italy) after the strong earthquake of magnitude M=6.4 occurred in 1976 in the Italian Friuli-Venezia Giulia region, started to operate the North-eastern Italy Seismic Network: it currently consists of 17 very sensitive broad band and 18 simpler short period seismic stations, all telemetered to and acquired in real time at the OGS-CRS data centre in Udine. Real time data exchange agreements in place with other Italian, Slovenian, Austrian and Swiss seismological institutes lead to a total number of about 100 seismic stations acquired in real time, which makes the OGS the reference institute for seismic monitoring of North-eastern Italy. The south-western edge of the OGS seismic network (Fig. 1) stands on the Po alluvial basin: earthquake localization and characterization in this area is affected by the presence of soft alluvial deposits. OGS ha already experience in running a local seismic network in high noise conditions making use of borehole installations in the case of the micro-seismicity monitoring of a local gas storage site for a private company. Following the ML = 5.9 earthquake that struck the Emilia region around Ferrara in Northern Italy on 20 May 2012 at 02:03:53 UTC, a cooperation of Istituto Nazionale di Geofisica e Vulcanologia, OGS, the Comune di Ferrara and the University of Ferrara lead to the reinstallation of a previously existing very broad band (VBB) borehole seismic station in Ferrara. The aim of the OGS intervention was on one hand to extend its real time seismic monitoring capabilities toward South-West, including Ferrara and its surroundings, and on the other hand to evaluate the seismic response at the site. We will describe improvements in running the North-eastern Italy Seismic Network, including details of

  16. K2-111 b - a short period super-Earth transiting a metal poor, evolved old star

    Science.gov (United States)

    Fridlund, Malcolm; Gaidos, Eric; Barragán, Oscar; Persson, Carina M.; Gandolfi, Davide; Cabrera, Juan; Hirano, Teruyuki; Kuzuhara, Masayuki; Csizmadia, Sz.; Nowak, Grzegorz; Endl, Michael; Grziwa, Sascha; Korth, Judith; Pfaff, Jeremias; Bitsch, Bertram; Johansen, Anders; Mustill, Alexander J.; Davies, Melvyn B.; Deeg, Hans J.; Palle, Enric; Cochran, William D.; Eigmüller, Philipp; Erikson, Anders; Guenther, Eike; Hatzes, Artie P.; Kiilerich, Amanda; Kudo, Tomoyuki; MacQueen, Phillip; Narita, Norio; Nespral, David; Pätzold, Martin; Prieto-Arranz, Jorge; Rauer, Heike; Van Eylen, Vincent

    2017-07-01

    Context. From a light curve acquired through the K2 space mission, the star K2-111(EPIC 210894022) has been identified as possibly orbited by a transiting planet. Aims: Our aim is to confirm the planetary nature of the object and derive its fundamental parameters. Methods: We analyse the light curve variations during the planetary transit using packages developed specifically for exoplanetary transits. Reconnaissance spectroscopy and radial velocity observations have been obtained using three separate telescope and spectrograph combinations. The spectroscopic synthesis package SME has been used to derive the stellar photospheric parameters that were used as input to various stellar evolutionary tracks in order to derive the parameters of the system. The planetary transit was also validated to occur on the assumed host star through adaptive imaging and statistical analysis. Results: The star is found to be located in the background of the Hyades cluster at a distance at least 4 times further away from Earth than the cluster itself. The spectrum and the space velocities of K2-111 strongly suggest it to be a member of the thick disk population. The co-added high-resolution spectra show that that it is a metal poor ([Fe/H] = - 0.53 ± 0.05 dex) and α-rich somewhat evolved solar-like star of spectral type G3. We find Teff = 5730 ± 50 K, log g⋆ = 4.15 ± 0.1 cgs, and derive a radius of R⋆ = 1.3 ± 0.1 R⊙ and a mass of M⋆ = 0.88 ± 0.02 M⊙. The currently available radial velocity data confirms a super-Earth class planet with a mass of 8.6 ± 3.9 M⊕ and a radius of 1.9 ± 0.2 R⊕. A second more massive object with a period longer than about 120 days is indicated by a long-term radial velocity drift. Conclusions: The radial velocity detection together with the imaging confirms with a high level of significance that the transit signature is caused by a planet orbiting the star K2-111. This planet is also confirmed in the radial velocity data. A second more

  17. Influence of the interface on growth rates in AlN/GaN short period superlattices via metal organic vapor phase epitaxy

    Science.gov (United States)

    Rodak, L. E.; Korakakis, D.

    2011-11-01

    AlN/GaN short period superlattices are well suited for a number of applications including, but not limited to, digital alloys, intersubband devices, and emitters. In this work, AlN/GaN superlattices with periodicities ranging from 10 to 20 Å have been grown via metal organic vapor phase epitaxy in order to investigate the influence of the interface on the binary alloy growth rates. The GaN growth rate at the interface was observed to decrease with increasing GaN thickness while the AlN growth rate remained constant. This has been attributed to a decrease in the decomposition rate of GaN at the hetero-interface as seen in other III-V hetero-structures.

  18. Using Seismic Interferometry to Investigate Seismic Swarms

    Science.gov (United States)

    Matzel, E.; Morency, C.; Templeton, D. C.

    2017-12-01

    Seismicity provides a direct means of measuring the physical characteristics of active tectonic features such as fault zones. Hundreds of small earthquakes often occur along a fault during a seismic swarm. This seismicity helps define the tectonically active region. When processed using novel geophysical techniques, we can isolate the energy sensitive to the fault, itself. Here we focus on two methods of seismic interferometry, ambient noise correlation (ANC) and the virtual seismometer method (VSM). ANC is based on the observation that the Earth's background noise includes coherent energy, which can be recovered by observing over long time periods and allowing the incoherent energy to cancel out. The cross correlation of ambient noise between a pair of stations results in a waveform that is identical to the seismogram that would result if an impulsive source located at one of the stations was recorded at the other, the Green function (GF). The calculation of the GF is often stable after a few weeks of continuous data correlation, any perturbations to the GF after that point are directly related to changes in the subsurface and can be used for 4D monitoring.VSM is a style of seismic interferometry that provides fast, precise, high frequency estimates of the Green's function (GF) between earthquakes. VSM illuminates the subsurface precisely where the pressures are changing and has the potential to image the evolution of seismicity over time, including changes in the style of faulting. With hundreds of earthquakes, we can calculate thousands of waveforms. At the same time, VSM collapses the computational domain, often by 2-3 orders of magnitude. This allows us to do high frequency 3D modeling in the fault region. Using data from a swarm of earthquakes near the Salton Sea, we demonstrate the power of these techniques, illustrating our ability to scale from the far field, where sources are well separated, to the near field where their locations fall within each other

  19. Effects of feeding strategy during a short finishing period on performance, carcass and meat quality in previously-grazed young bulls.

    Science.gov (United States)

    Cerdeño, A; Vieira, C; Serrano, E; Lavín, P; Mantecón, A R

    2006-04-01

    Twenty-one Brown Swiss×Limousin young bulls reared on pasture were housed for a short finishing period (60 days). CA group (concentrate-ad libitum group) received concentrate and straw ad libitum for the whole finishing period. CR group (concentrate-restricted group) received 4kg of concentrate/animal per day and ad libitum alfalfa hay throughout the 60days. CRA group (concentrate-restricted/ad libitum group) received the same diet as CR group for the first 30days and the same diet as CA group for the last 30days. CA and CRA groups presented higher fatness values. Myoglobin concentration in muscle was highest in CA group (P0.05). It is concluded that, in this type of young animal, 4kg concentrate plus ad libitum alfalfa hay for a 60-day finishing period, despite lower fatness, provides carcasses and meat with acceptable quality characteristics, similar to those obtained from ad libitum fed animals for the same period.

  20. Effects of Pre - Season Short - Term Daily Undulating Periodized Training on Muscle Strength and Sprint Performance of Under - 20 Soccer Players

    Directory of Open Access Journals (Sweden)

    Charles Ricardo L OPES

    2015-06-01

    Full Text Available The aim of this study was to evaluate the effects of daily undulating training periodization designed for maximal lower limb muscle strength and sprint performance in under - 20 soccer players. Twenty - four male athletes (age = 19.1 ± 1.2 yr; mass = 71.1 ± 6. 8 kg; height = 178.0 ± 0.1 cm participated in four weeks of a daily undulating periodized (DUP training soccer program. During the pre - and post - training periods the subjects performed a one repetition maximum (1 RM half back squat test and a 15 - meter s print. Significant training - induced changes were observed in sprint times (pre = 2.38 ± 0.01 s; post = 2.31 ± 0.02 s and 1 RM tests (pre = 107.0 ± 2.0 kg; post = 128.0 ± 2.2 kg. These results indicate that a DUP program is efficient in promoting positive neuromuscular adaptations in soccer players, even with a short - term preseason training period.

  1. Seismic moment tensor resolution on a local scale: Simulated rockburst and mine-induced seismic events in the Kopanang gold mine, South Africa

    CSIR Research Space (South Africa)

    Sileny, J

    2006-08-01

    Full Text Available of regional events in the western Mediterranean are summarized by STICH et al. (2003). The moderate regional events around Japan are documented in the NIED catalogue by KUBO et al. (2002). Several case studies were performed to invert short- period records... and Metallurgy 101, 223? 234. Vol. 163, 2006 Seismic Moment Tensor Resolution on a Local Scale 1511 KRAVANJA, S., PANZA, G.F., and S? I? LENY? , J. (1999), Robust retrieval of a seismic point-source time function, Geophys. J. Int. 136, 385?394. KUBO, A., FUKUYAMA...

  2. Seismic sequences in the Sombrero Seismic Zone

    Science.gov (United States)

    Pulliam, J.; Huerfano, V. A.; ten Brink, U.; von Hillebrandt, C.

    2007-05-01

    The northeastern Caribbean, in the vicinity of Puerto Rico and the Virgin Islands, has a long and well-documented history of devastating earthquakes and tsunamis, including major events in 1670, 1787, 1867, 1916, 1918, and 1943. Recently, seismicity has been concentrated to the north and west of the British Virgin Islands, in the region referred to as the Sombrero Seismic Zone by the Puerto Rico Seismic Network (PRSN). In the combined seismicity catalog maintained by the PRSN, several hundred small to moderate magnitude events can be found in this region prior to 2006. However, beginning in 2006 and continuing to the present, the rate of seismicity in the Sombrero suddenly increased, and a new locus of activity developed to the east of the previous location. Accurate estimates of seismic hazard, and the tsunamigenic potential of seismic events, depend on an accurate and comprehensive understanding of how strain is being accommodated in this corner region. Are faults locked and accumulating strain for release in a major event? Or is strain being released via slip over a diffuse system of faults? A careful analysis of seismicity patterns in the Sombrero region has the potential to both identify faults and modes of failure, provided the aggregation scheme is tuned to properly identify related events. To this end, we experimented with a scheme to identify seismic sequences based on physical and temporal proximity, under the assumptions that (a) events occur on related fault systems as stress is refocused by immediately previous events and (b) such 'stress waves' die out with time, so that two events that occur on the same system within a relatively short time window can be said to have a similar 'trigger' in ways that two nearby events that occurred years apart cannot. Patterns that emerge from the identification, temporal sequence, and refined locations of such sequences of events carry information about stress accommodation that is obscured by large clouds of

  3. Romanian earthquakes analysis using BURAR seismic array

    International Nuclear Information System (INIS)

    Borleanu, Felix; Rogozea, Maria; Nica, Daniela; Popescu, Emilia; Popa, Mihaela; Radulian, Mircea

    2008-01-01

    Bucovina seismic array (BURAR) is a medium-aperture array, installed in 2002 in the northern part of Romania (47.61480 N latitude, 25.21680 E longitude, 1150 m altitude), as a result of the cooperation between Air Force Technical Applications Center, USA and National Institute for Earth Physics, Romania. The array consists of ten elements, located in boreholes and distributed over a 5 x 5 km 2 area; nine with short-period vertical sensors and one with a broadband three-component sensor. Since the new station has been operating the earthquake survey of Romania's territory has been significantly improved. Data recorded by BURAR during 01.01.2005 - 12.31.2005 time interval are first processed and analyzed, in order to establish the array detection capability of the local earthquakes, occurred in different Romanian seismic zones. Subsequently a spectral ratios technique was applied in order to determine the calibration relationships for magnitude, using only the information gathered by BURAR station. The spectral ratios are computed relatively to a reference event, considered as representative for each seismic zone. This method has the advantage to eliminate the path effects. The new calibration procedure is tested for the case of Vrancea intermediate-depth earthquakes and proved to be very efficient in constraining the size of these earthquakes. (authors)

  4. Seismicity within the Irpinia Fault System As Monitored By Isnet (Irpinia Seismic Network) and Its Possible Relation with Fluid Storage

    Science.gov (United States)

    Festa, G.; Zollo, A.; Amoroso, O.; Ascione, A.; Colombelli, S.; Elia, L.; Emolo, A.; Martino, C.; Mazzoli, S.; Orefice, A.; Russo, G.

    2014-12-01

    ISNet (http://isnet.fisica.unina.it) is deployed in Southern Apennines along the active fault system responsible for the 1980, M 6.9 Irpinia earthquake. ISNet consists of 32 seismic stations equipped with both strong motion and velocimetric instruments (either broadband or short-period), with the aim of capture a broad set of seismic signals, from ambient noise to strong motion. Real time and near real time procedures run at ISNet with the goal of monitoring the seismicity, check possible space-time anomalies, detect seismic sequences and launch an earthquake early warning in the case of potential significant ground shaking in the area. To understand the role of fluids on the seismicity of the area, we investigated velocity and attenuation models. The former is built from accurate cross-correlation picking and S wave detection based onto polarization analysis. Joint inversion of both P and S arrival times is then based on a linearized multi-scale tomographic approach. Attenuation is instead obtained from inversion of displacement spectra, deconvolving for the source effect. High VP/VS and QS/QP >1 were found within a ~15 km wide rock volume where intense microseismicity is located. This indicates that concentration of seismicity is possibly controlled by high pore fluid pressure. This earthquake reservoir may come from a positive feedback between the seismic pumping that controls the fluid transmission through the fractured damage zone and the low permeability of cross fault barrier, increasing the fluid pore pressure within the fault bounded block. In this picture, sequences mostly occur at the base of this fluid rich layer. They show an anomalous pattern in the earthquake occurrence per magnitude classes; main events evolve with a complex source kinematics, as obtained from backprojection of apparent source time functions, indicating possible directivity effects. In this area sequences might be the key for understanding the transition between the deep

  5. A new event detector designed for the Seismic Research Observatories

    Science.gov (United States)

    Murdock, James N.; Hutt, Charles R.

    1983-01-01

    A new short-period event detector has been implemented on the Seismic Research Observatories. For each signal detected, a printed output gives estimates of the time of onset of the signal, direction of the first break, quality of onset, period and maximum amplitude of the signal, and an estimate of the variability of the background noise. On the SRO system, the new algorithm runs ~2.5x faster than the former (power level) detector. This increase in speed is due to the design of the algorithm: all operations can be performed by simple shifts, additions, and comparisons (floating point operations are not required). Even though a narrow-band recursive filter is not used, the algorithm appears to detect events competitively with those algorithms that employ such filters. Tests at Albuquerque Seismological Laboratory on data supplied by Blandford suggest performance commensurate with the on-line detector of the Seismic Data Analysis Center, Alexandria, Virginia.

  6. Dynamics of the Oso-Steelhead landslide from broadband seismic analysis

    Science.gov (United States)

    Hibert, C.; Stark, C. P.; Ekström, G.

    2015-06-01

    We carry out a combined analysis of the short- and long-period seismic signals generated by the devastating Oso-Steelhead landslide that occurred on 22 March 2014. The seismic records show that the Oso-Steelhead landslide was not a single slope failure, but a succession of multiple failures distinguished by two major collapses that occurred approximately 3 min apart. The first generated long-period surface waves that were recorded at several proximal stations. We invert these long-period signals for the forces acting at the source, and obtain estimates of the first failure runout and kinematics, as well as its mass after calibration against the mass-centre displacement estimated from remote-sensing imagery. Short-period analysis of both events suggests that the source dynamics of the second event is more complex than the first. No distinct long-period surface waves were recorded for the second failure, which prevents inversion for its source parameters. However, by comparing the seismic energy of the short-period waves generated by both events we are able to estimate the volume of the second. Our analysis suggests that the volume of the second failure is about 15-30% of the total landslide volume, giving a total volume mobilized by the two events between 7 × 106 and 10 × 106 m3, in agreement with estimates from ground observations and lidar mapping.

  7. A dearth of short-period massive binaries in the young massive star forming region M 17. Evidence for a large orbital separation at birth?

    Science.gov (United States)

    Sana, H.; Ramírez-Tannus, M. C.; de Koter, A.; Kaper, L.; Tramper, F.; Bik, A.

    2017-03-01

    Aims: The formation of massive stars remains poorly understood and little is known about their birth multiplicity properties. Here, we aim to quantitatively investigate the strikingly low radial-velocity dispersion measured for a sample of 11 massive pre- and near-main-sequence stars (σ1D= 5.6 ± 0.2 km s-1) in the very young massive star forming region M 17, in order to obtain first constraints on the multiplicity properties of young massive stellar objects. Methods: We compute the radial-velocity dispersion of synthetic populations of massive stars for various multiplicity properties and we compare the obtained σ1D distributions to the observed value. We specifically investigate two scenarios: a low binary fraction and a dearth of short-period binary systems. Results: Simulated populations with low binary fractions () or with truncated period distributions (Pcutoff > 9 months) are able to reproduce the low σ1D observed within their 68%-confidence intervals. Furthermore, parent populations with fbin > 0.42 or Pcutoff < 47 d can be rejected at the 5%-significance level. Both constraints are in stark contrast with the high binary fraction and plethora of short-period systems in few Myr-old, well characterized OB-type populations. To explain the difference in the context of the first scenario would require a variation of the outcome of the massive star formation process. In the context of the second scenario, compact binaries must form later on, and the cut-off period may be related to physical length-scales representative of the bloated pre-main-sequence stellar radii or of their accretion disks. Conclusions: If the obtained constraints for the M 17's massive-star population are representative of the multiplicity properties of massive young stellar objects, our results may provide support to a massive star formation process in which binaries are initially formed at larger separations, then harden or migrate to produce the typical (untruncated) power-law period

  8. Seismic Studies

    Energy Technology Data Exchange (ETDEWEB)

    R. Quittmeyer

    2006-09-25

    This technical work plan (TWP) describes the efforts to develop and confirm seismic ground motion inputs used for preclosure design and probabilistic safety 'analyses and to assess the postclosure performance of a repository at Yucca Mountain, Nevada. As part of the effort to develop seismic inputs, the TWP covers testing and analyses that provide the technical basis for inputs to the seismic ground-motion site-response model. The TWP also addresses preparation of a seismic methodology report for submission to the U.S. Nuclear Regulatory Commission (NRC). The activities discussed in this TWP are planned for fiscal years (FY) 2006 through 2008. Some of the work enhances the technical basis for previously developed seismic inputs and reduces uncertainties and conservatism used in previous analyses and modeling. These activities support the defense of a license application. Other activities provide new results that will support development of the preclosure, safety case; these results directly support and will be included in the license application. Table 1 indicates which activities support the license application and which support licensing defense. The activities are listed in Section 1.2; the methods and approaches used to implement them are discussed in more detail in Section 2.2. Technical and performance objectives of this work scope are: (1) For annual ground motion exceedance probabilities appropriate for preclosure design analyses, provide site-specific seismic design acceleration response spectra for a range of damping values; strain-compatible soil properties; peak motions, strains, and curvatures as a function of depth; and time histories (acceleration, velocity, and displacement). Provide seismic design inputs for the waste emplacement level and for surface sites. Results should be consistent with the probabilistic seismic hazard analysis (PSHA) for Yucca Mountain and reflect, as appropriate, available knowledge on the limits to extreme ground

  9. Seismic Studies

    International Nuclear Information System (INIS)

    R. Quittmeyer

    2006-01-01

    This technical work plan (TWP) describes the efforts to develop and confirm seismic ground motion inputs used for preclosure design and probabilistic safety 'analyses and to assess the postclosure performance of a repository at Yucca Mountain, Nevada. As part of the effort to develop seismic inputs, the TWP covers testing and analyses that provide the technical basis for inputs to the seismic ground-motion site-response model. The TWP also addresses preparation of a seismic methodology report for submission to the U.S. Nuclear Regulatory Commission (NRC). The activities discussed in this TWP are planned for fiscal years (FY) 2006 through 2008. Some of the work enhances the technical basis for previously developed seismic inputs and reduces uncertainties and conservatism used in previous analyses and modeling. These activities support the defense of a license application. Other activities provide new results that will support development of the preclosure, safety case; these results directly support and will be included in the license application. Table 1 indicates which activities support the license application and which support licensing defense. The activities are listed in Section 1.2; the methods and approaches used to implement them are discussed in more detail in Section 2.2. Technical and performance objectives of this work scope are: (1) For annual ground motion exceedance probabilities appropriate for preclosure design analyses, provide site-specific seismic design acceleration response spectra for a range of damping values; strain-compatible soil properties; peak motions, strains, and curvatures as a function of depth; and time histories (acceleration, velocity, and displacement). Provide seismic design inputs for the waste emplacement level and for surface sites. Results should be consistent with the probabilistic seismic hazard analysis (PSHA) for Yucca Mountain and reflect, as appropriate, available knowledge on the limits to extreme ground motion at

  10. Seismic protection

    International Nuclear Information System (INIS)

    Herbert, R.

    1988-01-01

    To ensure that a nuclear reactor or other damage-susceptible installation is, so far as possible, tripped and already shut down before the arrival of an earthquake shock at its location, a ring of monitoring seismic sensors is provided around it, each sensor being spaced from it by a distance (possibly several kilometres) such that (taking into account the seismic-shock propagation velocity through the intervening ground) a shock monitored by the sensor and then advancing to the installation site will arrive there later than a warning signal emitted by the sensor and received at the installation, by an interval sufficient to allow the installation to trip and shut down, or otherwise assume an optimum anti-seismic mode, in response to the warning signal. Extra sensors located in boreholes may define effectively a three-dimensional (hemispherical) sensing boundary rather than a mere two-dimensional ring. (author)

  11. Induced Seismicity

    Science.gov (United States)

    Keranen, Katie M.; Weingarten, Matthew

    2018-05-01

    The ability of fluid-generated subsurface stress changes to trigger earthquakes has long been recognized. However, the dramatic rise in the rate of human-induced earthquakes in the past decade has created abundant opportunities to study induced earthquakes and triggering processes. This review briefly summarizes early studies but focuses on results from induced earthquakes during the past 10 years related to fluid injection in petroleum fields. Study of these earthquakes has resulted in insights into physical processes and has identified knowledge gaps and future research directions. Induced earthquakes are challenging to identify using seismological methods, and faults and reefs strongly modulate spatial and temporal patterns of induced seismicity. However, the similarity of induced and natural seismicity provides an effective tool for studying earthquake processes. With continuing development of energy resources, increased interest in carbon sequestration, and construction of large dams, induced seismicity will continue to pose a hazard in coming years.

  12. Retention of a 24-hour time memory in Syrian hamsters carrying the 20-hour short circadian period mutation in casein kinase-1ε (ck1εtau/tau).

    Science.gov (United States)

    Cain, Sean W; Yoon, Jeena; Shrestha, Tenjin C; Ralph, Martin R

    2014-10-01

    Circadian rhythmic expression of conditioned place avoidance (CPA) was produced in Syrian hamsters homozygous for the circadian short period mutation, tau. In constant dim red light neither the 20 h endogenous period, nor a 20 h place conditioning schedule eliminated the 24 h modulation of CPA behavior described previously for wild type (wt) hamsters and other species. Tau mutants exhibited a 20 h rhythm superimposed on the 24 h modulation. The 20 h component was removed selectively with lesions of the suprachiasmatic nucleus. Wt animals conditioned on a 20 h schedule did not produce a 20 h rhythm, but still expressed the 24 h modulation. The results show that the context entrainable oscillator (CEO) underlying memory for the timing of an unconditioned stimulus, retains a period of about 24 h regardless of clock gene background (tau mutation) and/or the conditioning schedule (24 vs 20 h). Therefore the CEO responsible for time memory is distinct from the biological clock controlling activity; the underlying circadian molecular mechanisms may differ from the ubiquitous transcription-translation feedback oscillator; and time memory itself is not classically conditioned. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. IUE spectrophotometry of the DA4 primary in the short-period white dwarf-red dwarf spectroscopic binary Case 1

    Science.gov (United States)

    Sion, E. M.; Guinan, E. F.; Wesemael, F.

    1984-01-01

    Low-resolution ultraviolet International Ultraviolet Explorer spectra of the DA white dwarf Case 1 are presented. The spectra show the presence of the 1400 A feature, already discovered in several other DA stars, and of a shallower trough in the 1550-1700 A range. A model atmosphere analysis of the ultraviolet energy distribution of the Ly-alpha red wing yields T(e) = 13,000 + or - 500 K. Possible interpretations of the 1400 A feature are reviewed. Case 1 is the coolest white dwarf found in a short-period, detached white dwarf-red dwarf binary, and its cooling time is consistent with estimates of the efficiency of angular momentum removal mechanisms in the phases subsequent to common envelope binary evolution.

  14. THE MAXIMUM AMOUNTS OF RAINFALL FALLEN IN SHORT PERIODS OF TIME IN THE HILLY AREA OF CLUJ COUNTY - GENESIS, DISTRIBUTION AND PROBABILITY OF OCCURRENCE

    Directory of Open Access Journals (Sweden)

    BLAGA IRINA

    2014-03-01

    Full Text Available The maximum amounts of rainfall are usually characterized by high intensity, and their effects on the substrate are revealed, at slope level, by the deepening of the existing forms of torrential erosion and also by the formation of new ones, and by landslide processes. For the 1971-2000 period, for the weather stations in the hilly area of Cluj County: Cluj- Napoca, Dej, Huedin and Turda the highest values of rainfall amounts fallen in 24, 48 and 72 hours were analyzed and extracted, based on which the variation and the spatial and temporal distribution of the precipitation were analyzed. The annual probability of exceedance of maximum rainfall amounts fallen in short time intervals (24, 48 and 72 hours, based on thresholds and class values was determined, using climatological practices and the Hyfran program facilities.

  15. High Voltage Seismic Generator

    Science.gov (United States)

    Bogacz, Adrian; Pala, Damian; Knafel, Marcin

    2015-04-01

    This contribution describes the preliminary result of annual cooperation of three student research groups from AGH UST in Krakow, Poland. The aim of this cooperation was to develop and construct a high voltage seismic wave generator. Constructed device uses a high-energy electrical discharge to generate seismic wave in ground. This type of device can be applied in several different methods of seismic measurement, but because of its limited power it is mainly dedicated for engineering geophysics. The source operates on a basic physical principles. The energy is stored in capacitor bank, which is charged by two stage low to high voltage converter. Stored energy is then released in very short time through high voltage thyristor in spark gap. The whole appliance is powered from li-ion battery and controlled by ATmega microcontroller. It is possible to construct larger and more powerful device. In this contribution the structure of device with technical specifications is resented. As a part of the investigation the prototype was built and series of experiments conducted. System parameter was measured, on this basis specification of elements for the final device were chosen. First stage of the project was successful. It was possible to efficiently generate seismic waves with constructed device. Then the field test was conducted. Spark gap wasplaced in shallowborehole(0.5 m) filled with salt water. Geophones were placed on the ground in straight line. The comparison of signal registered with hammer source and sparker source was made. The results of the test measurements are presented and discussed. Analysis of the collected data shows that characteristic of generated seismic signal is very promising, thus confirms possibility of practical application of the new high voltage generator. The biggest advantage of presented device after signal characteristics is its size which is 0.5 x 0.25 x 0.2 m and weight approximately 7 kg. This features with small li-ion battery makes

  16. Impact of streamflow data assimilation and length of the verification period on the quality of short-term ensemble hydrologic forecasts

    Science.gov (United States)

    Randrianasolo, A.; Thirel, G.; Ramos, M. H.; Martin, E.

    2014-11-01

    Data assimilation has gained wide recognition in hydrologic forecasting due mainly to its capacity to improve the quality of short-term forecasts. In this study, a comparative analysis is conducted to assess the impact of discharge data assimilation on the quality of streamflow forecasts issued by two different modeling conceptualizations of catchment response. The sensitivity of the performance metrics to the length of the verification period is also investigated. The hydrological modeling approaches are: the coupled physically-based hydro-meteorological model SAFRAN-ISBA-MODCOU, a distributed model with a data assimilation procedure that uses streamflow measurements to assess the initial state of soil water content that optimizes discharge simulations, and the lumped soil moisture-accounting type rainfall-runoff model GRP, which assimilates directly the last observed discharge to update the state of the routing store. The models are driven by the weather ensemble prediction system PEARP of Météo-France, which is based on the global spectral ARPEGE model zoomed over France. It runs 11 perturbed members for a forecast range of 60 h. Forecast and observed data are available for 86 catchments over a 17-month period (March 2005-July 2006) for both models and for 82 catchments over a 52-month period (April 2005-July 2009) for the GRP model. The first dataset is used to investigate the impact of streamflow data assimilation on forecast quality, while the second is used to evaluate the impact of the length of the verification period on the assessment of forecast quality. Forecasts are compared to daily observed discharges and scores are computed for lead times 24 h and 48 h. Results indicate an overall good performance of both hydrological models forced by the PEARP ensemble predictions when the models are run with their data assimilation procedures. In general, when data assimilation is performed, the quality of the forecasts increases: median differences between

  17. Seismic Symphonies

    Science.gov (United States)

    Strinna, Elisa; Ferrari, Graziano

    2015-04-01

    The project started in 2008 as a sound installation, a collaboration between an artist, a barrel organ builder and a seismologist. The work differs from other attempts of sound transposition of seismic records. In this case seismic frequencies are not converted automatically into the "sound of the earthquake." However, it has been studied a musical translation system that, based on the organ tonal scale, generates a totally unexpected sequence of sounds which is intended to evoke the emotions aroused by the earthquake. The symphonies proposed in the project have somewhat peculiar origins: they in fact come to life from the translation of graphic tracks into a sound track. The graphic tracks in question are made up by copies of seismograms recorded during some earthquakes that have taken place around the world. Seismograms are translated into music by a sculpture-instrument, half a seismograph and half a barrel organ. The organ plays through holes practiced on paper. Adapting the documents to the instrument score, holes have been drilled on the waves' peaks. The organ covers about three tonal scales, starting from heavy and deep sounds it reaches up to high and jarring notes. The translation of the seismic records is based on a criterion that does match the highest sounds to larger amplitudes with lower ones to minors. Translating the seismogram in the organ score, the larger the amplitude of recorded waves, the more the seismogram covers the full tonal scale played by the barrel organ and the notes arouse an intense emotional response in the listener. Elisa Strinna's Seismic Symphonies installation becomes an unprecedented tool for emotional involvement, through which can be revived the memory of the greatest disasters of over a century of seismic history of the Earth. A bridge between art and science. Seismic Symphonies is also a symbolic inversion: the instrument of the organ is most commonly used in churches, and its sounds are derived from the heavens and

  18. HATS-43b, HATS-44b, HATS-45b, and HATS-46b: Four Short-period Transiting Giant Planets in the Neptune–Jupiter Mass Range

    Science.gov (United States)

    Brahm, R.; Hartman, J. D.; Jordán, A.; Bakos, G. Á.; Espinoza, N.; Rabus, M.; Bhatti, W.; Penev, K.; Sarkis, P.; Suc, V.; Csubry, Z.; Bayliss, D.; Bento, J.; Zhou, G.; Mancini, L.; Henning, T.; Ciceri, S.; de Val-Borro, M.; Shectman, S.; Crane, J. D.; Arriagada, P.; Butler, P.; Teske, J.; Thompson, I.; Osip, D.; Díaz, M.; Schmidt, B.; Lázár, J.; Papp, I.; Sári, P.

    2018-03-01

    We report the discovery of four short-period extrasolar planets transiting moderately bright stars from photometric measurements of the HATSouth network coupled to additional spectroscopic and photometric follow-up observations. While the planet masses range from 0.26 to 0.90 {M}{{J}}, the radii are all approximately a Jupiter radii, resulting in a wide range of bulk densities. The orbital period of the planets ranges from 2.7 days to 4.7 days, with HATS-43b having an orbit that appears to be marginally non-circular (e = 0.173 ± 0.089). HATS-44 is notable for having a high metallicity ([{Fe}/{{H}}] = 0.320 ± 0.071). The host stars spectral types range from late F to early K, and all of them are moderately bright (13.3 Carnegie Institute is operated by PU in conjunction with PUC, the station at the High Energy Spectroscopic Survey (H.E.S.S.) site is operated in conjunction with MPIA, and the station at Siding Spring Observatory (SSO) is operated jointly with ANU. This paper includes data gathered with the MPG 2.2 m and ESO 3.6 m telescopes at the ESO Observatory in La Silla. This paper includes data gathered with the 6.5 meter Magellan Telescopes located at Las Campanas Observatory, Chile.

  19. Magma replenishment and volcanic unrest inferred from the analysis of VT micro-seismicity and seismic velocity changes at Piton de la Fournaise Volcano

    Science.gov (United States)

    Brenguier, F.; Rivemale, E.; Clarke, D. S.; Schmid, A.; Got, J.; Battaglia, J.; Taisne, B.; Staudacher, T.; Peltier, A.; Shapiro, N. M.; Tait, S.; Ferrazzini, V.; Di Muro, A.

    2011-12-01

    Piton de la Fournaise volcano (PdF) is among the most active basaltic volcanoes worldwide with more than one eruption per year on average. Also, PdF is densely instrumented with short-period and broad-band seismometers as well as with GPS receivers. Continuous seismic waveforms are available from 1999. Piton de la Fournaise volcano has a moderate inter-eruptive seismic activity with an average of five detected Volcano-Tectonic (VT) earthquakes per day with magnitudes ranging from 0.5 to 3.5. These earthquakes are shallow and located about 2.5 kilometers beneath the edifice surface. Volcanic unrest is captured on average a few weeks before eruptions by measurements of increased VT seismicity rate, inflation of the edifice summit, and decreased seismic velocities from correlations of seismic noise. Eruptions are usually preceded by seismic swarms of VT earthquakes. Recently, almost 50 % of seismic swarms were not followed by eruptions. Within this work, we aim to gather results from different groups of the UnderVolc research project in order to better understand the processes of deep magma transfer, volcanic unrest, and pre-eruptive magma transport initiation. Among our results, we show that the period 1999-2003 was characterized by a long-term increase of VT seismicity rate coupled with a long-term decrease of seismic velocities. These observations could indicate a long-term replenishment of the magma storage area. The relocation of ten years of inter-eruptive micro-seismicity shows a narrow (~300 m long) sub-vertical fault zone thus indicating a conduit rather than an extended magma reservoir as the shallow magma feeder system. Also, we focus on the processes of short-term volcanic unrest and prove that magma intrusions within the edifice leading to eruptions activate specific VT earthquakes that are distinct from magma intrusions that do not lead to eruptions. We thus propose that, among the different pathways of magma transport within the edifice, only one will

  20. Seismicity and tectonics of Bangladesh

    International Nuclear Information System (INIS)

    Hossain, K.M.

    1989-05-01

    Northern and eastern Bangladesh and surrounding areas belong to a seismically active zone and are associated with the subduction of the Indian plate. The seismicity and tectonics have been studied in detail and the observations have been correlated to understand the earthquake phenomenon in the region. The morphotectonic behaviour of northern Bangladesh shows that it is deeply related to the movement of the Dauki fault system and relative upliftment of the Shillong plateau. Contemporary seismicity in the Dauki fault system is relatively quiet comparing to that in the Naga-Disang-Haflong thrust belt giving rise to the probability of sudden release of energy being accumulated in the vicinity of the Dauki fault system. This observation corresponds with the predicted average return period of a large earthquake (1897 type) and the possibility of M > 8 earthquake in the vicinity of the Dauki fault within this century should not be ruled out. The seismicity in the folded belt in the east follows the general trend of Arakan-Yoma anticlinorium and represents shallow and low-angled thrust movements in conformity with the field observation. Seismotectonic behaviour in the deep basin part of Bangladesh demonstrates that an intraplate movement in the basement rock has been taking place along the deep-seated faults causing relative upliftment and subsidence in the basin. Bangladesh has been divided into three seismic zones on the basis of morphotectonic and seismic behaviour. Zone-I has been identified as the zone of high seismic risk. (author). 43 refs, 5 figs, 3 tabs

  1. Objective-function Hybridization in Adjoint Seismic Tomography

    Science.gov (United States)

    Yuan, Y. O.; Bozdag, E.; Simons, F.; Gao, F.

    2016-12-01

    In the realm of seismic tomography, we are at the threshold of a new era of huge seismic datasets. However, how to assimilate as much information as possible from every seismogram is still a challenge. Cross-correlation measurements are generally tailored to some window selection algorithms, such as FLEXWIN (Maggie et al. 2008), to balance amplitude differences between seismic phases. However, these measurements naturally favor maximum picks in selected windows. It is also difficult to select all usable portions of seismograms in an optimum way that lots of information is generally lost, particularly the scattered waves. Instantaneous phase type of misfits extract information from every wiggle without cutting seismograms into small pieces, however, dealing with cycle skips at short periods can be challenging. For this purpose, we introduce a flexible hybrid approach for adjoint seismic tomography, to combine various objective functions. We initially focus on phase measurements and propose using instantaneous phase to take into account relatively small-magnitude scattered waves at long periods while using cross-correlation measurements on FLEXWIN windows to select distinct body-wave arrivals without complicating measurements due to non-linearities at short periods. To better deal with cycle skips and reliably measure instantaneous phases we design a new misfit function that incorporates instantaneous phase information implicitly instead of measuring it explicitly, through using normalized analytic signals. We present in our synthetic experiments how instantaneous phase, cross-correlation and their hybridization affect tomographic results. The combination of two different phase measurements in a hybrid approach constitutes progress towards using "anything and everything" in a data set, addressing data quality and measurement challenges simultaneously. We further extend hybridisation of misfit functions for amplitude measurements such as cross-correlation amplitude

  2. [The effects of 16-weeks pilates mat program on anthropometric variables and body composition in active adult women after a short detraining period].

    Science.gov (United States)

    Vaquero-Cristóbal, Raquel; Alacid, Fernando; Esparza-Ros, Francisco; Muyor, José M; López-Miñarro, Pedro Ángel

    2015-04-01

    previous studies have analysed the effect of mat Pilates practice on anthropometric variables and body composition in sedentaries. To date no researchs have investigated the benefits of Pilates on these variables after a short detraining period. to determine the effect of a 16-week mat Pilates program on anthropometric variables, body composition and somatotype of women with previous practice experience after three weeks of detraining period. twenty-one women underwent a complete anthropometric assessment according with ISAK guidelines before and after a 16 week mat Pilates program (two days, one hour). All women had one to three years of mat Pilates experience and came to three weeks of detraining period (Christmas holiday). women showed significant decreases for body mass, BMI, upper limb (biceps and triceps) and trunk (subscapular, iliac crest, supraspinale and abdominal) individual skinfolds, 6 and 8 skinfold sums, endomorphy and fat mass; and a significant increases for muscle mass. The mean somatotype was classified as mesomorphic endomorph in the pre- (4.91, 4.01, 1.47) and post-test (4.68, 4.16, 1.69). Eight women changed their somatotype clasification after the intervention program. the practice of mat Pilates for 16 weeks caused changes associated with health state improvements on anthropometric variables, especially on skinfolds which significantly decreased, body composition (fat and muscle masses decreased and increased, respectively) and somatotype (there was a significantly decreased on the endomorph component in experienced women after three week of detraning. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  3. Probabilistic seismic hazard at the archaeological site of Gol Gumbaz in Vijayapura, south India

    Science.gov (United States)

    Patil, Shivakumar G.; Menon, Arun; Dodagoudar, G. R.

    2018-03-01

    Probabilistic seismic hazard analysis (PSHA) is carried out for the archaeological site of Vijayapura in south India in order to obtain hazard consistent seismic input ground-motions for seismic risk assessment and design of seismic protection measures for monuments, where warranted. For this purpose the standard Cornell-McGuire approach, based on seismogenic zones with uniformly distributed seismicity is employed. The main features of this study are the usage of an updated and unified seismic catalogue based on moment magnitude, new seismogenic source models and recent ground motion prediction equations (GMPEs) in logic tree framework. Seismic hazard at the site is evaluated for level and rock site condition with 10% and 2% probabilities of exceedance in 50 years, and the corresponding peak ground accelerations (PGAs) are 0.074 and 0.142 g, respectively. In addition, the uniform hazard spectra (UHS) of the site are compared to the Indian code-defined spectrum. Comparisons are also made with results from National Disaster Management Authority (NDMA 2010), in terms of PGA and pseudo spectral accelerations (PSAs) at T = 0.2, 0.5, 1.0 and 1.25 s for 475- and 2475-yr return periods. Results of the present study are in good agreement with the PGA calculated from isoseismal map of the Killari earthquake, {M}w = 6.4 (1993). Disaggregation of PSHA results for the PGA and spectral acceleration ({S}a) at 0.5 s, displays the controlling scenario earthquake for the study region as low to moderate magnitude with the source being at a short distance from the study site. Deterministic seismic hazard (DSHA) is also carried out by taking into account three scenario earthquakes. The UHS corresponding to 475-yr return period (RP) is used to define the target spectrum and accordingly, the spectrum-compatible natural accelerograms are selected from the suite of recorded accelerograms.

  4. Regional passive seismic monitoring reveals dynamic glacier activity on Spitsbergen, Svalbard

    Directory of Open Access Journals (Sweden)

    Andreas Köhler

    2015-12-01

    Full Text Available Dynamic glacier activity is increasingly observed through passive seismic monitoring. We analysed near-regional-scale seismicity on the Arctic archipelago of Svalbard to identify seismic icequake signals and to study their spatial–temporal distribution within the 14-year period from 2000 until 2013. This is the first study that uses seismic data recorded on permanent broadband stations to detect and locate icequakes in different regions of Spitsbergen, the main island of the archipelago. A temporary local seismic network and direct observations of glacier calving and surging were used to identify icequake sources. We observed a high number of icequakes with clear spectral peaks between 1 and 8 Hz in different parts of Spitsbergen. Spatial clusters of icequakes could be associated with individual grounded tidewater glaciers and exhibited clear seasonal variability each year with more signals observed during the melt season. Locations at the termini of glaciers, and correlation with visual calving observations in situ at Kronebreen, a glacier in the Kongsfjorden region, show that these icequakes were caused dominantly by calving. Indirect evidence for glacier surging through increased calving seismicity was found in 2003 at Tunabreen, a glacier in central Spitsbergen. Another type of icequake was observed in the area of the Nathorstbreen glacier system. Seismic events occurred upstream of the glacier within a short time period between January and May 2009 during the initial phase of a major glacier surge. This study is the first step towards the generation and implementation of an operational seismic monitoring strategy for glacier dynamics in Svalbard.

  5. The 2017 Maple Creek Seismic Swarm in Yellowstone National Park

    Science.gov (United States)

    Pang, G.; Hale, J. M.; Farrell, J.; Burlacu, R.; Koper, K. D.; Smith, R. B.

    2017-12-01

    The University of Utah Seismograph Stations (UUSS) performs near-real-time monitoring of seismicity in the region around Yellowstone National Park in partnership with the United States Geological Survey and the National Park Service. UUSS operates and maintains 29 seismic stations with network code WY (short-period, strong-motion, and broadband) and records data from five other seismic networks—IW, MB, PB, TA, and US—to enhance the location capabilities in the Yellowstone region. A seismic catalog is produced using a conventional STA/LTA detector and single-event location techniques (Hypoinverse). On June 12, 2017, a seismic swarm began in Yellowstone National Park about 5 km east of Hebgen Lake. The swarm is adjacent to the source region of the 1959 MW 7.3 Hebgen Lake earthquake, in an area corresponding to positive Coulumb stress change from that event. As of Aug. 1, 2017, the swarm consists of 1481 earthquakes with 1 earthquake above magnitude 4, 8 earthquakes in the magnitude 3 range, 115 earthquakes in the magnitude 2 range, 469 earthquakes in the magnitude 1 range, 856 earthquakes in the magnitude 0 range, 22 earthquakes with negative magnitudes, and 10 earthquakes with no magnitude. Earthquake depths are mostly between 3 and 10 km and earthquake depth increases toward the northwest. Moment tensors for the 2 largest events (3.6 MW and 4.4. MW) show strike-slip faulting with T axes oriented NE-SW, consistent with the regional stress field. We are currently using waveform cross-correlation methods to measure differential travel times that are being used with the GrowClust program to generate high-accuracy relative relocations. Those locations will be used to identify structures in the seismicity and make inferences about the tectonic and magmatic processes causing the swarm.

  6. Performances of the UNDERground SEISmic array for the analysis of seismicity in Central Italy

    Directory of Open Access Journals (Sweden)

    R. Scarpa

    2006-06-01

    Full Text Available This paper presents the first results from the operation of a dense seismic array deployed in the underground Physics Laboratories at Gran Sasso (Central Italy. The array consists of 13 short-period, three-component seismometers with an aperture of about 550 m and average sensor spacing of 90 m. The reduced sensor spacing, joined to the spatially-white character of the background noise allows for quick and reliable detection of coherent wavefront arrivals even under very poor SNR conditions. We apply high-resolution frequency-slowness and polarization analyses to a set of 27 earthquakes recorded between November, 2002, and September, 2003, at epicentral distances spanning the 20-140 km interval. We locate these events using inversion of P- and S-wave backazimuths and S-P delay times, and compare the results with data from the Centralized National Seismic Network catalog. For the case of S-wave, the discrepancies among the two set of locations never exceed 10 km; the largest errors are instead observed for the case of P-waves. This observation may be due to the fact that the small array aperture does not allow for robust assessment of waves propagating at high apparent velocities. This information is discussed with special reference to the directions of future studies aimed at elucidating the location of seismogenetic structures in Central Italy from extended analysis of the micro-seismicity.

  7. Seismic gaps and plate tectonics: seismic potential for major boundaries

    Energy Technology Data Exchange (ETDEWEB)

    McCann, W R; Nishenko, S P; Sykes, L R; Krause, J

    1979-01-01

    The theory of plate tectonics provides a basic framework for evaluating the potential for future great earthquakes to occur along major plate boundaries. Along most of the transform and convergent plate boundaries considered in this paper, the majority of seismic slip occurs during large earthquakes, i.e., those of magnitude 7 or greater. The concepts that rupture zones, as delineated by aftershocks, tend to abut rather than overlap, and large events occur in regions with histories of both long-and short-term seismic quiescence are used in this paper to delineate major seismic gaps. The term seismic gap is taken to refer to any region along an active plate boundary that has not experienced a large thrust or strike-slip earthquake for more than 30 years. A region of high seismic potential is a seismic gap that, for historic or tectonic reasons, is considered likely to produce a large shock during the next few decades. The seismic gap technique provides estimates of the location, size of future events and origin time to within a few tens of years at best. The accompanying map summarizes six categories of seismic potential for major plate boundaries in and around the margins of the Pacific Ocean and the Caribbean, South Sandwich and Sunda (Indonesia) regions for the next few decades. These six categories are meant to be interpreted as forecasts of the location and size of future large shocks and should not be considered to be predictions in which a precise estimate of the time of occurrence is specified. The categories of potential assigned here provide a rationale for assigning priorities for instrumentation, for future studies aimed at predicting large earthquakes and for making estimates of tsunami potential.

  8. Cracking of reinforced concrete short walls submitted to seismic solicitations - estimation of cracks openings: contribution to the improvement of knowledge, of experimental data to engineering applications

    International Nuclear Information System (INIS)

    Gallitre, E.

    2008-01-01

    Until now, the codified methods of crack opening estimation of reinforced concrete structures are based on formulations taking into account stresses of steels supposed to take again the whole stresses which have led to crack: these methods are not valid in the case of shear solicitations in short walls. With the detailed exploitation of the SAFE campaign, it has been possible to establish a global deformation formulated law. The problem being thus reported on the determination of the distortion, different methods have been tested, the more realistic being those in which non linear calculations involve. This work has ended by a return on the codified methods for nuclear power plants design revealing thus the points able to be improved or adapted. (O.M.)

  9. Extraction of Pn seismic signals from air-gun shots recorded by the Cascadia Amphibious seismic experiment

    Science.gov (United States)

    Rathnayaka, S.; Gao, H.

    2017-12-01

    The goal of this study is to extract Pn (head wave) seismic waveforms recorded by both offshore and onshore (broadband and short period) seismic stations and evaluate the data quality. Two offshore active-source seismic experiments, MGL 1211 and MGL 1212, were conducted from 13th June to 24th July 2012, during the first year deployment of the Cascadia Initiative Amphibious Array. In total, we choose 110 ocean bottom seismometers and 209 inland stations that are located along the entire Cascadia subduction zone. We first remove the instrument response, and then explore the potential frequency ranges and the diurnal effect. We make the common receiver gathering for each seismic station and filter the seismic waveforms at multiple frequency bands, ranging from 3-5 Hz, 5-10 Hz, 10-20 Hz, to 20-40 Hz, respectively. To quantitatively evaluate the data quality, we calculate the signal-to-noise ratio (SNR) of the waveforms for usable stations that record clear Pn arrivals at multiple frequency bands. Our results show that most offshore stations located at deep water (>1.5 km) record clear air-gun shot signals at frequencies higher than 3 Hz and up to 550 km away from the source. For most stations located on the shallow continental shelf, the seismic recordings appear much noisier at all the frequencies compared to stations at deep water. Three general trends are observed for the SNR distribution; First, the SNR ratio increases from lower to higher frequency bands; Second, the ratio decreases with the increasing source-to-receiver distance; And third, the ratio increases from shallow to deep water. We also observe a rough negative relationship of the signal-to-noise ratio with the thickness of the marine sediment. Only 5 inland stations record clear air-gun shot arrivals up to 200 km away from the source. More detailed data quality analysis with more results will also be present.

  10. Seismic Discrimination

    Science.gov (United States)

    1979-09-30

    were presumed nuclear explosions announced by ERDA. Of the last, 11 were at the Semipalatinsk test site , 2 at the Western Kazakh test site , 2 in Novaya...which will fulfill U.S. ob- ligations that may be incurred under a possible future Comprehensive Test Ban Treaty. This report includes 9 contributions...which could assume U.S. seismic-data-management responsibilities in the event that international agreement is reached on a Comprehensive Test Ban

  11. The underground seismic array of Gran Sasso (UNDERSEIS), central Italy

    Science.gov (United States)

    Scarpa, R.; Muscente, R.; Tronca, F.; Fischione, C.; Rotella, P.; Abril, M.; Alguacil, G.; Martini, M.; de Cesare, W.

    2003-04-01

    Since early May, 2002, a small aperture seismic array has been installed in the underground Physics Laboratories of Gran Sasso, located near seismic active faults of central Apennines, Italy. This array is presently composed by 21 three-component short period seismic stations (Mark L4C-3D), with average distance 90 m and semi-circular aperture of 400 m x 600 m. It is intersecting a main seismogenic fault where the presence of slow earthquakes has been recently detected through two wide band geodetic laser interferometers. The underground Laboratories are shielded by a limestone rock layer having 1400 m thickness. Each seismometer is linked, through a 24 bits A/D board, to a set of 6 industrial PC via a serial RS-485 standard. The six PC transmit data to a server through an ethernet network. Time syncronization is provided by a Master Oscillator controlled by an atomic clock. Earthworm package is used for data selection and transmission. High quality data have been recorded since May 2002, including local and regional earthquakes. In particular the 31 October, 2002, Molise (Mw=5.8 earthquake) and its aftershocks have been recorded at this array. Array techniques such as polarisation and frequency-slowness analyses with the MUSIC noise algorithm indicate the high performance of this array, as compared to the national seismic network, for identifying the basic source parameters for earthquakes located at distance of few hundreds of km.

  12. Evaluation of Fourier and Response Spectra at Ichihasama and Koromogawa Seismic Intensity Observation Sites During the Iwate-Miyagi Nairiku Earthquake in 2008

    Science.gov (United States)

    Nishikawa, Hayato; Miyajima, Masakatsu

    In this study, we evaluate an acceleration Fourier and response spectra at Ichihasama and Koromogawa seismic intensity observation sites which observed JMA seismic intensity of 6 upper but seismic waveform records don't exist during the Iwate-Miyagi Nairiku earthquake in 2008. Firstly, formula to evaluate acceleration Fourier and response spectra are developed using peak ground acceleration, JMA seismic intensity and predominant period of earthquake spectra based on records obtained from crustal earthquakes with Magnitude of 6 to 7. Acceleration Fourier and response spectra are evaluated for another local government site which are not chosen for development of the formula. The evaluated values mostly agree with the observed ones. Finally, acceleration Fourier and response spectra are evaluated for Ichihasama and Koromogawa observation sites. It is clarified that short period below 1 second was predominated in the evaluated spectra.

  13. Joint analysis of short-period variations of ionospheric parameters in Siberia and the Far East and processes of the tropical cyclogenesis

    Science.gov (United States)

    Chernigovskaya, M. A.; Kurkin, V. I.; Orlov, I. I.; Sharkov, E. A.; Pokrovskaya, I. V.

    2009-04-01

    In this work a possibility of manifestation of strong meteorological disturbances in the Earth lower atmosphere in variations of ionospheric parameters in the zone remote from the disturbance source has been studied. The spectral analysis of short-period variations (about ten minutes, hours) in maximum observed frequencies (MOF) of one-skip signals of oblique sounding has been carried out. These variations were induced by changes in the upper atmosphere parameters along the Magadan-Irkutsk oblique-incidence sounding path on the background of diurnal variations in the parameter under study. Data on MOF measurements with off-duty factor approximately 5 min in equinoxes (September, March) of 2005-2007 were used. The analysis was made using the improved ISTP-developed technique of determining periodicities in time series. The increase of signal spectrum energy at certain frequencies is interpreted as manifestation of traveling ionospheric disturbances (TID) associated with propagation of internal gravity waves in the atmosphere. The analysis revealed TIDs of temporal scales under consideration. The question concerning localization of possible sources of revealed disturbances is discussed. Troposphere meteorological disturbances giant in their energy (tropical cyclones, typhoon) are considered as potential sources of observable TIDs. The needed information on tropical cyclones that occurred in the north area of the Indian Ocean, south-west and central areas of the Pacific Ocean in 2005-2007 is taken from the electron base of satellite data on the global tropical cyclogenesis "Global-TC" (ISR RAS). In order to effectively separate disturbances associated with the magnetospheric-ionospheric interaction and disturbances induced by the lower atmosphere influence on the upper atmosphere, we analyze the tropical cyclogenesis events that occurred in quiet helio-geomagnetic conditions. The study was supported by the Program of RAS Presidium N 16 (Part 3) and the RFBR Grant N 08-05-00658.

  14. Origin of short-period (30-300 s) Doppler frequency fluctuations of lower F region reflections in the equatorial electrojet region

    International Nuclear Information System (INIS)

    Sastri, J.H.; Ramesh, K.B.; Rao, J.V.S.V.; Somayajulu, V.V.

    1991-01-01

    Measurements of phase path P of lower F-region reflections at normal incidence at Kodaikanal revealed the ubiquitous presence of 30-300-s quasi-sinusoidal variations in the time rate of change of phase path, P (Doppler frequency shift) during day time. A study is made of the influence of the irregularities in the equatorial electrojet on the P fluctuations using simultaneous observations of F-region phase path at Kodaikanal and of equatorial electrojet with the VHF-backscatter radar at Thumba. It is shown that the spectral content of the Doppler fluctuations (quantified in terms of variance, sigma squared computed from P time series synthesized through FFT exp -1 (FFT) in the chosen period bands, 30-300 s/30-120 s of the FFT of original P times series) bears a significant positive linear relationship to the horizontal phase velocity of electrojet irregularities (3-m scale size) on a hourly basis. This result is in consonance with earlier findings (Sastri et al., 1990) of a significant linear relationship of sigma squared to the electrojet strength (estimated from H-field data) and a practical cessation of the P fluctuations at times of disappearance of Esq on ionograms (partial/complete counterelectrojet). The present work substantiates the interpretation that the short-period Doppler-frequency fluctuations are due to phase-path changes imposed on lower F region reflections by the refractive-index variations associated with the convective motions of plasma density irregularities (type I and II) in the daytime equatorial electrojet. 49 refs

  15. Quantum state engineering with ultra-short-period (AlN)m/(GaN)n superlattices for narrowband deep-ultraviolet detection.

    Science.gov (United States)

    Gao, Na; Lin, Wei; Chen, Xue; Huang, Kai; Li, Shuping; Li, Jinchai; Chen, Hangyang; Yang, Xu; Ji, Li; Yu, Edward T; Kang, Junyong

    2014-12-21

    Ultra-short-period (AlN)m/(GaN)n superlattices with tunable well and barrier atomic layer numbers were grown by metal-organic vapour phase epitaxy, and employed to demonstrate narrowband deep ultraviolet photodetection. High-resolution transmission electron microscopy and X-ray reciprocal space mapping confirm that superlattices containing well-defined, coherently strained GaN and AlN layers as thin as two atomic layers (∼ 0.5 nm) were grown. Theoretical and experimental results demonstrate that an optical absorption band as narrow as 9 nm (210 meV) at deep-ultraviolet wavelengths can be produced, and is attributable to interband transitions between quantum states along the [0001] direction in ultrathin GaN atomic layers isolated by AlN barriers. The absorption wavelength can be precisely engineered by adjusting the thickness of the GaN atomic layers because of the quantum confinement effect. These results represent a major advance towards the realization of wavelength selectable and narrowband photodetectors in the deep-ultraviolet region without any additional optical filters.

  16. A Bright Short Period M-M Eclipsing Binary from the KELT Survey: Magnetic Activity and the Mass-Radius Relationship for M Dwarfs

    Science.gov (United States)

    Lubin, Jack B.; Rodriguez, Joseph E.; Zhou, George; Conroy, Kyle E.; Stassun, Keivan G.; Collins, Karen; Stevens, Daniel J.; Labadie-Bartz, Jonathan; Stockdale, Christopher; Myers, Gordon; Colón, Knicole D.; Bento, Joao; Kehusmaa, Petri; Petrucci, Romina; Jofré, Emiliano; Quinn, Samuel N.; Lund, Michael B.; Kuhn, Rudolf B.; Siverd, Robert J.; Beatty, Thomas G.; Harlingten, Caisey; Pepper, Joshua; Gaudi, B. Scott; James, David; Jensen, Eric L. N.; Reichart, Daniel; Kedziora-Chudczer, Lucyna; Bailey, Jeremy; Melville, Graeme

    2017-08-01

    We report the discovery of KELT J041621-620046, a moderately bright (J ˜ 10.2) M-dwarf eclipsing binary system at a distance of 39 ± 3 pc. KELT J041621-620046 was first identified as an eclipsing binary using observations from the Kilodegree Extremely Little Telescope (KELT) survey. The system has a short orbital period of ˜1.11 days and consists of components with {M}1={0.447}+0.052-0.047 {M}⊙ and {M}2={0.399}+0.046-0.042 {M}⊙ in nearly circular orbits. The radii of the two stars are {R}1={0.540}+0.034-0.032 {R}⊙ and {\\text{}}{R}2=0.453+/- 0.017 {R}⊙ . Full system and orbital properties were determined (to ˜10% error) by conducting an EBOP (Eclipsing Binary Orbit Program) global modeling of the high precision photometric and spectroscopic observations obtained by the KELT Follow-up Network. Each star is larger by 17%-28% and cooler by 4%-10% than predicted by standard (non-magnetic) stellar models. Strong Hα emission indicates chromospheric activity in both stars. The observed radii and temperature discrepancies for both components are more consistent with those predicted by empirical relations that account for convective suppression due to magnetic activity.

  17. SEISMIC ANALYSIS FOR PRECLOSURE SAFETY

    Energy Technology Data Exchange (ETDEWEB)

    E.N. Lindner

    2004-12-03

    The purpose of this seismic preclosure safety analysis is to identify the potential seismically-initiated event sequences associated with preclosure operations of the repository at Yucca Mountain and assign appropriate design bases to provide assurance of achieving the performance objectives specified in the Code of Federal Regulations (CFR) 10 CFR Part 63 for radiological consequences. This seismic preclosure safety analysis is performed in support of the License Application for the Yucca Mountain Project. In more detail, this analysis identifies the systems, structures, and components (SSCs) that are subject to seismic design bases. This analysis assigns one of two design basis ground motion (DBGM) levels, DBGM-1 or DBGM-2, to SSCs important to safety (ITS) that are credited in the prevention or mitigation of seismically-initiated event sequences. An application of seismic margins approach is also demonstrated for SSCs assigned to DBGM-2 by showing a high confidence of a low probability of failure at a higher ground acceleration value, termed a beyond-design basis ground motion (BDBGM) level. The objective of this analysis is to meet the performance requirements of 10 CFR 63.111(a) and 10 CFR 63.111(b) for offsite and worker doses. The results of this calculation are used as inputs to the following: (1) A classification analysis of SSCs ITS by identifying potential seismically-initiated failures (loss of safety function) that could lead to undesired consequences; (2) An assignment of either DBGM-1 or DBGM-2 to each SSC ITS credited in the prevention or mitigation of a seismically-initiated event sequence; and (3) A nuclear safety design basis report that will state the seismic design requirements that are credited in this analysis. The present analysis reflects the design information available as of October 2004 and is considered preliminary. The evolving design of the repository will be re-evaluated periodically to ensure that seismic hazards are properly

  18. SEISMIC ANALYSIS FOR PRECLOSURE SAFETY

    International Nuclear Information System (INIS)

    E.N. Lindner

    2004-01-01

    The purpose of this seismic preclosure safety analysis is to identify the potential seismically-initiated event sequences associated with preclosure operations of the repository at Yucca Mountain and assign appropriate design bases to provide assurance of achieving the performance objectives specified in the Code of Federal Regulations (CFR) 10 CFR Part 63 for radiological consequences. This seismic preclosure safety analysis is performed in support of the License Application for the Yucca Mountain Project. In more detail, this analysis identifies the systems, structures, and components (SSCs) that are subject to seismic design bases. This analysis assigns one of two design basis ground motion (DBGM) levels, DBGM-1 or DBGM-2, to SSCs important to safety (ITS) that are credited in the prevention or mitigation of seismically-initiated event sequences. An application of seismic margins approach is also demonstrated for SSCs assigned to DBGM-2 by showing a high confidence of a low probability of failure at a higher ground acceleration value, termed a beyond-design basis ground motion (BDBGM) level. The objective of this analysis is to meet the performance requirements of 10 CFR 63.111(a) and 10 CFR 63.111(b) for offsite and worker doses. The results of this calculation are used as inputs to the following: (1) A classification analysis of SSCs ITS by identifying potential seismically-initiated failures (loss of safety function) that could lead to undesired consequences; (2) An assignment of either DBGM-1 or DBGM-2 to each SSC ITS credited in the prevention or mitigation of a seismically-initiated event sequence; and (3) A nuclear safety design basis report that will state the seismic design requirements that are credited in this analysis. The present analysis reflects the design information available as of October 2004 and is considered preliminary. The evolving design of the repository will be re-evaluated periodically to ensure that seismic hazards are properly

  19. Cirugía ambulatoria y de corta hospitalización en el cáncer de mama Ambulatory breast cancer surgery with short hospitalization period

    Directory of Open Access Journals (Sweden)

    Alexis Cantero Ronquillo

    2007-06-01

    Full Text Available La cirugía mayor ambulatoria y de corta estadía constituye un método eficaz y seguro si se hace una selección adecuada de los enfermos y se utilizan técnicas quirúrgicas depuradas con la creación consecuente de la infraestructura para tales fines. Tradicionalmente, el cáncer de mama ha requerido ingreso hospitalario por el riesgo de hemorragia posoperatoria, la necesidad del control de los drenajes quirúrgicos, etc. Internacionalmente esto ha cambiado tras la introducción de nuevas técnicas quirúrgicas como la biopsia del ganglio centinela, la estandarización de las técnicas preservadoras de tejido mamario, así como la especialización de grupos de cirugía en afecciones de la mama. La creación de un grupo de mastología en nuestro centro permitió incursionar en esta modalidad y ya podamos contar 31 pacientes operadas entre enero de 2004 y junio de 2006. Fueron utilizadas diferentes técnicas quirúrgicas con cirugía de corta estadía, previo establecimiento de los criterios de selección. Pudimos concluir que el tratamiento ambulatorio del cáncer de mama en casos seleccionados es factible, dado que se garantiza la seguridad de la paciente, la calidad asistencial y la continuidad en la atención, que además facilita la recuperación psicológica de la enferma y su reinserción temprana en la familiaAmbulatory major surgery with short hospitalization period is an efficient and safe method if a proper selection of patients is made and refined surgical techniques are used, all supported on adequate infrastructure to this end. Traditionally, breast cancer has required admission at hospital due to postsurgical hemorrhage risk, need for surgical drainage control, etc. This has changed worlwide after the introduction of new surgical techniques as sentinel node biopsy, standardization of preserving techniques for breast tissue and specialization of surgeon teams in breast illnesses. The creation of a mastology group in our center

  20. Enhancement of seismic resistance of buildings

    Directory of Open Access Journals (Sweden)

    Claudiu-Sorin Dragomir

    2014-03-01

    Full Text Available The objectives of the paper are both seismic instrumentation for damage assessment and enhancing of seismic resistance of buildings. In according with seismic design codes in force the buildings are designed to resist at seismic actions. Due to the time evolution of these design provisions, there are buildings that were designed decades ago, under the less stringent provisions. The conceptual conformation is nowadays provided in all Codes of seismic design. According to the Code of seismic design P100-1:2006 the asymmetric structures do not have an appropriate seismic configuration; they have disadvantageous distribution of volumes, mass and stiffness. Using results of temporary seismic instrumentation the safety condition of the building may be assessed in different phases of work. Based on this method, the strengthening solutions may be identified and the need of seismic joints may be emphasised. All the aforementioned ideas are illustrated through a case study. Therefore it will be analysed the dynamic parameter evolution of an educational building obtained in different periods. Also, structural intervention scenarios to enhance seismic resistance will be presented.

  1. Methodology of seismotectonic zoning in an intraplate low seismicity domain. Examples of France surrounding areas

    International Nuclear Information System (INIS)

    Philip, H.; Grellet, B.; Combes, P.; Haessler, H.

    1991-01-01

    Until now, the dominant factor in seismic hazard assessments has been historical seismicity. This approach is justified if the data derived from historical seismicity in a region are representative of its seismic activity and if we consider that in areas where damaging earthquakes have happened, they may happen again. This can be seen when seismotectonic relationships are well established in areas such as well localised plate boundaries (subduction zones, transform faults) and/or with a high rate of deformation. In these cases, the areas where future earthquakes might occur are usually well determined and the recurrences short enough on the time scale of historical observations. However, in areas where recent tectonic deformations are diffused and moderate, the historical period of seismicity data (a few centuries) is not long enough to observe a sample of historical seismicity representative of the present-day tectonic activity of the area. The studies on the most recent damaging earthquakes (El Asnam 1980, Spitak 1988, Cherchell Tipasa 1989) show that it would have been extremely difficult to predict the magnitude and the localisation of these events considering historical seismicity alone. It is the same in Provence (south of France) where the risk of occurrence of a damaging earthquake would have been underestimated before the June 1909 event. In all these cases, seismotectonic studies 'a posteriori' show that the geometry and kinematic of the faults responsible for these earthquakes can be identified and that all of them have presented seismic activity in the last thousand years. So it is necessary to emphasis a global approach of the problem through specific studies such as neotectonics, teledetection, geodesy, present-day stress field, strain field, paleoseismology etc. These studies will enlarge the period of observation compared with the data derived only from historical and present-day seismicity. In France seismicity is moderate and recent tectonic

  2. Improved Seismic Acquisition System and Data Processing for the Italian National Seismic Network

    Science.gov (United States)

    Badiali, L.; Marcocci, C.; Mele, F.; Piscini, A.

    2001-12-01

    A new system for acquiring and processing digital signals has been developed in the last few years at the Istituto Nazionale di Geofisica e Vulcanologia (INGV). The system makes extensive use of the internet communication protocol standards such as TCP and UDP which are used as the transport highway inside the Italian network, and possibly in a near future outside, to share or redirect data among processes. The Italian National Seismic Network has been working for about 18 years equipped with vertical short period seismometers and transmitting through analog lines, to the computer center in Rome. We are now concentrating our efforts on speeding the migration towards a fully digital network based on about 150 stations equipped with either broad band or 5 seconds sensors connected to the data center partly through wired digital communication and partly through satellite digital communication. The overall process is layered through intranet and/or internet. Every layer gathers data in a simple format and provides data in a processed format, ready to be distributed towards the next layer. The lowest level acquires seismic data (raw waveforms) coming from the remote stations. It handshakes, checks and sends data in LAN or WAN according to a distribution list where other machines with their programs are waiting for. At the next level there are the picking procedures, or "pickers", on a per instrument basis, looking for phases. A picker spreads phases, again through the LAN or WAN and according to a distribution list, to one or more waiting locating machines tuned to generate a seismic event. The event locating procedure itself, the higher level in this stack, can exchange information with other similar procedures. Such a layered and distributed structure with nearby targets allows other seismic networks to join the processing and data collection of the same ongoing event, creating a virtual network larger than the original one. At present we plan to cooperate with other

  3. An analysis of seismic background noise variation and evaluation of detection capability of Keskin Array (BRTR PS-43) in Turkey

    Science.gov (United States)

    Bakir, M. E.; Ozel, N. M.; Semin, K. U.

    2011-12-01

    Bogazici University, Kandilli Observatory and Earthquake Research Institute (KOERI) is currently operating the Keskin seismic array (BRTR-PS 43) located in town Keskin, providing real-time data to IDC. The instrumentaion of seismic array includes six short period borehole seismometers and one broadband borehole seismometer. The seismic background noise variation of Keskin array are studied in order to estimate the local and regional event detection capability in the frequency range from 1 Hz to 10 Hz. The Power density spectrum and also probability density function of Keskin array data were computed for seasonal and diurnal noise variations between 2008 and 2010. The computation will be extended to cover the period between 2005 and 2008. We attempt to determine the precise frequency characteristics of the background noise, which will help us to assess the station sensitivity. Minimum detectable magnitude versus distance for Keskin seismic array will be analyzed based on the seismic noise analysis. Detailed analysis results of seismic background noise and detection capability will be presented by this research.

  4. Probabilistic seismic hazard assessments of Sabah, east Malaysia: accounting for local earthquake activity near Ranau

    Science.gov (United States)

    Khalil, Amin E.; Abir, Ismail A.; Ginsos, Hanteh; Abdel Hafiez, Hesham E.; Khan, Sohail

    2018-02-01

    Sabah state in eastern Malaysia, unlike most of the other Malaysian states, is characterized by common seismological activity; generally an earthquake of moderate magnitude is experienced at an interval of roughly every 20 years, originating mainly from two major sources, either a local source (e.g. Ranau and Lahad Dato) or a regional source (e.g. Kalimantan and South Philippines subductions). The seismicity map of Sabah shows the presence of two zones of distinctive seismicity, these zones are near Ranau (near Kota Kinabalu) and Lahad Datu in the southeast of Sabah. The seismicity record of Ranau begins in 1991, according to the international seismicity bulletins (e.g. United States Geological Survey and the International Seismological Center), and this short record is not sufficient for seismic source characterization. Fortunately, active Quaternary fault systems are delineated in the area. Henceforth, the seismicity of the area is thus determined as line sources referring to these faults. Two main fault systems are believed to be the source of such activities; namely, the Mensaban fault zone and the Crocker fault zone in addition to some other faults in their vicinity. Seismic hazard assessments became a very important and needed study for the extensive developing projects in Sabah especially with the presence of earthquake activities. Probabilistic seismic hazard assessments are adopted for the present work since it can provide the probability of various ground motion levels during expected from future large earthquakes. The output results are presented in terms of spectral acceleration curves and uniform hazard curves for periods of 500, 1000 and 2500 years. Since this is the first time that a complete hazard study has been done for the area, the output will be a base and standard for any future strategic plans in the area.

  5. Micro-seismic earthquakes characteristics at natural and exploited hydrothermal systems in West Java, Indonesia

    Science.gov (United States)

    Jousset, P. G.; Jaya, M. S.; Sule, R.; Diningrat, W.; Gassner, A.; Akbar, F.; Ryannugroho, R.; Hendryana, A.; Kusnadi, Y.; Syahbana, D.; Nugraha, A. D.; Umar, M.; Indrinanto, Y.; Erbas, K.

    2013-12-01

    The assessment of geothermal resources requires the understanding of the structure and the dynamics of geothermal reservoirs. We deployed a multidisciplinary geophysical network around geothermal areas in the south of Bandung, West Java, Indonesia. The first deployment included a network of 30 broadband and 4 short-period seismic stations with Güralp and Trillium sensors (0.008 - 100 Hz) since October 2012. In a second step, we extended the network in June 2013 with 16 short-period (1 Hz) seismometers. We describe the set-up of the seismic networks and discuss first observations and results. The co-existence of a large variety of intense surface manifestations like geysers, hot-steaming grounds, hot water pools, and active volcanoes suggest an intimate coupling between volcanic, tectonic and hydrothermal processes in this area. Preliminary location of earthquakes is performed using a non-linear algorithm, which allows us to define at least 3 seismic clusters. We discuss this seismic pattern within the geothermal fields.

  6. Effect of re-expansion after short-period lung collapse on pulmonary capillary permeability and pro-inflammatory cytokine gene expression in isolated rabbit lungs.

    Science.gov (United States)

    Funakoshi, T; Ishibe, Y; Okazaki, N; Miura, K; Liu, R; Nagai, S; Minami, Y

    2004-04-01

    Re-expansion pulmonary oedema is a rare complication caused by rapid re-expansion of a chronically collapsed lung. Several cases of pulmonary oedema associated with one-lung ventilation (OLV) have been reported recently. Elevated levels of pro-inflammatory cytokines in pulmonary oedema fluid are suggested to play important roles in its development. Activation of cytokines after re-expansion of collapsed lung during OLV has not been thoroughly investigated. Here we investigated the effects of re-expansion of the collapsed lung on pulmonary oedema formation and pro-inflammatory cytokine expression. Lungs isolated from female white Japanese rabbits were perfused and divided into a basal (BAS) group (n=7, baseline measurement alone), a control (CONT) group (n=9, ventilated without lung collapse for 120 min) and an atelectasis (ATEL) group (n=9, lung collapsed for 55 min followed by re-expansion and ventilation for 65 min). Pulmonary vascular resistance (PVR) and the coefficient of filtration (Kfc) were measured at baseline and 60 and 120 min. At the end of perfusion, bronchoalveolar lavage fluid/plasma protein ratio (B/P), wet/dry lung weight ratio (W/D) and mRNA expressions of tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta and myeloperoxidase (MPO) were determined. TNF-alpha and IL-1beta mRNA were significantly up-regulated in lungs of the ATEL group compared with BAS and CONT, though no significant differences were noted in PVR, Kfc, B/P and W/D within and between groups. MPO increased at 120 min in CONT and ATEL groups. Pro-inflammatory cytokines were up-regulated upon re-expansion and ventilation after short-period lung collapse, though no changes were noted in pulmonary capillary permeability.

  7. Seismic instrumentation

    International Nuclear Information System (INIS)

    1984-06-01

    RFS or Regles Fondamentales de Surete (Basic Safety Rules) applicable to certain types of nuclear facilities lay down requirements with which compliance, for the type of facilities and within the scope of application covered by the RFS, is considered to be equivalent to compliance with technical French regulatory practice. The object of the RFS is to take advantage of standardization in the field of safety, while allowing for technical progress in that field. They are designed to enable the operating utility and contractors to know the rules pertaining to various subjects which are considered to be acceptable by the Service Central de Surete des Installations Nucleaires, or the SCSIN (Central Department for the Safety of Nuclear Facilities). These RFS should make safety analysis easier and lead to better understanding between experts and individuals concerned with the problems of nuclear safety. The SCSIN reserves the right to modify, when considered necessary, any RFS and specify, if need be, the terms under which a modification is deemed retroactive. The aim of this RFS is to define the type, location and operating conditions for seismic instrumentation needed to determine promptly the seismic response of nuclear power plants features important to safety to permit comparison of such response with that used as the design basis

  8. Research on performance-based seismic design criteria

    Institute of Scientific and Technical Information of China (English)

    谢礼立; 马玉宏

    2002-01-01

    The seismic design criterion adopted in the existing seismic design codes is reviewed. It is pointed out that the presently used seismic design criterion is not satisfied with the requirements of nowadays social and economic development. A new performance-based seismic design criterion that is composed of three components is presented in this paper. It can not only effectively control the economic losses and casualty, but also ensure the building(s function in proper operation during earthquakes. The three components are: classification of seismic design for buildings, determination of seismic design intensity and/or seismic design ground motion for controlling seismic economic losses and casualties, and determination of the importance factors in terms of service periods of buildings. For controlling the seismic human losses, the idea of socially acceptable casualty level is presented and the (Optimal Economic Decision Model( and (Optimal Safe Decision Model( are established. Finally, a new method is recommended for calculating the importance factors of structures by adjusting structures service period on the base of more important structure with longer service period than the conventional ones. Therefore, the more important structure with longer service periods will be designed for higher seismic loads, in case the exceedance probability of seismic hazard in different service period is same.

  9. Seismic monitoring at Deception Island volcano (Antarctica): the 2010-2011 survey

    Science.gov (United States)

    Martín, R.; Carmona, E.; Almendros, J.; Serrano, I.; Villaseñor, A.; Galeano, J.

    2012-04-01

    As an example of the recent advances introduced in seismic monitoring of Deception Island volcano (Antarctica) during recent years, we describe the instrumental network deployed during the 2010-2011 survey by the Instituto Andaluz de Geofísica of University of Granada, Spain (IAG-UGR). The period of operation extended from December 19, 2010 to March 5, 2011. We deployed a wireless seismic network composed by four three-component seismic stations. These stations are based on 24-bit SL04 SARA dataloggers sampling at 100 sps. They use a PC with embedded linux and SEISLOG data acquisition software. We use two types of three-component seismometers: short-period Mark L4C with natural frequency of 1 Hz and medium-period Lennartz3D/5s with natural frequency of 0.2 Hz. The network was designed for an optimum spatial coverage of the northern half of Deception, where a magma chamber has been reported. Station locations include the vicinity of the Spanish base "Gabriel de Castilla" (GdC), Obsidianas Beach, a zone near the craters from the 1970 eruptions, and the Chilean Shelter located south of Pendulum Cove. Continuous data from the local seismic network are received in real-time in the base by wifi transmission. We used Ubiquiti Networks Nanostation2 antennas with 2.4 GHz, dual-polarity, 10 dBi gain, and 54 Mbps transmission rate. They have shown a great robustness and speed for real-time applications. To prioritize data acquisition when the battery level is low, we have designed a circuit that allows independent power management for the seismic station and wireless transmission system. The reception antenna located at GdC is connected to a computer running SEISCOMP. This software supports several transmission protocols and manages the visualization and recording of seismic data, including the generation of summary plots to show the seismic activity. These twelve data channels are stored in miniseed format and displayed in real time, which allows for a rapid evaluation of

  10. The earthquake sequence of 21-22 February, 1983 at Ramnicu Sarat, Romania: source parameters retrieved by short period local data inversion

    International Nuclear Information System (INIS)

    Ardeleanu, L.; Radulian, M.; Sileny, J.; Panza, G. F.

    2002-01-01

    High-frequency seismograms from the Romanian telemetered local network are inverted to retrieve the seismic moment tensor of five weak earthquakes (2.9 ≤ M L ≤ 3.6) belonging to the seismic sequence of Ramnicu Sarat (Romania) of 21-22 February 1983. A grossly simplified 1-D approximation of the crust - the horizontally layered inelastic earth model - is used to construct the Green's function by modal summation. The deviation from the real velocity structure originates the error in forward modelling, which is roughly estimated from the differences in the moment tensor rate functions obtained from subsets of the complete station network. This error is transformed into estimates of confidence regions of the time function, moment tensor and its principal axes, and error bars of the scalar moment. The 1-D approximation of the crust results in a large uncertainty of the source time function, which is almost completely undetermined. The mechanism is more confident, especially the determination of the orientation of its deviatoric part. The most robust source parameter from the three investigated items is the scalar moment. (authors)

  11. Yield Estimation for Semipalatinsk Underground Nuclear Explosions Using Seismic Surface-wave Observations at Near-regional Distances

    Science.gov (United States)

    Adushkin, V. V.

    - A statistical procedure is described for estimating the yields of underground nuclear tests at the former Soviet Semipalatinsk test site using the peak amplitudes of short-period surface waves observed at near-regional distances (Δ Semipalatinsk explosions, including the Soviet JVE explosion of September 14, 1988, and it is demonstrated that it provides seismic estimates of explosion yield which are typically within 20% of the yields determined for these same explosions using more accurate, non-seismic techniques based on near-source observations.

  12. Quarterly seismic monitoring report 96B

    International Nuclear Information System (INIS)

    Reidel, S.P.

    1996-01-01

    This report summarizes the location, magnitude, and other pertinent information on earthquakes recorded on and near the Hanford Site by Westinghouse Seismic Monitoring during the period encompassing January 1, 1996 to March 31, 1996

  13. Seismic monitoring of the unstable rock slope at Aaknes, Norway

    Science.gov (United States)

    Roth, M.; Blikra, L. H.

    2009-04-01

    The unstable rock slope at Aaknes has an estimated volume of about 70 million cubic meters, and parts of the slope are moving at a rate between 2-15 cm/year. Amongst many other direct monitoring systems we have installed a small-scale seismic network (8 three-component geophones over an area of 250 x 150 meters) in order to monitor microseismic events related to the movement of the slope. The network has been operational since November 2005 with only a few short-term outages. Seismic data are transferred in real-time from the site to NORSAR for automatic detection processing. The resulting detection lists and charts and the associated waveform are forwarded immediately to the early warning centre of the Municipality of Stranda. Furthermore, we make them available after a delay of about 10-15 minutes on our public project web page (http://www.norsar.no/pc-47-48-Latest-Data.aspx). Seismic monitoring provides independent and complementary data to the more direct monitoring systems at Aaknes. We observe increased seismic activity in periods of heavy rain fall or snow melt, when laser ranging data and extensometer readings indicate temporary acceleration phases of the slope. The seismic network is too small and the velocity structure is too heterogeneous in order to obtain reliable localizations of the microseismic events. In summer 2009 we plan to install a high-sensitive broadband seismometer (60 s - 100 Hz) in the middle of the unstable slope. This will allow us to better constrain the locations of the microseismic events and to investigate potential low-frequency signals associated with the slope movement.

  14. Seismic qualification of equipment

    International Nuclear Information System (INIS)

    Heidebrecht, A.C.; Tso, W.K.

    1983-03-01

    This report describes the results of an investigation into the seismic qualification of equipment located in CANDU nuclear power plants. It is particularly concerned with the evaluation of current seismic qualification requirements, the development of a suitable methodology for the seismic qualification of safety systems, and the evaluation of seismic qualification analysis and testing procedures

  15. Probabilistic Seismic Hazard Analysis for Yemen

    Directory of Open Access Journals (Sweden)

    Rakesh Mohindra

    2012-01-01

    Full Text Available A stochastic-event probabilistic seismic hazard model, which can be used further for estimates of seismic loss and seismic risk analysis, has been developed for the territory of Yemen. An updated composite earthquake catalogue has been compiled using the databases from two basic sources and several research publications. The spatial distribution of earthquakes from the catalogue was used to define and characterize the regional earthquake source zones for Yemen. To capture all possible scenarios in the seismic hazard model, a stochastic event set has been created consisting of 15,986 events generated from 1,583 fault segments in the delineated seismic source zones. Distribution of horizontal peak ground acceleration (PGA was calculated for all stochastic events considering epistemic uncertainty in ground-motion modeling using three suitable ground motion-prediction relationships, which were applied with equal weight. The probabilistic seismic hazard maps were created showing PGA and MSK seismic intensity at 10% and 50% probability of exceedance in 50 years, considering local soil site conditions. The resulting PGA for 10% probability of exceedance in 50 years (return period 475 years ranges from 0.2 g to 0.3 g in western Yemen and generally is less than 0.05 g across central and eastern Yemen. The largest contributors to Yemen’s seismic hazard are the events from the West Arabian Shield seismic zone.

  16. Multicomponent ensemble models to forecast induced seismicity

    Science.gov (United States)

    Király-Proag, E.; Gischig, V.; Zechar, J. D.; Wiemer, S.

    2018-01-01

    In recent years, human-induced seismicity has become a more and more relevant topic due to its economic and social implications. Several models and approaches have been developed to explain underlying physical processes or forecast induced seismicity. They range from simple statistical models to coupled numerical models incorporating complex physics. We advocate the need for forecast testing as currently the best method for ascertaining if models are capable to reasonably accounting for key physical governing processes—or not. Moreover, operational forecast models are of great interest to help on-site decision-making in projects entailing induced earthquakes. We previously introduced a standardized framework following the guidelines of the Collaboratory for the Study of Earthquake Predictability, the Induced Seismicity Test Bench, to test, validate, and rank induced seismicity models. In this study, we describe how to construct multicomponent ensemble models based on Bayesian weightings that deliver more accurate forecasts than individual models in the case of Basel 2006 and Soultz-sous-Forêts 2004 enhanced geothermal stimulation projects. For this, we examine five calibrated variants of two significantly different model groups: (1) Shapiro and Smoothed Seismicity based on the seismogenic index, simple modified Omori-law-type seismicity decay, and temporally weighted smoothed seismicity; (2) Hydraulics and Seismicity based on numerically modelled pore pressure evolution that triggers seismicity using the Mohr-Coulomb failure criterion. We also demonstrate how the individual and ensemble models would perform as part of an operational Adaptive Traffic Light System. Investigating seismicity forecasts based on a range of potential injection scenarios, we use forecast periods of different durations to compute the occurrence probabilities of seismic events M ≥ 3. We show that in the case of the Basel 2006 geothermal stimulation the models forecast hazardous levels

  17. Short period strain balanced gallium arsenide nitride/indium arsenide nitride superlattice lattice matched to indium phosphide for mid-infrared photovoltaics

    Science.gov (United States)

    Bhusal, Lekhnath

    Dilute nitrogen-containing III-V-N alloys have been intensively studied for their unusual electronic and optical behavior in the presence of a small amount of nitrogen. Those behaviors can further be manipulated, with a careful consideration of the strain and strain balancing, for example, in the context of a strain-balanced superlattice (SL) based on those alloys. In this work, the k.p approximation and the band anti-crossing model modified for the strain have been used to describe the electronic states of the strained bulk-like GaAs1-xNx and InAs 1-yNy ternaries in the vicinity of the center of the Brillouin zone (Gamma-point). Band-offsets between the conduction and valence bands of GaAs1-xNx and InAs1-yN y have also been evaluated, before implementing them into the SL structure. By minimizing the total mechanical energy of the stack of the alternating layers of GaAs1-xNx and InAs1-yNy in the SL, the ratio of the thicknesses of the epilayers is determined to make the structure lattice-matching on the InP(001), through the strain-balancing. Mini-band energies of the strain-balanced GaAs1-xNx/InAs 1-yNy short-period SL on InP(001) is then investigated using the transfer matrix formalism. This enabled identifying the evolution of the band edge transition energies of the superlattice structure for different nitrogen compositions. Results show the potential of the new proposed design to exceed the existing limits of bulk-like InGaAsN alloys and offer the applications for photon absorption/emission energies in the range of ~0.65-0.35eV at 300K for a typical nitrogen composition of ≤5%. The optical absorption coefficient of such a SL is then estimated under the anisotropic medium approximation, where the optical absorption of the bulk structure is modified according to the anisotropy imposed by the periodic potential in the growth direction. As an application, the developed SL structure is used to investigate the performance of double, triple and quadruple junction

  18. German seismic regulations

    International Nuclear Information System (INIS)

    Danisch, Ruediger

    2002-01-01

    Rules and regulations for seismic design in Germany cover the following: seismic design of conventional buildings; and seismic design of nuclear facilities. Safety criteria for NPPs, accident guidelines, and guidelines for PWRs as well as safety standards are cited. Safety standards concerned with NPPs seismic design include basic principles, soil analysis, design of building structures, design of mechanical and electrical components, seismic instrumentation, and measures to be undertaken after the earthquake

  19. Seismicity and strain transients in the Gulf of Corinth (Greece)

    Science.gov (United States)

    Canitano, A.; Bernard, P.; Linde, A. T.; Sacks, S. I.; Boudin, F.

    2009-12-01

    The Gulf of Corinth (Greece) is one of the most seismic regions in Europe, producing some earthquakes of magnitude greater than 5.8 in the last 35 years, 1 to 1.5 cm/yr of north-south extension, and frequent seismic swarms. This structure is a 110 km long, N110°E oriented graben bounded by systems of very recent normal faults. This zone thus provides an ideal site for investigating in situ the physics of earthquake sources and for developing efficient seismic hazard reduction procedures. The Corinth Rift Laboratory (CRL) project is concentrated in the western part of the rift, around the city of Aigion, where instrumental seismicity and strain rate is highest. The CRL Network is made up about fifteen seismic stations as well as tiltmeters, strainmeters or GPS in order to study the local seismicity, and to observe and model the short and long term mechanics of the normal fault system. The instrumental seismicity in the Aigion zone clearly shows a strong concentration of small earthquakes between 5 and 10 km. In order to study slow transient deformation, two borehole strainmeters have been installed in the Gulf (Trizonia, Monasteraki). The strainmeter installed in the Trizonia island is continuously recording the horizontal strain at 150m depth with a resolution better than 10-9. The dominant signal is the earth and sea tidal effects (few 10-7 strain), this one is modulated by the mechanical effects of the free oscillations of the Gulf with periods between 8 and 40 min. The barometric pressure fluctuations acts in combination with the mean sea level variation at longer periods and both effects are not independant. The comparison between the strain data and the two forcing signals (sea-level, barometric pressure) shows clearly a non zero phase delay of the sea-level. The analysis of time correlations between the signals in differents frequency range exhibits that the sea level delay and the strainmeter/sea-level coupling coefficient are increasing with period (about

  20. Period-dependent source rupture behavior of the 2011 Tohoku earthquake estimated by multi period-band Bayesian waveform inversion

    Science.gov (United States)

    Kubo, H.; Asano, K.; Iwata, T.; Aoi, S.

    2014-12-01

    Previous studies for the period-dependent source characteristics of the 2011 Tohoku earthquake (e.g., Koper et al., 2011; Lay et al., 2012) were based on the short and long period source models using different method. Kubo et al. (2013) obtained source models of the 2011 Tohoku earthquake using multi period-bands waveform data by a common inversion method and discussed its period-dependent source characteristics. In this study, to achieve more in detail spatiotemporal source rupture behavior of this event, we introduce a new fault surface model having finer sub-fault size and estimate the source models in multi period-bands using a Bayesian inversion method combined with a multi-time-window method. Three components of velocity waveforms at 25 stations of K-NET, KiK-net, and F-net of NIED are used in this analysis. The target period band is 10-100 s. We divide this period band into three period bands (10-25 s, 25-50 s, and 50-100 s) and estimate a kinematic source model in each period band using a Bayesian inversion method with MCMC sampling (e.g., Fukuda & Johnson, 2008; Minson et al., 2013, 2014). The parameterization of spatiotemporal slip distribution follows the multi-time-window method (Hartzell & Heaton, 1983). The Green's functions are calculated by the 3D FDM (GMS; Aoi & Fujiwara, 1999) using a 3D velocity structure model (JIVSM; Koketsu et al., 2012). The assumed fault surface model is based on the Pacific plate boundary of JIVSM and is divided into 384 subfaults of about 16 * 16 km^2. The estimated source models in multi period-bands show the following source image: (1) First deep rupture off Miyagi at 0-60 s toward down-dip mostly radiating relatively short period (10-25 s) seismic waves. (2) Shallow rupture off Miyagi at 45-90 s toward up-dip with long duration radiating long period (50-100 s) seismic wave. (3) Second deep rupture off Miyagi at 60-105 s toward down-dip radiating longer period seismic waves then that of the first deep rupture. (4) Deep

  1. Seismic Imager Space Telescope

    Science.gov (United States)

    Sidick, Erkin; Coste, Keith; Cunningham, J.; Sievers,Michael W.; Agnes, Gregory S.; Polanco, Otto R.; Green, Joseph J.; Cameron, Bruce A.; Redding, David C.; Avouac, Jean Philippe; hide

    2012-01-01

    A concept has been developed for a geostationary seismic imager (GSI), a space telescope in geostationary orbit above the Pacific coast of the Americas that would provide movies of many large earthquakes occurring in the area from Southern Chile to Southern Alaska. The GSI movies would cover a field of view as long as 300 km, at a spatial resolution of 3 to 15 m and a temporal resolution of 1 to 2 Hz, which is sufficient for accurate measurement of surface displacements and photometric changes induced by seismic waves. Computer processing of the movie images would exploit these dynamic changes to accurately measure the rapidly evolving surface waves and surface ruptures as they happen. These measurements would provide key information to advance the understanding of the mechanisms governing earthquake ruptures, and the propagation and arrest of damaging seismic waves. GSI operational strategy is to react to earthquakes detected by ground seismometers, slewing the satellite to point at the epicenters of earthquakes above a certain magnitude. Some of these earthquakes will be foreshocks of larger earthquakes; these will be observed, as the spacecraft would have been pointed in the right direction. This strategy was tested against the historical record for the Pacific coast of the Americas, from 1973 until the present. Based on the seismicity recorded during this time period, a GSI mission with a lifetime of 10 years could have been in position to observe at least 13 (22 on average) earthquakes of magnitude larger than 6, and at least one (2 on average) earthquake of magnitude larger than 7. A GSI would provide data unprecedented in its extent and temporal and spatial resolution. It would provide this data for some of the world's most seismically active regions, and do so better and at a lower cost than could be done with ground-based instrumentation. A GSI would revolutionize the understanding of earthquake dynamics, perhaps leading ultimately to effective warning

  2. Seismic analysis for the ALMR

    International Nuclear Information System (INIS)

    Tajirian, F.F.

    1992-01-01

    The Advanced Liquid Metal Reactor (ALMR) design uses seismic isolation as a cost effective approach for simplifying seismic design of the reactor module, and for enhancing margins to handle beyond design basis earthquakes (BDBE). A comprehensive seismic analysis plan has been developed to confirm the adequacy of the design and to support regulatory licensing activities. In this plan state-of-the-art computer programs are used to evaluate the system response of the ALMR. Several factors that affect seismic response will be investigated. These include variability in the input earthquake mechanism, soil-structure interaction effects, and nonlinear response of the isolators. This paper reviews the type of analyses that are planned, and discuses the approach that will be used for validating the specific features of computer programs that are required in the analysis of isolated structures. To date, different linear and nonlinear seismic analyses have been completed. The results of recently completed linear analyses have been summarized elsewhere. The findings of three-dimensional seismic nonlinear analyses are presented in this paper. These analyses were performed to evaluate the effect of changes of isolator horizontal stiffness with horizontal displacement on overall response, to develop an approach for representing BDBE events with return periods exceeding 10,000 years, and to assess margins in the design for BDBEs. From the results of these analyses and bearing test data, it can be concluded that a properly designed and constructed seismic isolation system can accommodate displacements several times the design safe shutdown earthquake (SSE) for the ALMR. (author)

  3. Patterns in Seismicity at Mt St Helens and Mt Unzen

    Science.gov (United States)

    Lamb, Oliver; De Angelis, Silvio; Lavallee, Yan

    2014-05-01

    Cyclic behaviour on a range of timescales is a well-documented feature of many dome-forming volcanoes. Previous work on Soufrière Hills volcano (Montserrat) and Volcán de Colima (Mexico) revealed broad-scale similarities in behaviour implying the potential to develop general physical models of sub-surface processes [1]. Using volcano-seismic data from Mt St Helens (USA) and Mt Unzen (Japan) this study explores parallels in long-term behaviour of seismicity at two dome-forming systems. Within the last twenty years both systems underwent extended dome-forming episodes accompanied by large Vulcanian explosions or dome collapses. This study uses a suite of quantitative and analytical techniques which can highlight differences or similarities in volcano seismic behaviour, and compare the behaviour to changes in activity during the eruptive episodes. Seismic events were automatically detected and characterized on a single short-period seismometer station located 1.5km from the 2004-2008 vent at Mt St Helens. A total of 714 826 individual events were identified from continuous recording of seismic data from 22 October 2004 to 28 February 2006 (average 60.2 events per hour) using a short-term/long-term average algorithm. An equivalent count will be produced from seismometer recordings over the later stages of the 1991-1995 eruption at MT Unzen. The event count time-series from Mt St Helens is then analysed using Multi-taper Method and the Short-Term Fourier Transform to explore temporal variations in activity. Preliminary analysis of seismicity from Mt St Helens suggests cyclic behaviour of subannual timescale, similar to that described at Volcán de Colima and Soufrière Hills volcano [1]. Frequency Index and waveform correlation tools will be implemented to analyse changes in the frequency content of the seismicity and to explore their relations to different phases of activity at the volcano. A single station approach is used to gain a fine-scale view of variations in

  4. The Spatial Assessment of the Current Seismic Hazard State for Hard Rock Underground Mines

    Science.gov (United States)

    Wesseloo, Johan

    2018-06-01

    Mining-induced seismic hazard assessment is an important component in the management of safety and financial risk in mines. As the seismic hazard is a response to the mining activity, it is non-stationary and variable both in space and time. This paper presents an approach for implementing a probabilistic seismic hazard assessment to assess the current hazard state of a mine. Each of the components of the probabilistic seismic hazard assessment is considered within the context of hard rock underground mines. The focus of this paper is the assessment of the in-mine hazard distribution and does not consider the hazard to nearby public or structures. A rating system and methodologies to present hazard maps, for the purpose of communicating to different stakeholders in the mine, i.e. mine managers, technical personnel and the work force, are developed. The approach allows one to update the assessment with relative ease and within short time periods as new data become available, enabling the monitoring of the spatial and temporal change in the seismic hazard.

  5. Crustal and deep seismicity in Italy (30 years after

    Directory of Open Access Journals (Sweden)

    G. Selvaggi

    1997-06-01

    Full Text Available The first modern studies of seismicity in Italy date back to the late 60's and early 70's. Although with a sparse seismic network available and only a few telemetered short-period stations, significant studies were carried out that outlined the main features of Italian seismicity (see, e.g., Boschi et al., 1969. Among these studies, one of the most important achievements was the reconnaissance of a Wadati-Benioff zone in Southern Tyrrhenian, described for the first time in detail in the papers of Caputo et al.(1970, 1973. Today, after three decades of more and more detailed seismological monitoring of the Italian region and tens of thousands earthquakes located since then, the knowledge of the earthquake generation processes in our country is much improved, although some of the conclusions reached in these early papers still hold. These improvements were made possible by the efforts of many institutions and seismologists who have been working hard to bring seismological research in Italy to standards of absolute quality, under the pivoting role of the Istituto Nazionale di Geofisica (ING. From the relocation of about 30000 crustal earthquakes and detailed studies on intermediate and deep shocks carried out in the last few years, we show that seismic release in peninsular Italy is only weakly related to the Africa-Eurasia convergence, but rather is best explained by the existence of two separate subduction/collision arcs (Northern Apennines and Southern Apennines-Calabria-Sicily. The width of the deforming belt running along peninsular Italy is 30 to 60 km, it is broader in the north than in the south, and the two arcs are separated by a region of more distributed deformation and stress rotations in the Central Apennines. Along the belt, the reconnaissance of regions of continuous and weak release of seismic energy, adjacent to fault areas which are currently «locked» (and therefore are the best candidates for future earthquakes is another

  6. Adaptively smoothed seismicity earthquake forecasts for Italy

    Directory of Open Access Journals (Sweden)

    Yan Y. Kagan

    2010-11-01

    Full Text Available We present a model for estimation of the probabilities of future earthquakes of magnitudes m ≥ 4.95 in Italy. This model is a modified version of that proposed for California, USA, by Helmstetter et al. [2007] and Werner et al. [2010a], and it approximates seismicity using a spatially heterogeneous, temporally homogeneous Poisson point process. The temporal, spatial and magnitude dimensions are entirely decoupled. Magnitudes are independently and identically distributed according to a tapered Gutenberg-Richter magnitude distribution. We have estimated the spatial distribution of future seismicity by smoothing the locations of past earthquakes listed in two Italian catalogs: a short instrumental catalog, and a longer instrumental and historic catalog. The bandwidth of the adaptive spatial kernel is estimated by optimizing the predictive power of the kernel estimate of the spatial earthquake density in retrospective forecasts. When available and reliable, we used small earthquakes of m ≥ 2.95 to reveal active fault structures and 29 probable future epicenters. By calibrating the model with these two catalogs of different durations to create two forecasts, we intend to quantify the loss (or gain of predictability incurred when only a short, but recent, data record is available. Both forecasts were scaled to five and ten years, and have been submitted to the Italian prospective forecasting experiment of the global Collaboratory for the Study of Earthquake Predictability (CSEP. An earlier forecast from the model was submitted by Helmstetter et al. [2007] to the Regional Earthquake Likelihood Model (RELM experiment in California, and with more than half of the five-year experimental period over, the forecast has performed better than the others.

  7. Novel ST-MUSIC-based spectral analysis for detection of ULF geomagnetic signals anomalies associated with seismic events in Mexico

    Directory of Open Access Journals (Sweden)

    Omar Chavez

    2016-05-01

    Full Text Available Recently, the analysis of ultra-low-frequency (ULF geomagnetic signals in order to detect seismic anomalies has been reported in several works. Yet, they, although having promising results, present problems for their detection since these anomalies are generally too much weak and embedded in high noise levels. In this work, a short-time multiple signal classification (ST-MUSIC, which is a technique with high-frequency resolution and noise immunity, is proposed for the detection of seismic anomalies in the ULF geomagnetic signals. Besides, the energy (E of geomagnetic signals processed by ST-MUSIC is also presented as a complementary parameter to measure the fluctuations between seismic activity and seismic calm period. The usefulness and effectiveness of the proposal are demonstrated through the analysis of a synthetic signal and five real signals with earthquakes. The analysed ULF geomagnetic signals have been obtained using a tri-axial fluxgate magnetometer at the Juriquilla station, which is localized in Queretaro, Mexico (geographic coordinates: longitude 100.45° E and latitude 20.70° N. The results obtained show the detection of seismic perturbations before, during, and after the main shock, making the proposal a suitable tool for detecting seismic precursors.

  8. Adaptive neuro-fuzzy inference systems for semi-automatic discrimination between seismic events: a study in Tehran region

    Science.gov (United States)

    Vasheghani Farahani, Jamileh; Zare, Mehdi; Lucas, Caro

    2012-04-01

    Thisarticle presents an adaptive neuro-fuzzy inference system (ANFIS) for classification of low magnitude seismic events reported in Iran by the network of Tehran Disaster Mitigation and Management Organization (TDMMO). ANFIS classifiers were used to detect seismic events using six inputs that defined the seismic events. Neuro-fuzzy coding was applied using the six extracted features as ANFIS inputs. Two types of events were defined: weak earthquakes and mining blasts. The data comprised 748 events (6289 signals) ranging from magnitude 1.1 to 4.6 recorded at 13 seismic stations between 2004 and 2009. We surveyed that there are almost 223 earthquakes with M ≤ 2.2 included in this database. Data sets from the south, east, and southeast of the city of Tehran were used to evaluate the best short period seismic discriminants, and features as inputs such as origin time of event, distance (source to station), latitude of epicenter, longitude of epicenter, magnitude, and spectral analysis (fc of the Pg wave) were used, increasing the rate of correct classification and decreasing the confusion rate between weak earthquakes and quarry blasts. The performance of the ANFIS model was evaluated for training and classification accuracy. The results confirmed that the proposed ANFIS model has good potential for determining seismic events.

  9. ON THE POSSIBLE EXISTENCE OF SHORT-PERIOD g-MODE INSTABILITIES POWERED BY NUCLEAR-BURNING SHELLS IN POST-ASYMPTOTIC GIANT BRANCH H-DEFICIENT (PG1159-TYPE) STARS

    International Nuclear Information System (INIS)

    Corsico, A. H.; Althaus, L. G.; Miller Bertolami, M. M.; Gonzalez Perez, J. M.; Kepler, S. O.

    2009-01-01

    We present a pulsational stability analysis of hot post-asymptotic giant branch (AGB) H-deficient pre-white dwarf stars with active He-burning shells. The stellar models employed are state-of-the-art equilibrium structures representative of PG1159 stars derived from the complete evolution of the progenitor stars, through the thermally pulsing AGB phase and born-again episode. On the basis of fully nonadiabatic pulsation computations, we confirmed theoretical evidence for the existence of a separate PG1159 instability strip in the log T eff -log g diagram characterized by short-period g-modes excited by the ε-mechanism. This instability strip partially overlaps the already known GW Vir instability strip of intermediate/long-period g-modes destabilized by the classical κ-mechanism acting on the partial ionization of C and/or O in the envelope of PG1159 stars. We found that PG1159 stars characterized by thick He-rich envelopes and located inside this overlapping region could exhibit both short and intermediate/long periods simultaneously. As a natural application of our results, we study the particular case of VV 47, a pulsating planetary nebula nucleus (PG1159 type) that is particularly interesting because it has been reported to exhibit a rich and complex pulsation spectrum including a series of unusually short pulsation periods. We found that the long periods exhibited by VV 47 can be readily explained by the classical κ-mechanism, while the observed short-period branch below ∼300 s could correspond to modes triggered by the He-burning shell through the ε-mechanism, although more observational work is needed to confirm the reality of these short-period modes. Were the existence of short-period g-modes in this star convincingly confirmed by future observations, VV 47 could be the first known pulsating star in which both the κ-mechanism and the ε-mechanism of mode driving are simultaneously operating.

  10. Canadian seismic agreement

    International Nuclear Information System (INIS)

    Wetmiller, R.J.; Lyons, J.A.; Shannon, W.E.; Munro, P.S.; Thomas, J.T.; Andrew, M.D.; Lamontagne, M.; Wong, C.; Anglin, F.M.; Plouffe, M.; Lapointe, S.P.; Adams, J.; Drysdale, J.A.

    1990-04-01

    This is the twenty-first progress report under the agreement entitled Canadian Seismic Agreement between the US Nuclear Regulatory Commission (NRC) and the Canadian Commercial Corporation. Activities undertaken by the Geophysics Division of the Geological Survey of Canada (GD/GSC) during the period from July 01, 1988 to June 30, 1989 and supported in part by the NRC agreement are described below under four headings; Eastern Canada Telemetred Network and local network developments, Datalab developments, strong motion network developments and earthquake activity. In this time period eastern Canada experienced its largest earthquake in over 50 years. This earthquake, which has been christened the Saguenay earthquake, has provided a wealth of new data pertinent to earthquake engineering studies in eastern North America and is the subject of many continuing studies, which are presently being carried out at GD and elsewhere. 41 refs., 21 figs., 7 tabs

  11. Optimization of the seismic pit of the Tokamak building of ITER

    International Nuclear Information System (INIS)

    Beltran, F.; Combescure, D.; Hanna, G.; Ezeberry, J.

    2010-01-01

    The Tokamak Complex of ITER is the structure housing the Tokamak machine, the Tritium building and the Diagnostic building. This structure, with a plan of about 120 x 80 m, will be built with a base isolation system formed with over 500 steel reinforced neoprene pads. The pads will be mounted on top of short columns or plinths, supported by a bottom basemat resting directly on rock. Foundation level is about 20 m below grade level. Consequently, a ground supporting system, such as retaining walls, is required to protect the structure. The walls, together with the basemat, form the seismic pit of the Tokamak Complex. After the initial design of the seismic pit walls and basemat was closed, a new report on the water table levels to be expected for different return periods was issued. The report introduced a substantial reduction of ground water levels with respect to the previous design basis. Following this reduction, a new design for the seismic pit walls and basemat was developed. The goal was to introduce the new optimized design as an alternative in the Call for Tenders related to the construction of the seismic pit. The design of the seismic pit is governed by the seismic action, even though the whole pit is embedded in a limestone rock of medium to good quality. For optimizing the design, a review of geotechnical parameters has been carried out first, using the huge body of information generated after more than 20 years of site investigation. Afterwards, seismic thrusts on the walls have been computed using different procedures, from conventional rock wedged equilibrium analyses to more sophisticated techniques based on the interaction of discrete blocks configuring the rock massif. In addition, internal forces and moments have been determined at the basemat from the ground deformation parameters, using finite element models. Finally, steel reinforcement has been obtained for the several sections of the retaining walls and the basemat, complying with the

  12. Seismic monitoring experiment of raise boring in 2014

    International Nuclear Information System (INIS)

    Saari, J.; Malm, M.

    2015-01-01

    In Olkiluoto, Posiva Oy has operated a local seismic network since February 2002. The purpose of the microearthquake measurements at Olkiluoto is to improve understanding of the structure, behaviour and long term stability of the bedrock. The studies include both tectonic and excavation-induced microearthquakes. An additional task of monitoring is related to safeguarding of ONKALO. The possibility to excavate an illegal access to ONKALO has been concerned when the safeguards are discussed. Therefore all recorded explosions in the Olkiluoto area and in ONKALO are located. If a concentration of explosions is observed, the origin of that is found out. Also a concept of hidden illegal explosions, detonated at the same time as the real excavation blasts, has been examined. According to the experience gained in Olkiluoto, it can be concluded that, as long the seismic network is in operation and the results are analysed by a skilled person, it is practically impossible to do illegal undetected excavation by blasting within the Olkiluoto seismic network area. In this report a possibility of seismic monitoring of undeclared excavation done by tunnel boring machine (TBM) has been investigated. In the earlier investigations the instruments were at the ground surface and the sensors were triaxial short period (1 Hz) geophones or broadband geophones. The characteristics (frequency content, polarity and amplitude) of the continuous seismic vibration generated by TMB were studied. The onset time of the seismic signal were not distinguished. Altogether 16 new 10 kHz accelerometers were installed in boreholes inside ONKALO March 2012. The sensors comprised a new subnetwork that monitored the raise boring of two shafts done 2014, from the level -455 m to the level -290 m. The aim was to record the seismic signal generated when the drill bit hits the rock at the moment the tunnel boring begins. Altogether 113 seismic signals generated by the drill bit were located during the

  13. Seismic monitoring experiment of raise boring in 2014

    Energy Technology Data Exchange (ETDEWEB)

    Saari, J.; Malm, M. [AaF-Consult Oy, Espoo (Finland)

    2015-01-15

    In Olkiluoto, Posiva Oy has operated a local seismic network since February 2002. The purpose of the microearthquake measurements at Olkiluoto is to improve understanding of the structure, behaviour and long term stability of the bedrock. The studies include both tectonic and excavation-induced microearthquakes. An additional task of monitoring is related to safeguarding of ONKALO. The possibility to excavate an illegal access to ONKALO has been concerned when the safeguards are discussed. Therefore all recorded explosions in the Olkiluoto area and in ONKALO are located. If a concentration of explosions is observed, the origin of that is found out. Also a concept of hidden illegal explosions, detonated at the same time as the real excavation blasts, has been examined. According to the experience gained in Olkiluoto, it can be concluded that, as long the seismic network is in operation and the results are analysed by a skilled person, it is practically impossible to do illegal undetected excavation by blasting within the Olkiluoto seismic network area. In this report a possibility of seismic monitoring of undeclared excavation done by tunnel boring machine (TBM) has been investigated. In the earlier investigations the instruments were at the ground surface and the sensors were triaxial short period (1 Hz) geophones or broadband geophones. The characteristics (frequency content, polarity and amplitude) of the continuous seismic vibration generated by TMB were studied. The onset time of the seismic signal were not distinguished. Altogether 16 new 10 kHz accelerometers were installed in boreholes inside ONKALO March 2012. The sensors comprised a new subnetwork that monitored the raise boring of two shafts done 2014, from the level -455 m to the level -290 m. The aim was to record the seismic signal generated when the drill bit hits the rock at the moment the tunnel boring begins. Altogether 113 seismic signals generated by the drill bit were located during the

  14. Lunar seismicity, structure, and tectonics

    Science.gov (United States)

    Lammlein, D. R.; Latham, G. V.; Dorman, J.; Nakamura, Y.; Ewing, M.

    1974-01-01

    Natural seismic events have been detected by the long-period seismometers at Apollo stations 16, 14, 15, and 12 at annual rates of 3300, 1700, 800, and 700, respectively, with peak activity at 13- to 14-day intervals. The data are used to describe magnitudes, source characteristics, and periodic features of lunar seismicity. In a present model, the rigid lithosphere overlies an asthenosphere of reduced rigidity in which present-day partial melting is probable. Tidal deformation presumably leads to critical stress concentrations at the base of the lithosphere, where moonquakes are found to occur. The striking tidal periodicities in the pattern of moonquake occurrence and energy release suggest that tidal energy is the dominant source of energy released as moonquakes. Thus, tidal energy is dissipated by moonquakes in the lithosphere and probably by inelastic processes in the asthenosphere.

  15. Short-term alpha-tocopherol treatment during neonatal period modulates pro-inflammatory response to endotoxin (LPS) challenge in the same calves several months later

    Science.gov (United States)

    Vitamin E, a major natural antioxidant, has been previously shown to attenuate pro-inflammatory response to immune challenge in cattle. Our objective was to evaluate the effect of short-term treatment with alpha-tocopherol in newborn calves on selected elements of the pro-inflamatory response to LPS...

  16. Student Teachers of Technology and Design: Can Short Periods of STEM-Related Industrial Placement Change Student Perceptions of Engineering and Technology?

    Science.gov (United States)

    Gibson, Ken S.

    2012-01-01

    This is a report, on a small-scale case study, of a programme of short industrial placements (5 day block) for student teachers of technology and design in Northern Ireland. Such placements increase student awareness and understanding of the nature of Engineering and Technology and therefore better prepare them to teach these subjects, as integral…

  17. Characterization of Unstable Rock Slopes Through Passive Seismic Measurements

    Science.gov (United States)

    Kleinbrod, U.; Burjanek, J.; Fäh, D.

    2014-12-01

    Catastrophic rock slope failures have high social impact, causing significant damage to infrastructure and many casualties throughout the world each year. Both detection and characterization of rock instabilities are therefore of key importance. An analysis of ambient vibrations of unstable rock slopes might be a new alternative to the already existing methods, e.g. geotechnical displacement measurements. Systematic measurements have been performed recently in Switzerland to study the seismic response of potential rockslides concerning a broad class of slope failure mechanisms and material conditions. Small aperture seismic arrays were deployed at sites of interest for a short period of time (several hours) in order to record ambient vibrations. Each measurement setup included a reference station, which was installed on a stable part close to the instability. Recorded ground motion is highly directional in the unstable parts of the rock slope, and significantly amplified with respect to stable areas. These effects are strongest at certain frequencies, which were identified as eigenfrequencies of the unstable rock mass. In most cases the directions of maximum amplification are perpendicular to open cracks and in good agreement with the deformation directions obtained by geodetic measurements. Such unique signatures might improve our understanding of slope structure and stability. Thus we link observed vibration characteristics with available results of detailed geological characterization. This is supported by numerical modeling of seismic wave propagation in fractured media with complex topography.For example, a potential relation between eigenfrequencies and unstable rock mass volume is investigated.

  18. Seismic velocity variation along the Izu-Bonin arc estaimated from traveltime tomography using OBS data

    Science.gov (United States)

    Obana, K.; Tamura, Y.; Takahashi, T.; Kodaira, S.

    2014-12-01

    The Izu-Bonin (Ogasawara) arc is an intra-oceanic island arc along the convergent plate boundary between the subducting Pacific and overriding Philippine Sea plates. Recent active seismic studies in the Izu-Bonin arc reveal significant along-arc variations in crustal structure [Kodaira et al., 2007]. The thickness of the arc crust shows a remarkable change between thicker Izu (~30 km) and thinner Bonin (~10 km) arcs. In addition to this, several geological and geophysical contrasts, such as seafloor topography and chemical composition of volcanic rocks, between Izu and Bonin arc have been reported [e.g., Yuasa 1992]. We have conducted earthquake observations using ocean bottom seismographs (OBSs) to reveal seismic velocity structure of the crust and mantle wedge in the Izu-Bonin arc and to investigate origin of the along-arc structure variations. We deployed 40 short-period OBSs in Izu and Bonin area in 2006 and 2009, respectively. The OBS data were processed with seismic data recorded at routine seismic stations on Hachijo-jima, Aoga-shima, and Chichi-jima operated by National Research Institute for Earth Science and Disaster Prevention (NIED). More than 5000 earthquakes were observed during about three-months observation period in each experiment. We conducted three-dimensional seismic tomography using manually picked P- and S-wave arrival time data. The obtained image shows a different seismic velocity structures in the mantle beneath the volcanic front between Izu and Bonin arcs. Low P-wave velocity anomalies in the mantle beneath the volcanic front in the Izu arc are limited at depths deeper than those in the Bonin arc. On the other hand, P-wave velocity in the low velocity anomalies beneath volcanic front in the Bonin arc is slower than that in the Izu arc. These large-scale along-arc structure variations in the mantle could relate to the geological and geophysical contrasts between Izu and Bonin arcs.

  19. An Investigation of Seismicity for Western Anatolia

    International Nuclear Information System (INIS)

    Sayil, N.

    2007-01-01

    In order to determine the seismicity of western Anatolia limited with the coordinates of 36degree-40degreeN, 26degree-32degreeE, Gutenberg-Richter magnitude-frequency relation, seismic risk and recurrence period have been computed. The data belonging to both the historical period before 1900 (I0 3 6.0 corresponding to MS 3 5.0) and the instrumental period until 2005 (MS 3 4.0) have been used in the analysis. The study area has been divided into 13 sub-regions due to certain seismotectonic characteristics, plate tectonic models and geology of the region. Computations from a and b parameters and seismic risk and recurrence period for each sub-regions have showed that subregions 1 and 8 (Balikesir and Izmir-Sakiz Island), where have the lowest b values, have the highest risks and the shortest recurrence periods

  20. Multi scenario seismic hazard assessment for Egypt

    Science.gov (United States)

    Mostafa, Shaimaa Ismail; Abd el-aal, Abd el-aziz Khairy; El-Eraki, Mohamed Ahmed

    2018-05-01

    Egypt is located in the northeastern corner of Africa within a sensitive seismotectonic location. Earthquakes are concentrated along the active tectonic boundaries of African, Eurasian, and Arabian plates. The study area is characterized by northward increasing sediment thickness leading to more damage to structures in the north due to multiple reflections of seismic waves. Unfortunately, man-made constructions in Egypt were not designed to resist earthquake ground motions. So, it is important to evaluate the seismic hazard to reduce social and economic losses and preserve lives. The probabilistic seismic hazard assessment is used to evaluate the hazard using alternative seismotectonic models within a logic tree framework. Alternate seismotectonic models, magnitude-frequency relations, and various indigenous attenuation relationships were amended within a logic tree formulation to compute and develop the regional exposure on a set of hazard maps. Hazard contour maps are constructed for peak ground acceleration as well as 0.1-, 0.2-, 0.5-, 1-, and 2-s spectral periods for 100 and 475 years return periods for ground motion on rock. The results illustrate that Egypt is characterized by very low to high seismic activity grading from the west to the eastern part of the country. The uniform hazard spectra are estimated at some important cities distributed allover Egypt. The deaggregation of seismic hazard is estimated at some cities to identify the scenario events that contribute to a selected seismic hazard level. The results of this study can be used in seismic microzonation, risk mitigation, and earthquake engineering purposes.

  1. Seismic risk analysis for General Electric Plutonium Facility, Pleasanton, California

    International Nuclear Information System (INIS)

    1978-01-01

    This report presents the results of a seismic risk analysis that focuses on all possible sources of seismic activity, with the exception of the postulated Verona Fault. The best estimate curve indicates that the Vallecitos facility will experience 30% g with a return period of roughly 130 years and 60% g with a return period of roughly 700 years

  2. The Upper Limit of the Periodic Table of Elements Points out to the "Long" Version of the Table, Instead of the "Short" One

    Directory of Open Access Journals (Sweden)

    Khazan A.

    2012-01-01

    Full Text Available Herein we present an analysis of the internal constitution of the “short” and “long” forms of the Periodic Table of Elements. As a result, we conclude that the second (long version is more correct. We also suggest a long version of the Table consisting of 8 periods and 18 groups, with the last (heaviest element being element No. 155, which closes the Table.

  3. Seismic excitation by space shuttles

    Science.gov (United States)

    Kanamori, H.; Mori, J.; Sturtevant, B.; Anderson, D.L.; Heaton, T.

    1992-01-01

    Shock waves generated by the space shuttles Columbia (August 13, 1989), Atlantis (April 11, 1991) and Discovery (September 18, 1991) on their return to Edwards Air Force Base, California, were recorded by TERRAscope (Caltech's broadband seismic network), the Caltech-U.S.G.S Southern California Seismic Network (SCSN), and the University of Southern California (USC) Los Angeles Basin Seismic Network. The spatial pattern of the arrival times exhibits hyperbolic shock fronts from which the path, velocity and altitude of the space shuttle could be determined. The shock wave was acoustically coupled to the ground, converted to a seismic wave, and recorded clearly at the broadband TERRAscope stations. The acoustic coupling occurred very differently depending on the conditions of the Earth's surface surrounding the station. For a seismic station located on hard bedrock, the shock wave (N wave) was clearly recorded with little distortion. Aside from the N wave, very little acoustic coupling of the shock wave energy to the ground occurred at these sites. The observed N wave record was used to estimate the overpressure of the shock wave accurately; a pressure change of 0.5 to 2.2 mbars was obtained. For a seismic station located close to the ocean or soft sedimentary basins, a significant amount of shock wave energy was transferred to the ground through acoustic coupling of the shock wave and the oceanic Rayleigh wave. A distinct topography such as a mountain range was found effective to couple the shock wave energy to the ground. Shock wave energy was also coupled to the ground very effectively through large man made structures such as high rise buildings and offshore oil drilling platforms. For the space shuttle Columbia, in particular, a distinct pulse having a period of about 2 to 3 seconds was observed, 12.5 s before the shock wave, with a broadband seismograph in Pasadena. This pulse was probably excited by the high rise buildings in downtown Los Angeles which were

  4. PARAMETERS OF KAMCHATKA SEISMICITY IN 2008

    Directory of Open Access Journals (Sweden)

    Vadim A. Saltykov

    2010-01-01

    Full Text Available The paper describes seismicity of Kamchatka for the period of 2008 and presents 2D distribution of background seismicity parameters calculated from data published in the Regional Catalogue of Kamchatka Earthquakes. Parameters under study are total released seismic energy, seismic activity A10, slope of recurrence graph γ, parameters of RTL, ΔS and Z-function methods, and clustering of earthquakes. Estimations of seismicity are obtained for a region bordered by latitude 50.5–56.5N, longitude 156E–167E, with depths to 300 km. Earthquakes of energy classes not less than 8.5 as per the Fedotov’s classification are considered. The total seismic energy released in 2008 is estimated. According to a function of annual seismic energy distribution, an amount of seismic energy released in 2008 was close to the median level (Fig. 1. Over 2/3 of the total amount of seismic energy released in 2008 resulted from three largest earthquakes (МW ≥ 5.9. About 5 percent of the total number of seismic events are comprised of grouped earthquakes, i.e. aftershocks and swarms. A schematic map of the largest earthquakes (МW ≥ 5.9 and grouped seismic events which occurred in 2008 is given in Fig. 2; their parameters are listed in Table 1. Grouped earthquakes are excluded from the catalogue. A map showing epicenters of independent earthquakes is given in Fig. 3. The slope of recurrence graph γ and seismic activity A10 is based on the Gutenberg-Richter law stating the fundamental property of seismic process. The recurrence graph slope is calculated from continuous exponential distribution of earthquakes by energy classes. Using γ is conditioned by observations that in some cases the slope of the recurrence graph decreases prior to a large earthquake. Activity A10 is calculated from the number of earthquakes N and recurrence graph slope γ. Average slopes of recurrence graph γ and seismic activity A10 for the area under study in 2008 are calculated; our

  5. Seismic hazard estimation based on the distributed seismicity in northern China

    Science.gov (United States)

    Yang, Yong; Shi, Bao-Ping; Sun, Liang

    2008-03-01

    In this paper, we have proposed an alternative seismic hazard modeling by using distributed seismicites. The distributed seismicity model does not need delineation of seismic source zones, and simplify the methodology of probabilistic seismic hazard analysis. Based on the devastating earthquake catalogue, we established three seismicity model, derived the distribution of a-value in northern China by using Gaussian smoothing function, and calculated peak ground acceleration distributions for this area with 2%, 5% and 10% probability of exceedance in a 50-year period by using three attenuation models, respectively. In general, the peak ground motion distribution patterns are consistent with current seismic hazard map of China, but in some specific seismic zones which include Shanxi Province and Shijiazhuang areas, our results indicated a little bit higher peak ground motions and zonation characters which are in agreement with seismicity distribution patterns in these areas. The hazard curves have been developed for Beijing, Tianjin, Taiyuan, Tangshan, and Ji’nan, the metropolitan cities in the northern China. The results showed that Tangshan, Taiyuan, Beijing has a higher seismic hazard than that of other cities mentioned above.

  6. Seismic intrusion detector system

    Science.gov (United States)

    Hawk, Hervey L.; Hawley, James G.; Portlock, John M.; Scheibner, James E.

    1976-01-01

    A system for monitoring man-associated seismic movements within a control area including a geophone for generating an electrical signal in response to seismic movement, a bandpass amplifier and threshold detector for eliminating unwanted signals, pulse counting system for counting and storing the number of seismic movements within the area, and a monitoring system operable on command having a variable frequency oscillator generating an audio frequency signal proportional to the number of said seismic movements.

  7. Quantitative Seismic Amplitude Analysis

    NARCIS (Netherlands)

    Dey, A.K.

    2011-01-01

    The Seismic Value Chain quantifies the cyclic interaction between seismic acquisition, imaging and reservoir characterization. Modern seismic innovation to address the global imbalance in hydrocarbon supply and demand requires such cyclic interaction of both feed-forward and feed-back processes.

  8. RADIO FLARING FROM THE T6 DWARF WISEPC J112254.73+255021.5 WITH A POSSIBLE ULTRA-SHORT PERIODICITY

    Energy Technology Data Exchange (ETDEWEB)

    Route, Matthew; Wolszczan, Alexander, E-mail: mroute@purdue.edu, E-mail: alex@astro.psu.edu [Department of Astronomy and Astrophysics, the Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)

    2016-04-20

    We present new results from a continuing 5 GHz search for flaring radio emission from a sample of L and T brown dwarfs, conducted with the 305 m Arecibo radio telescope. In addition to the previously reported flaring from the T6.5 dwarf 2MASS J10475385+212423, we have detected and confirmed circularly polarized flares from another T6 dwarf, WISEPC J112254.73+255021.5. Although the flares are sporadic, they appear to occur at a stable period of 0.288 hr. Given the current constraints, periods equal to its second and third subharmonic cannot be ruled out. The stability of this period over the eight-month timespan of observations indicates that, if real, it likely reflects the star’s rapid rotation. If confirmed, any of the three inferred periodicities would be much shorter than the shortest, 1.41 hr, rotation period of a brown dwarf measured so far. This finding would place a new observational constraint on the angular momentum evolution and rotational stability of substellar objects. The detection of radio emission from the sixth ∼1000 K dwarf further demonstrates that the coolest brown dwarfs and, possibly, young giant planets, can be efficiently investigated using radio observations at centimeter wavelengths as a tool.

  9. Romanian Data Center: A modern way for seismic monitoring

    Science.gov (United States)

    Neagoe, Cristian; Marius Manea, Liviu; Ionescu, Constantin

    2014-05-01

    The main seismic survey of Romania is performed by the National Institute for Earth Physics (NIEP) which operates a real-time digital seismic network. The NIEP real-time network currently consists of 102 stations and two seismic arrays equipped with different high quality digitizers (Kinemetrics K2, Quanterra Q330, Quanterra Q330HR, PS6-26, Basalt), broadband and short period seismometers (CMG3ESP, CMG40T, KS2000, KS54000, KS2000, CMG3T,STS2, SH-1, S13, Mark l4c, Ranger, gs21, Mark l22) and acceleration sensors (Episensor Kinemetrics). The data are transmitted at the National Data Center (NDC) and Eforie Nord (EFOR) Seismic Observatory. EFOR is the back-up for the NDC and also a monitoring center for the Black Sea tsunami events. NIEP is a data acquisition node for the seismic network of Moldova (FDSN code MD) composed of five seismic stations. NIEP has installed in the northern part of Bulgaria eight seismic stations equipped with broadband sensors and Episensors and nine accelerometers (Episensors) installed in nine districts along the Danube River. All the data are acquired at NIEP for Early Warning System and for primary estimation of the earthquake parameters. The real-time acquisition (RT) and data exchange is done by Antelope software and Seedlink (from Seiscomp3). The real-time data communication is ensured by different types of transmission: GPRS, satellite, radio, Internet and a dedicated line provided by a governmental network. For data processing and analysis at the two data centers Antelope 5.2 TM is being used running on 3 workstations: one from a CentOS platform and two on MacOS. Also a Seiscomp3 server stands as back-up for Antelope 5.2 Both acquisition and analysis of seismic data systems produce information about local and global parameters of earthquakes. In addition, Antelope is used for manual processing (event association, calculation of magnitude, creating a database, sending seismic bulletins, calculation of PGA and PGV, etc.), generating

  10. Full Waveform Adjoint Seismic Tomography of the Antarctic Plate

    Science.gov (United States)

    Lloyd, A. J.; Wiens, D.; Zhu, H.; Tromp, J.; Nyblade, A.; Anandakrishnan, S.; Aster, R. C.; Huerta, A. D.; Winberry, J. P.; Wilson, T. J.; Dalziel, I. W. D.; Hansen, S. E.; Shore, P.

    2017-12-01

    Recent studies investigating the response and influence of the solid Earth on the evolution of the cryosphere demonstrate the need to account for 3D rheological structure to better predict ice sheet dynamics, stability, and future sea level impact, as well as to improve glacial isostatic adjustment models and more accurately measure ice mass loss. Critical rheological properties like mantle viscosity and lithospheric thickness may be estimated from shear wave velocity models that, for Antarctica, would ideally possess regional-scale resolution extending down to at least the base of the transition zone (i.e. 670 km depth). However, current global- and continental-scale seismic velocity models are unable to obtain both the resolution and spatial coverage necessary, do not take advantage of the full set of available Antarctic data, and, in most instance, employ traditional seismic imaging techniques that utilize limited seismogram information. We utilize 3-component earthquake waveforms from almost 300 Antarctic broadband seismic stations and 26 southern mid-latitude stations from 270 earthquakes (5.5 ≤ Mw ≤ 7.0) between 2001-2003 and 2007-2016 to conduct a full-waveform adjoint inversion for Antarctica and surrounding regions of the Antarctic plate. Necessary forward and adjoint wavefield simulations are performed utilizing SPECFEM3D_GLOBE with the aid of the Texas Advanced Computing Center. We utilize phase observations from seismogram segments containing P, S, Rayleigh, and Love waves, including reflections and overtones, which are autonomously identified using FLEXWIN. The FLEXWIN analysis is carried out over a short (15-50 s) and long (initially 50-150 s) period band that target body waves, or body and surface waves, respectively. As our model is iteratively refined, the short-period corner of the long period band is gradually reduced to 25 s as the model converges over 20 linearized inversion iterations. We will briefly present this new high

  11. Consequences of dietary energy source and energy level on energy balance, lactogenic hormones, and lactation curve characteristics of cows after a short or omitted dry period

    NARCIS (Netherlands)

    van Hoeij, R J; Dijkstra, J; Bruckmaier, R.M.; Gross, James J; Lam, T J G M; Remmelink, G J; Kemp, B.; Knegsel, A.T.M.

    2017-01-01

    Omitting the dry period (DP) generally reduces milk production in the subsequent lactation. The aim of this study was to evaluate the effect of dietary energy source-glucogenic (G) or lipogenic (L)-and energy level-standard (std) or low-on milk production; energy balance (EB); lactogenic hormones

  12. Udder health of dairy cows fed different dietary energy levels after a short or no dry period without use of dry cow antibiotics

    NARCIS (Netherlands)

    Hoeij, van R.J.; Lam, T.J.G.M.; Bruckmaier, R.M.; Dijkstra, J.; Remmelink, G.J.; Kemp, B.; Knegsel, van A.T.M.

    2018-01-01

    Reports on the effects of length of dry period (DP) on udder health of cows that were not treated with dry cow antibiotics are scarce. Additionally, the effects of a reduced dietary energy level for cows with a 0-d DP on udder health have not yet been studied. The aims of this study were (1) to

  13. Consequences of dietary energy source and energy level on energy balance, lactogenic hormones, and lactation curve characteristics of cows after a short or omitted dry period

    NARCIS (Netherlands)

    Hoeij, van R.J.; Dijkstra, J.; Bruckmaier, R.M.; Gross, J.J.; Lam, Theo J.G.M.; Remmelink, G.J.; Kemp, B.; Knegsel, van A.T.M.

    2017-01-01

    Omitting the dry period (DP) generally reduces milk production in the subsequent lactation. The aim of this study was to evaluate the effect of dietary energy source—glucogenic (G) or lipogenic (L)—and energy level—standard (std) or low—on milk production; energy balance (EB); lactogenic hormones

  14. Influence of winds on temporally varying short and long period gravity waves in the near shore regions of the eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Glejin, J.; SanilKumar, V.; Nair, T.M.B.; Singh, J.

    pro- vided by the NOAA-CIRES (Cooperative Institute for Re- search in the Environmental Sciences) Climate Diagnostics Center in Boulder, Colorado (http://www.cdc.noaa.gov/). To determine the sea/land breeze system at Ratnagiri during the study period...

  15. Seismic hazard studies in Egypt

    Directory of Open Access Journals (Sweden)

    Abuo El-Ela A. Mohamed

    2012-12-01

    Full Text Available The study of earthquake activity and seismic hazard assessment of Egypt is very important due to the great and rapid spreading of large investments in national projects, especially the nuclear power plant that will be held in the northern part of Egypt. Although Egypt is characterized by low seismicity, it has experienced occurring of damaging earthquake effect through its history. The seismotectonic sitting of Egypt suggests that large earthquakes are possible particularly along the Gulf of Aqaba–Dead Sea transform, the Subduction zone along the Hellenic and Cyprean Arcs, and the Northern Red Sea triple junction point. In addition some inland significant sources at Aswan, Dahshour, and Cairo-Suez District should be considered. The seismic hazard for Egypt is calculated utilizing a probabilistic approach (for a grid of 0.5° × 0.5° within a logic-tree framework. Alternative seismogenic models and ground motion scaling relationships are selected to account for the epistemic uncertainty. Seismic hazard values on rock were calculated to create contour maps for four ground motion spectral periods and for different return periods. In addition, the uniform hazard spectra for rock sites for different 25 periods, and the probabilistic hazard curves for Cairo, and Alexandria cities are graphed. The peak ground acceleration (PGA values were found close to the Gulf of Aqaba and it was about 220 gal for 475 year return period. While the lowest (PGA values were detected in the western part of the western desert and it is less than 25 gal.

  16. Ultra-short-period W/B4C multilayers for x-ray optics-microstructure limits on reflectivity

    Energy Technology Data Exchange (ETDEWEB)

    Walton, Christopher Charles [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering

    1997-12-01

    Multilayer thin films are used as Bragg reflectors for soft x-rays in the energy range 50eV < E < 1000eV in many x-ray optics applications such as x-ray microscopes and telescopes, reducing optics for extreme ultraviolet (EUV) lithography, and x-ray polarizers and phase retarders. Applications often depend critically on reflectivity, which has not been systematically characterized for multilayer periods below 20Å. For this study, W/B4C multilayers were fabricated by magnetron sputtering on Si(111), with periods from 48Å to as little as 4.7Å. The x-ray reflectivity measured at λ = 1.54Å and at 45° incidence (289 eV < E < 860 eV) was found to decrease sharply for multilayer periods less than 15-20Å. Examination by high-resolution transmission electron microscopy (HRTEM) showed an expansion of the thickness of the W-rich layers of 30-40% from the nominal values, consistent with intermixture of the two materials during sputter growth, and discontinuous W-rich layers for multilayer periods below about 15Å. The experimental data for the specular reflectivity in the hard and soft x-ray regimes and the diffuse scattering fit well to a model of multilayer roughness. The model is expressed as a power-law dependence of roughness on spatial frequency. Analysis of small-angle scattering in transmission from multilayers grown on freestanding Si3N4 membranes confirms the onset of discontinuity at periods between 14Å and 22Å. Spectroscopy studies by x-ray absorption (NEXAFS) and electron energy loss (EELS) at the boron K-edge (188eV) are consistent with changes in the average boron bonding environment, as the multilayer period decreases and the W-rich layers are increasingly thin and dispersed. A discrete W-rich phase is present for periods at least as small as 6.3Å.

  17. Seismic evaluation of existing nuclear power plants

    International Nuclear Information System (INIS)

    2003-01-01

    The IAEA nuclear safety standards publications address the site evaluation and the design of new nuclear power plants (NPPs), including seismic hazard assessment and safe seismic design, at the level of the Safety Requirements as well as at the level of dedicated Safety Guides. It rapidly became apparent that the existing nuclear safety standards documents were not adequate for handling specific issues in the seismic evaluation of existing NPPs, and that a dedicated document was necessary. This is the purpose of this Safety Report, which is written in the spirit of the nuclear safety standards and can be regarded as guidance for the interpretation of their intent. Worldwide experience shows that an assessment of the seismic capacity of an existing operating facility can be prompted for the following: (a) Evidence of a greater seismic hazard at the site than expected before, owing to new or additional data and/or to new methods; (b) Regulatory requirements, such as periodic safety reviews, to ensure that the plant has adequate margins for seismic loads; (c) Lack of anti-seismic design or poor anti-seismic design; (d) New technical finding such as vulnerability of some structures (masonry walls) or equipment (relays), other feedback and new experience from real earthquakes. Post-construction evaluation programmes evaluate the current capability of the plant to withstand the seismic concern and identify any necessary upgrades or changes in operating procedures. Seismic qualification is distinguished from seismic evaluation primarily in that seismic qualification is intended to be performed at the design stage of a plant, whereas seismic evaluation is intended to be applied after a plant has been constructed. Although some guidelines do exist for the evaluation of existing NPPs, these are not established at the level of a regulatory guide or its equivalent. Nevertheless, a number of existing NPPs throughout the world have been and are being subjected to review of their

  18. Statistical Seismology and Induced Seismicity

    Science.gov (United States)

    Tiampo, K. F.; González, P. J.; Kazemian, J.

    2014-12-01

    While seismicity triggered or induced by natural resources production such as mining or water impoundment in large dams has long been recognized, the recent increase in the unconventional production of oil and gas has been linked to rapid rise in seismicity in many places, including central North America (Ellsworth et al., 2012; Ellsworth, 2013). Worldwide, induced events of M~5 have occurred and, although rare, have resulted in both damage and public concern (Horton, 2012; Keranen et al., 2013). In addition, over the past twenty years, the increase in both number and coverage of seismic stations has resulted in an unprecedented ability to precisely record the magnitude and location of large numbers of small magnitude events. The increase in the number and type of seismic sequences available for detailed study has revealed differences in their statistics that previously difficult to quantify. For example, seismic swarms that produce significant numbers of foreshocks as well as aftershocks have been observed in different tectonic settings, including California, Iceland, and the East Pacific Rise (McGuire et al., 2005; Shearer, 2012; Kazemian et al., 2014). Similarly, smaller events have been observed prior to larger induced events in several occurrences from energy production. The field of statistical seismology has long focused on the question of triggering and the mechanisms responsible (Stein et al., 1992; Hill et al., 1993; Steacy et al., 2005; Parsons, 2005; Main et al., 2006). For example, in most cases the associated stress perturbations are much smaller than the earthquake stress drop, suggesting an inherent sensitivity to relatively small stress changes (Nalbant et al., 2005). Induced seismicity provides the opportunity to investigate triggering and, in particular, the differences between long- and short-range triggering. Here we investigate the statistics of induced seismicity sequences from around the world, including central North America and Spain, and

  19. Seismic changes industry

    International Nuclear Information System (INIS)

    Taylor, G.

    1992-01-01

    This paper discusses the growth in the seismic industry as a result of the recent increases in the foreign market. With the decline of communism and the opening of Latin America to exploration, seismic teams have moved out into these areas in support of the oil and gas industry. The paper goes on to discuss the improved technology available for seismic resolution and the subsequent use of computers to field-proof the data while the seismic team is still on-site. It also discusses the effects of new computer technology on reducing the amount of support staff that is required to both conduct and interpret seismic information

  20. The effects of short work vs. longer work periods within intermittent exercise on V̇o2p kinetics, muscle deoxygenation, and energy system contribution.

    Science.gov (United States)

    McCrudden, Michael C; Keir, Daniel A; Belfry, Glen R

    2017-06-01

    We examined the effects of inserting 3-s recovery periods during high-intensity cycling exercise at 25-s and 10-s intervals on pulmonary oxygen uptake (V̇o 2p ), muscle deoxygenation [deoxyhemoglobin (HHb)], their associated kinetics (τ), and energy system contributions. Eleven men (24 ± 3 yr) completed two trials of three cycling protocols: an 8-min continuous protocol (CONT) and two 8-min intermittent exercise protocols with work-to-rest periods of 25 s to 3 s (25INT) and 10 s to 3 s (10INT). Each protocol began with a step-transition from a 20-W baseline to a power output (PO) of 60% between lactate threshold and maximal V̇o 2p (Δ60). This PO was maintained for 8 min in CONT, whereas 3-s periods of 20-W cycling were inserted every 10 s and 25 s after the transition to Δ60 in 10INT and 25INT, respectively. Breath-by-breath gas exchange measured by mass spectrometry and turbine and vastus lateralis [HHb] measured by near-infrared spectroscopy were recorded throughout. Arterialized-capillary lactate concentration ([Lac - ]) was obtained before and 2 min postexercise. The τV̇o 2p was lowest ( P 0.05) between conditions. Postexercise [Lac - ] was lowest ( P exercise speeded V̇o 2p kinetics and reduced overall V̇o 2p , suggesting an increased reliance on PCr-derived phosphorylation during the work period of INT compared with an identical PO performed continuously. NEW & NOTEWORTHY We report novel observations on the effects of differing heavy-intensity work durations between 3-s recovery periods on pulmonary oxygen uptake (V̇o 2p ) kinetics, muscle deoxygenation, and energy system contributions. Relative to continuous exercise, V̇o 2p kinetics are faster in intermittent exercise, and increased frequency of 3-s recovery periods improves microvascular O 2 delivery and reduces V̇o 2p and arterialized-capillary lactate concentration. The metabolic burden of identical intensity work is altered when performed intermittently vs. continuously. Copyright

  1. Early feeding of carnivorous rainbow trout (Oncorhynchus mykiss) with a hyperglucidic diet during a short period: effect on dietary glucose utilization in juveniles.

    Science.gov (United States)

    Geurden, I; Aramendi, M; Zambonino-Infante, J; Panserat, S

    2007-06-01

    Based on the concept of nutritional programming in higher vertebrates, we tested whether an acute hyperglucidic stimulus during early life could induce a long-lasting effect on carbohydrate utilization in carnivorous rainbow trout. The trout were fed a hyperglucidic diet (60% dextrin) at two early stages of development: either at first feeding (3 days, stimulus 1) or after yolk absorption (5 days, stimulus 2). Before and after the hyperglucidic stimulus, they received a commercial diet until juvenile stage (>10 g). Fish that did not experience the hyperglucidic stimuli served as controls. The short- and long-term effects of the stimuli were evaluated by measuring the expression of five key genes involved in carbohydrate utilization: alpha-amylase, maltase (digestion), sodium-dependent glucose cotransporter (SGLT1; intestinal glucose transport), and glucokinase and glucose-6-phosphatase, involved in the utilization and production of glucose, respectively. The hyperglucidic diet rapidly increased expressions of maltase, alpha-amylase, and glucokinase in stimulus 1 fish and only of maltase in stimulus 2 fish, probably because of a lower plasticity at this later stage of development. In the final challenge test with juveniles fed a 25% dextrin diet, both digestive enzymes were upregulated in fish that had experienced the hyperglucidic stimulus at first feeding, confirming the possibility of modification of some long-term physiological functions in rainbow trout. In contrast, no persistent molecular adaptations were found for the genes involved in glucose transport or metabolism. In addition, growth and postprandial glycemia were unaffected by the stimuli. In summary, our data show that a short hyperglucidic stimulus during early trout life may permanently influence carbohydrate digestion.

  2. Studies of self focusing and filamentation instabilities in short wavelength laser fusion: Final technical report for the period 29 May 1986-28 April 1988

    International Nuclear Information System (INIS)

    Joshi, Chan.

    1988-04-01

    Azimuthal periodic breakup of a radially modulated 0.35 μm laser beam has been inferred in plasmas produced from solid targets. The breakup is more severe in gold plasmas compared to glass or aluminum plasmas and occurs at rather modest laser intensities of /approximately/5 /times/ 10 12 Wcm 2 . Thermal filamentation is suggested as the mechanism for the observed beam breakup

  3. Erosion influences the seismicity of active thrust faults.

    Science.gov (United States)

    Steer, Philippe; Simoes, Martine; Cattin, Rodolphe; Shyu, J Bruce H

    2014-11-21

    Assessing seismic hazards remains one of the most challenging scientific issues in Earth sciences. Deep tectonic processes are classically considered as the only persistent mechanism driving the stress loading of active faults over a seismic cycle. Here we show via a mechanical model that erosion also significantly influences the stress loading of thrust faults at the timescale of a seismic cycle. Indeed, erosion rates of about ~0.1-20 mm yr(-1), as documented in Taiwan and in other active compressional orogens, can raise the Coulomb stress by ~0.1-10 bar on the nearby thrust faults over the inter-seismic phase. Mass transfers induced by surface processes in general, during continuous or short-lived and intense events, represent a prominent mechanism for inter-seismic stress loading of faults near the surface. Such stresses are probably sufficient to trigger shallow seismicity or promote the rupture of deep continental earthquakes up to the surface.

  4. Seismic Noise Analysis and Reduction through Utilization of Collocated Seismic and Atmospheric Sensors at the GRO Chile Seismic Network

    Science.gov (United States)

    Farrell, M. E.; Russo, R. M.

    2013-12-01

    gain insight into how local atmospheric conditions couple with the ground to generate seismic noise, and to explore strategies for reducing this noise post data collection. Comparison of spectra of atmospheric data streams to the three broadband seismic channels for continuous signals recorded during May and June of 2013 shows high coherence between infrasound signals and time variation of air pressure (dP/dt) that we calculated from the air pressure data stream. Coherence between these signals is greatest for the east-west component of the seismic data in northern Chile. Although coherence between seismic, infrasound, and dP/dt is lower for all three seismic channels at other GRO Chile stations, for some of the data streams coherence can jump as much as 6 fold for certain frequency bands, with a common 3-fold increase for periods shorter than 10 seconds and the occasional 6-fold increase at long or very long periods.

  5. Seismic spectra of events at regional distances

    International Nuclear Information System (INIS)

    Springer, D.L.; Denny, M.D.

    1976-01-01

    About 40 underground nuclear explosions detonated at the Nevada Test Site (NTS) were chosen for analysis of their spectra and any relationships they might have to source parameters such as yield, depth of burial, etc. The sample covered a large yield range (less than 20 kt to greater than 1 Mt). Broadband (0.05 to 20 Hz) data recorded by the four-station seismic network operated by Lawrence Livermore Laboratory were analyzed in a search for unusual explosion signatures in their spectra. Long time windows (total wave train) as well as shorter windows (for instance, P/sub n/) were used as input to calculate the spectra. Much variation in the spectra of the long windows is typical although some gross features are similar, such as a dominant peak in the microseismic window. The variation is such that selection of corner frequencies is impractical and yield scaling could not be determined. Spectra for one NTS earthquake showed more energy in the short periods (less than 1 sec) as well as in the long periods (greater than 8 sec) compared to those for NTS explosions

  6. Short- and long-term effects of forage supplementation of calves during the preweaning period on performance, reproduction, and milk yield at first lactation.

    Science.gov (United States)

    Castells, Ll; Bach, A; Terré, M

    2015-07-01

    Sixty female Holstein calves [body weight (BW)=39.5±3.76kg] were fed a ground starter concentrate [19% crude protein, 19% neutral detergent fiber (NDF)] during the preweaning period. Furthermore, oats hay (68% NDF) was supplemented only during the postweaning period (CON) or during both pre- and postweaning periods (OH) to evaluate performance until first breeding, diet digestibility after weaning, reproductive performance, and milk yield at first lactation. Calves were individually housed and bedded with wood shavings. All calves were offered 6 L/d of milk replacer (MR) at 12% dry matter (DM) in 2 feedings until 28d of age, 3 L/d of MR at 12% DM in 2 feedings from 29 to 44d of age calves, and 1.5 L of MR at 12% DM in 1 feeding from 45 to 51d of age. Animals were weaned at 52d of age. Starter concentrate and forage intake were recorded daily and BW weekly until 65d of age. Two weeks after weaning, total-tract apparent digestibility was determined in 6 calves per treatment. Heifer BW was recorded at 10 mo of age. Breeding and milk yield at first lactation were also recorded. Starter concentrate intake was greater in OH compared with CON animals during the preweaning period. As a result, calves in the OH treatment had greater average daily gain (ADG) than CON animals during the preweaning period. After weaning, OH calves consumed more forage than CON animals, but we found no differences between treatments in ADG and starter concentrate intake. Similarly, total-tract apparent digestibility did not differ between treatments, and BW and ADG from 2wk after weaning to 10mo of age did not differ between treatments. Moreover, no differences in reproductive performance [age at first artificial insemination (AI), age at fertile insemination, conception rate at first AI, and number of AI] or milk yield at first lactation were observed between treatments, although a positive relationship between growth rate early in life and future energy-corrected milk yield was found. We

  7. Maturity of nearby faults influences seismic hazard from hydraulic fracturing

    Science.gov (United States)

    Kozłowska, Maria; Brudzinski, Michael R.; Friberg, Paul; Skoumal, Robert J.; Baxter, Nicholas D.; Currie, Brian S.

    2018-02-01

    Understanding the causes of human-induced earthquakes is paramount to reducing societal risk. We investigated five cases of seismicity associated with hydraulic fracturing (HF) in Ohio since 2013 that, because of their isolation from other injection activities, provide an ideal setting for studying the relations between high-pressure injection and earthquakes. Our analysis revealed two distinct groups: (i) deeper earthquakes in the Precambrian basement, with larger magnitudes (M > 2), b-values 1.5, and few post–shut-in earthquakes. Based on geologic history, laboratory experiments, and fault modeling, we interpret the deep seismicity as slip on more mature faults in older crystalline rocks and the shallow seismicity as slip on immature faults in younger sedimentary rocks. This suggests that HF inducing deeper seismicity may pose higher seismic hazards. Wells inducing deeper seismicity produced more water than wells with shallow seismicity, indicating more extensive hydrologic connections outside the target formation, consistent with pore pressure diffusion influencing seismicity. However, for both groups, the 2 to 3 h between onset of HF and seismicity is too short for typical fluid pressure diffusion rates across distances of ˜1 km and argues for poroelastic stress transfer also having a primary influence on seismicity.

  8. Maturity of nearby faults influences seismic hazard from hydraulic fracturing.

    Science.gov (United States)

    Kozłowska, Maria; Brudzinski, Michael R; Friberg, Paul; Skoumal, Robert J; Baxter, Nicholas D; Currie, Brian S

    2018-02-20

    Understanding the causes of human-induced earthquakes is paramount to reducing societal risk. We investigated five cases of seismicity associated with hydraulic fracturing (HF) in Ohio since 2013 that, because of their isolation from other injection activities, provide an ideal setting for studying the relations between high-pressure injection and earthquakes. Our analysis revealed two distinct groups: ( i ) deeper earthquakes in the Precambrian basement, with larger magnitudes (M > 2), b-values 1.5, and few post-shut-in earthquakes. Based on geologic history, laboratory experiments, and fault modeling, we interpret the deep seismicity as slip on more mature faults in older crystalline rocks and the shallow seismicity as slip on immature faults in younger sedimentary rocks. This suggests that HF inducing deeper seismicity may pose higher seismic hazards. Wells inducing deeper seismicity produced more water than wells with shallow seismicity, indicating more extensive hydrologic connections outside the target formation, consistent with pore pressure diffusion influencing seismicity. However, for both groups, the 2 to 3 h between onset of HF and seismicity is too short for typical fluid pressure diffusion rates across distances of ∼1 km and argues for poroelastic stress transfer also having a primary influence on seismicity.

  9. Seismic array processing and computational infrastructure for improved monitoring of Alaskan and Aleutian seismicity and volcanoes

    Science.gov (United States)

    Lindquist, Kent Gordon

    We constructed a near-real-time system, called Iceworm, to automate seismic data collection, processing, storage, and distribution at the Alaska Earthquake Information Center (AEIC). Phase-picking, phase association, and interprocess communication components come from Earthworm (U.S. Geological Survey). A new generic, internal format for digital data supports unified handling of data from diverse sources. A new infrastructure for applying processing algorithms to near-real-time data streams supports automated information extraction from seismic wavefields. Integration of Datascope (U. of Colorado) provides relational database management of all automated measurements, parametric information for located hypocenters, and waveform data from Iceworm. Data from 1997 yield 329 earthquakes located by both Iceworm and the AEIC. Of these, 203 have location residuals under 22 km, sufficient for hazard response. Regionalized inversions for local magnitude in Alaska yield Msb{L} calibration curves (logAsb0) that differ from the Californian Richter magnitude. The new curve is 0.2\\ Msb{L} units more attenuative than the Californian curve at 400 km for earthquakes north of the Denali fault. South of the fault, and for a region north of Cook Inlet, the difference is 0.4\\ Msb{L}. A curve for deep events differs by 0.6\\ Msb{L} at 650 km. We expand geographic coverage of Alaskan regional seismic monitoring to the Aleutians, the Bering Sea, and the entire Arctic by initiating the processing of four short-period, Alaskan seismic arrays. To show the array stations' sensitivity, we detect and locate two microearthquakes that were missed by the AEIC. An empirical study of the location sensitivity of the arrays predicts improvements over the Alaskan regional network that are shown as map-view contour plots. We verify these predictions by detecting an Msb{L} 3.2 event near Unimak Island with one array. The detection and location of four representative earthquakes illustrates the expansion

  10. Seismic rupture modelling, strong motion prediction and seismic hazard assessment: fundamental and applied approaches

    International Nuclear Information System (INIS)

    Berge-Thierry, C.

    2007-05-01

    The defence to obtain the 'Habilitation a Diriger des Recherches' is a synthesis of the research work performed since the end of my Ph D. thesis in 1997. This synthesis covers the two years as post doctoral researcher at the Bureau d'Evaluation des Risques Sismiques at the Institut de Protection (BERSSIN), and the seven consecutive years as seismologist and head of the BERSSIN team. This work and the research project are presented in the framework of the seismic risk topic, and particularly with respect to the seismic hazard assessment. Seismic risk combines seismic hazard and vulnerability. Vulnerability combines the strength of building structures and the human and economical consequences in case of structural failure. Seismic hazard is usually defined in terms of plausible seismic motion (soil acceleration or velocity) in a site for a given time period. Either for the regulatory context or the structural specificity (conventional structure or high risk construction), seismic hazard assessment needs: to identify and locate the seismic sources (zones or faults), to characterize their activity, to evaluate the seismic motion to which the structure has to resist (including the site effects). I specialized in the field of numerical strong-motion prediction using high frequency seismic sources modelling and forming part of the IRSN allowed me to rapidly working on the different tasks of seismic hazard assessment. Thanks to the expertise practice and the participation to the regulation evolution (nuclear power plants, conventional and chemical structures), I have been able to work on empirical strong-motion prediction, including site effects. Specific questions related to the interface between seismologists and structural engineers are also presented, especially the quantification of uncertainties. This is part of the research work initiated to improve the selection of the input ground motion in designing or verifying the stability of structures. (author)

  11. A dense microseismic monitoring network in Korea for uncovering relationship between seismic activity and neotectonic features

    Science.gov (United States)

    Kang, T.; Lee, J. M.; Kim, W.; Jo, B. G.; Chung, T.; Choi, S.

    2012-12-01

    A few tens of surface traces indicating movements in Quaternary were found in the southeastern part of the Korean Peninsula. Following both the geological and engineering definitions, those features are classified into "active", in geology, or "capable", in engineering, faults. On the other hand, the present-day seismicity of the region over a couple of thousand years is indistinguishable on the whole with the rest of the Korean Peninsula. It is therefore of great interest whether the present seismic activity is related to the neotectonic features or not. Either of conclusions is not intuitive in terms of the present state of seismic monitoring network in the region. Thus much interest in monitoring seismicity to provide an improved observation resolution and to lower the event-detection threshold has increased with many observations of the Quaternary faults. We installed a remote, wireless seismograph network which is composed of 20 stations with an average spacing of 10 km. Each station is equipped with a three-component Trillium Compact seismometer and Taurus digitizer. Instrumentation and analysis advancements are now offering better tools for this monitoring. This network is scheduled to be in operation over about one and a half year. In spite of the relatively short observation period, we expect that the high density of the network enables us to monitor seismic events with much lower magnitude threshold compared to the preexisting seismic network in the region. Following the Gutenberg-Richter relationship, the number of events with low magnitude is logarithmically larger than that with high magnitude. Following this rule, we can expect that many of microseismic events may reveal behavior of their causative faults, if any. We report the results of observation which has been performed over a year up to now.

  12. Study of attenuation structure for central Anatolia region, Turkey based on Keskin seismic array data

    Science.gov (United States)

    Semin, K. U.; Ozel, N. M.

    2011-12-01

    Central Anatolia is bounded in the north by the well-known north Anatolian fault system (NAFS) and on the south-southwest is bounded by the east Anatolian fault system (EAFS). The central area does not have major faults and acts as a single block moving westward. This region is not considered as seismically active as the NAFS or EAFS but the recent moderate-size Bala earthquakes (Ml=5.7, Ml= 5.5) on 20 and 27 December 2007 near the Tuz golu fault may be an indication of future seismic activity. In order to get a better picture of the crustal structure of this region we applied Coda Normalization method for the measurement of Qs-1 as a function of frequency for the frequencies 1.5, 3, 6, 8 Hz. 20 and 27 December 2007 Bala earthquakes (Ml magnitude 5.6 an 5.5) and their aftershocks recorded by the Keskin seismic array (International Monitoring System code BRTR) is analyzed in this study. Keskin seismic array has a small aperture circular design with 6 vertical short period and 1 broadband borehole seismometers. In addition, Multiple Lapse Time Window Analysis (MLTWA) method was applied to the data for the separation of intrinsic and scattering attenuation inm the region at the same frequencies. MLTWA method allowed a separation between the intrinsic attenuation and scattering attenuation. Preliminary results show a relatively low attenuation compared to western and eastern anatolia regions. This might be explained by the less seismicity in the region. A study of the regional and site attenuation of seismic waves of earthquakes in this area will contribute in predicting earthquake generated ground-motion and becomes vital in making decisions for earthquake regulations, building codes and to monitoring nuclear explosions.

  13. Design and Implementation of the National Seismic Monitoring Network in the Kingdom of Bhutan

    Science.gov (United States)

    Ohmi, S.; Inoue, H.; Chophel, J.; Pelgay, P.; Drukpa, D.

    2017-12-01

    Bhutan-Himalayan district is located along the plate collision zone between Indian and Eurasian plates, which is one of the most seismically active region in the world. Recent earthquakes such as M7.8 Gorkha Nepal earthquake in April 25, 2015 and M6.7 Imphal, India earthquake in January 3, 2016 are examples of felt earthquakes in Bhutan. However, there is no permanent seismic monitoring system ever established in Bhutan, whose territory is in the center of the Bhutan-Himalayan region. We started establishing permanent seismic monitoring network of minimum requirements and intensity meter network over the nation. The former is composed of six (6) observation stations in Bhutan with short period weak motion and strong motion seismometers as well as three (3) broad-band seismometers, and the latter is composed of twenty intensity meters located in every provincial government office. Obtained data are transmitted to the central processing system in the DGM office in Thimphu in real time. In this project, DGM will construct seismic vault with their own budget which is approved as the World Bank project, and Japan team assists the DGM for site survey of observation site, designing the observation vault, and designing the data telemetry system as well as providing instruments for the observation such as seismometers and digitizers. We already started the operation of the six (6) weak motion stations as well as twenty (20) intensity meter stations. Additionally, the RIMES (Regional Integrated Multi-hazard Early Warning System for Africa and Asia) is also providing eight (8) weak motion stations and we are keeping close communication to operate them as one single seismic monitoring network composed of fourteen (14) stations. This network will be definitely utilized for not only for seismic disaster mitigation of the country but also for studying the seismotectonics in the Bhutan-Himalayan region which is not yet precisely revealed due to the lack of observation data in the

  14. Ambient seismic noise interferometry in Hawai'i reveals long-range observability of volcanic tremor

    Science.gov (United States)

    Ballmer, Silke; Wolfe, Cecily; Okubo, Paul G.; Haney, Matt; Thurber, Clifford H.

    2013-01-01

    The use of seismic noise interferometry to retrieve Green's functions and the analysis of volcanic tremor are both useful in studying volcano dynamics. Whereas seismic noise interferometry allows long-range extraction of interpretable signals from a relatively weak noise wavefield, the characterization of volcanic tremor often requires a dense seismic array close to the source. We here show that standard processing of seismic noise interferometry yields volcanic tremor signals observable over large distances exceeding 50 km. Our study comprises 2.5 yr of data from the U.S. Geological Survey Hawaiian Volcano Observatory short period seismic network. Examining more than 700 station pairs, we find anomalous and temporally coherent signals that obscure the Green's functions. The time windows and frequency bands of these anomalous signals correspond well with the characteristics of previously studied volcanic tremor sources at Pu'u 'Ō'ō and Halema'uma'u craters. We use the derived noise cross-correlation functions to perform a grid-search for source location, confirming that these signals are surface waves originating from the known tremor sources. A grid-search with only distant stations verifies that useful tremor signals can indeed be recovered far from the source. Our results suggest that the specific data processing in seismic noise interferometry—typically used for Green's function retrieval—can aid in the study of both the wavefield and source location of volcanic tremor over large distances. In view of using the derived Green's functions to image heterogeneity and study temporal velocity changes at volcanic regions, however, our results illustrate how care should be taken when contamination by tremor may be present.

  15. General discrimination technique to determine between earthquake and nuclear test with seismic data

    International Nuclear Information System (INIS)

    Bashillah Baharuddin; Alawiah Musa; Roslan Mohd Ali

    2007-01-01

    The Comprehensive Nuclear-Test-Ban Treaty (CTBT) was developed to ban of any nuclear weapon test explosion moreover will restrict the development and qualitative improvement of nuclear weapons and end the development of advanced new types of these weapons. The Treaty provides for a comprehensive global verification regime, which includes an International Monitoring System (IMS). The IMS comprises a network of 321 monitoring stations and 16 radionuclide laboratories that monitor the Earth for evidence of nuclear explosions, which cover underground, underwater and atmosphere environments. Presently, Malaysia receives seismic, infrasound, hydroacoustic and radionuclide data from the International Data Centre (IDC) of the CTBT. In order to maximise the use of the data for the purposes of the CTBT, the Malaysian Nuclear Agency is developing capability to analyse the data in order to detect nuclear weapon test, with an initial focus on the seismic data. Through the CTBT IMS, seismic data is constantly being obtained to monitor and detect nuclear explosions. However, in the process, other natural and man-made activities that generate seismic waves, especially earthquakes and large man-made explosions, are also detectable through the IMS, and need to be differentiated and discriminated before any nuclear explosions can be identified. The detection capability by using seismological methods was proven through simulated explosion tests at selected nuclear weapon test sites. This is supported by data previously collected from a total of 2089 nuclear weapon tests that have been carried out globally, out of which 1567 were underground, 514 in the atmosphere, including outer space, and 8 underwater. The discrimination of seismic data to detect nuclear explosions from natural earthquake and explosions can be undertaken through the identification of the epicentre location, hypocentre depth, magnitude and short-period discrimination of the seismic events. (Author)

  16. Short periods of high temperature during meiosis prevent normal meiotic progression and reduce grain number in hexaploid wheat (Triticum aestivum L.).

    Science.gov (United States)

    Draeger, Tracie; Moore, Graham

    2017-09-01

    Exposure of wheat to high temperatures during male meiosis prevents normal meiotic progression and reduces grain number. We define a temperature-sensitive period and link heat tolerance to chromosome 5D. This study assesses the effects of heat on meiotic progression and grain number in hexaploid wheat (Triticum aestivum L. var. Chinese Spring), defines a heat-sensitive stage and evaluates the role of chromosome 5D in heat tolerance. Plants were exposed to high temperatures (30 or 35 °C) in a controlled environment room for 20-h periods during meiosis and the premeiotic interphase just prior to meiosis. Examination of pollen mother cells (PMCs) from immature anthers immediately before and after heat treatment enabled precise identification of the developmental phases being exposed to heat. A temperature-sensitive period was defined, lasting from premeiotic interphase to late leptotene, during which heat can prevent PMCs from progressing through meiosis. PMCs exposed to 35 °C were less likely to progress than those exposed to 30 °C. Grain number per spike was reduced at 30 °C, and reduced even further at 35 °C. Chinese Spring nullisomic 5D-tetrasomic 5B (N5DT5B) plants, which lack chromosome 5D, were more susceptible to heat during premeiosis-leptotene than Chinese Spring plants with the normal (euploid) chromosome complement. The proportion of plants with PMCs progressing through meiosis after heat treatment was lower for N5DT5B plants than for euploids, but the difference was not significant. However, following exposure to 30 °C, in euploid plants grain number was reduced (though not significantly), whereas in N5DT5B plants the reduction was highly significant. After exposure to 35 °C, the reduction in grain number was highly significant for both genotypes. Implications of these findings for the breeding of thermotolerant wheat are discussed.

  17. Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period

    Directory of Open Access Journals (Sweden)

    Ugur Erdemir

    2013-04-01

    Full Text Available Objectives: This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. Material and Methods: A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group. For the control groups, the specimens were stored in distilled water for 24 hours at 37°C and the water was renewed daily. For the experimental groups, the specimens were immersed in 5 mL of one of the following test solutions: Powerade, Gatorade, X-IR, Burn, and Red Bull, for two minutes daily for up to a 1-month test period and all the solutions were refreshed daily. Surface hardness was measured using a Vickers hardness measuring instrument at baseline, after 1-week and 1-month. Data were statistically analyzed using Multivariate repeated measure ANOVA and Bonferroni's multiple comparison tests (α=0.05. Results: Multivariate repeated measures ANOVA revealed that there were statistically significant differences in the hardness of the restorative materials in different immersion times (p<0.001 in different solutions (p<0.001. The effect of different solutions on the surface hardness values of the restorative materials was tested using Bonferroni's multiple comparison tests, and it was observed that specimens stored in distilled water demonstrated statistically significant lower mean surface hardness reductions when compared to the specimens immersed in sports and energy drinks after a 1-month evaluation period (p<0.001. The compomer was the most affected by an acidic environment, whereas the composite resin materials were the least affected materials. Conclusions: The effect of sports and energy drinks on the surface hardness of a restorative material depends on the duration of exposure time, and the composition of the material.

  18. Study of niobium isotopes having excess neutrons and a short half-life; Etude des isotopes du niobium excedentaires en neutrons et de courte periode

    Energy Technology Data Exchange (ETDEWEB)

    Huebenthal, K [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1968-02-01

    By irradiating Mo with 14 MeV neutrons isomers have been found for {sup 98}Nb (2.8 s half-life) {sup 99}Nb (9 s) and {sup 100}Nb (2.4 s). No isomer of this type seems to exist for {sup 96}Nb. Rapid separation methods are developed for isolating {sup 98}Zr from fission products, and for separating Zr and Nb. The half-life of {sup 98}Zr is measured (31 s) and the formation of {sup 98}Nb (2.8 s) from {sup 98}Zr (31 s) is shown by milking. Rough {beta} and {gamma} measurements of these nuclei are described. The {gamma} spectrum of {sup 98}Nb (51 mn) is studied with a high-resolution Ge/Li - detector. (authors) [French] Des irradiations des isotopes de molybdene avec des neutrons de 14 MeV ont mis en evidence l'existence des isomeres de {sup 98}Nb (periode 2.8 s) {sup 99}Nb (9 s) et {sup 100}Nb (2.4 s). Pour le {sup 96}Nb un isomere de ce type ne semble pas exister. Des methodes rapides de separation sont mises au point pour isoler le zirconium 98 des produits de fission, et pour separer ensuite le niobium du zirconium. La periode du {sup 98}Zr est de 3l s, et on demontre la formation du {sup 98}Nb (2.8 s) a partir du Zr (31 s). Ces corps sont etudies sommairement en spectroscopie {beta} et {gamma}. Le spectre gamma de {sup 98}Nb (periode 51 mn) est etudie avec un detecteur Ge/Li de haute resolution. (auteurs)

  19. Characterization by Raman scattering, x-ray diffraction, and transmission electron microscopy of (AlAs)m(InAs)m short period superlattices grown by migration enhanced epitaxy

    DEFF Research Database (Denmark)

    Bradshaw, J.; Song, X.J.; Shealy, J.R.

    1992-01-01

    We report growth of (InAs)1(AlAs)1 and (InAs)2(AlAs)2 strained layer superlattices by migration enhanced epitaxy. The samples were grown on InP (001) substrates and characterized by Raman spectroscopy, x-ray diffraction, and transmission electron microscopy. Satellite peaks in the x-ray data...... confirm the intended periodicity and indicate the presence of some disorder in the monolayer sample. The energies of the zone folded and quantum confined optic phonons are in reasonable agreement with calculations based on one-dimensional elastic continuum and linear chain models. Journal of Applied...

  20. Short communication: concentrations of nonesterified fatty acids and β-hydroxybutyrate in dairy cows are not well correlated during the transition period.

    Science.gov (United States)

    McCarthy, M M; Mann, S; Nydam, D V; Overton, T R; McArt, J A A

    2015-09-01

    The objective was to use longitudinal data of blood nonesterified fatty acids (NEFA) and β-hydroxybutyrate (BHBA) concentrations to describe the relationship between NEFA and BHBA in dairy cows during the periparturient period. Blood NEFA and BHBA concentration data collected from d 21 prepartum to 21 postpartum for 269 multiparous Holstein cows were selected from 4 different studies carried out within our research groups. Overall, NEFA concentrations were increased beginning near parturition with a relatively steady elevation of NEFA through d 9, after which concentrations gradually decreased. Prepartum BHBA concentrations began to increase beginning several days before parturition, continued to increase during the first week after parturition, and remained elevated through d 21 postpartum. Of the 269 cows included in the data set, 117 cows (43.5%) had at least one postpartum hyperketonemic event (BHBA ≥1.2mmol/L), and 202 cows (75.1%) had at least one event of elevated postpartum NEFA concentrations (≥0.70mmol/L) between 3 and 21 d in milk. Area under the curve (AUC) was used to investigate relationships between metabolites over time. Overall, the correlations between transition period NEFA and BHBA AUC were weak. We detected a negative correlation between prepartum BHBA AUC and postpartum NEFA AUC (r=-0.26). A positive correlation existed between postpartum NEFA AUC and postpartum BHBA AUC; however, the correlation coefficient was low (r=0.26). Large variation was found between the day of maximum NEFA concentration within the first 21 d in milk and day of maximum BHBA concentration for the same period. The mean and median times of maximum NEFA concentration were 6.8 and 6 d, respectively, whereas the mean and median times of maximum BHBA were 9.6 and 8 d, respectively; however, the range in days for both the mean and median day of maximum concentrations was very large. Overall, our data set indicates a weak relationship between blood concentrations of NEFA

  1. Short-wavelength multiline erbium-doped fiber ring laser by a broadband long-period fiber grating inscribed in a taper transition

    International Nuclear Information System (INIS)

    Anzueto-Sánchez, G; Martínez-Rios, A

    2014-01-01

    A stable multiwavelength all-fiber erbium-doped fiber ring laser (EDFRL) based on a broadband long-period fiber grating (LPFG) inscribed in a fiber taper transition is presented. The LPFG’s characteristics were engineered to provide a higher loss at the natural lasing wavelength of the laser cavity. The LPFG inscribed on a taper transition provided a depth greater than 25 dB, and posterior chemical etching provided a broad notch band to inhibit laser generation on the long-wavelength side of the EDF gain. Up to four simultaneous laser wavelengths are generated in the range of 1530–1535 nm. (paper)

  2. Input for seismic hazard assessment using Vrancea seismic source region

    International Nuclear Information System (INIS)

    Ivan, Iren-Adelina; Enescu, B.D.; Pantea, A.

    1998-01-01

    We use an extended and combined data base including historical and modern, qualitative and quantitative data, i.e., more than 25 events during the period 1790 - 1990 with epicentral/maximum intensities ranging from X to V degree (MSK scale), the variation interval of isoseismal curves ranging from IX th to III rd degree. The data set was analysed using both the sum phasor techniques of Ridelek and Sacks (1984) for different magnitudes and depth intervals and the Stepp's method. For the assessment of seismic hazard we need a pattern of seismic source regions including an estimation for the maximum expected magnitude and the return period for the studied regions. Another necessary step in seismic hazard assessment is to develop attenuation relationships specific to a seismogenic zone, particularly to sub-crustal earthquakes of Vrancea region. The conceptual frame involves the use of appropriate decay models and consideration of the randomness in the attenuation, taking into account the azimuthal variation of the isoseist shapes. (authors)

  3. Composition and variation of noise recorded at the Yellowknife Seismic Array, 1991-2007

    Science.gov (United States)

    Koper, K.D.; De Foy, B.; Benz, H.

    2009-01-01

    We analyze seismic noise recorded on the 18 short-period, vertical component seismometers of the Yellowknife Seismic Array (YKA). YKA has an aperture of 23 km and is sited on cratonic lithosphere in an area with low cultural noise. These properties make it ideal for studying natural seismic noise at periods of 1-3 s. We calculated frequency-wave number spectra in this band for over 6,000 time windows that were extracted once per day for 17 years (1991-2007). Slowness analysis reveals a rich variety of seismic phases originating from distinct source regions: Rg waves from the Great Slave Lake; Lg waves from the Atlantic, Pacific, and Arctic Oceans; and teleseismic P waves from the north Pacific and equatorial mid-Atlantic regions. The surface wave energy is generated along coastlines, while the body wave energy is generated at least in part in deep-water, pelagic regions. Surface waves tend to dominate at the longer periods and, just as in earthquake seismograms, Lg is the most prominent arrival. Although the periods we study are slightly shorter than the classic double-frequency microseismic band of 4-10 s, the noise at YKA has clear seasonal behavior that is consistent with the ocean wave climate in the Northern Hemisphere. The temporal variation of most of the noise sources can be well fit using just two Fourier components: yearly and biyearly terms that combine to give a fast rise in microseismic power from mid-June through mid-October, followed by a gradual decline. The exception is the Rg energy from the Great Slave Lake, which shows a sharp drop in noise power over a 2-week period in November as the lake freezes. The L g noise from the east has a small but statistically significant positive slope, perhaps implying increased ocean wave activity in the North Atlantic over the last 17 years. Copyright 2009 by the American Geophysical Union.

  4. Seismic monitoring of the Yucca Mountain facility

    International Nuclear Information System (INIS)

    Garbin, H.D.; Herrington, P.B.; Kromer, R.P.

    1997-01-01

    Questions have arisen regarding the applicability of seismic sensors to detect mining (re-entry) with a tunnel boring machine (TBM). Unlike cut and blast techniques of mining which produce impulsive seismic signals, the TBM produces seismic signals which are of long duration. (There are well established techniques available for detecting and locating the sources of the impulsive signals.) The Yucca Mountain repository offered an opportunity to perform field evaluations of the capabilities of seismic sensors because during much of 1996, mining there was progressing with the use of a TBM. During the mining of the repository's southern branch, an effort was designed to evaluate whether the TBM could be detected, identified and located using seismic sensors. Three data acquisition stations were established in the Yucca Mountain area to monitor the TBM activity. A ratio of short term average to long term average algorithm was developed for use in signal detection based on the characteristics shown in the time series. For location of the source of detected signals, FK analysis was used on the array data to estimate back azimuths. The back azimuth from the 3 component system was estimated from the horizontal components. Unique features in the timing of the seismic signal were used to identify the source as the TBM

  5. Shannon Entropy in a European Seabass (Dicentrarchus labrax System during the Initial Recovery Period after a Short-Term Exposure to Methylmercury

    Directory of Open Access Journals (Sweden)

    Harkaitz Eguiraun

    2016-05-01

    Full Text Available Methylmercury (MeHg is an environmental contaminant of increasing relevance as a seafood safety hazard that affects the health and welfare of fish. Non-invasive, on-line methodologies to monitor and evaluate the behavior of a fish system in aquaculture may make the identification of altered systems feasible—for example, due to the presence of agents that compromise their welfare and wholesomeness—and find a place in the implementation of Hazard Analysis and Critical Control Points and Fish Welfare Assurance Systems. The Shannon entropy (SE of a European seabass (Dicentrarchus labrax system has been shown to differentiate MeHg-treated from non-treated fish, the former displaying a lower SE value than the latter. However, little is known about the initial evolution of the system after removal of the toxicant. To help to cover this gap, the present work aims at providing information about the evolution of the SE of a European seabass system during a recuperation period of 11 days following a two-week treatment with 4 µg·MeHg/L. The results indicate that the SE of the system did not show a recovery trend during the examined period, displaying erratic responses with daily fluctuations and lacking a tendency to reach the initial SE values.

  6. An Ultra-short Period Rocky Super-Earth with a Secondary Eclipse and a Neptune-like Companion around K2-141

    DEFF Research Database (Denmark)

    Malavolta, Luca; Mayo, Andrew W.; Louden, Tom

    2018-01-01

    of USP planets, and it is therefore extremely important to increase the still limited sample of USP planets with precise and accurate mass and density measurements. We report here the characterization of a USP planet with a period of 0.28 days around K2-141 (EPIC 246393474), and the validation...... of an outer planet with a period of 7.7 days in a grazing transit configuration. We derived the radii of the planets from the K2 light curve and used high-precision radial velocities gathered with the HARPS-N spectrograph for mass measurements. For K2-141b, we thus inferred a radius of 1.51 ± 0.05 R......⊕ and a mass of 5.08 ± 0.41 M ⊕, consistent with a rocky composition and lack of a thick atmosphere. K2-141c is likely a Neptune-like planet, although due to the grazing transits and the non-detection in the RV data set, we were not able to put a strong constraint on its density. We also report the detection...

  7. Seismic Background Noise Analysis of BRTR (PS-43) Array

    Science.gov (United States)

    Ezgi Bakir, Mahmure; Meral Ozel, Nurcan; Umut Semin, Korhan

    2015-04-01

    The seismic background noise variation of BRTR array, composed of two sub arrays located in Ankara and in Ankara-Keskin, has been investigated by calculating Power Spectral Density and Probability Density Functions for seasonal and diurnal noise variations between 2005 and 2011. PSDs were computed within the frequency range of 100 s - 10 Hz. The results show us a little change in noise conditions in terms of time and location. Especially, noise level changes were observed at 3-5 Hz in diurnal variations at Keskin array and there is a 5-7 dB difference in day and night time in cultural noise band (1-10 Hz). On the other hand, noise levels of medium period array is high in 1-2 Hz frequency rather than short period array. High noise levels were observed in daily working times when we compare it to night-time in cultural noise band. The seasonal background noise variation at both sites also shows very similar properties to each other. Since these stations are borehole instruments and away from the coasts, we saw a small change in noise levels caused by microseism. Comparison between Keskin short period array and Ankara medium period array show us Keskin array is quiter than Ankara array.

  8. Angola Seismicity MAP

    Science.gov (United States)

    Neto, F. A. P.; Franca, G.

    2014-12-01

    The purpose of this job was to study and document the Angola natural seismicity, establishment of the first database seismic data to facilitate consultation and search for information on seismic activity in the country. The study was conducted based on query reports produced by National Institute of Meteorology and Geophysics (INAMET) 1968 to 2014 with emphasis to the work presented by Moreira (1968), that defined six seismogenic zones from macro seismic data, with highlighting is Zone of Sá da Bandeira (Lubango)-Chibemba-Oncócua-Iona. This is the most important of Angola seismic zone, covering the epicentral Quihita and Iona regions, geologically characterized by transcontinental structure tectono-magmatic activation of the Mesozoic with the installation of a wide variety of intrusive rocks of ultrabasic-alkaline composition, basic and alkaline, kimberlites and carbonatites, strongly marked by intense tectonism, presenting with several faults and fractures (locally called corredor de Lucapa). The earthquake of May 9, 1948 reached intensity VI on the Mercalli-Sieberg scale (MCS) in the locality of Quihita, and seismic active of Iona January 15, 1964, the main shock hit the grade VI-VII. Although not having significant seismicity rate can not be neglected, the other five zone are: Cassongue-Ganda-Massano de Amorim; Lola-Quilengues-Caluquembe; Gago Coutinho-zone; Cuima-Cachingues-Cambândua; The Upper Zambezi zone. We also analyzed technical reports on the seismicity of the middle Kwanza produced by Hidroproekt (GAMEK) region as well as international seismic bulletins of the International Seismological Centre (ISC), United States Geological Survey (USGS), and these data served for instrumental location of the epicenters. All compiled information made possible the creation of the First datbase of seismic data for Angola, preparing the map of seismicity with the reconfirmation of the main seismic zones defined by Moreira (1968) and the identification of a new seismic

  9. Seismic characterization of the NPP Krsko site

    International Nuclear Information System (INIS)

    Obreza, J.

    2000-01-01

    The goal of NPP Krsko PSA Project Update was the inclusion of plant changes (i.e. configuration/operational related) through the period January 1, 1993 till the OUTAGE99 (April 1999) into the integrated Internal/External Level 1/Level 2 NPP Krsko PSA RISK SPECTRUM model. NPP Krsko is located on seismotectonic plate. Highest earthquake was recorded in 1917 with magnitude 5.8 at a distance of 7-9 km. Site (founded) on Pliocene sediments which are as deep as several hundred meters. No surface faulting at the Krsko site has been observed and thus it is not to be expected. NPP Krsko is equipped with seismic instrumentation, which allows it to complete OBE (SSE). The seismic PSA successfully showed high seismic margin at Krsko plant. NPP Krsko seismic design is based on US regulations and standards

  10. Vrancea earthquakes. Courses for specific actions to mitigate seismic risk

    International Nuclear Information System (INIS)

    Marmureanu, Gheorghe; Marmureanu, Alexandru

    2005-01-01

    Earthquakes in the Carpathian-Pannonian region are confined to the crust, except the Vrancea zone, where earthquakes with focal depth down to 200 Km occur. For example, the ruptured area migrated from 150 km to 180 km (November 10,1940, M w = 7.7) from 90 km to 110 km (March 4, 1977, M w 7.4), from 130 km to 150 km (August 30, 1986, M w = 7.1) and from 70 km to 90 km (May 30, 1990, M w = 6.9) depth. The depth interval between 110 km and 130 km remains not ruptured since 1802, October 26, when it was the strongest earthquake occurred in this part of Central Europe. The magnitude is assumed to be M w = 7.9 - 8.0 and this depth interval is a natural candidate for the next strong Vrancea event. While no country in the world is entirely safe, the lack of capacity to limit the impact of seismic hazards remains a major burden for all countries and while the world has witnessed an exponential increase in human and material losses due to natural disasters given by earthquakes, there is a need to reverse trends in seismic risk mitigation to future events. Main courses for specific actions to mitigate the seismic risk given by strong deep Vrancea earthquakes should be considered as key for development actions: - Early warning system for industrial facilities. Early warning is more than a technological instrument to detect, monitor and submit warnings. It should become part of a management information system for decision-making in the context of national institutional frameworks for disaster management and part of national and local strategies and programmers for risk mitigation; - Prediction program of Vrancea strong earthquakes of short and long term; - Hazard seismic map of Romania. The wrong assessment of the seismic hazard can lead to dramatic situations as those from Bucharest or Kobe. Before the 1977 Vrancea earthquake, the city of Bucharest was designed to intensity I = VII (MMI) and the real intensity was I = IX1/2-X (MMI); - Seismic microzonation of large populated

  11. Vrancea earthquakes. Specific actions to mitigate seismic risk

    International Nuclear Information System (INIS)

    Marmureanu, Gheorghe; Marmureanu, Alexandru

    2005-01-01

    Earthquakes have been known in Romania since Roman times, when Trajan's legionnaires began the colonization of the rich plains stretching from the Carpathian Mountains to the Danube River. Since readings from seismographic stations became available, after 1940, it has been established that the most frequent largest earthquakes arise from deep Vrancea sources at the bend of the Carpathians Earthquakes in the Carpathian-Pannonian region are confined to the crust, except for the Vrancea zone, where earthquakes with focal depth down to 200 km occur. For example, the ruptured area migrated in depth from 150 km to 180 km (November 10, 1940, M w =7.7), from 90 to 110 km (March 4, 1977, M w =7.4), from 130 to 150 km (August 30, 1986, M w =7.1), and from 70 to 90 km (May 30, 1990, M w =6.9). The depth interval between 110 km and 130 km has remained unruptured since 1802, October 26, when the strongest known earthquake occurred in this part of Central Europe. The magnitude is assumed to have been M w =7.9 - 8.0, and this depth interval is a natural candidate for the next strong Vrancea event. The maximum intensity for strong deep Vrancea earthquakes is quite distant from the actual epicenter and greater than the epicentral intensity. For the 1977 strong earthquake (M w =7.4), the estimated intensity at its Vrancea region epicenter was only VII (MMI scale), while some 170 km away, in the capital city of Bucharest, the estimated maximum intensity was IX1/2 -X (MMI). The intensely deforming Vrancea zone shows a quite enigmatic seismic pattern (peak ground accelerations/intensity one, characteristic response spectra with large periods of 1.5 seconds, no significant attenuations on Romanian territory, large amplifications away, etc.). While no country in the world is entirely safe, the lack of capacity to limit the impact of seismic hazards remains a major burden for all countries and while the world has witnessed an exponential increase in human and material losses due to

  12. Some possible correlations between electro-magnetic emission and seismic activity during West Bohemia 2008 earthquake swarm

    Directory of Open Access Journals (Sweden)

    P. Kolář

    2010-10-01

    Full Text Available A potential link between electromagnetic emission (EME and seismic activity (SA has been the subject of scientific speculations for a long time. EME versus SA relations obtained during the 2008 earthquake swarm which occurred in West Bohemia are presented. First, a brief characterisation of the seismic region and then the EME recording method and data analysis will be described. No simple direct link between EME and SA intensity was observed, nevertheless a deeper statistical analysis indicates: (i slight increase of EME activity in the time interval 60 to 30 min before a seismic event with prevalent periods about 10 min, (ii some gap in EME activity approximately 2 h after the event, and (iii again a flat maximum about 4 h after the seismic events. These results qualitatively correspond with the observations from other seismically active regions (Fraser-Smith et al., 1990. The global decrease of EME activity correlating with the swarm activity decay was also observed. Due to the incomplete EME data and short observation time, these results are limited in reliability and are indicative only.

  13. Research and development activities of the seismology section for the period January 1986 to December 1987

    International Nuclear Information System (INIS)

    Basu, T.K.; Murty, G.S.

    1988-01-01

    This report sumarises the R and D in Seismology during the period from January 1986 to December 1987. Major topics of current study are (1) Forensic Seismology, (2) Seismicity and Seismic Risk estimates, (3) Reservoir induced seismicity and (4) Rockburst monitoring. Considerable effort is devoted to development of seismic data acquisition systems and theoretical aspects of seismology. (author)

  14. Mechanisms controlling primary and new production in a global ecosystem model – Part II: The role of the upper ocean short-term periodic and episodic mixing events

    Directory of Open Access Journals (Sweden)

    E. E. Popova

    2006-01-01

    Full Text Available The use of 6 h, daily, weekly and monthly atmospheric forcing resulted in dramatically different predictions of plankton productivity in a global 3-D coupled physical-biogeochemical model. Resolving the diurnal cycle of atmospheric variability by use of 6 h forcing, and hence also diurnal variability in UML depth, produced the largest difference, reducing predicted global primary and new production by 25% and 10% respectively relative to that predicted with daily and weekly forcing. This decrease varied regionally, being a 30% reduction in equatorial areas primarily because of increased light limitation resulting from deepening of the mixed layer overnight as well as enhanced storm activity, and 25% at moderate and high latitudes primarily due to increased grazing pressure resulting from late winter stratification events. Mini-blooms of phytoplankton and zooplankton occur in the model during these events, leading to zooplankton populations being sufficiently well developed to suppress the progress of phytoplankton blooms. A 10% increase in primary production was predicted in the peripheries of the oligotrophic gyres due to increased storm-induced nutrient supply end enhanced winter production during the short term stratification events that are resolved in the run forced by 6 h meteorological fields. By resolving the diurnal cycle, model performance was significantly improved with respect to several common problems: underestimated primary production in the oligotrophic gyres; overestimated primary production in the Southern Ocean; overestimated magnitude of the spring bloom in the subarctic Pacific Ocean, and overestimated primary production in equatorial areas. The result of using 6 h forcing on predicted ecosystem dynamics was profound, the effects persisting far beyond the hourly timescale, and having major consequences for predicted global and new production on an annual basis.

  15. Seismic risk map of Korea

    International Nuclear Information System (INIS)

    Lee, S.H.; Lee, Y.K.; Eum, S.H.; Yang, S.J.; Chun, M.S.

    1983-01-01

    A study on seismic hazard level in Korea has been performed and the main results of the study are summarized as follows: 1. Historians suggest that the quality of historical earthquake data may be accurate in some degree and the data should be used in seismic risk analysis. 2. The historical damage events are conformed in historical literatures and their intensities are re-evaluated by joint researchers. The maximum MM intensity of them is VIII evaluated for 17 events. 3. The relation of earthquakes to surface fault is not clear. It seems resonable to related them to tectonic provinces. 4. Statistical seismic risk analysis shows that the acceleration expected within 50O year return period is less than 0.25G when only instrumental earthquakes are used and less than 0.10G if all of instrumental and historical earthquakes are used. The acceleration in Western Coast and Kyungsang area is higher than the other regions in Korea. 5. The maximum horizontal acceleration determined by conservative method is 0.26G when historical earthquake data are used and less than 0.20G if only instrumental earthquakes are used. The return period of 0.26G is 240 years in Kyungsang province and longer in other provinces. (Author)

  16. Seismic assessment of a site using the time series method

    International Nuclear Information System (INIS)

    Krutzik, N.J.; Rotaru, I.; Bobei, M.; Mingiuc, C.; Serban, V.; Androne, M.

    1997-01-01

    To increase the safety of a NPP located on a seismic site, the seismic acceleration level to which the NPP should be qualified must be as representative as possible for that site, with a conservative degree of safety but not too exaggerated. The consideration of the seismic events affecting the site as independent events and the use of statistic methods to define some safety levels with very low annual occurrence probability (10 -4 ) may lead to some exaggerations of the seismic safety level. The use of some very high value for the seismic acceleration imposed by the seismic safety levels required by the hazard analysis may lead to very costly technical solutions that can make the plant operation more difficult and increase maintenance costs. The considerations of seismic events as a time series with dependence among the events produced, may lead to a more representative assessment of a NPP site seismic activity and consequently to a prognosis on the seismic level values to which the NPP would be ensured throughout its life-span. That prognosis should consider the actual seismic activity (including small earthquakes in real time) of the focuses that affect the plant site. The paper proposes the applications of Autoregressive Time Series to issue a prognosis on the seismic activity of a focus and presents the analysis on Vrancea focus that affects NPP Cernavoda site, by this method. The paper also presents the manner to analyse the focus activity as per the new approach and it assesses the maximum seismic acceleration that may affect NPP Cernavoda throughout its life-span (∼ 30 years). Development and applications of new mathematical analysis method, both for long - and short - time intervals, may lead to important contributions in the process of foretelling the seismic events in the future. (authors)

  17. Volcano dome dynamics at Mount St. Helens: Deformation and intermittent subsidence monitored by seismicity and camera imagery pixel offsets

    Science.gov (United States)

    Salzer, Jacqueline T.; Thelen, Weston A.; James, Mike R.; Walter, Thomas R.; Moran, Seth C.; Denlinger, Roger P.

    2016-01-01

    The surface deformation field measured at volcanic domes provides insights into the effects of magmatic processes, gravity- and gas-driven processes, and the development and distribution of internal dome structures. Here we study short-term dome deformation associated with earthquakes at Mount St. Helens, recorded by a permanent optical camera and seismic monitoring network. We use Digital Image Correlation (DIC) to compute the displacement field between successive images and compare the results to the occurrence and characteristics of seismic events during a 6 week period of dome growth in 2006. The results reveal that dome growth at Mount St. Helens was repeatedly interrupted by short-term meter-scale downward displacements at the dome surface, which were associated in time with low-frequency, large-magnitude seismic events followed by a tremor-like signal. The tremor was only recorded by the seismic stations closest to the dome. We find a correlation between the magnitudes of the camera-derived displacements and the spectral amplitudes of the associated tremor. We use the DIC results from two cameras and a high-resolution topographic model to derive full 3-D displacement maps, which reveals internal dome structures and the effect of the seismic activity on daily surface velocities. We postulate that the tremor is recording the gravity-driven response of the upper dome due to mechanical collapse or depressurization and fault-controlled slumping. Our results highlight the different scales and structural expressions during growth and disintegration of lava domes and the relationships between seismic and deformation signals.

  18. Intraplate seismicity across the Cape Verde swell

    Science.gov (United States)

    Vales, Dina; Matias, Luís.; Haberland, Christian; Silveira, Graça.; Weber, Michael; Carrilho, Fernando; Dias, Nuno

    2010-05-01

    The Cape Verde Archipelago ((15-17°N, 23-26°W) is located within the African plate, about 500km west of Senegal, in the African coast. The islands are located astride the Cape Verde mid-plate topographic swell, one of the largest features of its type in the world's ocean basins. The origin of this Cape Verde swell is still in debate. Previous determinations of the elastic thickness (Te) reveal a normal Te and a modest heat flow anomaly which suggest that the swell cannot be fully explained by uplift due to thermal reheating of the lithosphere by an underlying ‘‘hot spot'' and that other, deep-seated, mantle processes must be involved. The CV-PLUME (An investigation on the geometry and deep signature of the Cape Verde mantle plume) project intends to shape the geometry and deep origin of the Cape Verde mantle plume, via a combined study of seismic, magnetic, gravimetric and geochemical observations. Through this study we intend to characterize the structure beneath the archipelago from the surface down to the deep mantle. The core of this 3-year project was a temporary deployment of 39 Very Broad Band seismometers, across all the inhabited islands, to recorder local and teleseismic earthquakes. These instruments were operational from November 2007 to September 2008. In this work we report on the preliminary results obtained from the CV-PLUME network on the characterization of the local and regional seismicity. To detect the small magnitude seismic events the continuous data stream was screened using spectrograms. This proved to be a very robust technique in the face of the high short-period noise recorded by many of the stations, particularly during day time. The 10 month observation time showed that the background seismic activity in the Archipelago and surrounding area is low, with only a very few events recorded by the complete network. However, two clusters of earthquakes were detected close to the Brava Island, one to the NW and a second one, more active

  19. Geomorphology and seismic risk

    Science.gov (United States)

    Panizza, Mario

    1991-07-01

    The author analyses the contributions provided by geomorphology in studies suited to the assessment of seismic risk: this is defined as function of the seismic hazard, of the seismic susceptibility, and of the vulnerability. The geomorphological studies applicable to seismic risk assessment can be divided into two sectors: (a) morpho-neotectonic investigations conducted to identify active tectonic structures; (b) geomorphological and morphometric analyses aimed at identifying the particular situations that amplify or reduce seismic susceptibility. The morpho-neotectonic studies lead to the identification, selection and classification of the lineaments that can be linked with active tectonic structures. The most important geomorphological situations that can condition seismic susceptibility are: slope angle, debris, morphology, degradational slopes, paleo-landslides and underground cavities.

  20. An economical educational seismic system

    Science.gov (United States)

    Lehman, J. D.

    1980-01-01

    There is a considerable interest in seismology from the nonprofessional or amateur standpoint. The operation of a seismic system can be satisfying and educational, especially when you have built and operated the system yourself. A long-period indoor-type sensor and recording system that works extremely well has been developed in the James Madison University Physics Deparment. The system can be built quite economically, and any educational institution that cannot commit themselves to a professional installation need not be without first-hand seismic information. The system design approach has been selected by college students working a project or senior thesis, several elementary and secondary science teachers, as well as the more ambitious tinkerer or hobbyist at home 

  1. Local magnitude, duration magnitude and seismic moment of Dahshour 1992 earthquakes

    Directory of Open Access Journals (Sweden)

    M. F. Abdelwahed

    2000-06-01

    Full Text Available Local magnitudes ML have been calculated for 56 earthquakes of the Dahshour 1992 sequence using simulated records of the KEG broadband station and the estimated calibration function of the Dahshour area. These were compared with their corresponding values of duration magnitudes obtained from the analog short period seismograms of the HLW station. The local magnitudes M L and the duration magnitudes M D for this region imply a linear relation as follows: M L = 1.2988 (± 0.04 M D – 0.9032 (± 0.14. Seismic moment has also been estimated for these events using simple measurements from the time domain records. These measurements based on the simulated Wood Anderson seismograms are used for the local magnitude (ML estimation. The derived relationship between seismic moment (M 0 and magnitude (M L is: log (M 0 = 0.954 (± 0.019 M L + 17.258 (± 0.075.

  2. Anomalous Radon Levels in Thermal Water as an Indicator of Seismic Activity

    International Nuclear Information System (INIS)

    Zmazek, B.; Gregoric, A.; Vaupotic, J.; Kobal, I.

    2008-01-01

    Radon can be transported effectively from deep layers of the Earth to the surface by carrier gases and by water. This transport is affected by phenomena accompanying seismic events. If radon is therefore monitored shortly before or during an earthquake, at a thermal water spring, an anomaly, i. e. a sudden increase or decrease in radon level, may be observed. Thermal springs and ground waters in Slovenia have therefore been systematically surveyed for radon. The work presented here is a continuation of our previous radon monitoring related to seismic activity carried out on weekly analyses during 1981-82 in thermal waters of the Ljubljana basin. In this paper, we focus on radon anomalies in thermal springs at Hotavlje and Bled in the period from October 2005 to September 2007

  3. Earth modeling and estimation of the local seismic ground motion due to site geology in complex volcanoclastic areas

    Directory of Open Access Journals (Sweden)

    V. Di Fiore

    2002-06-01

    Full Text Available Volcanic areas often show complex behaviour as far as seismic waves propagation and seismic motion at surface are concerned. In fact, the finite lateral extent of surface layers such as lava flows, blocks, differential welding and/or zeolitization within pyroclastic deposits, introduces in the propagation of seismic waves effects such as the generation of surface waves at the edge, resonance in lateral direction, diffractions and scattering of energy, which tend to modify the amplitude as well as the duration of the ground motion. The irregular topographic surface, typical of volcanic areas, also strongly influences the seismic site response. Despite this heterogeneity, it is unfortunately a common geophysical and engineering practice to evaluate even in volcanic environments the subsurface velocity field with monodimensional investigation method (i.e. geognostic soundings, refraction survey, down-hole, etc. prior to the seismic site response computation which in a such cases is obviously also made with 1D algorithms. This approach often leads to highly inaccurate results. In this paper we use a different approach, i.e. a fully 2D P-wave Çturning rayÈ tomographic survey followed by 2D seismic site response modeling. We report here the results of this approach in three sites located at short distance from Mt. Vesuvius and Campi Flegrei and characterized by overburdens constituted by volcanoclastic deposits with large lateral and vertical variations of their elastic properties. Comparison between 1D and 2D Dynamic Amplification Factor shows in all reported cases entirely different results, both in terms of peak period and spectral contents, as expected from the clear bidimensionality of the geological section. Therefore, these studies suggest evaluating carefully the subsoil geological structures in areas characterized by possible large lateral and vertical variations of the elastic properties in order to reach correct seismic site response

  4. Energy compensation in the real world: good compensation for small portions of chocolate and biscuits over short time periods in complicit consumers using commercially available foods.

    Science.gov (United States)

    Appleton, Katherine M; McKeown, Pascal P; Woodside, Jayne V

    2015-02-01

    While investigations using covert food manipulations tend to suggest that individuals are poor at adjusting for previous energy intake, in the real world adults rarely consume foods of which they are ill-informed. This study investigated the impact in fully complicit consumers of consuming commercially available dark chocolate, milk chocolate, sweet biscuits and fruit bars on subsequent appetite. Using a repeated measures design, participants received four small portions (4 × 10-11 g) of either dark chocolate, milk chocolate, sweet biscuits, fruit bars or no food throughout five separate study days (counterbalanced in order), and test meal intake, hunger, liking and acceptability were measured. Participants consumed significantly less at lunch following dark chocolate, milk chocolate and sweet biscuits compared to no food (smallest t(19) = 2.47, p = 0.02), demonstrating very good energy compensation (269-334%). No effects were found for fruit bars (t(19) = 1.76, p = 0.09), in evening meal intakes (F(4,72) = 0.62, p = 0.65) or in total intake (lunch + evening meal + food portions) (F(4,72) = 0.40, p = 0.69). No differences between conditions were found in measures of hunger (largest F(4,76) = 1.26, p = 0.29), but fruit bars were significantly less familiar than all other foods (smallest t(19) = 3.14, p = 0.01). These findings demonstrate good compensation over the short term for small portions of familiar foods in complicit consumers. Findings are most plausibly explained as a result of participant awareness and cognitions, although the nature of these cognitions cannot be discerned from this study. These findings however, also suggest that covert manipulations may have limited transfer to real world scenarios. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Do French macroseismic intensity observations agree with expectations from the European Seismic Hazard Model 2013?

    Science.gov (United States)

    Rey, Julien; Beauval, Céline; Douglas, John

    2018-02-01

    Probabilistic seismic hazard assessments are the basis of modern seismic design codes. To test fully a seismic hazard curve at the return periods of interest for engineering would require many thousands of years' worth of ground-motion recordings. Because strong-motion networks are often only a few decades old (e.g. in mainland France the first accelerometric network dates from the mid-1990s), data from such sensors can be used to test hazard estimates only at very short return periods. In this article, several hundreds of years of macroseismic intensity observations for mainland France are interpolated using a robust kriging-with-a-trend technique to establish the earthquake history of every French mainland municipality. At 24 selected cities representative of the French seismic context, the number of exceedances of intensities IV, V and VI is determined over time windows considered complete. After converting these intensities to peak ground accelerations using the global conversion equation of Caprio et al. (Ground motion to intensity conversion equations (GMICEs): a global relationship and evaluation of regional dependency, Bulletin of the Seismological Society of America 105:1476-1490, 2015), these exceedances are compared with those predicted by the European Seismic Hazard Model 2013 (ESHM13). In half of the cities, the number of observed exceedances for low intensities (IV and V) is within the range of predictions of ESHM13. In the other half of the cities, the number of observed exceedances is higher than the predictions of ESHM13. For intensity VI, the match is closer, but the comparison is less meaningful due to a scarcity of data. According to this study, the ESHM13 underestimates hazard in roughly half of France, even when taking into account the uncertainty in the conversion from intensity to acceleration. However, these results are valid only for the acceleration range tested in this study (0.01 to 0.09 g).

  6. Do French macroseismic intensity observations agree with expectations from the European Seismic Hazard Model 2013?

    Science.gov (United States)

    Rey, Julien; Beauval, Céline; Douglas, John

    2018-05-01

    Probabilistic seismic hazard assessments are the basis of modern seismic design codes. To test fully a seismic hazard curve at the return periods of interest for engineering would require many thousands of years' worth of ground-motion recordings. Because strong-motion networks are often only a few decades old (e.g. in mainland France the first accelerometric network dates from the mid-1990s), data from such sensors can be used to test hazard estimates only at very short return periods. In this article, several hundreds of years of macroseismic intensity observations for mainland France are interpolated using a robust kriging-with-a-trend technique to establish the earthquake history of every French mainland municipality. At 24 selected cities representative of the French seismic context, the number of exceedances of intensities IV, V and VI is determined over time windows considered complete. After converting these intensities to peak ground accelerations using the global conversion equation of Caprio et al. (Ground motion to intensity conversion equations (GMICEs): a global relationship and evaluation of regional dependency, Bulletin of the Seismological Society of America 105:1476-1490, 2015), these exceedances are compared with those predicted by the European Seismic Hazard Model 2013 (ESHM13). In half of the cities, the number of observed exceedances for low intensities (IV and V) is within the range of predictions of ESHM13. In the other half of the cities, the number of observed exceedances is higher than the predictions of ESHM13. For intensity VI, the match is closer, but the comparison is less meaningful due to a scarcity of data. According to this study, the ESHM13 underestimates hazard in roughly half of France, even when taking into account the uncertainty in the conversion from intensity to acceleration. However, these results are valid only for the acceleration range tested in this study (0.01 to 0.09 g).

  7. Effects of Source RDP Models and Near-source Propagation: Implication for Seismic Yield Estimation

    Science.gov (United States)

    Saikia, C. K.; Helmberger, D. V.; Stead, R. J.; Woods, B. B.

    - It has proven difficult to uniquely untangle the source and propagation effects on the observed seismic data from underground nuclear explosions, even when large quantities of near-source, broadband data are available for analysis. This leads to uncertainties in our ability to quantify the nuclear seismic source function and, consequently the accuracy of seismic yield estimates for underground explosions. Extensive deterministic modeling analyses of the seismic data recorded from underground explosions at a variety of test sites have been conducted over the years and the results of these studies suggest that variations in the seismic source characteristics between test sites may be contributing to the observed differences in the magnitude/yield relations applicable at those sites. This contributes to our uncertainty in the determination of seismic yield estimates for explosions at previously uncalibrated test sites. In this paper we review issues involving the relationship of Nevada Test Site (NTS) source scaling laws to those at other sites. The Joint Verification Experiment (JVE) indicates that a magnitude (mb) bias (δmb) exists between the Semipalatinsk test site (STS) in the former Soviet Union (FSU) and the Nevada test site (NTS) in the United States. Generally this δmb is attributed to differential attenuation in the upper-mantle beneath the two test sites. This assumption results in rather large estimates of yield for large mb tunnel shots at Novaya Zemlya. A re-examination of the US testing experiments suggests that this δmb bias can partly be explained by anomalous NTS (Pahute) source characteristics. This interpretation is based on the modeling of US events at a number of test sites. Using a modified Haskell source description, we investigated the influence of the source Reduced Displacement Potential (RDP) parameters ψ ∞ , K and B by fitting short- and long-period data simultaneously, including the near-field body and surface waves. In general

  8. Probabilistic and Scenario Seismic and Liquefaction Hazard Analysis of the Mississippi Embayment Incorporating Nonlinear Site Effects

    Science.gov (United States)

    Cramer, C. H.; Dhar, M. S.

    2017-12-01

    The influence of deep sediment deposits of the Mississippi Embayment (ME) on the propagation of seismic waves is poorly understood and remains a major source of uncertainty for site response analysis. Many researchers have studied the effects of these deposits on seismic hazard of the area using available information at the time. In this study, we have used updated and newly available resources for seismic and liquefaction hazard analyses of the ME. We have developed an improved 3D geological model. Additionally, we used surface geological maps from Cupples and Van Arsdale (2013) to prepare liquefaction hazard maps. Both equivalent linear and nonlinear site response codes were used to develop site amplification distributions for use in generating hazard maps. The site amplification distributions are created using the Monte Carlo approach of Cramer et al. (2004, 2006) on a 0.1-degree grid. The 2014 National Seismic Hazard model and attenuation relations (Petersen et al., 2014) are used to prepare seismic hazard maps. Then liquefaction hazard maps are generated using liquefaction probability curves from Holzer (2011) and Cramer et al. (2015). Equivalent linear response (w/ increased precision, restricted nonlinear behavior with depth) shows similar hazard for the ME compared to nonlinear analysis (w/o pore pressure) results. At short periods nonlinear deamplification dominates the hazard, but at long periods resonance amplification dominates. The liquefaction hazard tends to be high in Holocene and late Pleistocene lowland sediments, even with lowered ground water levels, and low in Pleistocene loess of the uplands. Considering pore pressure effects in nonlinear site response analysis at a test site on the lowlands shows amplification of ground motion at short periods. PGA estimates from ME liquefaction and MMI observations are in the 0.25 to 0.4 g range. Our estimated M7.5 PGA hazard within 10 km of the fault can exceed this. Ground motion observations from

  9. FORECASTING ENERGY CONSUMPTION IN SHORT-TERM AND LONG-TERM PERIOD BY USING ARIMAX MODEL IN THE CONSTRUCTION AND MATERIALS SECTOR IN THAILAND

    Directory of Open Access Journals (Sweden)

    Pruethsan Sutthichaimethee

    2017-07-01

    Full Text Available This study aims to analyze the forecasting of energy consumption in the Construction and Materials sectors. The scope of the study covers the forecasting periods of energy consumption for the next 10 years, 2017-2026, 20 years, 2017-2036, and 30 years, 2017-2046, by using ARIMAX Model. The prediction results show that these models are effective in the forecast measured by RMSE, MAE, and MAPE. The results show that from the first model (2,1,1, which predicted the duration of 10 years, 2017-2026, indicates that Thailand has increased an energy consumption rate with the average of 18.09%, while the second model (2,1,2 with the prediction of 20 years, 2017-2036, Thailand arises its energy consumption up to 37.32%. In addition, the third model (2,1,3 predicted the duration of 30 years from 2017 to 2046, and it has found that Thailand increases its energy consumption up to 49.72%.

  10. Probability Estimates of Solar Particle Event Doses During a Period of Low Sunspot Number for Thinly-Shielded Spacecraft and Short Duration Missions

    Science.gov (United States)

    Atwell, William; Tylka, Allan J.; Dietrich, William; Rojdev, Kristina; Matzkind, Courtney

    2016-01-01

    In an earlier paper (Atwell, et al., 2015), we investigated solar particle event (SPE) radiation exposures (absorbed dose) to small, thinly-shielded spacecraft during a period when the sunspot number (SSN) was less than 30. These SPEs contain Ground Level Events (GLE), sub-GLEs, and sub-sub-GLEs (Tylka and Dietrich, 2009, Tylka and Dietrich, 2008, and Atwell, et al., 2008). GLEs are extremely energetic solar particle events having proton energies extending into the several GeV range and producing secondary particles in the atmosphere, mostly neutrons, observed with ground station neutron monitors. Sub-GLE events are less energetic, extending into the several hundred MeV range, but do not produce secondary atmospheric particles. Sub-sub GLEs are even less energetic with an observable increase in protons at energies greater than 30 MeV, but no observable proton flux above 300 MeV. In this paper, we consider those SPEs that occurred during 1973-2010 when the SSN was greater than 30 but less than 50. In addition, we provide probability estimates of absorbed dose based on mission duration with a 95% confidence level (CL). We also discuss the implications of these data and provide some recommendations that may be useful to spacecraft designers of these smaller spacecraft.

  11. Application-driven ground motion prediction equation for seismic hazard assessments in non-cratonic moderate-seismicity areas

    Science.gov (United States)

    Bindi, D.; Cotton, F.; Kotha, S. R.; Bosse, C.; Stromeyer, D.; Grünthal, G.

    2017-09-01

    We present a ground motion prediction equation (GMPE) for probabilistic seismic hazard assessments (PSHA) in low-to-moderate seismicity areas, such as Germany. Starting from the NGA-West2 flat-file (Ancheta et al. in Earthquake Spectra 30:989-1005, 2014), we develop a model tailored to the hazard application in terms of data selection and implemented functional form. In light of such hazard application, the GMPE is derived for hypocentral distance (along with the Joyner-Boore one), selecting recordings at sites with vs30 ≥ 360 m/s, distances within 300 km, and magnitudes in the range 3 to 8 (being 7.4 the maximum magnitude for the PSHA in the target area). Moreover, the complexity of the considered functional form is reflecting the availability of information in the target area. The median predictions are compared with those from the NGA-West2 models and with one recent European model, using the Sammon's map constructed for different scenarios. Despite the simplification in the functional form, the assessed epistemic uncertainty in the GMPE median is of the order of those affecting the NGA-West2 models for the magnitude range of interest of the hazard application. On the other hand, the simplification of the functional form led to an increment of the apparent aleatory variability. In conclusion, the GMPE developed in this study is tailored to the needs for applications in low-to-moderate seismic areas and for short return periods (e.g., 475 years); its application in studies where the hazard is involving magnitudes above 7.4 and for long return periods is not advised.

  12. Seismicity associated with dome growth and collapse at the Soufriere Hills Volcano, Montserrat

    Science.gov (United States)

    Miller, A.D.; Stewart, R.C.; White, R.A.; Luckett, R.; Baptie, B.J.; Aspinall, W.P.; Latchman, J.L.; Lynch, L.L.; Voight, B.

    1998-01-01

    Varied seismicity has accompanied growth and collapse of the lava dome of the Soufriere Hills Volcano, Montserrat. Earthquakes have been classified as either volcano-tectonic, long-period or hybrid, and daily variations in the numbers of events have mapped changes in the style of eruption. Repetitive hybrid earthquakes were common during the first months of dome growth. In July 1996 the style of seismicity changed and regular short-lived hybrid earthquake swarms became common. This change was probably caused by an increase in the magma flux. Earthquake swarms have preceded almost all major dome collapses, and have accompanied cyclical deformation, thought to be due to a built-up of pressure in the upper conduit which is later released by magma moving into the dome.Varied seismicity has accompanied growth and collapse of the lava dome of the Soufriere Hills Volcano, Montserrat. Earthquakes have been classified as either volcano-tectonic, long-period or hybrid, and daily variations in the numbers of events have mapped changes in the style of eruption. Repetitive hybrid earthquakes were common during the first months of dome growth. In July 1996 the style of seismicity changed and regular, short-lived hybrid earthquake swarms became common. This change was probably caused by an increase in the magma flux. Earthquake swarms have preceded almost all major dome collapses, and have accompanied cyclical deformation, thought to be due to a build-up of pressure in the upper conduit which is later released by magma moving into the dome.

  13. Seismic Risk Perception compared with seismic Risk Factors

    Science.gov (United States)

    Crescimbene, Massimo; La Longa, Federica; Pessina, Vera; Pino, Nicola Alessandro; Peruzza, Laura

    2016-04-01

    The communication of natural hazards and their consequences is one of the more relevant ethical issues faced by scientists. In the last years, social studies have provided evidence that risk communication is strongly influenced by the risk perception of people. In order to develop effective information and risk communication strategies, the perception of risks and the influencing factors should be known. A theory that offers an integrative approach to understanding and explaining risk perception is still missing. To explain risk perception, it is necessary to consider several perspectives: social, psychological and cultural perspectives and their interactions. This paper presents the results of the CATI survey on seismic risk perception in Italy, conducted by INGV researchers on funding by the DPC. We built a questionnaire to assess seismic risk perception, with a particular attention to compare hazard, vulnerability and exposure perception with the real data of the same factors. The Seismic Risk Perception Questionnaire (SRP-Q) is designed by semantic differential method, using opposite terms on a Likert scale to seven points. The questionnaire allows to obtain the scores of five risk indicators: Hazard, Exposure, Vulnerability, People and Community, Earthquake Phenomenon. The questionnaire was administered by telephone interview (C.A.T.I.) on a statistical sample at national level of over 4,000 people, in the period January -February 2015. Results show that risk perception seems be underestimated for all indicators considered. In particular scores of seismic Vulnerability factor are extremely low compared with house information data of the respondents. Other data collected by the questionnaire regard Earthquake information level, Sources of information, Earthquake occurrence with respect to other natural hazards, participation at risk reduction activities and level of involvement. Research on risk perception aims to aid risk analysis and policy-making by

  14. Comparative study of codes for the seismic design of structures

    Directory of Open Access Journals (Sweden)

    S. H. C. Santos

    Full Text Available A general evaluation of some points of the South American seismic codes is presented herein, comparing them among themselves and with the American Standard ASCE/SEI 7/10 and with the European Standard Eurocode 8. The study is focused in design criteria for buildings. The Western border of South America is one of the most seismically active regions of the World. It corresponds to the confluence of the South American and Nazca plates. This region corresponds roughly to the vicinity of the Andes Mountains. This seismicity diminishes in the direction of the comparatively seismically quieter Eastern South American areas. The South American countries located in its Western Border possess standards for seismic design since some decades ago, being the Brazilian Standard for seismic design only recently published. This study is focused in some critical topics: definition of the recurrence periods for establishing the seismic input; definition of the seismic zonation and design ground motion values; definition of the shape of the design response spectra; consideration of soil amplification, soil liquefaction and soil-structure interaction; classification of the structures in different importance levels; definition of the seismic force-resisting systems and respective response modification coefficients; consideration of structural irregularities and definition of the allowable procedures for the seismic analyses. A simple building structure is analyzed considering the criteria of the several standards and obtained results are compared.

  15. Seismic isolation of buildings using composite foundations based on metamaterials

    Science.gov (United States)

    Casablanca, O.; Ventura, G.; Garescı, F.; Azzerboni, B.; Chiaia, B.; Chiappini, M.; Finocchio, G.

    2018-05-01

    Metamaterials can be engineered to interact with waves in entirely new ways, finding application on the nanoscale in various fields such as optics and acoustics. In addition, acoustic metamaterials can be used in large-scale experiments for filtering and manipulating seismic waves (seismic metamaterials). Here, we propose seismic isolation based on a device that combines some properties of seismic metamaterials (e.g., periodic mass-in-mass systems) with that of a standard foundation positioned right below the building for isolation purposes. The concepts on which this solution is based are the local resonance and a dual-stiffness structure that preserves large (small) rigidity for compression (shear) effects. In other words, this paper introduces a different approach to seismic isolation by using certain principles of seismic metamaterials. The experimental demonstrator tested on the laboratory scale exhibits a spectral bandgap that begins at 4.5 Hz. Within the bandgap, it filters more than 50% of the seismic energy via an internal dissipation process. Our results open a path toward the seismic resilience of buildings and a critical infrastructure to shear seismic waves, achieving higher efficiency compared to traditional seismic insulators and passive energy-dissipation systems.

  16. Structure of Suasselkä Postglacial Fault in northern Finland obtained by analysis of ambient seismic noise

    Science.gov (United States)

    Afonin, Nikita; Kozlovskaya, Elena

    2016-04-01

    Understanding inner structure of seismogenic faults and their ability to reactivate is particularly important in investigating the continental intraplate seismicity regime. In our study we address this problem using analysis of ambient seismic noise recorded by the temporary DAFNE array in northern Fennoscandian Shield. The main purpose of the DAFNE/FINLAND passive seismic array experiment was to characterize the present-day seismicity of the Suasselkä post-glacial fault (SPGF) that was proposed as one potential target for the DAFNE (Drilling Active Faults in Northern Europe) project. The DAFNE/FINLAND array comprised the area of about 20 to 100 km and consisted of 8 short-period and 4 broad-band 3-component autonomous seismic stations installed in the close vicinity of the fault area. The array recorded continuous seismic data during September, 2011-May, 2013. Recordings of the array have being analyzed in order to identify and locate natural earthquakes from the fault area and to discriminate them from the blasts in the Kittilä Gold Mine. As a result, we found several dozens of natural seismic events originating from the fault area, which proves that the fault is still seismically active. In order to study the inner structure of the SPGF we use cross-correlation of ambient seismic noise recorded by the array. Analysis of azimuthal distribution of noise sources demonstrated that that during the time interval under consideration the distribution of noise sources is close to the uniform one. The continuous data were processed in several steps including single station data analysis, instrument response removal and time-domain stacking. The data were used to estimate empirical Green's functions between pairs of stations in the frequency band of 0.1-1 Hz and to calculate correspondent surface wave dispersion curves. After that S-wave velocity models were obtained as a result of dispersion curves inversion using Geopsy software. The results suggest that the area of

  17. Cumhuriyet Tarihi Üzerine Kısa Bir Dönemlendirme Denemesi / A Short Essay on Periodization of History of Republic

    Directory of Open Access Journals (Sweden)

    Cengiz SUNAY

    2016-01-01

    Full Text Available Türkiye Cumhuriyeti tarihi, bir asra yaklaşan geçmişiyle oldukça keskin dönüşümlerin gözlendiği bir süreci ifade ediyor. Bu dönüşümlerin içeride ve dışarıdaki hangi değişimler ekseninde meydana geldiği konusunda, nesnel araştırmaların yapıldığı bilinmekle birlikte; son tahlilde, cumhuriyet tarihinde olan bitenleri ileri-geri; devrimci-karşı devrimci şeklindeki öznel değerlendirmelerin belirlediği de söylenebilir. Geçmişte, nelerin olup bittiğine dair çoğu anlatımın, örtülü de olsa bu zaafla malul olduğu söylenebilir; bu çerçevede, tarihin bilimden ziyade, ideoloji olduğuna ilişkin tezler üzerinde düşünmek gerekiyor. Tarihin bilim olduğu kabul edilse bile, güçlünün kaleminden okunduğu, bu nedenle bilimlerin en Darwinist’i olduğu tezi, ihmal edilebilir gibi gözükmüyor. Bu çalışmada, Türkiye Cumhuriyeti tarihinin ana hatları üzerinden kuşbakışı bir gözlem deneniyor; ek okumalar öneriliyor. Son doksan beş yılda nelerin olup, nelerin bittiğine ilişkin kimi zaman alternatif bir perspektiften bakılmaya çalışılıyor. / History of the Turkish Republic expresses a period with considerably sharp transformations with its past which almost reaches one century. It is known that objective studies have been made on the axises on which these transformations took place at home and abroad; nevertheless, in the last analysis, it can be claimed that the occurrences in republican history are determined by subjective evaluations such as forward-backward, revolutionary-counter revolutionary etc. It can be said that most narrations as to what happened in the past suffer from this weakness albeit implicitly; within this framework, the thesis that history is more an ideology than a science should be contemplated. Even if it is accepted that history is science, it is hardly negligible that it is read from the pen of the mighty, for which reason it is the most Darwinist of all sciences

  18. Consequences of dietary energy source and energy level on energy balance, lactogenic hormones, and lactation curve characteristics of cows after a short or omitted dry period.

    Science.gov (United States)

    van Hoeij, R J; Dijkstra, J; Bruckmaier, R M; Gross, J J; Lam, T J G M; Remmelink, G J; Kemp, B; van Knegsel, A T M

    2017-10-01

    Omitting the dry period (DP) generally reduces milk production in the subsequent lactation. The aim of this study was to evaluate the effect of dietary energy source-glucogenic (G) or lipogenic (L)-and energy level-standard (std) or low-on milk production; energy balance (EB); lactogenic hormones insulin, insulin-like growth factor 1 (IGF-1), and growth hormone (GH); and lactation curve characteristics between wk 1 and 44 postpartum in cows after a 0-d or 30-d DP. Cows (n = 110) were assigned randomly to 3 transition treatments: a 30-d DP with a standard energy level required for expected milk yield [30-d DP(std)], a 0-d DP with the same energy level as cows with a 30-d DP [0-d DP(std)], and a 0-d DP with a low energy level [0-d DP(low)]. In wk 1 to 7, cows were fed the same basal ration but the level of concentrate increased to 6.7 kg/d for cows fed the low energy level and to 8.5 kg/d for cows fed the standard energy level in wk 4. From wk 8 postpartum onward, cows received a G ration (mainly consisting of corn silage and grass silage) or an L ration (mainly consisting of grass silage and sugar beet pulp) with the same energy level contrast (low or std) as in early lactation. Cows fed the G ration had greater milk, lactose, and protein yields, lower milk fat percentage, greater dry matter and energy intakes, and greater plasma IGF-1 concentration compared with cows fed the L ration. Dietary energy source did not affect EB or lactation curve characteristics. In cows with a 0-d DP, the reduced energy level decreased energy intake, EB, and weekly body weight gain, but did not affect milk production or lactation curve characteristics. A 30-d DP resulted in a greater total predicted lactation yield, initial milk yield after calving, peak milk yield, energy intake, energy output in milk, days to conception [only when compared with 0-d DP(low)], plasma GH concentration [only when compared with 0-d DP(std)], and decreased weekly body weight gain compared with a 0-d DP. A

  19. Seismic-induced accelerations detected by two parallel gravity meters in continuous recording with a high sampling rate at Etna volcano

    Directory of Open Access Journals (Sweden)

    P. Stefanelli

    2008-06-01

    Full Text Available We analyse a microgravity data set acquired from two spring LaCoste & Romberg gravity meters operated in parallel at the same site on Etna volcano (Italy for about two months (August – September 2005. The high sampling rate acquisition (2Hz allowed the correlation of short-lasting gravity fluctuations with seismic events. After characterizing the oscillation behavior of the meters, through the study of spectral content and the background noise level of both sequences, we recognized fluctuations in the gravity data, spanning a range of periods from 1 second to about 30 seconds dominated by components with a period of about 15 ÷ 25 seconds, during time intervals encompassing both local seismic events and large worldwide earthquakes. The data analyses demonstrate that observed earthquake-induced gravity fluctuations have some differences due to diverse spectral content of the earthquakes. When local seismic events which present high frequency content excite the meters, the correlation between the two gravity signals is poor (factor < 0.3. Vice versa, when large worldwide earthquakes occur and low frequency seismic waves dominate the ensuing seismic wavefield, the resonance frequencies of the meters are excited and they react according to more common features. In the latter case, the signals from the two instruments are strongly correlated to each other (up to 0.9. In this paper the behaviors of spring gravimeters in the frequency range of the disturbances produced by local and large worldwide earthquakes are presented and discussed.

  20. The seismic monitoring network of Mt. Vesuvius

    Directory of Open Access Journals (Sweden)

    Massimo Orazi

    2013-11-01

    Full Text Available Mt. Vesuvius (southern Italy is one of the most hazardous volcanoes in the world. Its activity is currently characterized by moderate seismicity, with hypocenters located beneath the crater zone with depth rarely exceeding 5 km and magnitudes generally less than 3. The current configuration of the seismic monitoring network of Mt. Vesuvius consists of 18 seismic stations and 7 infrasound microphones. During the period 2006-2010 a seismic array with 48 channels was also operative. The station distribution provides appropriate coverage of the area around the volcanic edifice. The current development of the network and its geometry, under conditions of low seismic noise, allows locating seismic events with M<1. Remote instruments continuously transmit data to the main acquisition center in Naples. Data transmission is realized using different technological solutions based on UHF, Wi-Fi radio links, and TCP/IP client-server applications. Data are collected in the monitoring center of the Osservatorio Vesuviano (Italian National Institute of Geophysics and Volcanology, Naples section, which is equipped with systems for displaying and analyzing signals, using both real-time automatic and manual procedures. 24-hour surveillance allows to immediately communicate any significant anomaly to the Civil Protection authorities.

  1. Continuous recording of seismic signals in Alpine permafrost

    Science.gov (United States)

    Hausmann, H.; Krainer, K.; Staudinger, M.; Brückl, E.

    2009-04-01

    Over the past years various geophysical methods were applied to study the internal structure and the temporal variation of permafrost whereof seismic is of importance. For most seismic investigations in Alpine permafrost 24-channel equipment in combination with long data and trigger cables is used. Due to the harsh environment source and geophone layouts are often limited to 2D profiles. With prospect for future 3D-layouts we introduce an alternative of seismic equipment that can be used for several applications in Alpine permafrost. This study is focussed on controlled and natural source seismic experiments in Alpine permafrost using continuous data recording. With recent data from an ongoing project ("Permafrost in Austria") we will highlight the potential of the used seismic equipment for three applications: (a) seismic permafrost mapping of unconsolidated sediments, (b) seismic tomography in rock mass, and (c) passive seismic monitoring of rock falls. Single recording units (REFTEK 130, 6 channels) are used to continuously record the waveforms of both the seismic signals and a trigger signal. The combination of a small number of recording units with different types of geophones or a trigger allow numerous applications in Alpine permafrost with regard to a high efficiency and flexible seismic layouts (2D, 3D, 4D). The efficiency of the light and robust seismic equipment is achieved by the simple acquisition and the flexible and fast deployment of the (omni-directional) geophones. Further advantages are short (data and trigger) cables and the prevention of trigger errors. The processing of the data is aided by 'Seismon' which is an open source software project based on Matlab® and MySQL (see SM1.0). For active-source experiments automatic stacking of the seismic signals is implemented. For passive data a program for automatic detection of events (e.g. rock falls) is available which allows event localization. In summer 2008 the seismic equipment was used for the

  2. Multiple Seismic Array Observations for Tracing Deep Tremor Activity in Western Shikoku, Japan

    Science.gov (United States)

    Takeda, T.; Matsuzawa, T.; Shiomi, K.; Obara, K.

    2011-12-01

    Deep non-volcanic tremors become very active during episodic slow-slip events in western Japan and Cascadia. The episodic tremor and slow-slip events in western Shikoku, Japan, occur at a typical interval of 6 months. Recently, it has been reported that tremor migration activity is complex and shows different migrating directions depending on time scales (Ghosh et al., 2010). Such characteristics of tremor are important to understand the mechanism of tremor and the relationship between tremor and SSEs. However it is difficult to determine the location of tremors with high accuracy because tremors show faint signals and make the identification of P/S-wave arrivals difficult. Seismic array analysis is useful to evaluate tremor activity, especially to estimate the arrival direction of seismic energy (e.g. Ueno et al., 2010, Ghosh et al., 2010), as it can distinguish multiple tremor sources occurring simultaneously. Here, we have conducted seismic array observation and analyzed seismic data during tremor activity by applying the MUSIC method to trace tremor location and its migration in western Shikoku. We have installed five seismic arrays in western Shikoku since January 2011. One of the arrays contains 30 stations with 3-component seismometers with a natural frequency of 2 Hz (Type-L array). The array aperture size is 2 km and the mean interval between stations is approximately 200 m. Each of the other arrays (Type-S array) contains 9 seismic stations with the same type of seismometers of the Type-L array, and is deployed surrounding the Type-L array. The small array aperture size is 800 m and its mean station interval is approximately 150 m. All array stations have recorded continuous waveform data at a sampling of 200Hz. In May 2011, an episodic tremor and a short-term slip event occurred for the first time during the observation period. We could retrieve the array seismic data during the whole tremor episode. The analysis of data from the type-L array confirms

  3. New Site Coefficients and Site Classification System Used in Recent Building Seismic Code Provisions

    Science.gov (United States)

    Dobry, R.; Borcherdt, R.D.; Crouse, C.B.; Idriss, I.M.; Joyner, W.B.; Martin, G.R.; Power, M.S.; Rinne, E.E.; Seed, R.B.

    2000-01-01

    Recent code provisions for buildings and other structures (1994 and 1997 NEHRP Provisions, 1997 UBC) have adopted new site amplification factors and a new procedure for site classification. Two amplitude-dependent site amplification factors are specified: Fa for short periods and Fv for longer periods. Previous codes included only a long period factor S and did not provide for a short period amplification factor. The new site classification system is based on definitions of five site classes in terms of a representative average shear wave velocity to a depth of 30 m (V?? s). This definition permits sites to be classified unambiguously. When the shear wave velocity is not available, other soil properties such as standard penetration resistance or undrained shear strength can be used. The new site classes denoted by letters A - E, replace site classes in previous codes denoted by S1 - S4. Site classes A and B correspond to hard rock and rock, Site Class C corresponds to soft rock and very stiff / very dense soil, and Site Classes D and E correspond to stiff soil and soft soil. A sixth site class, F, is defined for soils requiring site-specific evaluations. Both Fa and Fv are functions of the site class, and also of the level of seismic hazard on rock, defined by parameters such as Aa and Av (1994 NEHRP Provisions), Ss and S1 (1997 NEHRP Provisions) or Z (1997 UBC). The values of Fa and Fv decrease as the seismic hazard on rock increases due to soil nonlinearity. The greatest impact of the new factors Fa and Fv as compared with the old S factors occurs in areas of low-to-medium seismic hazard. This paper summarizes the new site provisions, explains the basis for them, and discusses ongoing studies of site amplification in recent earthquakes that may influence future code developments.

  4. Simulations of seismic acquisition footprint

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, J.; Margrave, G.; Lawton, D. [Calgary Univ., AB (Canada)

    2008-07-01

    Numerical simulations were performed to investigate the causes of commonly observed artefacts in seismic field data. These seismic acquisition footprints typically consist of modulations in recorded amplitudes that are spatially correlated to the surface locations of sources and receivers used in a survey. Two broad classes of footprint were considered, notably amplitude variations related to the edges of the survey and the amplitude variations in the interior of the survey. The variations in amplitude obscure the true reflection response of the subsurface. The MATLAB numerical modelling code was used to produce the synthetic seismic data and create a thorough dataset using a survey design incorporating dense grids of sources and receivers. The footprint consisting of periodic amplitude variations in the interior of the surveys, similar to that observed in field data and likely produced by poor sampling, was observed in the decimated dataset. This type of footprint varied in strength between images produced with different processing algorithms. The observed footprint in these simulations was most organized in the unmigrated stack and was somewhat randomized after poststack. 2 refs., 1 tab., 3 figs.

  5. Astor Pass Seismic Surveys Preliminary Report

    Energy Technology Data Exchange (ETDEWEB)

    Louie, John [UNR; Pullammanappallil, Satish [Optim; Faulds, James; Eisses, Amy; Kell, Annie; Frary, Roxanna; Kent, Graham

    2011-08-05

    In collaboration with the Pyramid Lake Paiute Tribe (PLPT), the University of Nevada, Reno (UNR) and Optim re-processed, or collected and processed, over 24 miles of 2d seismic-reflection data near the northwest corner of Pyramid Lake, Nevada. The network of 2d land surveys achieved a near-3d density at the Astor Pass geothermal prospect that the PLPT drilled during Nov. 2010 to Feb. 2011. The Bureau of Indian Affairs funded additional seismic work around the Lake, and an extensive, detailed single-channel marine survey producing more than 300 miles of section, imaging more than 120 ft below the Lake bottom. Optim’s land data collection utilized multiple heavy vibrators and recorded over 200 channels live, providing a state-of-the-art reflection-refraction data set. After advanced seismic analysis including first-arrival velocity optimization and prestack depth migration, the 2d sections show clear fault-plane reflections, in some areas as deep as 4000 ft, tying to distinct terminations of the mostly volcanic stratigraphy. Some lines achieved velocity control to 3000 ft depth; all lines show reflections and terminations to 5000 ft depth. Three separate sets of normal faults appear in an initial interpretation of fault reflections and stratigraphic terminations, after loading the data into the OpendTect 3d seismic visualization system. Each preliminary fault set includes a continuous trace more than 3000 ft long, and a swarm of short fault strands. The three preliminary normal-fault sets strike northerly with westward dip, northwesterly with northeast dip, and easterly with north dip. An intersection of all three fault systems documented in the seismic sections at the end of Phase I helped to locate the APS-2 and APS-3 slimholes. The seismic sections do not show the faults connected to the Astor Pass tufa spire, suggesting that we have imaged mostly Tertiary-aged faults. We hypothesize that the Recent, active faults that produced the tufa through hotspring

  6. Comparison between seismic and domestic risk in moderate seismic hazard prone region: the Grenoble City (France test site

    Directory of Open Access Journals (Sweden)

    F. Dunand

    2012-02-01

    Full Text Available France has a moderate level of seismic activity, characterized by diffuse seismicity, sometimes experiencing earthquakes of a magnitude of more than 5 in the most active zones. In this seismicity context, Grenoble is a city of major economic and social importance. However, earthquakes being rare, public authorities and the decision makers are only vaguely committed to reducing seismic risk: return periods are long and local policy makers do not have much information available. Over the past 25 yr, a large number of studies have been conducted to improve our knowledge of seismic hazard in this region. One of the decision-making concerns of Grenoble's public authorities, as managers of a large number of public buildings, is to know not only the seismic-prone regions, the variability of seismic hazard due to site effects and the city's overall vulnerability, but also the level of seismic risk and exposure for the entire city, also compared to other natural or/and domestic hazards. Our seismic risk analysis uses a probabilistic approach for regional and local hazards and the vulnerability assessment of buildings. Its applicability to Grenoble offers the advantage of being based on knowledge acquired by previous projects conducted over the years. This paper aims to compare the level of seismic risk with that of other risks and to introduce the notion of risk acceptability in order to offer guidance in the management of seismic risk. This notion of acceptability, which is now part of seismic risk consideration for existing buildings in Switzerland, is relevant in moderately seismic-prone countries like France.

  7. Seismic texture classification. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Vinther, R.

    1997-12-31

    The seismic texture classification method, is a seismic attribute that can both recognize the general reflectivity styles and locate variations from these. The seismic texture classification performs a statistic analysis for the seismic section (or volume) aiming at describing the reflectivity. Based on a set of reference reflectivities the seismic textures are classified. The result of the seismic texture classification is a display of seismic texture categories showing both the styles of reflectivity from the reference set and interpolations and extrapolations from these. The display is interpreted as statistical variations in the seismic data. The seismic texture classification is applied to seismic sections and volumes from the Danish North Sea representing both horizontal stratifications and salt diapers. The attribute succeeded in recognizing both general structure of successions and variations from these. Also, the seismic texture classification is not only able to display variations in prospective areas (1-7 sec. TWT) but can also be applied to deep seismic sections. The seismic texture classification is tested on a deep reflection seismic section (13-18 sec. TWT) from the Baltic Sea. Applied to this section the seismic texture classification succeeded in locating the Moho, which could not be located using conventional interpretation tools. The seismic texture classification is a seismic attribute which can display general reflectivity styles and deviations from these and enhance variations not found by conventional interpretation tools. (LN)

  8. The ISC Seismic Event Bibliography

    Science.gov (United States)

    Di Giacomo, Domenico; Storchak, Dmitry

    2015-04-01

    The International Seismological Centre (ISC) is a not-for-profit organization operating in the UK for the last 50 years and producing the ISC Bulletin - the definitive worldwide summary of seismic events, both natural and anthropogenic - starting from the beginning of 20th century. Often researchers need to gather information related to specific seismic events for various reasons. To facilitate such task, in 2012 we set up a new database linking earthquakes and other seismic events in the ISC Bulletin to bibliographic records of scientific articles (mostly peer-reviewed journals) that describe those events. Such association allows users of the ISC Event Bibliography (www.isc.ac.uk/event_bibliography/index.php) to run searches for publications via a map-based web interface and, optionally, selecting scientific publications related to either specific events or events in the area of interest. Some of the greatest earthquakes were described in several hundreds of articles published over a period of few years. The journals included in our database are not limited to seismology but bring together a variety of fields in geosciences (e.g., engineering seismology, geodesy and remote sensing, tectonophysics, monitoring research, tsunami, geology, geochemistry, hydrogeology, atmospheric sciences, etc.) making this service useful in multidisciplinary studies. Usually papers dealing with large data set are not included (e.g., papers describing a seismic catalogue). Currently the ISC Event Bibliography includes over 17,000 individual publications from about 500 titles related to over 14,000 events that occurred in last 100+ years. The bibliographic records in the Event Bibliography start in the 1950s, and it is updated as new publications become available.

  9. Hierarchical Bayesian Modeling of Fluid-Induced Seismicity

    Science.gov (United States)

    Broccardo, M.; Mignan, A.; Wiemer, S.; Stojadinovic, B.; Giardini, D.

    2017-11-01

    In this study, we present a Bayesian hierarchical framework to model fluid-induced seismicity. The framework is based on a nonhomogeneous Poisson process with a fluid-induced seismicity rate proportional to the rate of injected fluid. The fluid-induced seismicity rate model depends upon a set of physically meaningful parameters and has been validated for six fluid-induced case studies. In line with the vision of hierarchical Bayesian modeling, the rate parameters are considered as random variables. We develop both the Bayesian inference and updating rules, which are used to develop a probabilistic forecasting model. We tested the Basel 2006 fluid-induced seismic case study to prove that the hierarchical Bayesian model offers a suitable framework to coherently encode both epistemic uncertainty and aleatory variability. Moreover, it provides a robust and consistent short-term seismic forecasting model suitable for online risk quantification and mitigation.

  10. Strain, Stress and Seismicity pattern in Switzerland

    Science.gov (United States)

    Houlié, Nicolas; Woessner, Jochen; Villiger, Arturo; Deichmann, Nicholas; Rothacher, Markus; Giardini, Domenico; Geiger, Alain

    2013-04-01

    Switzerland lies across one of the most complex plate boundary in the world. With a 100 Ma of deformation history, and a wide diversity of deformation mechanism, it is an ideal place to study the link(s) between small strain rates measured at the surface and stress dissipated at depth. The link is of genuine interest for seismic hazard assessment as it provides an independent estimate for moment release within the seismogenic volume. We use geodetic (GPS velocities, shortening axes, strain maps) and seismic (anisotropy, P-axes, focal mechanisms) datasets in order to assess whether the stress accumulated at depth due to the continental collision reflects the deformation rates measured at the surface and correlates with the seismic activity as well as the stress directions deduced from earthquake focal mechanisms throughout the area - or not. While the deformation amplitudes of the area are small (less than 10-7 yr-1) in some areas of Switzerland, we can relate long- and short-term features of the tectonic processes occurring over the last 10+ Ma. Preliminary results suggest that while deformation rates measured by GPS are large in the Ticino compared to the Valais region - its seismic activity rate is lower. This implies other processes might play important roles in the generation of seismicity.

  11. OGS improvements in the year 2011 in running the Northeastern Italy Seismic Network

    Science.gov (United States)

    Bragato, P. L.; Pesaresi, D.; Saraò, A.; Di Bartolomeo, P.; Durı, G.

    2012-04-01

    The Centro di Ricerche Sismologiche (CRS, Seismological Research Center) of the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS, Italian National Institute for Oceanography and Experimental Geophysics) in Udine (Italy) after the strong earthquake of magnitude M=6.4 occurred in 1976 in the Italian Friuli-Venezia Giulia region, started to operate the Northeastern Italy Seismic Network: it currently consists of 15 very sensitive broad band and 21 simpler short period seismic stations, all telemetered to and acquired in real time at the OGS-CRS data center in Udine. Real time data exchange agreements in place with other Italian, Slovenian, Austrian and Swiss seismological institutes lead to a total number of about 100 seismic stations acquired in real time, which makes the OGS the reference institute for seismic monitoring of Northeastern Italy. Since 2002 OGS-CRS is using the Antelope software suite on several workstations plus a SUN Cluster as the main tool for collecting, analyzing, archiving and exchanging seismic data, initially in the framework of the EU Interreg IIIA project "Trans-national seismological networks in the South-Eastern Alps". SeisComP is also used as a real time data exchange server tool. In order to improve the seismological monitoring of the Northeastern Italy area, at OGS-CRS we tuned existing programs and created ad hoc ones like: a customized web server named PickServer to manually relocate earthquakes, a script for automatic moment tensor determination, scripts for web publishing of earthquake parametric data, waveforms, state of health parameters and shaking maps, noise characterization by means of automatic spectra analysis, and last but not least scripts for email/SMS/fax alerting. The OGS-CRS Real Time Seismological website (RTS, http://rts.crs.inogs.it/) operative since several years was initially developed in the framework of the Italian DPC-INGV S3 Project: the RTS website shows classic earthquake locations

  12. Seismicity at Old Faithful Geyser: an isolated source of geothermal noise and possible analogue of volcanic seismicity

    Science.gov (United States)

    Kieffer, Susan Werner

    1984-09-01

    Old Faithful Geyser in Yellowstone National Park, U.S.A., is a relatively isolated source of seismic noise and exhibits seismic behavior similar to that observed at many volcanoes, including "bubblequakes" that resemble B-type "earthquakes", harmonic tremor before and during eruptions, and periods of seismic quiet prior to eruptions. Although Old Faithful differs from volcanoes in that the conduit is continuously open, that rock-fracturing is not a process responsible for seismicity, and that the erupting fluid is inviscid H 2O rather than viscous magma, there are also remarkable similarities in the problems of heat and mass recharge to the system, in the eruption dynamics, and in the seismicity. Water rises irregularly into the immediate reservoir of Old Faithful as recharge occurs, a fact that suggests that there are two enlarged storage regions: one between 18 and 22 m (the base of the immediate reservoir) and one between about 10 and 12 m depth. Transport of heat from hot water or steam entering at the base of the recharging water column into cooler overlying water occurs by migration of steam bubbles upward and their collapse in the cooler water, and by episodes of convective overturn. An eruption occurs when the temperature of the near-surface water exceeds the boiling point if the entire water column is sufficiently close to the boiling curve that the propagation of pressure-release waves (rarefactions) down the column can bring the liquid water onto the boiling curve. The process of conversion of the liquid water in the conduit at the onset of an eruption into a two-phase liquid-vapor mixture takes on the order of 30 s. The seismicity is directly related to the sequence of filling and heating during the recharge cycle, and to the fluid mechanics of the eruption. Short (0.2-0.3 s), monochromatic, high-frequency events (20-60 Hz) resembling unsustained harmonic tremor and, in some instances, B-type volcanic earthquakes, occur when exploding or imploding

  13. Seismic Investigation of the Glacier de la Plaine Morte, Switzerland

    Science.gov (United States)

    Laske, Gabi; Lindner, Fabian; Walter, Fabian; Krage, Manuel

    2017-04-01

    Glacier de la Plaine Morte is a plateau glacier along the border between Valais and Berne cantons. It covers a narrow elevation range and is extremely vulnerable to climate change. During snow melt, it feeds three marginal lakes that have experienced sudden subglacial drainage in recent years, thereby causing flooding in the Simme Valley below. Of greatest concern is Lac des Faverges at the southeastern end of the glacier that has drained near the end of July in recent years, with flood levels reaching capacity of flood control systems downstream. The lake levels are carefully monitored but precise prediction has not yet been achieved. In the search for precursory ice fracturing to the lake drainage to improve forecast, four seismic arrays comprised of five short-period borehole seismometers provided by Eidgenössische Technische Hochschule (ETH), Zürich as well as fifteen 3-component geophones from the Geophysical Instrument Pool Potsdam (GIPP) collected continuous seismic data for about seven weeks during the summer of 2016. We present initial results on discharge dynamics as well as changing noise levels and seismicity before, during and after the drainage of Lac des Faverges. Compared to previous recent years, the 2016 drainage of Lac des Faverges occurred unusually late on August 28. With an aperture between 100 and 200 m, the small arrays recorded many hundred ice quakes per day. A majority of the events exhibits clearly dispersed, high-frequency Rayleigh waves at about 10 Hz and higher. A wide distribution of events allows us to study azimuthal anisotropy and its relationship with the orientation of glacial crevasses.

  14. Monitoring Seasonal Changes in Permafrost Using Seismic Interferometry

    Science.gov (United States)

    James, S. R.; Knox, H. A.; Abbott, R. E.

    2015-12-01

    The effects of climate change in polar regions and their incorporation in global climate models has recently become an area of great interest. Permafrost holds entrapped greenhouse gases, e.g. CO2 and CH4, which are released to the atmosphere upon thawing, creating a positive feedback mechanism. Knowledge of seasonal changes in active layer thickness as well as long term degradation of permafrost is critical to the management of high latitude infrastructures, hazard mitigation, and increasing the accuracy of climate predictions. Methods for effectively imaging the spatial extent, depth, thickness, and discontinuous nature of permafrost over large areas are needed. Furthermore, continuous monitoring of permafrost over annual time scales would provide valuable insight into permafrost degradation. Seismic interferometry using ambient seismic noise has proven effective for recording velocity changes within the subsurface for a variety of applications, but has yet to be applied to permafrost studies. To this end, we deployed 7 Nanometrics Trillium posthole broadband seismometers within Poker Flat Research Range, located 30 miles north of Fairbanks, Alaska in a zone of discontinuous permafrost. Approximately 2 years worth of nearly continuous ambient noise data was collected. Using the python package MSNoise, relative changes in velocity were calculated. Results show high amounts of variability throughout the study period. General trends of negative relative velocity shifts can be seen between August and October followed by a positive relative velocity shift between November and February. Differences in relative velocity changes with both frequency and spatial location are also observed, suggesting this technique is sensitive to permafrost variation with depth and extent. Overall, short and long term changes in shallow subsurface velocity can be recovered using this method proposing seismic interferometry is a promising new technique for permafrost monitoring. Sandia

  15. Localization of Short Duration Periodic Signals

    Science.gov (United States)

    2013-09-30

    TDOA m, referenced to the hydrophone that is common between TDOA l and m. This measure is effectively a count of the number of matching click times...the localization of multiple interfering sperm whales using multi- sensor time difference of arrival”, 130 Journal of the Acoustical Society of

  16. Large-Strain Monitoring Above a Longwall Coal Mine With GPS and Seismic Measurements

    Science.gov (United States)

    Swanson, P. L.; Andreatta, V.; Meertens, C. M.; Krahenbuhl, T.; Kenner, B.

    2001-12-01

    As part of an effort to evaluate continuous GPS measurements for use in mine safety studies, a joint GPS-seismic experiment was conducted at an underground longwall coal mine near Paonia, Colorado in June, 2001. Seismic and deformation signals were measured using prototype low-cost monitoring systems as a longwall panel was excavated 150 m beneath the site. Data from both seismic and GPS instruments were logged onto low-power PC-104 Linux computers which were networked using a wireless LAN. The seismic system under development at NIOSH/SRL is based on multiple distributed 8-channel 24-bit A/D converters. The GPS system uses a serial single-frequency (L1) receiver and UNAVCO's "Jstream" Java data logging software. For this experiment, a continuously operating dual-frequency GPS receiver was installed 2.4 km away to serve as a reference site. In addition to the continuously operating sites, 10 benchmarks were surveyed daily with short "rapid-static" occupations in order to provide greater spatial sampling. Two single-frequency sites were located 35 meters apart on a relatively steep north-facing slope. As mining progressed from the east, net displacements of 1.2 meters to the north and 1.65 meters of subsidence were observed over a period of 6 days. The east component exhibited up to 0.45 meters of eastward displacement (toward the excavation) followed by reverse movement to the west. This cycle, observed approximately two days earlier at the eastern L1 site, is consistent with a change in surface strain from tension to compression as the excavation front passed underneath. As this strain "wave" propagated across the field site, surface deformation underwent a cycle of tension crack nucleation, crack opening (up to 15 cm normal displacements), subsequent crack closure, and production of low-angle-thrust compressional deformation features. Analysis of seismic results, surface deformation, and additional survey results are presented.

  17. The Seismic Analyzer: Interpreting and Illustrating 2D Seismic Data

    OpenAIRE

    Patel, Daniel; Giertsen, Christopher; Thurmond, John; Gjelberg, John; Gröller, Eduard

    2008-01-01

    We present a toolbox for quickly interpreting and illustrating 2D slices of seismic volumetric reflection data. Searching for oil and gas involves creating a structural overview of seismic reflection data to identify hydrocarbon reservoirs. We improve the search of seismic structures by precalculating the horizon structures of the seismic data prior to interpretation. We improve the annotation of seismic structures by applying novel illustrative rendering algorithms tailored to seism...

  18. From Geodetic Imaging of Seismic and Aseismic Fault Slip to Dynamic Modeling of the Seismic Cycle

    Science.gov (United States)

    Avouac, Jean-Philippe

    2015-05-01

    Understanding the partitioning of seismic and aseismic fault slip is central to seismotectonics as it ultimately determines the seismic potential of faults. Thanks to advances in tectonic geodesy, it is now possible to develop kinematic models of the spatiotemporal evolution of slip over the seismic cycle and to determine the budget of seismic and aseismic slip. Studies of subduction zones and continental faults have shown that aseismic creep is common and sometimes prevalent within the seismogenic depth range. Interseismic coupling is generally observed to be spatially heterogeneous, defining locked patches of stress accumulation, to be released in future earthquakes or aseismic transients, surrounded by creeping areas. Clay-rich tectonites, high temperature, and elevated pore-fluid pressure seem to be key factors promoting aseismic creep. The generally logarithmic time evolution of afterslip is a distinctive feature of creeping faults that suggests a logarithmic dependency of fault friction on slip rate, as observed in laboratory friction experiments. Most faults can be considered to be paved with interlaced patches where the friction law is either rate-strengthening, inhibiting seismic rupture propagation, or rate-weakening, allowing for earthquake nucleation. The rate-weakening patches act as asperities on which stress builds up in the interseismic period; they might rupture collectively in a variety of ways. The pattern of interseismic coupling can help constrain the return period of the maximum- magnitude earthquake based on the requirement that seismic and aseismic slip sum to match long-term slip. Dynamic models of the seismic cycle based on this conceptual model can be tuned to reproduce geodetic and seismological observations. The promise and pitfalls of using such models to assess seismic hazard are discussed.

  19. Engineering Seismic Base Layer for Defining Design Earthquake Motion

    International Nuclear Information System (INIS)

    Yoshida, Nozomu

    2008-01-01

    Engineer's common sense that incident wave is common in a widespread area at the engineering seismic base layer is shown not to be correct. An exhibiting example is first shown, which indicates that earthquake motion at the ground surface evaluated by the analysis considering the ground from a seismic bedrock to a ground surface simultaneously (continuous analysis) is different from the one by the analysis in which the ground is separated at the engineering seismic base layer and analyzed separately (separate analysis). The reason is investigated by several approaches. Investigation based on eigen value problem indicates that the first predominant period in the continuous analysis cannot be found in the separate analysis, and predominant period at higher order does not match in the upper and lower ground in the separate analysis. The earthquake response analysis indicates that reflected wave at the engineering seismic base layer is not zero, which indicates that conventional engineering seismic base layer does not work as expected by the term ''base''. All these results indicate that wave that goes down to the deep depths after reflecting in the surface layer and again reflects at the seismic bedrock cannot be neglected in evaluating the response at the ground surface. In other words, interaction between the surface layer and/or layers between seismic bedrock and engineering seismic base layer cannot be neglected in evaluating the earthquake motion at the ground surface

  20. SHC, Seismic Hazard Assessment for Eastern US

    International Nuclear Information System (INIS)

    Savy, J.; Davis, B.

    2001-01-01

    magnitude-recurrence relationship. The seismic hazard methodology is based on a probability model of the occurrence and distribution of earthquakes and the attenuation of the ground motion from a source to a site. It also includes modeling of local site effects, such as soil types. The earthquake location is assumed to be uniformly distributed throughout the zone, and the ground-motion model expresses the decay with distance of the median value of a ground-motion parameter. In addition, the methodology incorporates the uncertainty in all parameters into the results. The uncertainty in the hazard is estimated by a Monte Carlo simulation process in which all levels of confidence are normalized and treated as probability values. It includes a probability distribution of the maps for each seismicity expert, distributions for the uncertainty in each of the seismicity parameters, and distribution of the ground-motion models for each of the ground-motion experts. 3 - Restrictions on the complexity of the problem: Maxima of: 150 zones per combination; 100 combinations; 96 zones; 50 simulations per attenuation expert; 50 zone clusters for alternative boundaries; 35 zones per cluster; 30 maps; 30 zones per map; 21 distances per distribution of a zone; 20 zones in a circle of influence; 20 coefficients per attenuation model; 11 seismic experts; 10 accelerations; 9 frequencies; 7 attenuation models per expert; 6 attenuation experts for ALEAS; 5 attenuation experts for COMBS; 5 return periods; 4 regions

  1. Data processing of natural and induced events recorded at the seismic station Ostrava-Kr¨¢sn¨¦ Pole (OKC

    Directory of Open Access Journals (Sweden)

    Nov¨¢k Josef

    2001-09-01

    Full Text Available The operation of the seismic station Ostrava-Kr¨¢sn¨¦ Pole (OKC (¦Õ = 49.8352¡ãN; ¦Ë = 18.1422¡ãE which is situated at present in an experimental gallery nearby the Ostrava planetarium started in the year 1983 being equiped initially by analogue instrumentation. Modernization of instrumentation at the station was aimed at the installation of a new digital data acquisition system and the respective software packages for data interpretation and transmission.Data acquisition system VISTEC is based on PC which enables continuous recording of three- component short-period and medium-period systems with the sampling frequency of 20 Hz. The basic advantage of the OS Linux adopted allows remote access (telnet and the possibility of the recorded data transmission (ftp. Possible troubles in the seismic station operation can be quickly detected (even automatically and all recorded data are with minimum delay on disposal. The use of the remote access makes possible also to change the parameters of measuring set-up. The standard form of output data allows the application of standard software packages for visualisation and evaluation. There are on disposal following formates: GSE2/CM6, GSE2/INT and MiniSEED. The output data sets can be compressed by a special procedure. For interactive interpretation od digital seismic data, software package EVENT developed in the Geophysical Institute AS CR and package WAVE developed in the Institute of Geonics AS CR are used.Experimental operation of digital seismographs at the station OKC confirmed justification of its incorporation into the seismic stations of the Czech national seismological network (CNSN. Based on the preliminary analysis of digital data it proved that following groups of seismic events are recorded: earthquakes, induced seismic events from Polish copper and coal mines, induced seismic events from the Ostrava-Karvin¨¢ Coal Basin, quarry blasts and weak regional seismic events of the

  2. Seismic and geological interpretation on petroleum exploration in the Cuban economic area in the Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Sora Monroy, America; Lopez, Sofia; Dominguez, Rene; Socorro, Rafael; Sanchez, Jorge; Toucet, Sonia [Cupet -Companhia Cubana de Petroleo, Havana (Cuba)

    2004-07-01

    From the decade of the 50'up to now, many seismic survey were acquired in the Cuban Economic area in the Gulf of Mexico, both, deep water and near short along the littoral, which have contribute to prepare the structural model as well the evolutional one. During the period comprise from June to December 2000, 7330 Km. of seismic lines were acquired over 70 lines in an area of 110000 square Km. that covers the Exclusive Economic area of Cuba. In this area the water depth varies from 500 m to 3500 m. The biggest depth is located at the central part of the whole area. The depth decreases toward the shell and the island's littoral (up to less than 1000 m). Seismic data were processed at CGG' processing in France. Geovector Plus was used as seismic processing software. All the information was calibrate by the wells in the area. The principal wells were DP535 and DP540. The general featuring of seismic image let us to get the map from the main geological elements in this area. In the area we were following two principal horizons: the green one associated to the Middle Cretaceous and the blue one associated to the top of Jurassic. We made the structural maps from the Middle Cretaceous and the Top of Jurassic, and did the seism stratigraphic analysis. We found 16 sequences. We did the chronograph table in this area and we made six maps from different seismic sequences. This analysis let us to define the most important area to continue studying in the Cuban economic area in the Gulf of Mexico on the petroleum exploration. (author)

  3. BUILDING 341 Seismic Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Halle, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-06-15

    The Seismic Evaluation of Building 341 located at Lawrence Livermore National Laboratory in Livermore, California has been completed. The subject building consists of a main building, Increment 1, and two smaller additions; Increments 2 and 3.

  4. Seismic data acquisition systems

    International Nuclear Information System (INIS)

    Kolvankar, V.G.; Nadre, V.N.; Rao, D.S.

    1989-01-01

    Details of seismic data acquisition systems developed at the Bhabha Atomic Research Centre, Bombay are reported. The seismic signals acquired belong to different signal bandwidths in the band from 0.02 Hz to 250 Hz. All these acquisition systems are built around a unique technique of recording multichannel data on to a single track of an audio tape and in digital form. Techniques of how these signals in different bands of frequencies were acquired and recorded are described. Method of detecting seismic signals and its performance is also discussed. Seismic signals acquired in different set-ups are illustrated. Time indexing systems for different set-ups and multichannel waveform display systems which form essential part of the data acquisition systems are also discussed. (author). 13 refs., 6 figs., 1 tab

  5. PSMG switchgear seismic analysis

    International Nuclear Information System (INIS)

    Kuehster, C.J.

    1977-01-01

    LOFT primary coolant system motor generator (PSMG) switchgear boxes were analyzed for sliding and overturning during a seismic event. Boxes are located in TAN-650, Room B-239, with the PSMG generators. Both boxes are sufficiently anchored to the floor

  6. Seismically observed seiching in the Panama Canal

    Science.gov (United States)

    McNamara, D.E.; Ringler, A.T.; Hutt, C.R.; Gee, L.S.

    2011-01-01

    A large portion of the seismic noise spectrum is dominated by water wave energy coupled into the solid Earth. Distinct mechanisms of water wave induced ground motions are distinguished by their spectral content. For example, cultural noise is generally Panama Canal there is an additional source of long-period noise generated by standing water waves, seiches, induced by disturbances such as passing ships and wind pressure. We compare seismic waveforms to water level records and relate these observations to changes in local tilt and gravity due to an oscillating seiche. The methods and observations discussed in this paper provide a first step toward quantifying the impact of water inundation as recorded by seismometers. This type of quantified understanding of water inundation will help in future estimates of similar phenomena such as the seismic observations of tsunami impact. Copyright 2011 by the American Geophysical Union.

  7. Seismic facies; Facies sismicas

    Energy Technology Data Exchange (ETDEWEB)

    Johann, Paulo Roberto Schroeder [PETROBRAS, Rio de Janeiro, RJ (Brazil). Exploracao e Producao Corporativo. Gerencia de Reservas e Reservatorios]. E-mail: johann@petrobras.com.br

    2004-11-01

    The method presented herein describes the seismic facies as representations of curves and vertical matrixes of the lithotypes proportions. The seismic facies are greatly interested in capturing the spatial distributions (3D) of regionalized variables, as for example, lithotypes, sedimentary facies groups and/ or porosity and/or other properties of the reservoirs and integrate them into the 3D geological modeling (Johann, 1997). Thus when interpreted as curves or vertical matrixes of proportions, seismic facies allow us to build a very important tool for structural analysis of regionalized variables. The matrixes have an important application in geostatistical modeling. In addition, this approach provides results about the depth and scale of the wells profiles, that is, seismic data is integrated to the characterization of reservoirs in depth maps and in high resolution maps. The link between the different necessary technical phases involved in the classification of the segments of seismic traces is described herein in groups of predefined traces of two approaches: a) not supervised and b) supervised by the geological knowledge available on the studied reservoir. The multivariate statistical methods used to obtain the maps of the seismic facies units are interesting tools to be used to provide a lithostratigraphic and petrophysical understanding of a petroleum reservoir. In the case studied these seismic facies units are interpreted as representative of the depositional system as a part of the Namorado Turbiditic System, Namorado Field, Campos Basin.Within the scope of PRAVAP 19 (Programa Estrategico de Recuperacao Avancada de Petroleo - Strategic Program of Advanced Petroleum Recovery) some research work on algorithms is underway to select new optimized attributes to apply seismic facies. One example is the extraction of attributes based on the wavelet transformation and on the time-frequency analysis methodology. PRAVAP is also carrying out research work on an

  8. Seismic Consequence Abstraction

    International Nuclear Information System (INIS)

    Gross, M.

    2004-01-01

    The primary purpose of this model report is to develop abstractions for the response of engineered barrier system (EBS) components to seismic hazards at a geologic repository at Yucca Mountain, Nevada, and to define the methodology for using these abstractions in a seismic scenario class for the Total System Performance Assessment - License Application (TSPA-LA). A secondary purpose of this model report is to provide information for criticality studies related to seismic hazards. The seismic hazards addressed herein are vibratory ground motion, fault displacement, and rockfall due to ground motion. The EBS components are the drip shield, the waste package, and the fuel cladding. The requirements for development of the abstractions and the associated algorithms for the seismic scenario class are defined in ''Technical Work Plan For: Regulatory Integration Modeling of Drift Degradation, Waste Package and Drip Shield Vibratory Motion and Seismic Consequences'' (BSC 2004 [DIRS 171520]). The development of these abstractions will provide a more complete representation of flow into and transport from the EBS under disruptive events. The results from this development will also address portions of integrated subissue ENG2, Mechanical Disruption of Engineered Barriers, including the acceptance criteria for this subissue defined in Section 2.2.1.3.2.3 of the ''Yucca Mountain Review Plan, Final Report'' (NRC 2003 [DIRS 163274])

  9. Seismic Consequence Abstraction

    Energy Technology Data Exchange (ETDEWEB)

    M. Gross

    2004-10-25

    The primary purpose of this model report is to develop abstractions for the response of engineered barrier system (EBS) components to seismic hazards at a geologic repository at Yucca Mountain, Nevada, and to define the methodology for using these abstractions in a seismic scenario class for the Total System Performance Assessment - License Application (TSPA-LA). A secondary purpose of this model report is to provide information for criticality studies related to seismic hazards. The seismic hazards addressed herein are vibratory ground motion, fault displacement, and rockfall due to ground motion. The EBS components are the drip shield, the waste package, and the fuel cladding. The requirements for development of the abstractions and the associated algorithms for the seismic scenario class are defined in ''Technical Work Plan For: Regulatory Integration Modeling of Drift Degradation, Waste Package and Drip Shield Vibratory Motion and Seismic Consequences'' (BSC 2004 [DIRS 171520]). The development of these abstractions will provide a more complete representation of flow into and transport from the EBS under disruptive events. The results from this development will also address portions of integrated subissue ENG2, Mechanical Disruption of Engineered Barriers, including the acceptance criteria for this subissue defined in Section 2.2.1.3.2.3 of the ''Yucca Mountain Review Plan, Final Report'' (NRC 2003 [DIRS 163274]).

  10. High-resolution seismic monitoring of rockslide activity in the Illgraben, Switzerland

    Science.gov (United States)

    Burtin, Arnaud; Hovius, Niels; Dietze, Michael; McArdell, Brian

    2014-05-01

    Rockfalls and rockslides are important geomorphic processes in landscape dynamics. They contribute to the evolution of slopes and supply rock materials to channels, enabling fluvial incision. Hillslope processes are also a natural hazard that we need to quantify and, if possible, predict. For these reasons, it is necessary to determine the triggering conditions and mechanisms involved in rockfalls. Rainfall is a well-known contributor since water, through soil moisture or pore pressure, may lead to the inception and propagation of cracks and can induce slope failure. Water can also affect slope stability through effects of climatic conditions such as the fluctuations of temperature around the freezing point. During the winter of 2012, we have recorded with a seismic array of 8 instruments substantial rockslide activity that affected a gully in the Illgraben catchment in the Swiss Alps. Three stations were positioned directly around the gully with a nearest distance of 400 m. The period of intense activity did not start during a rainstorm as it is common in summer but during a period of oscillation of temperatures around the freezing point. The activity did not occur in a single event but lasted about a week with a decay in time of the event frequency. Many individual events had two distinct seismic signals, with first, a short duration phase of about 10 s at frequencies below 5 Hz that we interpret as a slope failure signature, followed by a second long duration signal of > 60 s at frequencies above 10 Hz that we attribute to the propagation of rock debris down the slope. Thanks to the array of seismic sensors, we can study the fine details of this rockslide sequence by locating the different events, determining their distribution in time, and systematic quantification of seismic metrics (energy, duration, intensity...). These observations are compared to independent meteorological constrains and laser scan data to obtain an estimate of the volume mobilized by the

  11. Global earthquake catalogs and long-range correlation of seismic activity (Invited)

    Science.gov (United States)

    Ogata, Y.

    2009-12-01

    In view of the long-term seismic activity in the world, homogeneity of a global catalog is indispensable. Lately, Engdahl and Villaseñor (2002) compiled a global earthquake catalog of magnitude (M)7.0 or larger during the last century (1900-1999). This catalog is based on the various existing catalogs such as Abe catalog (Abe, 1981, 1984; Abe and Noguchi, 1983a, b) for the world seismicity (1894-1980), its modified catalogs by Perez and Scholz (1984) and by Pacheco and Sykes (1992), and also the Harvard University catalog since 1975. However, the original surface wave magnitudes of Abe catalog were systematically changed by Perez and Scholz (1984) and Pacheco and Sykes (1992). They suspected inhomogeneity of the Abe catalog and claimed that the two seeming changes in the occurrence rate around 1922 and 1948 resulted from magnitude shifts for some instrumental-related reasons. They used a statistical test assuming that such a series of large earthquakes in the world should behave as the stationary Poisson process (uniform occurrences). It is obvious that their claim strongly depends on their a priori assumption of an independent or short-range dependence of earthquake occurrence. We question this assumption from the viewpoint of long-range dependence of seismicity. We make some statistical analyses of the spectrum, dispersion-time diagrams and R/S for estimating and testing of the long-range correlations. We also attempt to show the possibility that the apparent rate change in the global seismicity can be simulated by a certain long-range correlated process. Further, if we divide the globe into the two regions of high and low latitudes, for example, we have different shapes of the cumulative curves to each other, and the above mentioned apparent change-points disappear from the both regions. This suggests that the Abe catalog shows the genuine seismic activity rather than the artifact of the suspected magnitude shifts that should appear in any wide enough regions

  12. Historical seismicity in France. Its role in the assessment of seismic risk on French nuclear sites

    International Nuclear Information System (INIS)

    Levret, A.

    1987-11-01

    Since 1975 in order to be in conformity with the requirements of the French nuclear program, a review of historical seismicity was undertaken in France. The assessment of seismic hazard for the safety of nuclear plants is in fact based upon a seismotectonic approach which needs to take into account the seismic activity over as long a period of time as possible. The method adopted for reviewing historical earthquakes entails a systematic consultation of the original sources and a critical analysis there of in the light of the historical, geographical and political contexts of the time. The same standards apply where the acquisition of new elements of information is involved. Each item of information is assigned a degree of reliability, then compiled in a computer file, up-dated annually; this file currently contains more than 4.500 events covering a period of time of about a millenary

  13. Seismic isolation of small modular reactors using metamaterials

    Directory of Open Access Journals (Sweden)

    Witarto Witarto

    2018-04-01

    Full Text Available Adaptation of metamaterials at micro- to nanometer scales to metastructures at much larger scales offers a new alternative for seismic isolation systems. These new isolation systems, known as periodic foundations, function both as a structural foundation to support gravitational weight of the superstructure and also as a seismic isolator to isolate the superstructure from incoming seismic waves. Here we describe the application of periodic foundations for the seismic protection of nuclear power plants, in particular small modular reactors (SMR. For this purpose, a large-scale shake table test on a one-dimensional (1D periodic foundation supporting an SMR building model was conducted. The 1D periodic foundation was designed and fabricated using reinforced concrete and synthetic rubber (polyurethane materials. The 1D periodic foundation structural system was tested under various input waves, which include white noise, stepped sine and seismic waves in the horizontal and vertical directions as well as in the torsional mode. The shake table test results show that the 1D periodic foundation can reduce the acceleration response (transmissibility of the SMR building up to 90%. In addition, the periodic foundation-isolated structure also exhibited smaller displacement than the non-isolated SMR building. This study indicates that the challenge faced in developing metastructures can be overcome and the periodic foundations can be applied to isolating vibration response of engineering structures.

  14. Seismic isolation of small modular reactors using metamaterials

    Science.gov (United States)

    Witarto, Witarto; Wang, S. J.; Yang, C. Y.; Nie, Xin; Mo, Y. L.; Chang, K. C.; Tang, Yu; Kassawara, Robert

    2018-04-01

    Adaptation of metamaterials at micro- to nanometer scales to metastructures at much larger scales offers a new alternative for seismic isolation systems. These new isolation systems, known as periodic foundations, function both as a structural foundation to support gravitational weight of the superstructure and also as a seismic isolator to isolate the superstructure from incoming seismic waves. Here we describe the application of periodic foundations for the seismic protection of nuclear power plants, in particular small modular reactors (SMR). For this purpose, a large-scale shake table test on a one-dimensional (1D) periodic foundation supporting an SMR building model was conducted. The 1D periodic foundation was designed and fabricated using reinforced concrete and synthetic rubber (polyurethane) materials. The 1D periodic foundation structural system was tested under various input waves, which include white noise, stepped sine and seismic waves in the horizontal and vertical directions as well as in the torsional mode. The shake table test results show that the 1D periodic foundation can reduce the acceleration response (transmissibility) of the SMR building up to 90%. In addition, the periodic foundation-isolated structure also exhibited smaller displacement than the non-isolated SMR building. This study indicates that the challenge faced in developing metastructures can be overcome and the periodic foundations can be applied to isolating vibration response of engineering structures.

  15. Induced seismicity in Carbon and Emery counties, Utah

    Science.gov (United States)

    Brown, Megan R. M.

    Utah is one of the top producers of oil and natural gas in the United States. Over the past 18 years, more than 4.2 billion gallons of wastewater from the petroleum industry have been injected into the Navajo Sandstone, Kayenta Formation, and Wingate Sandstone in two areas in Carbon and Emery County, Utah, where seismicity has increased during the same period. In this study, I investigated whether or not wastewater injection is related to the increased seismicity. Previous studies have attributed all of the seismicity in central Utah to coal mining activity. I found that water injection might be a more important cause. In the coal mining area, seismicity rate increased significantly 1-5 years following the commencement of wastewater injection. The increased seismicity consists almost entirely of earthquakes with magnitudes of less than 3, and is localized in areas seismically active prior to the injection. I have established the spatiotemporal correlations between the coal mining activities, the wastewater injection, and the increased seismicity. I used simple groundwater models to estimate the change in pore pressure and evaluate the observed time gap between the start of injection and the onset of the increased seismicity in the areas surrounding the injection wells. To ascertain that the increased seismicity is not fluctuation of background seismicity, I analyzed the magnitude-frequency relation of these earthquakes and found a clear increase in the b-value following the wastewater injection. I conclude that the marked increase of seismicity rate in central Utah is induced by both mining activity and wastewater injection, which raised pore pressure along pre-existing faults.

  16. Seismicity Structure of the Downgoing Nazca Slab in Northern Chile

    Science.gov (United States)

    Sippl, C.; Schurr, B.

    2017-12-01

    We applied an automatized earthquake detection and location algorithm to 8 years of continuous seismic data from the IPOC network in Northern Chile, located in the forearc between about 18.5°S and 24°S. The resulting seismicity catalog contains more than 113k double-difference relocated earthquake hypocenters and features a completeness magnitude around 2.8. Despite the occurrence of two megathrust earthquakes with vigorous aftershock seismicity in the studied time period (the 2007 Tocopilla and the 2014 Iquique earthquakes), >60% of the retrieved seismicity is located in a highly active band of intermediate-depth earthquakes (80-120 km deep) within the downgoing Nazca slab.We obtain a triple seismic zone in the updip part of the slab, with the three parallel dipping planes corresponding to the plate interface, the oceanic Moho (ca. 8 km below the interface) and a third band in the mantle lithosphere 26-28 km beneath the slab top. The plate interface seismicity terminates abruptly at a depth of 55 km. At about 80-90 km depth, the remaining two planes of seismicity then merge into the single, 20 km thick cluster of vigorous seismicity mentioned above, which terminates at 120 km depth. This cluster is located directly beneath the volcanic arc and shows a pronounced kink in the slab dipping angle. Intra-slab seismicity is most likely related to metamorphic dehydration reactions, hence our high-resolution earthquake distribution can be considered a map of metamorphic reactions (although a possibly incomplete one, since not all reactions necessarily invoke seismicity). By correlating this distribution with isotherms from thermal models as well as geophysical imaging results from previous studies, we attempt to get a glimpse at the processes that produce the different patches of intraslab seismicity at intermediate depths.

  17. An experimental overview of the seismic cycle

    Science.gov (United States)

    Spagnuolo, E.; Violay, M.; Passelegue, F. X.; Nielsen, S. B.; Di Toro, G.

    2017-12-01

    Earthquake nucleation is the last stage of the inter-seismic cycle where the fault surface evolves through the interplay of friction, healing, stress perturbations and strain events. Slip stability under rate-and state friction has been extensively discussed in terms of loading point velocity and equivalent fault stiffness, but fault evolution towards seismic runaway under complex loading histories (e.g. slow variations of tectonic stress, stress transfer from impulsive nearby seismic events) is not yet fully investigated. Nevertheless, the short term earthquake forecasting is based precisely on a relation between seismic productivity and loading history which remains up to date still largely unresolved. To this end we propose a novel experimental approach which avails of a closed loop control of the shear stress, a nominally infinite equivalent slip and transducers for continuous monitoring of acoustic emissions. This experimental simulation allows us to study the stress dependency and temporal evolution of spontaneous slip events occurring on a pre-existing fault subjected to different loading histories. The experimental fault has an initial roughness which mimic a population of randomly distributed asperities, which here are used as a proxy for patches which are either far or close to failure on an extended fault. Our observations suggest that the increase of shear stress may trigger either spontaneous slow slip (creep) or short-lived stick-slip bursts, eventually leading to a fast slip instability (seismic runaway) when slip rates are larger than a few cm/s. The event type and the slip rate are regulated at first order by the background shear stress whereas the ultimate strength of the entire fault is dominated by the number of asperities close to failure under a stress step. The extrapolation of these results to natural conditions might explain the plethora of events that often characterize seismic sequences. Nonetheless this experimental approach helps the

  18. A seismic network to investigate the sedimentary hosted hydrothermal Lusi system

    Science.gov (United States)

    Javad Fallahi, Mohammad; Mazzini, Adriano; Lupi, Matteo; Obermann, Anne; Karyono, Karyono

    2016-04-01

    The 29th of May 2006 marked the beginning of the sedimentary hosted hydrothermal Lusi system. During the last 10 years we witnessed numerous alterations of the Lusi system behavior that coincide with the frequent seismic and volcanic activity occurring in the region. In order to monitor the effect that the seismicity and the activity of the volcanic arc have on Lusi, we deployed a ad hoc seismic network. This temporary network consist of 10 broadband and 21 short period stations and is currently operating around the Arjuno-Welirang volcanic complex, along the Watukosek fault system and around Lusi, in the East Java basin since January 2015. We exploit this dataset to investigate surface wave and shear wave velocity structure of the upper-crust beneath the Arjuno-Welirang-Lusi complex in the framework of the Lusi Lab project (ERC grant n° 308126). Rayleigh and Love waves travelling between each station-pair are extracted by cross-correlating long time series of ambient noise data recorded at the stations. Group and phase velocity dispersion curves are obtained by time-frequency analysis of cross-correlation functions, and are tomographically inverted to provide 2D velocity maps corresponding to different sampling depths. 3D shear wave velocity structure is then acquired by inverting the group velocity maps.

  19. Goals and activities of the JICA technical cooperation project on reduction of seismic risk in Romania

    International Nuclear Information System (INIS)

    Vacareanu, R.; Kato, H.

    2007-01-01

    Japan International Cooperation Agency (JICA) Technical Cooperation Project on Reduction of Seismic Risk for Buildings and Structures started in Romania on October 1, 2002. The aim of the Project is to strengthen the capacity of earthquake disaster related activities in Romania. The Project approval is the result of four years of intensive efforts made by professionals from Technical University of Civil Engineering Bucharest (UTCB), Ministry of Transport, Constructions and Tourism (MTCT), Romania, National Building Research Institute (INCERC) Bucharest, JICA, Building Research Institute (BRI), Tsukuba, and National Institute for Land, Infrastructure and Management (NILIM), Tsukuba, Japan. The duration of the Project is five years. The implementing agency is the National Center for Seismic Risk Reduction (NCSRR) as a public institution of national interest under MTCT. The activities are carried out by NCSRR in partnership with UTCB and INCERC. During the Project period, 29 young Romanian engineers were trained in Japan, 7 Japanese experts and 37 Japanese experts worked for long-term and short-term, respectively in Romania. Equipment for seismic instrumentation, dynamic characterization of soil and structural testing rising up approximately to 260 million yens (i.e. 2.17 million USD) were donated by JICA to Romania, through NCSRR. The total cost of the Project is roughly 7 million USD. The paper describes the main activities and results of the Project until the JICA Final Evaluation Mission (March 2007). (authors)

  20. Seismic Responses of Shot Span Bridge under Three Different Patterns of Earthquake Excitations

    International Nuclear Information System (INIS)

    Zhou Daochuan; Chen Guorong; Lu Yan

    2010-01-01

    This paper presents a study of the influence of three different types of seismic input methods on the longitudinal seismic response of a short, three-span, variable cross-section, reinforced concrete bridge. Research progress of the seismic model is introduced briefly. Finite element model is created for the bridge and time history analysis conducted. Three different types of illustrative excitations are considered: 1) the EI-Centro seismic wave is used as uniform excitations at all bridge supports; 2) fixed apparent wave velocity is used for response analysis of traveling wave excitations on the bridge; 3) conforming to a selected coherency model, the multiple seismic excitation time histories considering spatially variable effects are generated. The contrast study of the response analysis result under the three different seismic excitations is conducted and the influence of different seismic input methods is studied. The comparative analysis of the bridge model shows that the uniform ground motion input can not provide conservative seismic demands-in a number of cases it results in lower response than that predicted by multiple seismic excitations. The result of uniform excitation and traveling wave excitation shows very small difference. Consequently, multiple seismic excitations needs to be applied at the bridge supports for response analysis of short span bridge.