WorldWideScience

Sample records for earthquake motion estimates

  1. Ground motion modeling of the 1906 San Francisco earthquake II: Ground motion estimates for the 1906 earthquake and scenario events

    Energy Technology Data Exchange (ETDEWEB)

    Aagaard, B; Brocher, T; Dreger, D; Frankel, A; Graves, R; Harmsen, S; Hartzell, S; Larsen, S; McCandless, K; Nilsson, S; Petersson, N A; Rodgers, A; Sjogreen, B; Tkalcic, H; Zoback, M L

    2007-02-09

    We estimate the ground motions produced by the 1906 San Francisco earthquake making use of the recently developed Song et al. (2008) source model that combines the available geodetic and seismic observations and recently constructed 3D geologic and seismic velocity models. Our estimates of the ground motions for the 1906 earthquake are consistent across five ground-motion modeling groups employing different wave propagation codes and simulation domains. The simulations successfully reproduce the main features of the Boatwright and Bundock (2005) ShakeMap, but tend to over predict the intensity of shaking by 0.1-0.5 modified Mercalli intensity (MMI) units. Velocity waveforms at sites throughout the San Francisco Bay Area exhibit characteristics consistent with rupture directivity, local geologic conditions (e.g., sedimentary basins), and the large size of the event (e.g., durations of strong shaking lasting tens of seconds). We also compute ground motions for seven hypothetical scenarios rupturing the same extent of the northern San Andreas fault, considering three additional hypocenters and an additional, random distribution of slip. Rupture directivity exerts the strongest influence on the variations in shaking, although sedimentary basins do consistently contribute to the response in some locations, such as Santa Rosa, Livermore, and San Jose. These scenarios suggest that future large earthquakes on the northern San Andreas fault may subject the current San Francisco Bay urban area to stronger shaking than a repeat of the 1906 earthquake. Ruptures propagating southward towards San Francisco appear to expose more of the urban area to a given intensity level than do ruptures propagating northward.

  2. Strong earthquake motion estimates for three sites on the U.C. San Diego campus

    Energy Technology Data Exchange (ETDEWEB)

    Day, S; Doroudian, M; Elgamal, A; Gonzales, S; Heuze, F; Lai, T; Minster, B; Oglesby, D; Riemer, M; Vernon, F; Vucetic, M; Wagoner, J; Yang, Z

    2002-05-07

    The approach of the Campus Earthquake Program (CEP) is to combine the substantial expertise that exists within the UC system in geology, seismology, and geotechnical engineering, to estimate the earthquake strong motion exposure of UC facilities. These estimates draw upon recent advances in hazard assessment, seismic wave propagation modeling in rocks and soils, and dynamic soil testing. The UC campuses currently chosen for application of our integrated methodology are Riverside, San Diego, and Santa Barbara. The procedure starts with the identification of possible earthquake sources in the region and the determination of the most critical fault(s) related to earthquake exposure of the campus. Combined geological, geophysical, and geotechnical studies are then conducted to characterize each campus with specific focus on the location of particular target buildings of special interest to the campus administrators. We drill, sample, and geophysically log deep boreholes next to the target structure, to provide direct in-situ measurements of subsurface material properties, and to install uphole and downhole 3-component seismic sensors capable of recording both weak and strong motions. The boreholes provide access below the soil layers, to deeper materials that have relatively high seismic shear-wave velocities. Analyses of conjugate downhole and uphole records provide a basis for optimizing the representation of the low-strain response of the sites. Earthquake rupture scenarios of identified causative faults are combined with the earthquake records and with nonlinear soil models to provide site-specific estimates of strong motions at the selected target locations. The predicted ground motions are shared with the UC consultants, so that they can be used as input to the dynamic analysis of the buildings. Thus, for each campus targeted by the CEP project, the strong motion studies consist of two phases, Phase 1--initial source and site characterization, drilling

  3. Estimation of regression laws for ground motion parameters using as case of study the Amatrice earthquake

    Science.gov (United States)

    Tiberi, Lara; Costa, Giovanni

    2017-04-01

    The possibility to directly associate the damages to the ground motion parameters is always a great challenge, in particular for civil protections. Indeed a ground motion parameter, estimated in near real time that can express the damages occurred after an earthquake, is fundamental to arrange the first assistance after an event. The aim of this work is to contribute to the estimation of the ground motion parameter that better describes the observed intensity, immediately after an event. This can be done calculating for each ground motion parameter estimated in a near real time mode a regression law which correlates the above-mentioned parameter to the observed macro-seismic intensity. This estimation is done collecting high quality accelerometric data in near field, filtering them at different frequency steps. The regression laws are calculated using two different techniques: the non linear least-squares (NLLS) Marquardt-Levenberg algorithm and the orthogonal distance methodology (ODR). The limits of the first methodology are the needed of initial values for the parameters a and b (set 1.0 in this study), and the constraint that the independent variable must be known with greater accuracy than the dependent variable. While the second algorithm is based on the estimation of the errors perpendicular to the line, rather than just vertically. The vertical errors are just the errors in the 'y' direction, so only for the dependent variable whereas the perpendicular errors take into account errors for both the variables, the dependent and the independent. This makes possible also to directly invert the relation, so the a and b values can be used also to express the gmps as function of I. For each law the standard deviation and R2 value are estimated in order to test the quality and the reliability of the found relation. The Amatrice earthquake of 24th August of 2016 is used as case of study to test the goodness of the calculated regression laws.

  4. Source Rupture Process and Near-Fault Ground Motions of the 2016 Kumamoto Earthquake Sequence Estimated from Strong Motion Data

    Science.gov (United States)

    Asano, K.; Iwata, T.

    2016-12-01

    The 2016 Kumamoto earthquake sequence started with an MJMA 6.5 foreshock on April 14, 2016 occurring along the northern part of the Hinagu fault, central Kyushu, Japan, and the MJMA 7.3 mainshock occurred just 28 h after the foreshock. Both events brought severe ground motions to the near-source region. We analyzed the kinematic source rupture processes of the foreshock and mainshock by the multiple time window linear waveform inversion using strong motion data (e.g., Hartzell and Heaton, 1983). The foreshock (Mw 6.1) was characterized by right-lateral strike-slip occurring on a nearly vertical fault plane along the northern part of the Hinagu fault, and it had two large-slip areas: one near the hypocenter and another at a shallow depth. These two large-slip areas mainly contribute ground motions in the near-source area. For the analysis of the mainshock, we assumed a fault geometry changing strike and dip angles along the Hinagu and Futagawa faults in accordance with the surface ruptures mapped by emergency field surveys (Kumahara et al., 2016). We assigned point sources densely with an interval of 0.2 km on the assumed fault planes in order to reproduce appropriately near-fault ground motions, and estimated spatiotemporal slip history, which was discretized with an interval of 1.8 km on the fault planes. The estimated source model reveals that the rupture of the mainshock started at a northwest-dipping fault plane along the Hinagu fault, which is close to the vertical fault plane of the foreshock, and almost continuously propagated across the junction of the Hinagu and Futagawa faults. Then the rupture propagated northeastward along the Futagawa fault, and stopped to rupture in the western part of the Aso caldera. The significant slip with 3-5 m were observed on the Futagawa fault, and shallowest part has slip ranging from 1 to 2 m. We also tried to reproduce ground motions observed at some near-fault strong motion stations, which recorded significant coseismic

  5. Estimation of slip scenarios of mega-thrust earthquakes and strong motion simulations for Central Andes, Peru

    Science.gov (United States)

    Pulido, N.; Tavera, H.; Aguilar, Z.; Chlieh, M.; Calderon, D.; Sekiguchi, T.; Nakai, S.; Yamazaki, F.

    2012-12-01

    We have developed a methodology for the estimation of slip scenarios for megathrust earthquakes based on a model of interseismic coupling (ISC) distribution in subduction margins obtained from geodetic data, as well as information of recurrence of historical earthquakes. This geodetic slip model (GSM) delineates the long wavelength asperities within the megathrust. For the simulation of strong ground motion it becomes necessary to introduce short wavelength heterogeneities to the source slip to be able to efficiently simulate high frequency ground motions. To achieve this purpose we elaborate "broadband" source models constructed by combining the GSM with several short wavelength slip distributions obtained from a Von Karman PSD function with random phases. Our application of the method to Central Andes in Peru, show that this region has presently the potential of generating an earthquake with moment magnitude of 8.9, with a peak slip of 17 m and a source area of approximately 500 km along strike and 165 km along dip. For the strong motion simulations we constructed 12 broadband slip models, and consider 9 possible hypocenter locations for each model. We performed strong motion simulations for the whole central Andes region (Peru), spanning an area from the Nazca ridge (16^o S) to the Mendana fracture (9^o S). For this purpose we use the hybrid strong motion simulation method of Pulido et al. (2004), improved to handle a general slip distribution. Our simulated PGA and PGV distributions indicate that a region of at least 500 km along the coast of central Andes is subjected to a MMI intensity of approximately 8, for the slip model that yielded the largest ground motions among the 12 slip models considered, averaged for all assumed hypocenter locations. This result is in agreement with the macroseismic intensity distribution estimated for the great 1746 earthquake (M~9) in central Andes (Dorbath et al. 1990). Our results indicate that the simulated PGA and PGV for

  6. Earthquake ground motion: Chapter 3

    Science.gov (United States)

    Luco, Nicolas; Kircher, Charles A.; Crouse, C. B.; Charney, Finley; Haselton, Curt B.; Baker, Jack W.; Zimmerman, Reid; Hooper, John D.; McVitty, William; Taylor, Andy

    2016-01-01

    Most of the effort in seismic design of buildings and other structures is focused on structural design. This chapter addresses another key aspect of the design process—characterization of earthquake ground motion into parameters for use in design. Section 3.1 describes the basis of the earthquake ground motion maps in the Provisions and in ASCE 7 (the Standard). Section 3.2 has examples for the determination of ground motion parameters and spectra for use in design. Section 3.3 describes site-specific ground motion requirements and provides example site-specific design and MCER response spectra and example values of site-specific ground motion parameters. Section 3.4 discusses and provides an example for the selection and scaling of ground motion records for use in various types of response history analysis permitted in the Standard.

  7. Estimation of Seismic Ground Motions and Attendant Potential Human Fatalities from Scenario Earthquakes on the Chishan Fault in Southern Taiwan

    Directory of Open Access Journals (Sweden)

    Kun-Sung Liu

    2017-01-01

    Full Text Available The purpose of this study is to estimate maximum ground motions in southern Taiwan as well as to assess potential human fatalities from scenario earthquakes on the Chishan active faults in this area. The resultant Shake Map patterns of maximum ground motion in a case of Mw 7.2 show the areas of PGA above 400 gals are located in the northeastern, central and northern parts of southwestern Kaohsiung as well as the southern part of central Tainan, as shown in the regions inside the yellow lines in the corresponding figure. Comparing cities with similar distances located in Tainan, Kaohsiung, and Pingtung to the Chishan fault, the cities in Tainan area have relatively greater PGA and PGV, due to large site response factors in Tainan area. Furthermore, seismic hazards in terms of PGA and PGV in the vicinity of the Chishan fault are not completely dominated by the Chishan fault. The main reason is that some areas located in the vicinity of the Chishan fault are marked with low site response amplification values from 0.55 - 1.1 and 0.67 - 1.22 for PGA and PGV, respectively. Finally, from estimation of potential human fatalities from scenario earthquakes on the Chishan active fault, it is noted that potential fatalities increase rapidly in people above age 45. Total fatalities reach a high peak in age groups of 55 - 64. Another to pay special attention is Kaohsiung City has more than 540 thousand households whose residences over 50 years old. In light of the results of this study, I urge both the municipal and central governments to take effective seismic hazard mitigation measures in the highly urbanized areas with a large number of old buildings in southern Taiwan.

  8. Earthquake Ground Motion Selection

    Science.gov (United States)

    2012-05-01

    Nonlinear analyses of soils, structures, and soil-structure systems offer the potential for more accurate characterization of geotechnical and structural response under strong earthquake shaking. The increasing use of advanced performance-based desig...

  9. Ground Motions Due to Earthquakes on Creeping Faults

    Science.gov (United States)

    Harris, R.; Abrahamson, N. A.

    2014-12-01

    We investigate the peak ground motions from the largest well-recorded earthquakes on creeping strike-slip faults in active-tectonic continental regions. Our goal is to evaluate if the strong ground motions from earthquakes on creeping faults are smaller than the strong ground motions from earthquakes on locked faults. Smaller ground motions might be expected from earthquakes on creeping faults if the fault sections that strongly radiate energy are surrounded by patches of fault that predominantly absorb energy. For our study we used the ground motion data available in the PEER NGA-West2 database, and the ground motion prediction equations that were developed from the PEER NGA-West2 dataset. We analyzed data for the eleven largest well-recorded creeping-fault earthquakes, that ranged in magnitude from M5.0-6.5. Our findings are that these earthquakes produced peak ground motions that are statistically indistinguishable from the peak ground motions produced by similar-magnitude earthquakes on locked faults. These findings may be implemented in earthquake hazard estimates for moderate-size earthquakes in creeping-fault regions. Further investigation is necessary to determine if this result will also apply to larger earthquakes on creeping faults. Please also see: Harris, R.A., and N.A. Abrahamson (2014), Strong ground motions generated by earthquakes on creeping faults, Geophysical Research Letters, vol. 41, doi:10.1002/2014GL060228.

  10. Site amplification and strong ground motion of the 2007 Noto Hanto, Japan, earthquake estimated from aftershock observation

    Science.gov (United States)

    Yoshimi, M.; Yoshida, K.

    2008-03-01

    Site amplifications in the lowlands most affected by the 2007 Noto Hanto earthquake, Monzen, Anamizu, and Wajima, are examined using aftershock records observed at eight temporary seismic stations installed just after the mainshock and at two K-NET stations. The predominant frequencies of spectral ratios at alluvium sites in Anamizu and Wajima are approximately 1 Hz. Site amplifications at the alluvium sites are successfully reproduced from 1-D response analysis, except for that at ISK005 where 2-D or higher amplification effects are inferred to play a significant role. A source model composed of two asperities reproduces the ground motions of the mainshock using the empirical Green's function method. The seismic moments of the asperities are 3.76×1018 N m and 2.21×1018 N m, respectively. Peak ground velocity (PGV) at alluvium sites during the mainshock are estimated to be 70-110 cm/s for Monzen, 50-110 cm/s for Anamizu, and 60-70 cm/s for Wajima.

  11. Comparison of ground motions estimated from prediction equations and from observed damage during the M = 4.6 1983 Liège earthquake (Belgium

    Directory of Open Access Journals (Sweden)

    D. García Moreno

    2013-08-01

    Full Text Available On 8 November 1983 an earthquake of magnitude 4.6 damaged more than 16 000 buildings in the region of Liège (Belgium. The extraordinary damage produced by this earthquake, considering its moderate magnitude, is extremely well documented, giving the opportunity to compare the consequences of a recent moderate earthquake in a typical old city of Western Europe with scenarios obtained by combining strong ground motions and vulnerability modelling. The present study compares 0.3 s spectral accelerations estimated from ground motion prediction equations typically used in Western Europe with those obtained locally by applying the statistical distribution of damaged masonry buildings to two fragility curves, one derived from the HAZUS programme of FEMA (FEMA, 1999 and another developed for high-vulnerability buildings by Lang and Bachmann (2004, and to a method proposed by Faccioli et al. (1999 relating the seismic vulnerability of buildings to the damage and ground motions. The results of this comparison reveal good agreement between maxima spectral accelerations calculated from these vulnerability and fragility curves and those predicted from attenuation law equations, suggesting peak ground accelerations for the epicentral area of the 1983 earthquake of 0.13–0.20 g (g: gravitational acceleration.

  12. Variable anelastic attenuation and site effect in estimating source parameters of various major earthquakes including M w 7.8 Nepal and M w 7.5 Hindu kush earthquake by using far-field strong-motion data

    Science.gov (United States)

    Kumar, Naresh; Kumar, Parveen; Chauhan, Vishal; Hazarika, Devajit

    2017-10-01

    Strong-motion records of recent Gorkha Nepal earthquake ( M w 7.8), its strong aftershocks and seismic events of Hindu kush region have been analysed for estimation of source parameters. The M w 7.8 Gorkha Nepal earthquake of 25 April 2015 and its six aftershocks of magnitude range 5.3-7.3 are recorded at Multi-Parametric Geophysical Observatory, Ghuttu, Garhwal Himalaya (India) >600 km west from the epicentre of main shock of Gorkha earthquake. The acceleration data of eight earthquakes occurred in the Hindu kush region also recorded at this observatory which is located >1000 km east from the epicentre of M w 7.5 Hindu kush earthquake on 26 October 2015. The shear wave spectra of acceleration record are corrected for the possible effects of anelastic attenuation at both source and recording site as well as for site amplification. The strong-motion data of six local earthquakes are used to estimate the site amplification and the shear wave quality factor ( Q β) at recording site. The frequency-dependent Q β( f) = 124 f 0.98 is computed at Ghuttu station by using inversion technique. The corrected spectrum is compared with theoretical spectrum obtained from Brune's circular model for the horizontal components using grid search algorithm. Computed seismic moment, stress drop and source radius of the earthquakes used in this work range 8.20 × 1016-5.72 × 1020 Nm, 7.1-50.6 bars and 3.55-36.70 km, respectively. The results match with the available values obtained by other agencies.

  13. Estimation of 1-D velocity models beneath strong-motion observation sites in the Kathmandu Valley using strong-motion records from moderate-sized earthquakes

    Science.gov (United States)

    Bijukchhen, Subeg M.; Takai, Nobuo; Shigefuji, Michiko; Ichiyanagi, Masayoshi; Sasatani, Tsutomu; Sugimura, Yokito

    2017-07-01

    The Himalayan collision zone experiences many seismic activities with large earthquakes occurring at certain time intervals. The damming of the proto-Bagmati River as a result of rapid mountain-building processes created a lake in the Kathmandu Valley that eventually dried out, leaving thick unconsolidated lacustrine deposits. Previous studies have shown that the sediments are 600 m thick in the center. A location in a seismically active region, and the possible amplification of seismic waves due to thick sediments, have made Kathmandu Valley seismically vulnerable. It has suffered devastation due to earthquakes several times in the past. The development of the Kathmandu Valley into the largest urban agglomerate in Nepal has exposed a large population to seismic hazards. This vulnerability was apparent during the Gorkha Earthquake (Mw7.8) on April 25, 2015, when the main shock and ensuing aftershocks claimed more than 1700 lives and nearly 13% of buildings inside the valley were completely damaged. Preparing safe and up-to-date building codes to reduce seismic risk requires a thorough study of ground motion amplification. Characterizing subsurface velocity structure is a step toward achieving that goal. We used the records from an array of strong-motion accelerometers installed by Hokkaido University and Tribhuvan University to construct 1-D velocity models of station sites by forward modeling of low-frequency S-waves. Filtered records (0.1-0.5 Hz) from one of the accelerometers installed at a rock site during a moderate-sized (mb4.9) earthquake on August 30, 2013, and three moderate-sized (Mw5.1, Mw5.1, and Mw5.5) aftershocks of the 2015 Gorkha Earthquake were used as input motion for modeling of low-frequency S-waves. We consulted available geological maps, cross-sections, and borehole data as the basis for initial models for the sediment sites. This study shows that the basin has an undulating topography and sediment sites have deposits of varying thicknesses

  14. Identification of resonant earthquake ground motion

    Indian Academy of Sciences (India)

    Resonant ground motion has been observed in earthquake records measured at several parts of the world. This class of ground motion is characterized by its energy being contained in a narrow frequency band. This paper develops measures to quantify the frequency content of the ground motion using the entropy ...

  15. Strong motion duration and earthquake magnitude relationships

    Energy Technology Data Exchange (ETDEWEB)

    Salmon, M.W.; Short, S.A. [EQE International, Inc., San Francisco, CA (United States); Kennedy, R.P. [RPK Structural Mechanics Consulting, Yorba Linda, CA (United States)

    1992-06-01

    Earthquake duration is the total time of ground shaking from the arrival of seismic waves until the return to ambient conditions. Much of this time is at relatively low shaking levels which have little effect on seismic structural response and on earthquake damage potential. As a result, a parameter termed ``strong motion duration`` has been defined by a number of investigators to be used for the purpose of evaluating seismic response and assessing the potential for structural damage due to earthquakes. This report presents methods for determining strong motion duration and a time history envelope function appropriate for various evaluation purposes, for earthquake magnitude and distance, and for site soil properties. There are numerous definitions of strong motion duration. For most of these definitions, empirical studies have been completed which relate duration to earthquake magnitude and distance and to site soil properties. Each of these definitions recognizes that only the portion of an earthquake record which has sufficiently high acceleration amplitude, energy content, or some other parameters significantly affects seismic response. Studies have been performed which indicate that the portion of an earthquake record in which the power (average rate of energy input) is maximum correlates most closely with potential damage to stiff nuclear power plant structures. Hence, this report will concentrate on energy based strong motion duration definitions.

  16. Strong ground motion prediction using virtual earthquakes.

    Science.gov (United States)

    Denolle, M A; Dunham, E M; Prieto, G A; Beroza, G C

    2014-01-24

    Sedimentary basins increase the damaging effects of earthquakes by trapping and amplifying seismic waves. Simulations of seismic wave propagation in sedimentary basins capture this effect; however, there exists no method to validate these results for earthquakes that have not yet occurred. We present a new approach for ground motion prediction that uses the ambient seismic field. We apply our method to a suite of magnitude 7 scenario earthquakes on the southern San Andreas fault and compare our ground motion predictions with simulations. Both methods find strong amplification and coupling of source and structure effects, but they predict substantially different shaking patterns across the Los Angeles Basin. The virtual earthquake approach provides a new approach for predicting long-period strong ground motion.

  17. A stochastic estimate of ground motion at Oceano, California, for the M 6.5 22 December 2003 San Simeon earthquake, derived from aftershock recordings

    Science.gov (United States)

    Di, Alessandro C.; Boatwright, J.

    2006-01-01

    The U.S. Geological Survey deployed a digital seismic station in Oceano, California, in February 2004, to investigate the cause of damage and liquefaction from the 22 December 2003 M 6.5 San Simeon earthquake. This station recorded 11 M > 2.8 aftershocks in almost 8 weeks. We analyze these recordings, together with recordings of the mainshock and the same aftershocks obtained from nearby stations in Park Hill and San Luis Obispo, to estimate the mainshock ground motion in Oceano. We estimate the Fourier amplitude spectrum using generalized spectral ratio analysis. We test a set of aftershocks as Green's functions by comparing simulated and recorded acceleration amplitude spectra for the mainshock at San Luis Obispo and Park Hill. We convolve the aftershock accelerograms with a stochastic operator to simulate the duration and phase of the mainshock accelerograms. This approximation allows us to extend the range of aftershocks that can be used as Green's functions to events nearly three magnitude units smaller than the mainshock. Our realizations for the mainshock accelerogram at Oceano yield peak ground accelerations distributed as 28% ?? 4%g. We interpret these realizations as upper bounds for the actual ground motion, because our analysis assumes a linear response, whereas the presence of liquefaction indicates that the ground behaved nonlinearly in Oceano.

  18. Identification of resonant earthquake ground motion

    Indian Academy of Sciences (India)

    Rom pave the way for better ... identified critical ground motion for nonlinear structures using inelastic time-history analysis. The effect of energy .... of earthquake records for time-history analysis of structures (Moustafa et al 2010). To gain more ...

  19. Quantitative prediction of strong motion for a potential earthquake fault

    Directory of Open Access Journals (Sweden)

    Shamita Das

    2010-02-01

    Full Text Available This paper describes a new method for calculating strong motion records for a given seismic region on the basis of the laws of physics using information on the tectonics and physical properties of the earthquake fault. Our method is based on a earthquake model, called a «barrier model», which is characterized by five source parameters: fault length, width, maximum slip, rupture velocity, and barrier interval. The first three parameters may be constrained from plate tectonics, and the fourth parameter is roughly a constant. The most important parameter controlling the earthquake strong motion is the last parameter, «barrier interval». There are three methods to estimate the barrier interval for a given seismic region: 1 surface measurement of slip across fault breaks, 2 model fitting with observed near and far-field seismograms, and 3 scaling law data for small earthquakes in the region. The barrier intervals were estimated for a dozen earthquakes and four seismic regions by the above three methods. Our preliminary results for California suggest that the barrier interval may be determined if the maximum slip is given. The relation between the barrier interval and maximum slip varies from one seismic region to another. For example, the interval appears to be unusually long for Kilauea, Hawaii, which may explain why only scattered evidence of strong ground shaking was observed in the epicentral area of the Island of Hawaii earthquake of November 29, 1975. The stress drop associated with an individual fault segment estimated from the barrier interval and maximum slip lies between 100 and 1000 bars. These values are about one order of magnitude greater than those estimated earlier by the use of crack models without barriers. Thus, the barrier model can resolve, at least partially, the well known discrepancy between the stress-drops measured in the laboratory and those estimated for earthquakes.

  20. Source rupture process of the 2016 Kaikoura, New Zealand earthquake estimated from the kinematic waveform inversion of strong-motion data

    Science.gov (United States)

    Zheng, Ao; Wang, Mingfeng; Yu, Xiangwei; Zhang, Wenbo

    2018-03-01

    On 2016 November 13, an Mw 7.8 earthquake occurred in the northeast of the South Island of New Zealand near Kaikoura. The earthquake caused severe damages and great impacts on local nature and society. Referring to the tectonic environment and defined active faults, the field investigation and geodetic evidence reveal that at least 12 fault sections ruptured in the earthquake, and the focal mechanism is one of the most complicated in historical earthquakes. On account of the complexity of the source rupture, we propose a multisegment fault model based on the distribution of surface ruptures and active tectonics. We derive the source rupture process of the earthquake using the kinematic waveform inversion method with the multisegment fault model from strong-motion data of 21 stations (0.05-0.35 Hz). The inversion result suggests the rupture initiates in the epicentral area near the Humps fault, and then propagates northeastward along several faults, until the offshore Needles fault. The Mw 7.8 event is a mixture of right-lateral strike and reverse slip, and the maximum slip is approximately 19 m. The synthetic waveforms reproduce the characteristics of the observed ones well. In addition, we synthesize the coseismic offsets distribution of the ruptured region from the slips of upper subfaults in the fault model, which is roughly consistent with the surface breaks observed in the field survey.

  1. Strong ground motion from the michoacan, Mexico, earthquake.

    Science.gov (United States)

    Anderson, J G; Bodin, P; Brune, J N; Prince, J; Singh, S K; Quaas, R; Onate, M

    1986-09-05

    The network of strong motion accelerographs in Mexico includes instruments that were installed, under an international cooperative research program, in sites selected for the high potenial of a large earthquake. The 19 September 1985 earthquake (magnitude 8.1) occurred in a seismic gap where an earthquake was expected. As a result, there is an excellent descripton of the ground motions that caused the disaster.

  2. Determination of Design Basis Earthquake ground motion

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Muneaki [Japan Atomic Power Co., Tokyo (Japan)

    1997-03-01

    This paper describes principle of determining of Design Basis Earthquake following the Examination Guide, some examples on actual sites including earthquake sources to be considered, earthquake response spectrum and simulated seismic waves. In sppendix of this paper, furthermore, seismic safety review for N.P.P designed before publication of the Examination Guide was summarized with Check Basis Earthquake. (J.P.N.)

  3. Rapid Earthquake Magnitude Estimation for Early Warning Applications

    Science.gov (United States)

    Goldberg, Dara; Bock, Yehuda; Melgar, Diego

    2017-04-01

    Earthquake magnitude is a concise metric that provides invaluable information about the destructive potential of a seismic event. Rapid estimation of magnitude for earthquake and tsunami early warning purposes requires reliance on near-field instrumentation. For large magnitude events, ground motions can exceed the dynamic range of near-field broadband seismic instrumentation (clipping). Strong motion accelerometers are designed with low gains to better capture strong shaking. Estimating earthquake magnitude rapidly from near-source strong-motion data requires integration of acceleration waveforms to displacement. However, integration amplifies small errors, creating unphysical drift that must be eliminated with a high pass filter. The loss of the long period information due to filtering is an impediment to magnitude estimation in real-time; the relation between ground motion measured with strong-motion instrumentation and magnitude saturates, leading to underestimation of earthquake magnitude. Using station displacements from Global Navigation Satellite System (GNSS) observations, we can supplement the high frequency information recorded by traditional seismic systems with long-period observations to better inform rapid response. Unlike seismic-only instrumentation, ground motions measured with GNSS scale with magnitude without saturation [Crowell et al., 2013; Melgar et al., 2015]. We refine the current magnitude scaling relations using peak ground displacement (PGD) by adding a large GNSS dataset of earthquakes in Japan. Because it does not suffer from saturation, GNSS alone has significant advantages over seismic-only instrumentation for rapid magnitude estimation of large events. The earthquake's magnitude can be estimated within 2-3 minutes of earthquake onset time [Melgar et al., 2013]. We demonstrate that seismogeodesy, the optimal combination of GNSS and seismic data at collocated stations, provides the added benefit of improving the sensitivity of

  4. Strong Motion Earthquake Data Values of Digitized Strong-Motion Accelerograms, 1933-1994

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Strong Motion Earthquake Data Values of Digitized Strong-Motion Accelerograms is a database of over 15,000 digitized and processed accelerograph records from...

  5. Earthquake source model using strong motion displacement as ...

    Indian Academy of Sciences (India)

    Thus, if the part of the earth participating in ground motion is modelled as a known finite elastic medium, one can attempt to model the source location and forces generated during an earthquake as an inverse problem in structural dynamics. Based on this analogy, a simple model for the basic earthquake source is proposed ...

  6. Ground motion observations of the 2014 South Napa earthquake

    Science.gov (United States)

    Baltay, Annemarie S.; Boatwright, John

    2015-01-01

    Ground motions of the South Napa earthquake (24 August 2014; M 6.0) were recorded at 19 stations within 20 km and 292 stations within 100 km of the rupture surface trace, generating peak ground motions in excess of 50%g and 50  cm/s in and near Napa Valley. This large dataset allows us to compare the ground motion from the earthquake to existing ground‐motion prediction equations (GMPEs) in considerable detail.

  7. Simultaneous estimation of earthquake source parameters and ...

    Indian Academy of Sciences (India)

    This paper presents the simultaneous estimation of source parameters and crustal Q values for small to moderate-size aftershocks (Mw 2.1–5.1) of the Mw 7.7 2001 Bhuj earthquake. The horizontal-component. S-waves of 144 well located earthquakes (2001–2010) recorded at 3–10 broadband seismograph sites in.

  8. Simultaneous estimation of earthquake source parameters and ...

    Indian Academy of Sciences (India)

    This paper presents the simultaneous estimation of source parameters and crustal Q values for small to moderate-size aftershocks ( 2.1–5.1) of the 7.7 2001 Bhuj earthquake. The horizontal-component S-waves of 144 well located earthquakes (2001–2010) recorded at 3–10 broadband seismograph sites in the ...

  9. Estimation of Maximum Ground Motions in the Form of ShakeMaps and Assessment of Potential Human Fatalities from Scenario Earthquakes on the Chishan Active Fault in southern Taiwan

    Science.gov (United States)

    Liu, Kun Sung; Huang, Hsiang Chi; Shen, Jia Rong

    2017-04-01

    Historically, there were many damaging earthquakes in southern Taiwan during the last century. Some of these earthquakes had resulted in heavy loss of human lives. Accordingly, assessment of potential seismic hazards has become increasingly important in southern Taiwan, including Kaohsiung, Tainan and northern Pingtung areas since the Central Geological Survey upgraded the Chishan active fault from suspected fault to Category I in 2010. In this study, we first estimate the maximum seismic ground motions in term of PGA, PGV and MMI by incorporating a site-effect term in attenuation relationships, aiming to show high seismic hazard areas in southern Taiwan. Furthermore, we will assess potential death tolls due to large future earthquakes occurring on Chishan active fault. As a result, from the maximum PGA ShakeMap for an Mw7.2 scenario earthquake on the Chishan active fault in southern Taiwan, we can see that areas with high PGA above 400 gals, are located in the northeastern, central and northern parts of southwestern Kaohsiung as well as the southern part of central Tainan. In addition, comparing the cities located in Tainan City at similar distances from the Chishan fault have relatively greater PGA and PGV than those in Kaohsiung City and Pingtung County. This is mainly due to large site response factors in Tainan. On the other hand, seismic hazard in term of PGA and PGV, respectively, show that they are not particular high in the areas near the Chishan fault. The main reason is that these areas are marked with low site response factors. Finally, the estimated fatalities in Kaohsiung City at 5230, 4285 and 2786, respectively, for Mw 7.2, 7.0 and 6.8 are higher than those estimated for Tainan City and Pingtung County. The main reason is high population density above 10000 persons per km2 are present in Fongshan, Zuoying, Sanmin, Cianjin, Sinsing, Yancheng, Lingya Districts and between 5,000 and 10,000 persons per km2 are present in Nanzih and Gushan Districts in

  10. Earthquake source model using strong motion displacement as ...

    Indian Academy of Sciences (India)

    The strong motion displacement records available during an earthquake can be treated as the response of the earth as the a structural system to unknown forces acting at unknown locations. Thus, if the part of the earth participating in ground motion is modelled as a known finite elastic medium, one can attempt to model the ...

  11. Hypocentre estimation of induced earthquakes in Groningen

    Science.gov (United States)

    Spetzler, Jesper; Dost, Bernard

    2017-04-01

    Induced earthquakes due to gas production have taken place in the province of Groningen in the northeast of The Netherlands since 1986. In the first years of seismicity, a sparse seismological network with large station distances from the seismogenic area in Groningen was used. The location of induced earthquakes was limited by the few and wide spread stations. Recently, the station network has been extended significantly and the location of induced earthquakes in Groningen has become routine work. Except for the depth estimation of the events. In the hypocentre method used for source location by the Royal Netherlands Meteorological Institute (KNMI), the depth of the induced earthquakes is by default set to 3 km which is the average depth of the gas-reservoir. Alternatively, a differential traveltime for P-waves approach for source location is applied on recorded data from the extended network. The epicentre and depth of 87 induced earthquakes from 2014 to July 2016 have been estimated. The newly estimated epicentres are close to the induced earthquake locations from the current method applied by the KNMI. It is observed that most induced earthquakes take place at reservoir level. Several events in the same magnitude order are found near a brittle anhydrite layer in the overburden of mainly rock salt evaporites.

  12. ARMA models for earthquake ground motions. Seismic safety margins research program

    Energy Technology Data Exchange (ETDEWEB)

    Chang, M. K.; Kwiatkowski, J. W.; Nau, R. F.; Oliver, R. M.; Pister, K. S.

    1981-02-01

    Four major California earthquake records were analyzed by use of a class of discrete linear time-domain processes commonly referred to as ARMA (Autoregressive/Moving-Average) models. It was possible to analyze these different earthquakes, identify the order of the appropriate ARMA model(s), estimate parameters, and test the residuals generated by these models. It was also possible to show the connections, similarities, and differences between the traditional continuous models (with parameter estimates based on spectral analyses) and the discrete models with parameters estimated by various maximum-likelihood techniques applied to digitized acceleration data in the time domain. The methodology proposed is suitable for simulating earthquake ground motions in the time domain, and appears to be easily adapted to serve as inputs for nonlinear discrete time models of structural motions. 60 references, 19 figures, 9 tables.

  13. Database for earthquake strong motion studies in Italy

    Science.gov (United States)

    Scasserra, G.; Stewart, J.P.; Kayen, R.E.; Lanzo, G.

    2009-01-01

    We describe an Italian database of strong ground motion recordings and databanks delineating conditions at the instrument sites and characteristics of the seismic sources. The strong motion database consists of 247 corrected recordings from 89 earthquakes and 101 recording stations. Uncorrected recordings were drawn from public web sites and processed on a record-by-record basis using a procedure utilized in the Next-Generation Attenuation (NGA) project to remove instrument resonances, minimize noise effects through low- and high-pass filtering, and baseline correction. The number of available uncorrected recordings was reduced by 52% (mostly because of s-triggers) to arrive at the 247 recordings in the database. The site databank includes for every recording site the surface geology, a measurement or estimate of average shear wave velocity in the upper 30 m (Vs30), and information on instrument housing. Of the 89 sites, 39 have on-site velocity measurements (17 of which were performed as part of this study using SASW techniques). For remaining sites, we estimate Vs30 based on measurements on similar geologic conditions where available. Where no local velocity measurements are available, correlations with surface geology are used. Source parameters are drawn from databanks maintained (and recently updated) by Istituto Nazionale di Geofisica e Vulcanologia and include hypocenter location and magnitude for small events (M< ??? 5.5) and finite source parameters for larger events. ?? 2009 A.S. Elnashai & N.N. Ambraseys.

  14. Analyses of surface motions caused by the magnitude 9.0 2004 Sumatra earthquake

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Gudmundsson, Ó.

    The Sumatra, Indonesia, earthquake on December 26th was one of the most devastating earthquakes in history. With a magnitude of Mw = 9.0 it is the forth largest earthquake recorded since 1900. It occurred about one hundred kilometers off the west coast of northern Sumatra, where the relatively thin...... of years. The result was a devastating tsunami hitting coastlines across the Indian Ocean killing more than 225,000 people in Sri Lanka, India, Indonesia, Thailand and Malaysia. An earthquake of this magnitude is expected to involve a displacement on the fault on the order of 10 meters. But, what...... was the actual amplitude of the surface motions that triggered the tsunami? This can be constrained using the amplitudes of elastic waves radiated from the earthquake, or by direct measurements of deformation. Here we present estimates of the deformation based on continuous Global Positioning System (GPS...

  15. Estimation of Motion Vector Fields

    DEFF Research Database (Denmark)

    Larsen, Rasmus

    1993-01-01

    This paper presents an approach to the estimation of 2-D motion vector fields from time varying image sequences. We use a piecewise smooth model based on coupled vector/binary Markov random fields. We find the maximum a posteriori solution by simulated annealing. The algorithm generate sample...

  16. Earthquake Early Warning with Seismogeodesy: Detection, Location, and Magnitude Estimation

    Science.gov (United States)

    Goldberg, D.; Bock, Y.; Melgar, D.

    2016-12-01

    Earthquake early warning is critical to reducing injuries and casualties in case of a large magnitude earthquake. The system must rely on near-source data to minimize the time between event onset and issuance of a warning. Early warning systems typically use seismic instruments (seismometers and accelerometers), but these instruments experience difficulty maintaining reliable data in the near-source region and undergo magnitude saturation for large events. Global Navigation Satellite System (GNSS) instruments capture the long period motions and have been shown to produce robust estimates of the true size of the earthquake source. However, GNSS is often overlooked in this context in part because it is not precise enough to record the first seismic wave arrivals (P-wave detection), an important consideration for issuing an early warning. GNSS instruments are becoming integrated into early warning, but are not yet fully exploited. Our approach involves the combination of direct measurements from collocated GNSS and accelerometer stations to estimate broadband coseismic displacement and velocity waveforms [Bock et al., 2011], a method known as seismogeodesy. We present the prototype seismogeodetic early warning system developed at Scripps and demonstrate that the seismogeodetic dataset can be used for P-wave detection, hypocenter location, and shaking onset determination. We discuss uncertainties in each of these estimates and include discussion of the sensitivity of our estimates as a function of the azimuthal distribution of monitoring stations. The seismogeodetic combination has previously been shown to be immune to magnitude saturation [Crowell et al., 2013; Melgar et al., 2015]. Rapid magnitude estimation is an important product in earthquake early warning, and is the critical metric in current tsunami hazard warnings. Using the seismogeodetic approach, we refine earthquake magnitude scaling using P-wave amplitudes (Pd) and peak ground displacements (PGD) for a

  17. The 2011 Mineral, VA M5.8 Earthquake Ground Motions and Stress Drop: An Important Contribution to the NGA East Ground Motion Database

    Science.gov (United States)

    Cramer, C. H.; Kutliroff, J.; Dangkua, D.

    2011-12-01

    The M5.8 Mineral, Virginia earthquake of August 23, 2011 is the largest instrumentally recorded earthquake in eastern North America since the 1988 M5.9 Saguenay, Canada earthquake. Historically, a similar magnitude earthquake occurred on May 31, 1897 at 18:58 UCT in western Virginia west of Roanoke. Paleoseismic evidence for larger magnitude earthquakes has also been found in the central Virginia region. The Next Generation Attenuation (NGA) East project to develop new ground motion prediction equations for stable continental regions (SCRs), including eastern North America (ENA), is ongoing at the Pacific Earthquake Engineering Research Center funded by the U.S. Nuclear Regulatory Commission, the U.S. Geological Survey, the Electric Power Research Institute, and the U.S. Department of Energy. The available recordings from the M5.8 Virginia are being added to the NGA East ground motion database. Close in (less than 100 km) strong motion recordings are particularly interesting for both ground motion and stress drop estimates as most close-in broadband seismometers clipped on the mainshock. A preliminary estimate for earthquake corner frequency for the M5.8 Virginia earthquake of ~0.7 Hz has been obtained from a strong motion record 57 km from the mainshock epicenter. For a M5.8 earthquake this suggests a Brune stress drop of ~300 bars for the Virginia event. Very preliminary comparisons using accelerometer data suggest the ground motions from the M5.8 Virginia earthquake agree well with current ENA ground motion prediction equations (GMPEs) at short periods (PGA, 0.2 s) and are below the GMPEs at longer periods (1.0 s), which is the same relationship seen from other recent M5 ENA earthquakes. We will present observed versus GMPE ground motion comparisons for all the ground motion observations and stress drop estimates from strong motion recordings at distances less than 100 km. A review of the completed NGA East ENA ground motion database will also be provided.

  18. Development of an Earthquake Early Warning System Using Real-Time Strong Motion Signals

    Directory of Open Access Journals (Sweden)

    Hiroo Kanamori

    2008-01-01

    Full Text Available As urbanization progresses worldwide, earthquakes pose serious threat to livesand properties for urban areas near major active faults on land or subduction zonesoffshore. Earthquake Early Warning (EEW can be a useful tool for reducing earthquakehazards, if the spatial relation between cities and earthquake sources is favorable for suchwarning and their citizens are properly trained to respond to earthquake warning messages.An EEW system forewarns an urban area of forthcoming strong shaking, normally with afew sec to a few tens of sec of warning time, i.e., before the arrival of the destructive Swavepart of the strong ground motion. Even a few second of advanced warning time willbe useful for pre-programmed emergency measures for various critical facilities, such asrapid-transit vehicles and high-speed trains to avoid potential derailment; it will be alsouseful for orderly shutoff of gas pipelines to minimize fire hazards, controlled shutdown ofhigh-technological manufacturing operations to reduce potential losses, and safe-guardingof computer facilities to avoid loss of vital databases. We explored a practical approach toEEW with the use of a ground-motion period parameter τc and a high-pass filtered verticaldisplacement amplitude parameter Pd from the initial 3 sec of the P waveforms. At a givensite, an earthquake magnitude could be determined from τc and the peak ground-motionvelocity (PGV could be estimated from Pd. In this method, incoming strong motion acceleration signals are recursively converted to ground velocity and displacement. A Pwavetrigger is constantly monitored. When a trigger occurs, τc and Pd are computed. Theearthquake magnitude and the on-site ground-motion intensity could be estimated and thewarning could be issued. In an ideal situation, such warnings would be available within 10sec of the origin time of a large earthquake whose subsequent ground motion may last fortens of seconds.

  19. Broadband Ground Motion Simulation of the 2004 and 1977 Vrancea, Romania, Earthquakes Using Empirical Green's Function Method

    Science.gov (United States)

    Poiata, Natalia; Miyake, Hiroe

    2017-09-01

    We estimated the parameters of strong motion generation areas and simulated broadband ground motions for the moderate October 27, 2004 ( M w 5.8) and damaging March 4, 1977 ( M w 7.4) Vrancea (Romania) intermediate-depth subduction earthquakes using the empirical Green's function method. The method allows the simulation of ground motions in a broadband frequency range by summing up the subevent records, corresponding to small magnitude events in the near-source areas, which are assumed to follow the source-scaling relationship and the omega-square source spectral model. We first estimated the strong motion generation area that reproduces near-source ground motions in a broadband frequency range of 0.3-10 Hz for the 2004 earthquake, by fitting the synthetic acceleration, velocity, and displacement waveforms to the observed data. The source properties of the obtained strong motion generation area are in agreement with the predictions made using an empirical source scaling relationship for crustal earthquakes, implying a stress drop of approximately 10 MPa for the 2004 earthquake. We then modeled the strong motion generation area for the 1977 damaging earthquake using the 2004 earthquake as an empirical Green's function and constructing a source model based on its estimated source parameters. To simulate the unique record at Bucharest, capital city of Romania, the rupture was assumed to have propagated from the northeast bottom of the strong motion generation area having a stress drop of 50 MPa. Broadband ground motion simulations were further compared in terms of the modified Mercalli intensity values, calculated from the peak ground accelerations and peak ground velocities of synthetic waveforms, with the observed Medvedev-Sponheuer-Karnik intensity values. Our estimates of the source properties for the 2004 and 1977 Vrancea intermediate-depth earthquakes support the size-dependent stress drop.

  20. Smoothing Motion Estimates for Radar Motion Compensation.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-07-01

    Simple motion models for complex motion environments are often not adequate for keeping radar data coherent. Eve n perfect motion samples appli ed to imperfect models may lead to interim calculations e xhibiting errors that lead to degraded processing results. Herein we discuss a specific i ssue involving calculating motion for groups of pulses, with measurements only available at pulse-group boundaries. - 4 - Acknowledgements This report was funded by General A tomics Aeronautical Systems, Inc. (GA-ASI) Mission Systems under Cooperative Re search and Development Agre ement (CRADA) SC08/01749 between Sandia National Laboratories and GA-ASI. General Atomics Aeronautical Systems, Inc. (GA-ASI), an affilia te of privately-held General Atomics, is a leading manufacturer of Remotely Piloted Aircraft (RPA) systems, radars, and electro-optic and rel ated mission systems, includin g the Predator(r)/Gray Eagle(r)-series and Lynx(r) Multi-mode Radar.

  1. COMPARISONS BETWEEN DAMAGES AND MOTION PARAMETERS CAUSED BY THE 2008 IWAT-MIYAGI NAIRIKU EARTHQUAKE

    Science.gov (United States)

    Kamiyama, Makoto; Matsukawa, Tadashi; Anazawa, Masahiro

    The 2008 Iwate-Miyagi-Nairiku Earthquake, which hit Iwate, Miyagi and Akita Prefectures in Japan with a JMA magnitude of 7.2 on June 14, 2008, caused various kinds of geotechnical damages in the epicentral area. This paper describes the relations between the permanent displacements of ground and damages of soils mainly including slope failure caused by the earthquake. The permanent displacements of ground were obtained using both the position data of the GEONET system operated with aid of GPS and the displacement records numerically estimated from strong ground motions. It is concluded that the permanent displacement of ground can explain well the geotechnical damages occurred during the earthquake rather than strong motion data such as acceleration amplitude and seismic intensity scale.

  2. Conditional spectrum computation incorporating multiple causal earthquakes and ground-motion prediction models

    Science.gov (United States)

    Lin, Ting; Harmsen, Stephen C.; Baker, Jack W.; Luco, Nicolas

    2013-01-01

    The conditional spectrum (CS) is a target spectrum (with conditional mean and conditional standard deviation) that links seismic hazard information with ground-motion selection for nonlinear dynamic analysis. Probabilistic seismic hazard analysis (PSHA) estimates the ground-motion hazard by incorporating the aleatory uncertainties in all earthquake scenarios and resulting ground motions, as well as the epistemic uncertainties in ground-motion prediction models (GMPMs) and seismic source models. Typical CS calculations to date are produced for a single earthquake scenario using a single GMPM, but more precise use requires consideration of at least multiple causal earthquakes and multiple GMPMs that are often considered in a PSHA computation. This paper presents the mathematics underlying these more precise CS calculations. Despite requiring more effort to compute than approximate calculations using a single causal earthquake and GMPM, the proposed approach produces an exact output that has a theoretical basis. To demonstrate the results of this approach and compare the exact and approximate calculations, several example calculations are performed for real sites in the western United States. The results also provide some insights regarding the circumstances under which approximate results are likely to closely match more exact results. To facilitate these more precise calculations for real applications, the exact CS calculations can now be performed for real sites in the United States using new deaggregation features in the U.S. Geological Survey hazard mapping tools. Details regarding this implementation are discussed in this paper.

  3. Earthquake Strong Ground Motion Scenario at the 2008 Olympic Games Sites, Beijing, China

    Science.gov (United States)

    Liu, L.; Rohrbach, E. A.; Chen, Q.; Chen, Y.

    2006-12-01

    Historic earthquake record indicates mediate to strong earthquakes have been frequently hit greater Beijing metropolitan area where is going to host the 2008 summer Olympic Games. For the readiness preparation of emergency response to the earthquake shaking for a mega event in a mega city like Beijing in summer 2008, this paper tries to construct the strong ground motion scenario at a number of gymnasium sites for the 2008 Olympic Games. During the last 500 years (the Ming and Qing Dynasties) in which the historic earthquake record are thorough and complete, there are at least 12 earthquake events with the maximum intensity of VI or greater occurred within 100 km radius centered at the Tiananmen Square, the center of Beijing City. Numerical simulation of the seismic wave propagation and surface strong ground motion is carried out by the pseudospectral time domain methods with viscoelastic material properties. To improve the modeling efficiency and accuracy, a multi-scale approach is adapted: the seismic wave propagation originated from an earthquake rupture source is first simulated by a model with larger physical domain with coarser grids. Then the wavefield at a given plane is taken as the source input for the small-scale, fine grid model for the strong ground motion study at the sites. The earthquake source rupture scenario is based on two particular historic earthquake events: One is the Great 1679 Sanhe-Pinggu Earthquake (M~8, Maximum Intensity XI at the epicenter and Intensity VIII in city center)) whose epicenter is about 60 km ENE of the city center. The other one is the 1730 Haidian Earthquake (M~6, Maximum Intensity IX at the epicenter and Intensity VIII in city center) with the epicentral distance less than 20 km away from the city center in the NW Haidian District. The exist of the thick Tertiary-Quaternary sediments (maximum thickness ~ 2 km) in Beijing area plays a critical role on estimating the surface ground motion at the Olympic Games sites, which

  4. Simulation of Strong Ground Motion of the 2009 Bhutan Earthquake Using Modified Semi-Empirical Technique

    Science.gov (United States)

    Sandeep; Joshi, A.; Lal, Sohan; Kumar, Parveen; Sah, S. K.; Vandana; Kamal

    2017-09-01

    On 21st September 2009 an earthquake of magnitude (M w 6.1) occurred in the East Bhutan. This earthquake caused serious damage to the residential area and was widely felt in the Bhutan Himalaya and its adjoining area. We estimated the source model of this earthquake using modified semi empirical technique. In the rupture plane, several locations of nucleation point have been considered and finalised based on the minimum root mean square error of waveform comparison. In the present work observed and simulated waveforms has been compared at all the eight stations. Comparison of horizontal components of actual and simulated records at these stations confirms the estimated parameters of final rupture model and efficacy of the modified semi-empirical technique (Joshi et al., Nat Hazards 64:1029-1054, 2012b) of strong ground motion simulation.

  5. Directivity in NGA earthquake ground motions: Analysis using isochrone theory

    Science.gov (United States)

    Spudich, P.; Chiou, B.S.J.

    2008-01-01

    We present correction factors that may be applied to the ground motion prediction relations of Abrahamson and Silva, Boore and Atkinson, Campbell and Bozorgnia, and Chiou and Youngs (all in this volume) to model the azimuthally varying distribution of the GMRotI50 component of ground motion (commonly called 'directivity') around earthquakes. Our correction factors may be used for planar or nonplanar faults having any dip or slip rake (faulting mechanism). Our correction factors predict directivity-induced variations of spectral acceleration that are roughly half of the strike-slip variations predicted by Somerville et al. (1997), and use of our factors reduces record-to-record sigma by about 2-20% at 5 sec or greater period. ?? 2008, Earthquake Engineering Research Institute.

  6. Chapter A. The Loma Prieta, California, Earthquake of October 17, 1989 - Strong Ground Motion

    Science.gov (United States)

    Borcherdt, Roger D.

    1994-01-01

    Strong ground motion generated by the Loma Prieta, Calif., earthquake (MS~7.1) of October 17, 1989, resulted in at least 63 deaths, more than 3,757 injuries, and damage estimated to exceed $5.9 billion. Strong ground motion severely damaged critical lifelines (freeway overpasses, bridges, and pipelines), caused severe damage to poorly constructed buildings, and induced a significant number of ground failures associated with liquefaction and landsliding. It also caused a significant proportion of the damage and loss of life at distances as far as 100 km from the epicenter. Consequently, understanding the characteristics of the strong ground motion associated with the earthquake is fundamental to understanding the earthquake's devastating impact on society. The papers assembled in this chapter address this problem. Damage to vulnerable structures from the earthquake varied substantially with the distance from the causative fault and the type of underlying geologic deposits. Most of the damage and loss of life occurred in areas underlain by 'soft soil'. Quantifying these effects is important for understanding the tragic concentrations of damage in such areas as Santa Cruz and the Marina and Embarcadero Districts of San Francisco, and the failures of the San Francisco-Oakland Bay Bridge and the Interstate Highway 880 overpass. Most importantly, understanding these effects is a necessary prerequisite for improving mitigation measures for larger earthquakes likely to occur much closer to densely urbanized areas in the San Francisco Bay region. The earthquake generated an especially important data set for understanding variations in the severity of strong ground motion. Instrumental strong-motion recordings were obtained at 131 sites located from about 6 to 175 km from the rupture zone. This set of recordings, the largest yet collected for an event of this size, was obtained from sites on various geologic deposits, including a unique set on 'soft soil' deposits

  7. Toward automated directivity estimates in earthquake moment tensor inversion

    OpenAIRE

    Huang, Hsin-Hua; Aso, Naofumi; Tsai, Victor C.

    2017-01-01

    Rapid estimates of earthquake rupture properties are useful for both scientific characterization of earthquakes and emergency response to earthquake hazards. Rupture directivity is a particularly important property to constrain since seismic waves radiated in the direction of rupture can be greatly amplified, and even moderate magnitude earthquakes can sometimes cause serious damage. Knowing the directivity of earthquakes is important for ground shaking prediction and hazard mitigation, and i...

  8. Model and parametric uncertainty in source-based kinematic models of earthquake ground motion

    Science.gov (United States)

    Hartzell, Stephen; Frankel, Arthur; Liu, Pengcheng; Zeng, Yuehua; Rahman, Shariftur

    2011-01-01

    Four independent ground-motion simulation codes are used to model the strong ground motion for three earthquakes: 1994 Mw 6.7 Northridge, 1989 Mw 6.9 Loma Prieta, and 1999 Mw 7.5 Izmit. These 12 sets of synthetics are used to make estimates of the variability in ground-motion predictions. In addition, ground-motion predictions over a grid of sites are used to estimate parametric uncertainty for changes in rupture velocity. We find that the combined model uncertainty and random variability of the simulations is in the same range as the variability of regional empirical ground-motion data sets. The majority of the standard deviations lie between 0.5 and 0.7 natural-log units for response spectra and 0.5 and 0.8 for Fourier spectra. The estimate of model epistemic uncertainty, based on the different model predictions, lies between 0.2 and 0.4, which is about one-half of the estimates for the standard deviation of the combined model uncertainty and random variability. Parametric uncertainty, based on variation of just the average rupture velocity, is shown to be consistent in amplitude with previous estimates, showing percentage changes in ground motion from 50% to 300% when rupture velocity changes from 2.5 to 2.9 km/s. In addition, there is some evidence that mean biases can be reduced by averaging ground-motion estimates from different methods.

  9. PET motion correction using PRESTO with ITK motion estimation

    Energy Technology Data Exchange (ETDEWEB)

    Botelho, Melissa [Institute of Biophysics and Biomedical Engineering, Science Faculty of University of Lisbon (Portugal); Caldeira, Liliana; Scheins, Juergen [Institute of Neuroscience and Medicine (INM-4), Forschungszentrum Jülich (Germany); Matela, Nuno [Institute of Biophysics and Biomedical Engineering, Science Faculty of University of Lisbon (Portugal); Kops, Elena Rota; Shah, N Jon [Institute of Neuroscience and Medicine (INM-4), Forschungszentrum Jülich (Germany)

    2014-07-29

    The Siemens BrainPET scanner is a hybrid MRI/PET system. PET images are prone to motion artefacts which degrade the image quality. Therefore, motion correction is essential. The library PRESTO converts motion-corrected LORs into highly accurate generic projection data [1], providing high-resolution PET images. ITK is an open-source software used for registering multidimensional data []. ITK provides motion estimation necessary to PRESTO.

  10. Seismology and Earthquake Ground Motions of the August 24, 2014 M6 South Napa Earthquake

    Science.gov (United States)

    Kishida, T.; Wang, S.; Mazzoni, S.; Markam, C.; Lu, Y.; Bozorgnia, Y.; Mahin, S.; Bray, J.; Panagiotou, M.; Stewart, J. P.; Darragh, R. B.; Abrahamson, N. A.; Hollenback, J. C.; Gutierrez, C.; Chiou, B.; Muin, S.; Dreger, D. S.

    2014-12-01

    The M6.0 South Napa earthquake produced strong ground motions in the northern San Francisco Bay area. A total of 214 three-component uncorrected digital accelerograms were downloaded from the CESMD website and processed following the PEER standard procedure (Ancheta et al. 2014). Intense ground motions were recorded in the heavily damaged area of Napa with peak acceleration greater than 0.3 g. Pulse-like waveforms were observed in several of the velocity time series at the near-fault stations. Near-fault velocity time series were rotated into fault normal and fault parallel directions and then characterized as pulse-like or non pulse-like according to previous studies by Hayden et al. (2014), Shahi (2013), and Lu and Panagiotou (2014). The near-fault velocity time series at five stations contained pulses with periods within the expected range of 0.7 s to 2.0 s for soil sites (Bray et al. 2009). However, they also contained longer period pulses than the expected range. High-frequency spikes were recorded at Carquinez Bridge Geotechnical Array #1 (CBGA1) of approximately 1.0 g on the NS component. These spikes were in the S-wave portion and were consistently observed in the downhole arrays and several other sites along the same azimuth from the source. The spikes increase in amplitude both from the Hwy 37/Napa River East Geotechnical Array to CBGA1 and from a depth below 100 m to the surface. This suggests that the spikes could be a result of path effects and site amplification through the surficial soft soil deposits. However, these observations do not exclude the possibility of soil-structure interaction effects on the measured recordings. The 5% damped pseudo-spectral accelerations (PSA) from the recorded ground motions compared well to those estimated from the recent NGA-West2 GMPEs. The exceptions are that PSA is under predicted from 1 to 3 seconds at several near fault records due to the velocity pulses and for short periods at Carquinez Bridge where the large

  11. Interactive inverse kinematics for human motion estimation

    DEFF Research Database (Denmark)

    Engell-Nørregård, Morten Pol; Hauberg, Søren; Lapuyade, Jerome

    2009-01-01

    We present an application of a fast interactive inverse kinematics method as a dimensionality reduction for monocular human motion estimation. The inverse kinematics solver deals efficiently and robustly with box constraints and does not suffer from shaking artifacts. The presented motion...... estimation system uses a single camera to estimate the motion of a human. The results show that inverse kinematics can significantly speed up the estimation process, while retaining a quality comparable to a full pose motion estimation system. Our novelty lies primarily in use of inverse kinematics...

  12. Analysis of strong-motion data of the 1990 Eastern Sicily earthquake

    Directory of Open Access Journals (Sweden)

    E. Boschi

    1995-06-01

    Full Text Available The strong motion accelerograms recorded during the 1990 Eastern Sicily earthquake have been analyzed to investigate source and attenuation parameters. Peak ground motions (peak acceleration, velocity and displacement overestimate the values predicted by the empirical scaling law proposed for other Italian earthquakes, suggesting that local site response and propagation path effects play an important role in interpreting the observed time histories. The local magnitude, computed from the strong motion accelerograms by synthesizing the Wood-Anderson response, is ML = 5.9, that is sensibly larger than the local magnitude estimated at regional distances from broad-band seismograms (ML = 5.4. The standard omega-square source spectral model seems to be inadequate to describe the observed spectra over the entire frequency band from 0.2 to 20 Hz. The seismic moment estimated from the strong motion accelerogram recorded at the closest rock site (Sortino is Mo = 0.8 x 1024 dyne.cm, that is roughly 4.5 times lower than the value estimated at regional distances (Mo = 3.7 x 1024 dyne.cm from broad-band seismograms. The corner frequency estimated from the accelera- tion spectra i.5 J; = 1.3 Hz, that is close to the inverse of the dUl.ation of displacement pulses at the two closest recording sites. This value of corner tì.equency and the two values of seismic moment yield a Brune stress drop larger than 500 bars. However, a corner frequency value off; = 0.6 Hz and the seismic moment resulting from regional data allows the acceleration spectra to be reproduced on the entire available frequency band yielding to a Brune stress drop of 210 bars. The ambiguity on the corner frequency value associated to this earthquake is due to the limited frequency bandwidth available on the strong motion recordil1gs. Assuming the seismic moment estimated at regional distances from broad-band data, the moment magnitude for this earthquake is 5.7. The higher local magnitude (5

  13. Motion estimation techniques for digital video coding

    CERN Document Server

    Metkar, Shilpa

    2013-01-01

    The book deals with the development of a methodology to estimate the motion field between two frames for video coding applications. This book proposes an exhaustive study of the motion estimation process in the framework of a general video coder. The conceptual explanations are discussed in a simple language and with the use of suitable figures. The book will serve as a guide for new researchers working in the field of motion estimation techniques.

  14. Overview of Ground-Motion Issues for Cascadia Megathrust Events: Simulation of Ground-Motions and Earthquake Site Response

    Directory of Open Access Journals (Sweden)

    Hadi Ghofrani

    2017-09-01

    Full Text Available Ground motions for earthquakes of M7.5 to 9.0 on the Cascadia subduction interface are simulated based on a stochastic finite-fault model and used to estimate average response spectra for reference firm soil conditions. The simulations are first validated by modeling the wealth of ground-motion data from the 2011 M9.0 Tohoku earthquake of Japan. Adjustments to the calibrated model are then made to consider average source, attenuation and site parameters for the Cascadia region. This includes an evaluation of the likely variability in stress drop for large interface earthquakes and an assessment of regional attenuation and site effects. We perform best-estimate simulations for a preferred set of input parameters. Typical results suggest mean values of 5%-damped pseudoacceleration in the range from about 100 to 200 cm/s2, at frequencies from 1 to 4 Hz, for firm-ground conditions in Vancouver. Uncertainty in most-likely value of the parameter representing stress drop causes variability in simulated response spectra of about ±50%. Uncertainties in the attenuation model produce even larger variability in response spectral amplitudes—a factor of about two at a closest distance to the rupture plane (Rcd of 100 km, becoming even larger at greater distances. It is thus important to establish the regional attenuation model for ground-motion simulations and to bound the source properties controlling radiation of ground motion. We calculate theoretical one-dimensional spectral amplification estimates for four selected Fraser River Delta sites to show how the presence of softer sediments in the region may alter the predicted ground motions. The amplification functions are largely consistent with observed spectral amplification at Fraser River delta sites, suggesting amplification by factors of 2.5–5 at the peak frequency of the site; we note that deep sites in the delta have a low peak frequency, ∼0.3 Hz. This work will aid in seismic hazard

  15. Stochastic ground-motion simulations for the 2016 Kumamoto, Japan, earthquake

    Science.gov (United States)

    Zhang, Long; Chen, Guangqi; Wu, Yanqiang; Jiang, Han

    2016-11-01

    On April 15, 2016, Kumamoto, Japan, was struck by a large earthquake sequence, leading to severe casualty and building damage. The stochastic finite-fault method based on a dynamic corner frequency has been applied to perform ground-motion simulations for the 2016 Kumamoto earthquake. There are 53 high-quality KiK-net stations available in the Kyushu region, and we employed records from all stations to determine region-specific source, path and site parameters. The calculated S-wave attenuation for the Kyushu region beneath the volcanic and non-volcanic areas can be expressed in the form of Q s = (85.5 ± 1.5) f 0.68±0.01 and Q s = (120 ± 5) f 0.64±0.05, respectively. The effects of lateral S-wave velocity and attenuation heterogeneities on the ground-motion simulations were investigated. Site amplifications were estimated using the corrected cross-spectral ratios technique. Zero-distance kappa filter was obtained to be the value of 0.0514 ± 0.0055 s, using the spectral decay method. The stress drop of the mainshock based on the USGS slip model was estimated optimally to have a value of 64 bars. Our finite-fault model with optimized parameters was validated through the good agreement of observations and simulations at all stations. The attenuation characteristics of the simulated peak ground accelerations were also successfully captured by the ground-motion prediction equations. Finally, the ground motions at two destructively damaged regions, Kumamoto Castle and Minami Aso village, were simulated. We conclude that the stochastic finite-fault method with well-determined parameters can reproduce the ground-motion characteristics of the 2016 Kumamoto earthquake in both the time and frequency domains. This work is necessary for seismic hazard assessment and mitigation.[Figure not available: see fulltext.

  16. Fault Structural Control on Earthquake Strong Ground Motions: The 2008 Wenchuan Earthquake as an Example

    Science.gov (United States)

    Zhang, Yan; Zhang, Dongli; Li, Xiaojun; Huang, Bei; Zheng, Wenjun; Wang, Yuejun

    2017-12-01

    Continental thrust faulting earthquakes pose severe threats to megacities across the world. Recent events show the possible control of fault structures on strong ground motions. The seismogenic structure of the 2008 Wenchuan earthquake is associated with high-angle listric reverse fault zones. Its peak ground accelerations (PGAs) show a prominent feature of fault zone amplification: the values within the 30- to 40-km-wide fault zone block are significantly larger than those on both the hanging wall and the footwall. The PGA values attenuate asymmetrically: they decay much more rapidly in the footwall than in the hanging wall. The hanging wall effects can be seen on both the vertical and horizontal components of the PGAs, with the former significantly more prominent than the latter. All these characteristics can be adequately interpreted by upward extrusion of the high-angle listric reverse fault zone block. Through comparison with a low-angle planar thrust fault associated with the 1999 Chi-Chi earthquake, we conclude that different fault structures might have controlled different patterns of strong ground motion, which should be taken into account in seismic design and construction.

  17. Long-period ocean-bottom motions in the source areas of large subduction earthquakes.

    Science.gov (United States)

    Nakamura, Takeshi; Takenaka, Hiroshi; Okamoto, Taro; Ohori, Michihiro; Tsuboi, Seiji

    2015-11-30

    Long-period ground motions in plain and basin areas on land can cause large-scale, severe damage to structures and buildings and have been widely investigated for disaster prevention and mitigation. However, such motions in ocean-bottom areas are poorly studied because of their relative insignificance in uninhabited areas and the lack of ocean-bottom strong-motion data. Here, we report on evidence for the development of long-period (10-20 s) motions using deep ocean-bottom data. The waveforms and spectrograms demonstrate prolonged and amplified motions that are inconsistent with attenuation patterns of ground motions on land. Simulated waveforms reproducing observed ocean-bottom data demonstrate substantial contributions of thick low-velocity sediment layers to development of these motions. This development, which could affect magnitude estimates and finite fault slip modelling because of its critical period ranges on their estimations, may be common in the source areas of subduction earthquakes where thick, low-velocity sediment layers are present.

  18. Effects of Ground Motion Input on the Derived Fragility Functions: Case study of 2010 Haiti Earthquake

    Science.gov (United States)

    Hancilar, Ufuk; Harmandar, Ebru; Çakti, Eser

    2014-05-01

    Empirical fragility functions are derived by statistical processing of the data on: i) Damaged and undamaged buildings, and ii) Ground motion intensity values at the buildings' locations. This study investigates effects of different ground motion inputs on the derived fragility functions. The previously constructed fragility curves (Hancilar et al. 2013), which rely on specific shaking intensity maps published by the USGS after the 2010 Haiti Earthquake, are compared with the fragility functions computed in the present study. Building data come from field surveys of 6,347 buildings that are grouped with respect to structural material type and number of stories. For damage assessment, the European Macroseismic Scale (EMS-98) damage grades are adopted. The simplest way to account for the variability in ground motion input could have been achieved by employing different ground motion prediction equations (GMPEs) and their standard variations. However, in this work, we prefer to rely on stochastically simulated ground motions of the Haiti earthquake. We employ five different source models available in the literature and calculate the resulting strong ground motion in time domain. In our simulations we also consider the local site effects by published studies on NEHRP site classes and micro-zoning maps of the city of Port-au-Prince. We estimate the regional distributions from the waveforms simulated at the same coordinates that we have damage information from. The estimated spatial distributions of peak ground accelerations and velocities, PGA and PGV respectively, are then used as input to fragility computations. The results show that changing the ground motion input causes significant variability in the resulting fragility functions.

  19. Estimating the size of an earthquake using short-period seismograms of the first three seconds: A simulated experiment using the 1999 Chi-Chi earthquake sequence

    Science.gov (United States)

    Xu, Yang; Wu, Zhong-Liang; Jiang, Chang-Sheng; Yu, Yan-Xiang; Yang, Jian-Si

    2008-03-01

    Most of the present earthquake early warning systems are based on broadband or strong motion recordings. However, the short-period instruments are still deployed. It is well-known that short-period recordings have saturation problems for large earthquakes when estimating the size of an earthquake. Thus, it is necessary to make clear the magnitude at which saturation starts to occur for the commonly used τ c and Pd measurements, respectively. To investigate the possibility of using short-period seismic recordings for earthquake early warning, we conducted a simulated experiment using the strong motion data of the 1999 Chi-Chi earthquake sequence including its main shock and 31 aftershocks, with magnitude span from 4 to 7.6. The strong motion acceleration recordings were convolved with the instrument response of short-period seismographs in northern China to simulate short-period seismograms. Parameters τ c and Pd from the first-three-second seismograms were calculated for the simulated short-period recordings and compared with that obtained by the original strong ground motion recordings. The result showed that to some extent, short-period recordings can be used for threshold earthquake early warning, while the magnitude saturation of Pd estimation can be up to 6.5, better than τ c estimation.

  20. Estimation of source parameters of Chamoli Earthquake, India

    Indian Academy of Sciences (India)

    R. Narasimhan, Krishtel eMaging Solutions

    earthquake in south Iceland. In the present study the source parameters for the 1999 Chamoli earth- quake are calculated at three different sites using strong motion data recorded on Delhi Strong Motion. Accelerograph (DSMA) network maintained by the. CBRI. 2. Data and methodology. Sixteen Digital Triaxial Strong ...

  1. A novel approach for classification of earthquake ground-motion records

    Science.gov (United States)

    Yaghmaei-Sabegh, Saman

    2017-07-01

    This paper presents a new clustering procedure based on K-means and self-organizing map (SOM) network algorithms for classification of earthquake ground-motion records. Six scalar indicators are used in data analysis for describing the frequency content features of earthquake ground motions, named as the average spectral period ( T avg ), the mean period ( T m ), the smoothed spectral predominant period ( T 0), the characteristic period ( T 4.3), the predominant period based on velocity spectrum ( T gSv ), and the shape factor (Ω). Different clustering validity indexes were applied to determine the best estimates of the number of clusters on real and synthetic data. Results showed the high performance of proposed procedure to reveal salient features of complex seismic data. The comparison between the results of clustering analyses recommend the smoothed spectral predominant period as an effective indicator to describe ground-motion classes. The results also showed that K-means algorithm has better performance than SOM algorithm in identification and classification procedure of ground-motion records.

  2. Estimation of Subpixel Motion Using Bispectrum

    Directory of Open Access Journals (Sweden)

    El Mehdi Ismaili Aalaoui

    2008-01-01

    Full Text Available Motion estimation techniques are widely used in today's video processing systems. The frequently used techniques are frequency-domain motion estimation methods, most notably phase correlation (PC. If the image frames are corrupted by Gaussian noises, then cross-correlation and related techniques do not work well. In this paper, however, we have studied this topic from a viewpoint different from the above. Our scheme is based on the bispectrum method for sub-pixel motion estimation of noisy image sequences. Experimental results show that our proposed method performs significantly better than PC technique.

  3. Update of Earthquake Strong-Motion Instrumentation at Lawrence Livermore National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Murray, Robert C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-09-01

    Following the January 1980 earthquake that was felt at Lawrence Livermore National Laboratory (LLNL), a network of strong-motion accelerographs was installed at LLNL. Prior to the 1980 earthquake, there were no accelerographs installed. The ground motion from the 1980 earthquake was estimated from USGS instruments around the Laboratory to be between 0.2 – 0.3 g horizontal peak ground acceleration. These instruments were located at the Veterans Hospital, 5 miles southwest of LLNL, and in San Ramon, about 12 miles west of LLNL. In 2011, the Department of Energy (DOE) requested to know the status of our seismic instruments. We conducted a survey of our instrumentation systems and responded to DOE in a letter. During this survey, it was found that the recorders in Buildings 111 and 332 were not operational. The instruments on Nova had been removed, and only three of the 10 NIF instruments installed in 2005 were operational (two were damaged and five had been removed from operation at the request of the program). After the survey, it was clear that the site seismic instrumentation had degraded substantially and would benefit from an overhaul and more attention to ongoing maintenance. LLNL management decided to update the LLNL seismic instrumentation system. The updated system is documented in this report.

  4. Fine‐Motion Estimation Using Ego/Exo‐Cameras

    National Research Council Canada - National Science Library

    Uhm, Taeyoung; Ryu, Minsoo; Park, Jong‐Il

    2015-01-01

    .... Existing pose estimation using a monocular camera employs either ego‐motion or exo‐motion, both of which are not sufficiently accurate for estimating fine motion due to the motion ambiguity of rotation and translation...

  5. Estimating the macroseismic parameters of earthquakes in eastern Iran

    Science.gov (United States)

    Amini, H.; Gasperini, P.; Zare, M.; Vannucci, G.

    2017-10-01

    Macroseismic intensity values allow assessing the macroseismic parameters of earthquakes such as location, magnitude, and fault orientation. This information is particularly useful for historical earthquakes whose parameters were estimated with low accuracy. Eastern Iran (56°-62°E, 29.5°-35.5°N), which is characterized by several active faults, was selected for this study. Among all earthquakes occurred in this region, only 29 have some macroseismic information. Their intensity values were reported in various intensity scales. After collecting the descriptions, their intensity values were re-estimated in a uniform intensity scale. Thereafter, Boxer method was applied to estimate their corresponding macroseismic parameters. Boxer estimates of macroseismic parameters for instrumental earthquakes (after 1964) were found to be consistent with those published by Global Centroid Moment Tensor Catalog (GCMT). Therefore, this method was applied to estimate location, magnitude, source dimension, and orientation of these earthquakes with macroseismic description in the period 1066-2012. Macroseismic parameters seem to be more reliable than instrumental ones not only for historical earthquakes but also for instrumental earthquakes especially for the ones occurred before 1960. Therefore, as final results of this study we propose to use the macroseismically determined parameters in preparing a catalog for earthquakes before 1960.

  6. Influence of spatial variations in ground motion on earthquake response of arch dams

    Energy Technology Data Exchange (ETDEWEB)

    Chopra, A. [California Univ., Berkeley, CA (United States). Dept. of Civil and Environmental Engineering; Wang, J. [Tsinghua Univ., Beijing (China). Dept. of Hydraulic Engineering

    2010-07-01

    Ground motion recorded at arch dams demonstrate spatial variation or non-uniformity along the dam-foundation interface. Records obtained at two dams demonstrated this phenomena, notably the Pacoima Dam located in California during the magnitude 4.3 earthquake on January 13, 2001, and the magnitude 6.9 Northridge earthquake on January 17, 1994; and the Mauvoisin Dam located in Switzerland during the magnitude 4.6 Valpelline earthquake on March 31, 1996. These spatial variations in ground motion are hardly ever considered in earthquake analysis of arch dams. When they are included, dam-water-interaction is generally oversimplified. This paper discussed the use of the linear analysis procedure, which includes dam-water-foundation rock interaction effects and recognizes the semi-unbounded extent of the rock and impounded water domains in examining the response of the two arch dams to spatially-varying ground motions recorded during earthquakes. Specifically, the paper discussed the Mauvoisin Dam and earthquake records; system and excitation; influence of spatial variations in ground motion; Pacoima Dam and earthquake records; and influence of spatial variations in excitation. It was concluded that spatial variations in ground motion, typically ignored in dam engineering practice, can have profound influence on the earthquake-induced stresses in the dam. This influence depends on the degree to which ground motion varies spatially along the dam-rock interface. 11 refs., 9 figs.

  7. Analyses of computer programs for the probabilistic estimation of design earthquake and seismological characteristics of the Korean Peninsula

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Gi Hwa [Seoul National Univ., Seoul (Korea, Republic of)

    1997-11-15

    The purpose of the present study is to develop predictive equations from simulated motions which are adequate for the Korean Peninsula and analyze and utilize the computer programs for the probabilistic estimation of design earthquakes. In part I of the report, computer programs for the probabilistic estimation of design earthquake are analyzed and applied to the seismic hazard characterizations in the Korean Peninsula. In part II of the report, available instrumental earthquake records are analyzed to estimate earthquake source characteristics and medium properties, which are incorporated into simulation process. And earthquake records are simulated by using the estimated parameters. Finally, predictive equations constructed from the simulation are given in terms of magnitude and hypocentral distances.

  8. Source Process and Ground Motions of the 2008 Wenchuan, China, Earthquake

    Science.gov (United States)

    Koketsu, K.; Hikima, K.; Miyake, H.; Maruyama, T.; Wang, Z.

    2008-12-01

    The 2008 Wenchuan, China, earthquake occurred on May 12 (local time), and ground motions from this earthquake propagated around the world. We obtained the ground motion records observed at stations of FDSN from IRIS DMC. According to surface fault investigations (this study; Hao and Si, 2008) and the aftershock distribution by USGS, we defined a two-segment fault plane. The strike and dip angles for the southern and northern segments are respectively given to be (228, 35) and (232, 65) based on the results of point source analyses. We then carried out a finite source inversion of the first 140 s of 43 P and 8 SH teleseismic waves using the Green's functions of Kikuchi and Kanamori (1991) and the inverse algorithm of Yoshida et al. (1996) with modifications. We also used the location of the hypocenter determined by USGS (103.33E, 30.99N, depth 12 km) as a rupture initiation point. The resultant slip distribution indicates the first asperity with the largest reverse-faulting slip of about 9 m and the second asperity with a strike slip of about 4 m to be located 45 and 170 km northeast of the hypocenter, respectively. Major aftershocks are located surrounding these two asperities. The total seismic moment is 1.0 x 10**21 Nm, which corresponds to a moment magnitude (Mw) of 7.9, and the rupture duration is estimated to be 100 to 120 s. Significant slips appear in a 250 km long region (10,000 km**2) of the source fault, and these length and area are close to averages for an Mw 7.9 low-angle reverse-faulting earthquake. The area is ten times larger than that of the 1995 Kobe, Japan, earthquake. This fault area and the maximum slip three times larger result in energy release about thirty times larger than that of the 1995 Kobe earthquake (Mw 6.9). This difference almost coincides with the difference in the number of fatalities between the 2008 Sichuan and 1995 Kobe earthquakes. Heavily damaged towns such as Wenchuan and Beichuan are located within the surface projection of

  9. Non-Stationary Modelling and Simulation of Near-Source Earthquake Ground Motion

    DEFF Research Database (Denmark)

    Skjærbæk, P. S.; Kirkegaard, Poul Henning; Fouskitakis, G. N.

    This paper is concerned with modelling and simulation of near-source earthquake ground motion. Recent studies have revealed that these motions show heavy non-stationary behaviour with very low frequencies dominating parts of the earthquake sequence. Modelling and simulation of this behaviour...... by an epicentral distance of 16 km and measured during the 1979 Imperial valley earthquake in California (USA). The results of the study indicate that while all three approaches can succesfully predict near-source ground motions, the Neural Network based one gives somewhat poorer simulation results....

  10. Non-Stationary Modelling and Simulation of Near-Source Earthquake Ground Motion

    DEFF Research Database (Denmark)

    Skjærbæk, P. S.; Kirkegaard, Poul Henning; Fouskitakis, G. N.

    1997-01-01

    This paper is concerned with modelling and simulation of near-source earthquake ground motion. Recent studies have revealed that these motions show heavy non-stationary behaviour with very low frequencies dominating parts of the earthquake sequence. Modeling and simulation of this behaviour...... by an epicentral distance of 16 km and measured during the 1979 Imperial Valley earthquake in California (U .S .A.). The results of the study indicate that while all three approaches can successfully predict near-source ground motions, the Neural Network based one gives somewhat poorer simulation results....

  11. The Quake-Catcher Network: Improving Earthquake Strong Motion Observations Through Community Engagement

    Science.gov (United States)

    Cochran, E. S.; Lawrence, J. F.; Christensen, C. M.; Chung, A. I.; Neighbors, C.; Saltzman, J.

    2010-12-01

    The Quake-Catcher Network (QCN) involves the community in strong motion data collection by utilizing volunteer computing techniques and low-cost MEMS accelerometers. Volunteer computing provides a mechanism to expand strong-motion seismology with minimal infrastructure costs, while promoting community participation in science. Micro-Electro-Mechanical Systems (MEMS) triaxial accelerometers can be attached to a desktop computer via USB and are internal to many laptops. Preliminary shake table tests show the MEMS accelerometers can record high-quality seismic data with instrument response similar to research-grade strong-motion sensors. QCN began distributing sensors and software to K-12 schools and the general public in April 2008 and has grown to roughly 1500 stations worldwide. We also recently tested whether sensors could be quickly deployed as part of a Rapid Aftershock Mobilization Program (RAMP) following the 2010 M8.8 Maule, Chile earthquake. Volunteers are recruited through media reports, web-based sensor request forms, as well as social networking sites. Using data collected to date, we examine whether a distributed sensing network can provide valuable seismic data for earthquake detection and characterization while promoting community participation in earthquake science. We utilize client-side triggering algorithms to determine when significant ground shaking occurs and this metadata is sent to the main QCN server. On average, trigger metadata are received within 1-10 seconds from the observation of a trigger; the larger data latencies are correlated with greater server-station distances. When triggers are detected, we determine if the triggers correlate to others in the network using spatial and temporal clustering of incoming trigger information. If a minimum number of triggers are detected then a QCN-event is declared and an initial earthquake location and magnitude is estimated. Initial analysis suggests that the estimated locations and magnitudes are

  12. Estimation of visual motion in image sequences

    DEFF Research Database (Denmark)

    Larsen, Rasmus

    1994-01-01

    are given. In particular we have investigated the use of smoothness of the second order derivatives, and the use of edge model and prior destributions for the field that favor discontinuities to characterize the motion field. A succesful implementation of a temporal interpolation in a sequence of weather...... of motion under an assumption of translatory motion has been considered. Furthermore we have described methods for quantifying the directional certainty with which we have measured the local displacement. A method based on local estimation of the spatio temporal orientation is generalized to give...

  13. Estimation of source parameters of Chamoli Earthquake, India

    Indian Academy of Sciences (India)

    The devastating earthquake (mb = 6.6) at Chamoli, Garhwal Himalaya, which occurred in the morning hours on 29th March 1999, was recorded on Delhi Strong Motion Accelerograph (DSMA) Network operated by the Central Building Research Institute, Roorkee. In this paper the source parameters of this event calculated ...

  14. The SCEC-USGS Dynamic Earthquake Rupture Code Comparison Exercise - Simulations of Large Earthquakes and Strong Ground Motions

    Science.gov (United States)

    Harris, R.

    2015-12-01

    I summarize the progress by the Southern California Earthquake Center (SCEC) and U.S. Geological Survey (USGS) Dynamic Rupture Code Comparison Group, that examines if the results produced by multiple researchers' earthquake simulation codes agree with each other when computing benchmark scenarios of dynamically propagating earthquake ruptures. These types of computer simulations have no analytical solutions with which to compare, so we use qualitative and quantitative inter-code comparisons to check if they are operating satisfactorily. To date we have tested the codes against benchmark exercises that incorporate a range of features, including single and multiple planar faults, single rough faults, slip-weakening, rate-state, and thermal pressurization friction, elastic and visco-plastic off-fault behavior, complete stress drops that lead to extreme ground motion, heterogeneous initial stresses, and heterogeneous material (rock) structure. Our goal is reproducibility, and we focus on the types of earthquake-simulation assumptions that have been or will be used in basic studies of earthquake physics, or in direct applications to specific earthquake hazard problems. Our group's goals are to make sure that when our earthquake-simulation codes simulate these types of earthquake scenarios along with the resulting simulated strong ground shaking, that the codes are operating as expected. For more introductory information about our group and our work, please see our group's overview papers, Harris et al., Seismological Research Letters, 2009, and Harris et al., Seismological Research Letters, 2011, along with our website, scecdata.usc.edu/cvws.

  15. Benchmark for Country-Level Earthquake Strong-Motion Instrumentation Program

    National Research Council Canada - National Science Library

    Widjojo Prakoso; I Nyoman Sukanta

    2013-01-01

    An empirical study to develop benchmark models at country-level to assess the suggested number of earthquake strong-motion stations based on a framework encompassing geographic, demographic, and socio...

  16. Rotational Response of Toe-Restrained Retaining Walls to Earthquake Ground Motions

    National Research Council Canada - National Science Library

    Ebeling, Robert M; White, Barry C

    2006-01-01

    This research report describes the engineering formulation and corresponding software developed for the rotational response of rock-founded, toe-restrained Corps retaining walls to earthquake ground motions...

  17. Rapid decision tool to predict earthquake destruction in Sumatra by using first motion study

    Science.gov (United States)

    Bhakta, Shardul Sanjay

    The main idea of this project is to build an interactive and smart Geographic Information system tool which can help predict intensity of real time earthquakes in Sumatra Island of Indonesia. The tool has an underlying intelligence to predict the intensity of an earthquake depending on analysis of similar earthquakes in the past in that specific region. Whenever an earthquake takes place in Sumatra, a First Motion Study is conducted; this decides its type, depth, latitude and longitude. When the user inputs this information into the input string, the tool will try to find similar earthquakes with a similar First Motion Survey and depth. It will do a survey of similar earthquakes and predict if this real time earthquake can be disastrous or not. This tool has been developed in JAVA. I have used MOJO (Map Objects JAVA Objects) to show map of Indonesia and earthquake locations in the form of points. ESRI has created MOJO which is a set of JAVA API's. The Indonesia map, earthquake location points and its co-relation was all designed using MOJO. MOJO is a powerful tool which made it easy to design the tool. This tool is easy to use and the user has to input only a few parameters for the end result. I hope this tool justifies its use in prediction of earthquakes and help save lives in Sumatra.

  18. Strong motions observed by K-NET and KiK-net during the 2016 Kumamoto earthquake sequence

    Science.gov (United States)

    Suzuki, Wataru; Aoi, Shin; Kunugi, Takashi; Kubo, Hisahiko; Morikawa, Nobuyuki; Nakamura, Hiromitsu; Kimura, Takeshi; Fujiwara, Hiroyuki

    2017-01-01

    The nationwide strong-motion seismograph network of K-NET and KiK-net in Japan successfully recorded the strong ground motions of the 2016 Kumamoto earthquake sequence, which show the several notable characteristics. For the first large earthquake with a JMA magnitude of 6.5 (21:26, April 14, 2016, JST), the large strong motions are concentrated near the epicenter and the strong-motion attenuations are well predicted by the empirical relation for crustal earthquakes with a moment magnitude of 6.1. For the largest earthquake of the sequence with a JMA magnitude of 7.3 (01:25, April 16, 2016, JST), the large peak ground accelerations and velocities extend from the epicentral area to the northeast direction. The attenuation feature of peak ground accelerations generally follows the empirical relation, whereas that for velocities deviates from the empirical relation for stations with the epicentral distance of greater than 200 km, which can be attributed to the large Love wave having a dominant period around 10 s. The large accelerations were observed at stations even in Oita region, more than 70 km northeast from the epicenter. They are attributed to the local induced earthquake in Oita region, whose moment magnitude is estimated to be 5.5 by matching the amplitudes of the corresponding phases with the empirical attenuation relation. The real-time strong-motion observation has a potential for contributing to the mitigation of the ongoing earthquake disasters. We test a methodology to forecast the regions to be exposed to the large shaking in real time, which has been developed based on the fact that the neighboring stations are already shaken, for the largest event of the Kumamoto earthquakes, and demonstrate that it is simple but effective to quickly make warning. We also shows that the interpolation of the strong motions in real time is feasible, which will be utilized for the real-time forecast of ground motions based on the observed shakings.[Figure not available

  19. Rapid estimation of the economic consequences of global earthquakes

    Science.gov (United States)

    Jaiswal, Kishor; Wald, David J.

    2011-01-01

    The U.S. Geological Survey's (USGS) Prompt Assessment of Global Earthquakes for Response (PAGER) system, operational since mid 2007, rapidly estimates the most affected locations and the population exposure at different levels of shaking intensities. The PAGER system has significantly improved the way aid agencies determine the scale of response needed in the aftermath of an earthquake. For example, the PAGER exposure estimates provided reasonably accurate assessments of the scale and spatial extent of the damage and losses following the 2008 Wenchuan earthquake (Mw 7.9) in China, the 2009 L'Aquila earthquake (Mw 6.3) in Italy, the 2010 Haiti earthquake (Mw 7.0), and the 2010 Chile earthquake (Mw 8.8). Nevertheless, some engineering and seismological expertise is often required to digest PAGER's exposure estimate and turn it into estimated fatalities and economic losses. This has been the focus of PAGER's most recent development. With the new loss-estimation component of the PAGER system it is now possible to produce rapid estimation of expected fatalities for global earthquakes (Jaiswal and others, 2009). While an estimate of earthquake fatalities is a fundamental indicator of potential human consequences in developing countries (for example, Iran, Pakistan, Haiti, Peru, and many others), economic consequences often drive the responses in much of the developed world (for example, New Zealand, the United States, and Chile), where the improved structural behavior of seismically resistant buildings significantly reduces earthquake casualties. Rapid availability of estimates of both fatalities and economic losses can be a valuable resource. The total time needed to determine the actual scope of an earthquake disaster and to respond effectively varies from country to country. It can take days or sometimes weeks before the damage and consequences of a disaster can be understood both socially and economically. The objective of the U.S. Geological Survey's PAGER system is

  20. Estimating earthquake magnitudes from reported intensities in the central and eastern United States

    Science.gov (United States)

    Boyd, Oliver; Cramer, Chris H.

    2014-01-01

    A new macroseismic intensity prediction equation is derived for the central and eastern United States and is used to estimate the magnitudes of the 1811–1812 New Madrid, Missouri, and 1886 Charleston, South Carolina, earthquakes. This work improves upon previous derivations of intensity prediction equations by including additional intensity data, correcting magnitudes in the intensity datasets to moment magnitude, and accounting for the spatial and temporal population distributions. The new relation leads to moment magnitude estimates for the New Madrid earthquakes that are toward the lower range of previous studies. Depending on the intensity dataset to which the new macroseismic intensity prediction equation is applied, mean estimates for the 16 December 1811, 23 January 1812, and 7 February 1812 mainshocks, and 16 December 1811 dawn aftershock range from 6.9 to 7.1, 6.8 to 7.1, 7.3 to 7.6, and 6.3 to 6.5, respectively. One‐sigma uncertainties on any given estimate could be as high as 0.3–0.4 magnitude units. We also estimate a magnitude of 6.9±0.3 for the 1886 Charleston, South Carolina, earthquake. We find a greater range of magnitude estimates when also accounting for multiple macroseismic intensity prediction equations. The inability to accurately and precisely ascertain magnitude from intensities increases the uncertainty of the central United States earthquake hazard by nearly a factor of two. Relative to the 2008 national seismic hazard maps, our range of possible 1811–1812 New Madrid earthquake magnitudes increases the coefficient of variation of seismic hazard estimates for Memphis, Tennessee, by 35%–42% for ground motions expected to be exceeded with a 2% probability in 50 years and by 27%–35% for ground motions expected to be exceeded with a 10% probability in 50 years.

  1. PROBABILISTIC SEISMIC ASSESSMENT OF BASE-ISOLATED NPPS SUBJECTED TO STRONG GROUND MOTIONS OF TOHOKU EARTHQUAKE

    Directory of Open Access Journals (Sweden)

    AHMER ALI

    2014-10-01

    Full Text Available The probabilistic seismic performance of a standard Korean nuclear power plant (NPP with an idealized isolation is investigated in the present work. A probabilistic seismic hazard analysis (PSHA of the Wolsong site on the Korean peninsula is performed by considering peak ground acceleration (PGA as an earthquake intensity measure. A procedure is reported on the categorization and selection of two sets of ground motions of the Tohoku earthquake, i.e. long-period and common as Set A and Set B respectively, for the nonlinear time history response analysis of the base-isolated NPP. Limit state values as multiples of the displacement responses of the NPP base isolation are considered for the fragility estimation. The seismic risk of the NPP is further assessed by incorporation of the rate of frequency exceedance and conditional failure probability curves. Furthermore, this framework attempts to show the unacceptable performance of the isolated NPP in terms of the probabilistic distribution and annual probability of limit states. The comparative results for long and common ground motions are discussed to contribute to the future safety of nuclear facilities against drastic events like Tohoku.

  2. Hypocentre estimation of induced earthquakes in Groningen

    NARCIS (Netherlands)

    Spetzler, J.; Dost, Bernard

    2017-01-01

    Induced earthquakes due to gas production have taken place in the province of Groningen in the northeast of The Netherlands since 1986. In the first years of seismicity, a sparse seismological network with large station distances from the seismogenic area in Groningen was used. The location of

  3. Estimation of Natural Frequencies During Earthquakes

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Rytter, A

    1997-01-01

    This paper presents two different recursive prediction error method (RPEM} implementations of multivariate Auto-Regressive Moving- Average (ARMAV) models for identification of a time variant civil engineering structure subject to an earthquake. The two techniques are tested on measurements made...

  4. Earthquake ground-motion in presence of source and medium heterogeneities

    KAUST Repository

    Vyas, Jagdish Chandra

    2017-01-01

    This dissertation work investigates the effects of earthquake rupture complexity and heterogeneities in Earth structure on near-field ground-motions. More specifically, we address two key issues in seismology: (1) near-field ground-shaking variability as function of distance and azimuth for unilateral directive ruptures, and (2) impact of rupture complexity and seismic scattering on Mach wave coherence associated with supershear rupture propagation. We examine earthquake ground-motion variability associated with unilateral ruptures based on ground-motion simulations of the MW 7.3 1992 Landers earthquake, eight simplified source models, and a MW 7.8 rupture simulation (ShakeOut) for the San Andreas fault. Our numerical modeling reveals that the ground-shaking variability in near-fault distances (< 20 km) is larger than that given by empirical ground motion prediction equations. In addition, the variability decreases with increasing distance from the source, exhibiting a power-law decay. The high near-field variability can be explained by strong directivity effects whose influence weaken as we move away from the fault. At the same time, the slope of the power-law decay is found to be dominantly controlled by slip heterogeneity. Furthermore, the ground-shaking variability is high in the rupture propagation direction whereas low in the directions perpendicular to it. However, the variability expressed as a function of azimuth is not only sensitive to slip heterogeneity, but also to rupture velocity. To study Mach wave coherence for supershear ruptures, we consider heterogeneities in rupture parameters (variations in slip, rise time and rupture speed) and 3D scattering media having small-scale random heterogeneities. The Mach wave coherence is reduced at near-fault distances (< 10 km) by the source heterogeneities. At the larger distances from the source, medium scattering plays the dominant role in reducing the Mach wave coherence. Combined effect of the source and

  5. Cerebral palsy characterization by estimating ocular motion

    Science.gov (United States)

    González, Jully; Atehortúa, Angélica; Moncayo, Ricardo; Romero, Eduardo

    2017-11-01

    Cerebral palsy (CP) is a large group of motion and posture disorders caused during the fetal or infant brain development. Sensorial impairment is commonly found in children with CP, i.e., between 40-75 percent presents some form of vision problems or disabilities. An automatic characterization of the cerebral palsy is herein presented by estimating the ocular motion during a gaze pursuing task. Specifically, After automatically detecting the eye location, an optical flow algorithm tracks the eye motion following a pre-established visual assignment. Subsequently, the optical flow trajectories are characterized in the velocity-acceleration phase plane. Differences are quantified in a small set of patients between four to ten years.

  6. Structure-specific selection of earthquake ground motions for the reliable design and assessment of structures

    DEFF Research Database (Denmark)

    Katsanos, E. I.; Sextos, A. G.

    2017-01-01

    A decision support process is presented to accommodate selecting and scaling of earthquake motions as required for the time domain analysis of structures. Code-compatible suites of seismic motions are provided being, at the same time, prequalified through a multi-criterion approach to induce...... was subjected to numerous suites of motions that were highly ranked according to both the proposed approach (δsv–sc) and the conventional one (δconv), that is commonly used for earthquake records selection and scaling. The findings from numerous linear response history analyses reveal the superiority...

  7. Reliable selection of earthquake ground motions for performance-based design

    DEFF Research Database (Denmark)

    Katsanos, Evangelos; Sextos, A.G.

    2016-01-01

    A decision support process is presented to accommodate selecting and scaling of earthquake motions as required for the time domain analysis of structures. Prequalified code-compatible suites of seismic motions are provided through a multi-criterion approach to satisfy prescribed reduced variability...... of the method, by being subjected to numerous suites of motions that were highly ranked according to both the proposed approach (δsv-sc) and the conventional index (δconv), already used by most existing code-based earthquake records selection and scaling procedures. The findings reveal the superiority...

  8. Fundamental questions of earthquake statistics, source behavior, and the estimation of earthquake probabilities from possible foreshocks

    Science.gov (United States)

    Michael, Andrew J.

    2012-01-01

    Estimates of the probability that an ML 4.8 earthquake, which occurred near the southern end of the San Andreas fault on 24 March 2009, would be followed by an M 7 mainshock over the following three days vary from 0.0009 using a Gutenberg–Richter model of aftershock statistics (Reasenberg and Jones, 1989) to 0.04 using a statistical model of foreshock behavior and long‐term estimates of large earthquake probabilities, including characteristic earthquakes (Agnew and Jones, 1991). I demonstrate that the disparity between the existing approaches depends on whether or not they conform to Gutenberg–Richter behavior. While Gutenberg–Richter behavior is well established over large regions, it could be violated on individual faults if they have characteristic earthquakes or over small areas if the spatial distribution of large‐event nucleations is disproportional to the rate of smaller events. I develop a new form of the aftershock model that includes characteristic behavior and combines the features of both models. This new model and the older foreshock model yield the same results when given the same inputs, but the new model has the advantage of producing probabilities for events of all magnitudes, rather than just for events larger than the initial one. Compared with the aftershock model, the new model has the advantage of taking into account long‐term earthquake probability models. Using consistent parameters, the probability of an M 7 mainshock on the southernmost San Andreas fault is 0.0001 for three days from long‐term models and the clustering probabilities following the ML 4.8 event are 0.00035 for a Gutenberg–Richter distribution and 0.013 for a characteristic‐earthquake magnitude–frequency distribution. Our decisions about the existence of characteristic earthquakes and how large earthquakes nucleate have a first‐order effect on the probabilities obtained from short‐term clustering models for these large events.

  9. Neuromorphic Configurable Architecture for Robust Motion Estimation

    Directory of Open Access Journals (Sweden)

    Guillermo Botella

    2008-01-01

    Full Text Available The robustness of the human visual system recovering motion estimation in almost any visual situation is enviable, performing enormous calculation tasks continuously, robustly, efficiently, and effortlessly. There is obviously a great deal we can learn from our own visual system. Currently, there are several optical flow algorithms, although none of them deals efficiently with noise, illumination changes, second-order motion, occlusions, and so on. The main contribution of this work is the efficient implementation of a biologically inspired motion algorithm that borrows nature templates as inspiration in the design of architectures and makes use of a specific model of human visual motion perception: Multichannel Gradient Model (McGM. This novel customizable architecture of a neuromorphic robust optical flow can be constructed with FPGA or ASIC device using properties of the cortical motion pathway, constituting a useful framework for building future complex bioinspired systems running in real time with high computational complexity. This work includes the resource usage and performance data, and the comparison with actual systems. This hardware has many application fields like object recognition, navigation, or tracking in difficult environments due to its bioinspired and robustness properties.

  10. Strong ground motion inferred from liquefaction caused by the 1811-1812 New Madrid, Missouri, earthquakes

    Science.gov (United States)

    Holzer, Thomas L.; Noce, Thomas E.; Bennett, Michael J.

    2015-01-01

    Peak ground accelerations (PGAs) in the epicentral region of the 1811–1812 New Madrid, Missouri, earthquakes are inferred from liquefaction to have been no greater than ∼0.35g. PGA is inferred in an 11,380  km2 area in the Lower Mississippi Valley in Arkansas and Missouri where liquefaction was extensive in 1811–1812. PGA was inferred by applying liquefaction probability curves, which were originally developed for liquefaction hazard mapping, to detailed maps of liquefaction by Obermeier (1989). The low PGA is inferred because both a shallow (1.5 m deep) water table and a large moment magnitude (M 7.7) earthquake were assumed in the analysis. If a deep (5.0 m) water table and a small magnitude (M 6.8) earthquake are assumed, the maximum inferred PGA is 1.10g. Both inferred PGA values are based on an assumed and poorly constrained correction for sand aging. If an aging correction is not assumed, then the inferred PGA is no greater than 0.22g. A low PGA value may be explained by nonlinear site response. Soils in the study area have an averageVS30 of 220±15  m/s. A low inferred PGA is consistent with PGA values estimated from ground‐motion prediction equations that have been proposed for the New Madrid seismic zone when these estimates are corrected for nonlinear soil site effects. This application of liquefaction probability curves demonstrates their potential usefulness in paleoseismology.

  11. Rapid Estimation of Tsunami Impact Following the Samoa Earthquake

    Science.gov (United States)

    Thio, H. K.; Polet, J.

    2009-12-01

    Rapid estimation of the tsunami waveheight after a large earthquake can significantly aid in disaster recovery efforts, planning of post-tsunami surveys and even early warning for more distant regions. We are exploring methods for refining these estimates by addressing variability due to uncertainties in the source parameters. After the Samoa earthquake, we used the solution from the near real-time Research CMT system at the National Earthquake Information Center to compute the tsunami wavefield. Given the close proximity to Samoa and American Samoa, details of the rupture geometry are very important for the character of the tsunami wavefield and we computed tsunami waveforms for several different geometries that are consistent with the rCMT solution. We will evaluate these results by comparing them with observed runups and explore ways to express the uncertainties in the simulated runup maps. We will also evaluate other real-time source estimates for use in rapid tsunami impact simulation.

  12. Motion Estimation System Utilizing Point Cloud Registration

    Science.gov (United States)

    Chen, Qi (Inventor)

    2016-01-01

    A system and method of estimation motion of a machine is disclosed. The method may include determining a first point cloud and a second point cloud corresponding to an environment in a vicinity of the machine. The method may further include generating a first extended gaussian image (EGI) for the first point cloud and a second EGI for the second point cloud. The method may further include determining a first EGI segment based on the first EGI and a second EGI segment based on the second EGI. The method may further include determining a first two dimensional distribution for points in the first EGI segment and a second two dimensional distribution for points in the second EGI segment. The method may further include estimating motion of the machine based on the first and second two dimensional distributions.

  13. Performance of Irikura Recipe Rupture Model Generator in Earthquake Ground Motion Simulations with Graves and Pitarka Hybrid Approach

    Science.gov (United States)

    Pitarka, Arben; Graves, Robert; Irikura, Kojiro; Miyake, Hiroe; Rodgers, Arthur

    2017-09-01

    We analyzed the performance of the Irikura and Miyake (Pure and Applied Geophysics 168(2011):85-104, 2011) (IM2011) asperity-based kinematic rupture model generator, as implemented in the hybrid broadband ground motion simulation methodology of Graves and Pitarka (Bulletin of the Seismological Society of America 100(5A):2095-2123, 2010), for simulating ground motion from crustal earthquakes of intermediate size. The primary objective of our study is to investigate the transportability of IM2011 into the framework used by the Southern California Earthquake Center broadband simulation platform. In our analysis, we performed broadband (0-20 Hz) ground motion simulations for a suite of M6.7 crustal scenario earthquakes in a hard rock seismic velocity structure using rupture models produced with both IM2011 and the rupture generation method of Graves and Pitarka (Bulletin of the Seismological Society of America, 2016) (GP2016). The level of simulated ground motions for the two approaches compare favorably with median estimates obtained from the 2014 Next Generation Attenuation-West2 Project (NGA-West2) ground motion prediction equations (GMPEs) over the frequency band 0.1-10 Hz and for distances out to 22 km from the fault. We also found that, compared to GP2016, IM2011 generates ground motion with larger variability, particularly at near-fault distances (1 s). For this specific scenario, the largest systematic difference in ground motion level for the two approaches occurs in the period band 1-3 s where the IM2011 motions are about 20-30% lower than those for GP2016. We found that increasing the rupture speed by 20% on the asperities in IM2011 produced ground motions in the 1-3 s bandwidth that are in much closer agreement with the GMPE medians and similar to those obtained with GP2016. The potential implications of this modification for other rupture mechanisms and magnitudes are not yet fully understood, and this topic is the subject of ongoing study. We concluded

  14. Performance of Irikura recipe rupture model generator in earthquake ground motion simulations with Graves and Pitarka hybrid approach

    Science.gov (United States)

    Pitarka, Arben; Graves, Robert; Irikura, Kojiro; Miyake, Hiroe; Rodgers, Arthur

    2017-01-01

    We analyzed the performance of the Irikura and Miyake (Pure and Applied Geophysics 168(2011):85–104, 2011) (IM2011) asperity-based kinematic rupture model generator, as implemented in the hybrid broadband ground motion simulation methodology of Graves and Pitarka (Bulletin of the Seismological Society of America 100(5A):2095–2123, 2010), for simulating ground motion from crustal earthquakes of intermediate size. The primary objective of our study is to investigate the transportability of IM2011 into the framework used by the Southern California Earthquake Center broadband simulation platform. In our analysis, we performed broadband (0–20 Hz) ground motion simulations for a suite of M6.7 crustal scenario earthquakes in a hard rock seismic velocity structure using rupture models produced with both IM2011 and the rupture generation method of Graves and Pitarka (Bulletin of the Seismological Society of America, 2016) (GP2016). The level of simulated ground motions for the two approaches compare favorably with median estimates obtained from the 2014 Next Generation Attenuation-West2 Project (NGA-West2) ground motion prediction equations (GMPEs) over the frequency band 0.1–10 Hz and for distances out to 22 km from the fault. We also found that, compared to GP2016, IM2011 generates ground motion with larger variability, particularly at near-fault distances (1 s). For this specific scenario, the largest systematic difference in ground motion level for the two approaches occurs in the period band 1–3 s where the IM2011 motions are about 20–30% lower than those for GP2016. We found that increasing the rupture speed by 20% on the asperities in IM2011 produced ground motions in the 1–3 s bandwidth that are in much closer agreement with the GMPE medians and similar to those obtained with GP2016. The potential implications of this modification for other rupture mechanisms and magnitudes are not yet fully understood, and this topic is the subject of ongoing study

  15. Loss estimates for a Puente Hills blind-thrust earthquake in Los Angeles, California

    Science.gov (United States)

    Field, E.H.; Seligson, H.A.; Gupta, N.; Gupta, V.; Jordan, T.H.; Campbell, K.W.

    2005-01-01

    Based on OpenSHA and HAZUS-MH, we present loss estimates for an earthquake rupture on the recently identified Puente Hills blind-thrust fault beneath Los Angeles. Given a range of possible magnitudes and ground motion models, and presuming a full fault rupture, we estimate the total economic loss to be between $82 and $252 billion. This range is not only considerably higher than a previous estimate of $69 billion, but also implies the event would be the costliest disaster in U.S. history. The analysis has also provided the following predictions: 3,000-18,000 fatalities, 142,000-735,000 displaced households, 42,000-211,000 in need of short-term public shelter, and 30,000-99,000 tons of debris generated. Finally, we show that the choice of ground motion model can be more influential than the earthquake magnitude, and that reducing this epistemic uncertainty (e.g., via model improvement and/or rejection) could reduce the uncertainty of the loss estimates by up to a factor of two. We note that a full Puente Hills fault rupture is a rare event (once every ???3,000 years), and that other seismic sources pose significant risk as well. ?? 2005, Earthquake Engineering Research Institute.

  16. Seismic design technology for breeder reactor structures. Volume 1. Special topics in earthquake ground motion

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, D.P.

    1983-04-01

    This report is divided into twelve chapters: seismic hazard analysis procedures, statistical and probabilistic considerations, vertical ground motion characteristics, vertical ground response spectrum shapes, effects of inclined rock strata on site response, correlation of ground response spectra with intensity, intensity attenuation relationships, peak ground acceleration in the very mean field, statistical analysis of response spectral amplitudes, contributions of body and surface waves, evaluation of ground motion characteristics, and design earthquake motions. (DLC)

  17. A Test of a Strong Ground Motion Prediction Methodology for the 7 September 1999, Mw=6.0 Athens Earthquake

    Energy Technology Data Exchange (ETDEWEB)

    Hutchings, L; Ioannidou, E; Voulgaris, N; Kalogeras, I; Savy, J; Foxall, W; Stavrakakis, G

    2004-08-06

    magnitude earthquake in the particular source zone, thereby having simulated a catalog of ground motion for a period of 500,000 years. The distribution of traditional ground motion parameters of peak acceleration or spectral ordinates then becomes the synthesized record from which we develop hazard curves in the form of the annual probability of exceedance. This approach replaces the aleatory uncertainty that current PSHA studies estimate by regression of empirical parameters from the worldwide database with epistemic uncertainty on what specific sources actually do at specific sites. This is a fundamental change for PSHA and eliminates the need to extrapolate current empirical data that was gathered over about 50 years to represent values for 10{sup -3} annual probability of exceedance or less. This difference becomes especially significant for very sensitive structures that require estimates for 10{sup -5} or less exceedance.

  18. Analysis of the earthquake data and estimation of source parameters in the Kyungsang basin

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Jeong-Moon; Lee, Jun-Hee [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2000-04-01

    The purpose of the present study is to determine the response spectrum for the Korean Peninsula and estimate the seismic source parameters and analyze and simulate the ground motion adequately from the seismic characteristics of Korean Peninsula and compare this with the real data. The estimated seismic source parameters such as apparent seismic stress drop is somewhat unstable because the data are insufficient. When the instrumental earthquake data were continuously accumulated in the future, the modification of these parameters may be developed. Although equations presented in this report are derived from the limited data, they can be utilized both in seismology and earthquake engineering. Finally, predictive equations may be given in terms of magnitude and hypocentral distances using these parameters. The estimation of the predictive equation constructed from the simulation is the object of further study. 34 refs., 27 figs., 10 tabs. (Author)

  19. Estimation of loss caused by earthquakes and secondary technological hazards

    Directory of Open Access Journals (Sweden)

    N. I. Frolova

    2011-11-01

    Full Text Available Assessment of expected loss and damage caused by earthquakes and secondary technological accidents are of primary importance for the development and implementation of preventive measure plans, as well as for emergency management just after the disaster. The paper addresses the procedures for estimations of loss caused by strong events and secondary hazards with information technology application. Examples of individual seismic risk zoning at Russian federal and regional levels are given, as well as that of scenario earthquakes consequences estimation, taking into account secondary technological hazards.

  20. Ego-Motion Estimation of Drones

    OpenAIRE

    Ay, Emre

    2017-01-01

    To remove the dependency on external structure for drone positioning in GPS-denied environments, it is desirable to estimate the ego-motion of drones on-board. Visual positioning systems have been studied for quite some time and the literature on the area is diligent. The aim of this project is to investigate the currently available methods and implement a visual odometry system for drones which is capable of giving continuous estimates with a lightweight solution. In that manner, the state o...

  1. Global Building Inventory for Earthquake Loss Estimation and Risk Management

    Science.gov (United States)

    Jaiswal, Kishor; Wald, David; Porter, Keith

    2010-01-01

    We develop a global database of building inventories using taxonomy of global building types for use in near-real-time post-earthquake loss estimation and pre-earthquake risk analysis, for the U.S. Geological Survey’s Prompt Assessment of Global Earthquakes for Response (PAGER) program. The database is available for public use, subject to peer review, scrutiny, and open enhancement. On a country-by-country level, it contains estimates of the distribution of building types categorized by material, lateral force resisting system, and occupancy type (residential or nonresidential, urban or rural). The database draws on and harmonizes numerous sources: (1) UN statistics, (2) UN Habitat’s demographic and health survey (DHS) database, (3) national housing censuses, (4) the World Housing Encyclopedia and (5) other literature.

  2. Earthquake ground motion simulation at Zoser pyramid using the stochastic method: A step toward the preservation of an ancient Egyptian heritage

    Science.gov (United States)

    Khalil, Amin E.; Abdel Hafiez, H. E.; Girgis, Milad; Taha, M. A.

    2017-06-01

    Strong ground shaking during earthquakes can greatly affect the ancient monuments and subsequently demolish the human heritage. On October 12th 1992, a moderate earthquake (Ms = 5.8) shocked the greater Cairo area causing widespread damages. Unfortunately, the focus of that earthquake is located about 14 km to the south of Zoser pyramid. After the earthquake, the Egyptian Supreme council of antiquities issued an alarm that Zoser pyramid is partially collapsed and international and national efforts are exerted to restore this important human heritage that was built about 4000 years ago. Engineering and geophysical work is thus needed for the restoration process. The definition of the strong motion parameters is one of the required studies since seismically active zone is recorded in its near vicinity. The present study adopted the stochastic method to determine the peak ground motion (acceleration, velocity and displacement) for the three largest earthquakes recorded in the Egypt's seismological history. These earthquakes are Shedwan earthquake with magnitude Ms = 6.9, Aqaba earthquake with magnitude Mw = 7.2 and Cairo (Dahshour earthquake) with magnitude Ms = 5.8. The former two major earthquakes took place few hundred kilometers away. It is logic to have the predominant effects from the epicentral location of the Cairo earthquake; however, the authors wanted to test also the long period effects of the large distance earthquakes expected from the other two earthquakes under consideration. In addition, the dynamic site response was studied using the Horizontal to vertical spectral ratio (HVSR) technique. HVSR can provide information about the fundamental frequency successfully; however, the amplification estimation is not accepted. The result represented as either peak ground motion parameters or response spectra indicates that the effects from Cairo earthquake epicenter are the largest for all periods considered in the present study. The level of strong motion as

  3. Earthquake Hazards Program: Risk-Targeted Ground Motion Calculator

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This tool is used to calculate risk-targeted ground motion values from probabilistic seismic hazard curves in accordance with the site-specific ground motion...

  4. Hybrid Broadband Ground-Motion Simulation Using Scenario Earthquakes for the Istanbul Area

    KAUST Repository

    Reshi, Owais A.

    2016-04-13

    Seismic design, analysis and retrofitting of structures demand an intensive assessment of potential ground motions in seismically active regions. Peak ground motions and frequency content of seismic excitations effectively influence the behavior of structures. In regions of sparse ground motion records, ground-motion simulations provide the synthetic seismic records, which not only provide insight into the mechanisms of earthquakes but also help in improving some aspects of earthquake engineering. Broadband ground-motion simulation methods typically utilize physics-based modeling of source and path effects at low frequencies coupled with high frequency semi-stochastic methods. I apply the hybrid simulation method by Mai et al. (2010) to model several scenario earthquakes in the Marmara Sea, an area of high seismic hazard. Simulated ground motions were generated at 75 stations using systematically calibrated model parameters. The region-specific source, path and site model parameters were calibrated by simulating a w4.1 Marmara Sea earthquake that occurred on November 16, 2015 on the fault segment in the vicinity of Istanbul. The calibrated parameters were then used to simulate the scenario earthquakes with magnitudes w6.0, w6.25, w6.5 and w6.75 over the Marmara Sea fault. Effects of fault geometry, hypocenter location, slip distribution and rupture propagation were thoroughly studied to understand variability in ground motions. A rigorous analysis of waveforms reveal that these parameters are critical for determining the behavior of ground motions especially in the near-field. Comparison of simulated ground motion intensities with ground-motion prediction quations indicates the need of development of the region-specific ground-motion prediction equation for Istanbul area. Peak ground motion maps are presented to illustrate the shaking in the Istanbul area due to the scenario earthquakes. The southern part of Istanbul including Princes Islands show high amplitudes

  5. A flatfile of ground motion intensity measurements from induced earthquakes in Oklahoma and Kansas

    Science.gov (United States)

    Rennolet, Steven B.; Moschetti, Morgan P.; Thompson, Eric M.; Yeck, William

    2018-01-01

    We have produced a uniformly processed database of orientation-independent (RotD50, RotD100) ground motion intensity measurements containing peak horizontal ground motions (accelerations and velocities) and 5-percent-damped pseudospectral accelerations (0.1–10 s) from more than 3,800 M ≥ 3 earthquakes in Oklahoma and Kansas that occurred between January 2009 and December 2016. Ground motion time series were collected from regional, national, and temporary seismic arrays out to 500 km. We relocated the majority of the earthquake hypocenters using a multiple-event relocation algorithm to produce a set of near-uniformly processed hypocentral locations. Ground motion processing followed standard methods, with the primary objective of reducing the effects of noise on the measurements. Regional wave-propagation features and the high seismicity rate required careful selection of signal windows to ensure that we captured the entire ground motion record and that contaminating signals from extraneous earthquakes did not contribute to the database. Processing was carried out with an automated scheme and resulted in a database comprising more than 174,000 records (https://dx.doi.org/10.5066/F73B5X8N). We anticipate that these results will be useful for improved understanding of earthquake ground motions and for seismic hazard applications.

  6. Response spectra for differential motion of structures supports during earthquakes in Egypt

    Directory of Open Access Journals (Sweden)

    Mohamed I.S. Elmasry

    2012-12-01

    Full Text Available Differential motions of ground supports of stiff structures with large plan dimensions and separate foundations under earthquakes were studied by researchers during the last few decades. Such a type of structural response was previously underestimated. The importance of studying such a response comes up from the fact that usually the structures affected are of strategic importance such as bridges. During their expected life, structures may experience vibrations excited by ground waves of short wavelengths during near-source earthquakes, or during amplified earthquake signals, during explosions, or during vibrations induced from nearby strong vibration sources. This is the case when the differential motion of supports becomes considerable. This paper aims to review the effects of seismic signal variations along the structures dimensions with emphasis on Egypt as a case study. The paper shows some patterns of the damage imposed by such differential motion. A replication of the differential motion in the longitudinal direction is applied on a frame bridge model. The resulting straining actions show the necessity for considering the differential motion of supports in the design of special structures in Egypt. Finally, response spectra for the differential motion of supports, based on the available data from previous earthquakes in Egypt, is derived and proposed for designers to include in the design procedure when accounting for such type of structural response, and especially in long-span bridges.

  7. Earthquakes

    Science.gov (United States)

    Shedlock, Kaye M.; Pakiser, Louis Charles

    1998-01-01

    One of the most frightening and destructive phenomena of nature is a severe earthquake and its terrible aftereffects. An earthquake is a sudden movement of the Earth, caused by the abrupt release of strain that has accumulated over a long time. For hundreds of millions of years, the forces of plate tectonics have shaped the Earth as the huge plates that form the Earth's surface slowly move over, under, and past each other. Sometimes the movement is gradual. At other times, the plates are locked together, unable to release the accumulating energy. When the accumulated energy grows strong enough, the plates break free. If the earthquake occurs in a populated area, it may cause many deaths and injuries and extensive property damage. Today we are challenging the assumption that earthquakes must present an uncontrollable and unpredictable hazard to life and property. Scientists have begun to estimate the locations and likelihoods of future damaging earthquakes. Sites of greatest hazard are being identified, and definite progress is being made in designing structures that will withstand the effects of earthquakes.

  8. The 26 January 2001 M 7.6 Bhuj, India, earthquake: Observed and predicted ground motions

    Science.gov (United States)

    Hough, S.E.; Martin, S.; Bilham, R.; Atkinson, G.M.

    2002-01-01

    Although local and regional instrumental recordings of the devastating 26, January 2001, Bhuj earthquake are sparse, the distribution of macroseismic effects can provide important constraints on the mainshock ground motions. We compiled available news accounts describing damage and other effects and interpreted them to obtain modified Mercalli intensities (MMIs) at >200 locations throughout the Indian subcontinent. These values are then used to map the intensity distribution throughout the subcontinent using a simple mathematical interpolation method. Although preliminary, the maps reveal several interesting features. Within the Kachchh region, the most heavily damaged villages are concentrated toward the western edge of the inferred fault, consistent with western directivity. Significant sediment-induced amplification is also suggested at a number of locations around the Gulf of Kachchh to the south of the epicenter. Away from the Kachchh region, intensities were clearly amplified significantly in areas that are along rivers, within deltas, or on coastal alluvium, such as mudflats and salt pans. In addition, we use fault-rupture parameters inferred from teleseismic data to predict shaking intensity at distances of 0-1000 km. We then convert the predicted hard-rock ground-motion parameters to MMI by using a relationship (derived from Internet-based intensity surveys) that assigns MMI based on the average effects in a region. The predicted MMIs are typically lower by 1-3 units than those estimated from news accounts, although they do predict near-field ground motions of approximately 80%g and potentially damaging ground motions on hard-rock sites to distances of approximately 300 km. For the most part, this discrepancy is consistent with the expected effect of sediment response, but it could also reflect other factors, such as unusually high building vulnerability in the Bhuj region and a tendency for media accounts to focus on the most dramatic damage, rather than

  9. Annualized earthquake loss estimates for California and their sensitivity to site amplification

    Science.gov (United States)

    Chen, Rui; Jaiswal, Kishor; Bausch, D; Seligson, H; Wills, C.J.

    2016-01-01

    Input datasets for annualized earthquake loss (AEL) estimation for California were updated recently by the scientific community, and include the National Seismic Hazard Model (NSHM), site‐response model, and estimates of shear‐wave velocity. Additionally, the Federal Emergency Management Agency’s loss estimation tool, Hazus, was updated to include the most recent census and economic exposure data. These enhancements necessitated a revisit to our previous AEL estimates and a study of the sensitivity of AEL estimates subjected to alternate inputs for site amplification. The NSHM ground motions for a uniform site condition are modified to account for the effect of local near‐surface geology. The site conditions are approximated in three ways: (1) by VS30 (time‐averaged shear‐wave velocity in the upper 30 m) value obtained from a geology‐ and topography‐based map consisting of 15 VS30 groups, (2) by site classes categorized according to National Earthquake Hazards Reduction Program (NEHRP) site classification, and (3) by a uniform NEHRP site class D. In case 1, ground motions are amplified using the Seyhan and Stewart (2014) semiempirical nonlinear amplification model. In cases 2 and 3, ground motions are amplified using the 2014 version of the NEHRP site amplification factors, which are also based on the Seyhan and Stewart model but are approximated to facilitate their use for building code applications. Estimated AELs are presented at multiple resolutions, starting with the state level assessment and followed by detailed assessments for counties, metropolitan statistical areas (MSAs), and cities. AEL estimate at the state level is ∼$3.7  billion, 70% of which is contributed from Los Angeles–Long Beach–Santa Ana, San Francisco–Oakland–Fremont, and Riverside–San Bernardino–Ontario MSAs. The statewide AEL estimate is insensitive to alternate assumptions of site amplification. However, we note significant differences in AEL estimates

  10. The Quake-Catcher Network: A Community-Led, Strong-Motion Network with Implications for Earthquake Advanced Alert

    Science.gov (United States)

    Cochran, E. S.; Lawrence, J. F.; Christensen, C. M.; Jakka, R. S.; Chung, A. I.

    2009-12-01

    The goal of the Quake-Catcher Network (QCN) is to dramatically increase the number of strong-motion observations by exploiting recent advances in sensing technologies and cyberinfrastructure. Micro-Electro-Mechanical Systems (MEMS) triaxial accelerometers are very low cost (50-100), interface to any desktop computer via USB cable, and provide high-quality acceleration data. Preliminary shake table tests show the MEMS accelerometers can record high-fidelity seismic data and provide linear phase and amplitude response over a wide frequency range. Volunteer computing provides a mechanism to expand strong-motion seismology with minimal infrastructure costs, while promoting community participation in science. Volunteer computing also allows for rapid transfer of metadata, such as that used to rapidly determine the magnitude and location of an earthquake, from participating stations. QCN began distributing sensors and software to K-12 schools and the general public in April 2008 and has grown to roughly 1000 stations. Initial analysis shows metadata are received within 1-14 seconds from the observation of a trigger; the larger data latencies are correlated with greater server-station distances. Currently, we are testing a series of triggering algorithms to maximize the number of earthquakes captured while minimizing false triggers. We are also testing algorithms to automatically detect P- and S-wave arrivals in real time. Trigger times, wave amplitude, and station information are currently uploaded to the server for each trigger. Future work will identify additional metadata useful for quickly determining earthquake location and magnitude. The increased strong-motion observations made possible by QCN will greatly augment the capability of seismic networks to quickly estimate the location and magnitude of an earthquake for advanced alert to the public. In addition, the dense waveform observations will provide improved source imaging of a rupture in near-real-time. These

  11. Robust Global Motion Estimation with Matrix Completion

    Directory of Open Access Journals (Sweden)

    F. Arrigoni

    2014-06-01

    Full Text Available In this paper we address the problem of estimating the attitudes and positions of a set of cameras in an external coordinate system. Starting from a conventional global structure-from-motion pipeline, we present some substantial advances. In order to detect outlier relative rotations extracted from pairs of views, we improve a state-of-the-art algorithm based on cycle consistency, by introducing cycle bases. We estimate the angular attitudes of the cameras by proposing a novel gradient descent algorithm based on low-rank matrix completion, that naturally copes with the case of missing data. As for position recovery, we analyze an existing technique from a theoretical point of view, providing some insights on the conditions that guarantee solvability. We provide experimental results on both synthetic and real image sequences for which ground truth calibration is provided.

  12. Rapid estimate of earthquake source duration: application to tsunami warning.

    Science.gov (United States)

    Reymond, Dominique; Jamelot, Anthony; Hyvernaud, Olivier

    2016-04-01

    We present a method for estimating the source duration of the fault rupture, based on the high-frequency envelop of teleseismic P-Waves, inspired from the original work of (Ni et al., 2005). The main interest of the knowledge of this seismic parameter is to detect abnormal low velocity ruptures that are the characteristic of the so called 'tsunami-earthquake' (Kanamori, 1972). The validation of the results of source duration estimated by this method are compared with two other independent methods : the estimated duration obtained by the Wphase inversion (Kanamori and Rivera, 2008, Duputel et al., 2012) and the duration calculated by the SCARDEC process that determines the source time function (M. Vallée et al., 2011). The estimated source duration is also confronted to the slowness discriminant defined by Newman and Okal, 1998), that is calculated routinely for all earthquakes detected by our tsunami warning process (named PDFM2, Preliminary Determination of Focal Mechanism, (Clément and Reymond, 2014)). Concerning the point of view of operational tsunami warning, the numerical simulations of tsunami are deeply dependent on the source estimation: better is the source estimation, better will be the tsunami forecast. The source duration is not directly injected in the numerical simulations of tsunami, because the cinematic of the source is presently totally ignored (Jamelot and Reymond, 2015). But in the case of a tsunami-earthquake that occurs in the shallower part of the subduction zone, we have to consider a source in a medium of low rigidity modulus; consequently, for a given seismic moment, the source dimensions will be decreased while the slip distribution increased, like a 'compact' source (Okal, Hébert, 2007). Inversely, a rapid 'snappy' earthquake that has a poor tsunami excitation power, will be characterized by higher rigidity modulus, and will produce weaker displacement and lesser source dimensions than 'normal' earthquake. References: CLément, J

  13. Nonlinear Responses of High-rise Buildings in Seattle for Simulated Ground Motions From Giant Cascadia Subduction Earthquakes (Mw 9.2)

    Science.gov (United States)

    Yang, J.; Heaton, T. H.

    2008-12-01

    With the exception of the 2003 Tokachi-oki earthquake, strong ground recordings from large subduction earthquakes (Mw > 8.0) are meager. Furthermore there are no strong motion recordings of giant earthquakes. However, there is a growing set of high-quality broadband teleseismic recordings of large and giant earthquakes. In this poster, we use recordings from the 2003 Tokachi-oki (Mw 8.3) earthquake as empirical Green's functions to simulate the rock and soil ground motions from a scenario Mw 9.2 subduction earthquake on Cascadia subduction zone in the frequency band of interest to flexible and large- scale buildings (0.075 to 1 Hz). The effect of amplification by the Seattle basin is considered by using a basin response Green's function which is derived from deconvolving the teleseismic waves recorded at rock sites from soil sites at the SHIP02 experiment. These strong ground motions are used to excite simulation of the fully nonlinear seismic responses of 20-story and 6-story steel moment-frame buildings designed according to both the U.S. 1994 UBC and also the Japanese building code published in 1987. We consider several realizations of the hypothetical subduction earthquake; the down-dip limit of rupture is of particular importance to the simulated ground motions in Seattle. If slip is assumed to be limited to offshore regions, then the building simulations indicate that the building responses are mostly in the linear range. However, our simulation shows that buildings with brittle welds would collapse for rupture models where rupture extends beneath the Olympic Mountains. The ground motions all have very long durations (more than 4 minutes), and our building simulations should be considered as a minimum estimate since we have used a very simple model of degradation of the structure.

  14. Uncertainty of earthquake losses due to model uncertainty of input ground motions in the Los Angeles area

    Science.gov (United States)

    Cao, T.; Petersen, M.D.

    2006-01-01

    In a recent study we used the Monte Carlo simulation method to evaluate the ground-motion uncertainty of the 2002 update of the California probabilistic seismic hazard model. The resulting ground-motion distribution is used in this article to evaluate the contribution of the hazard model to the uncertainty in earthquake loss ratio, the ratio of the expected loss to the total value of a structure. We use the Hazards U.S. (HAZUS) methodology for loss estimation because it is a widely used and publicly available risk model and intended for regional studies by public agencies and for use by governmental decision makers. We found that the loss ratio uncertainty depends not only on the ground-motion uncertainty but also on the mean ground-motion level. The ground-motion uncertainty, as measured by the coefficient of variation (COV), is amplified when converting to the loss ratio uncertainty because loss increases concavely with ground motion. By comparing the ground-motion uncertainty with the corresponding loss ratio uncertainty for the structural damage of light wood-frame buildings in Los Angeles area, we show that the COV of loss ratio is almost twice the COV of ground motion with a return period of 475 years around the San Andreas fault and other major faults in the area. The loss ratio for the 2475-year ground-motion maps is about a factor of three higher than for the 475-year maps. However, the uncertainties in ground motion and loss ratio for the longer return periods are lower than for the shorter return periods because the uncertainty parameters in the hazard logic tree are independent of the return period, but the mean ground motion increases with return period.

  15. Ground Motion Prediction of Subduction Earthquakes using the Onshore-Offshore Ambient Seismic Field

    Science.gov (United States)

    Viens, L.; Miyake, H.; Koketsu, K.

    2014-12-01

    Seismic waves produced by earthquakes already caused plenty of damages all around the world and are still a real threat to human beings. To reduce seismic risk associated with future earthquakes, accurate ground motion predictions are required, especially for cities located atop sedimentary basins that can trap and amplify these seismic waves. We focus this study on long-period ground motions produced by subduction earthquakes in Japan which have the potential to damage large-scale structures, such as high-rise buildings, bridges, and oil storage tanks. We extracted the impulse response functions from the ambient seismic field recorded by two stations using one as a virtual source, without any preprocessing. This method allows to recover the reliable phases and relative, rather than absolute, amplitudes. To retrieve corresponding Green's functions, the impulse response amplitudes need to be calibrated using observational records of an earthquake which happened close to the virtual source. We show that Green's functions can be extracted between offshore submarine cable-based sea-bottom seismographic observation systems deployed by JMA located atop subduction zones and on-land NIED/Hi-net stations. In contrast with physics-based simulations, this approach has the great advantage to predict ground motions of moderate earthquakes (Mw ~5) at long-periods in highly populated sedimentary basin without the need of any external information about the velocity structure.

  16. Ground motion modeling of Hayward fault scenario earthquakes II:Simulation of long-period and broadband ground motions

    Energy Technology Data Exchange (ETDEWEB)

    Aagaard, B T; Graves, R W; Rodgers, A; Brocher, T M; Simpson, R W; Dreger, D; Petersson, N A; Larsen, S C; Ma, S; Jachens, R C

    2009-11-04

    We simulate long-period (T > 1.0-2.0 s) and broadband (T > 0.1 s) ground motions for 39 scenarios earthquakes (Mw 6.7-7.2) involving the Hayward, Calaveras, and Rodgers Creek faults. For rupture on the Hayward fault we consider the effects of creep on coseismic slip using two different approaches, both of which reduce the ground motions compared with neglecting the influence of creep. Nevertheless, the scenario earthquakes generate strong shaking throughout the San Francisco Bay area with about 50% of the urban area experiencing MMI VII or greater for the magnitude 7.0 scenario events. Long-period simulations of the 2007 Mw 4.18 Oakland and 2007 Mw 4.5 Alum Rock earthquakes show that the USGS Bay Area Velocity Model version 08.3.0 permits simulation of the amplitude and duration of shaking throughout the San Francisco Bay area, with the greatest accuracy in the Santa Clara Valley (San Jose area). The ground motions exhibit a strong sensitivity to the rupture length (or magnitude), hypocenter (or rupture directivity), and slip distribution. The ground motions display a much weaker sensitivity to the rise time and rupture speed. Peak velocities, peak accelerations, and spectral accelerations from the synthetic broadband ground motions are, on average, slightly higher than the Next Generation Attenuation (NGA) ground-motion prediction equations. We attribute at least some of this difference to the relatively narrow width of the Hayward fault ruptures. The simulations suggest that the Spudich and Chiou (2008) directivity corrections to the NGA relations could be improved by including a dependence on the rupture speed and increasing the areal extent of rupture directivity with period. The simulations also indicate that the NGA relations may under-predict amplification in shallow sedimentary basins.

  17. Site-Dependent Ground Motions from Distant Earthquakes. Revised.

    Science.gov (United States)

    1980-12-01

    affect Wing V due in part to a favorable fault plane orientation and attenu- ation through the Yellowstone caldera , both minimizing seismic radiation... formation thick- nesses in the Denver Basin on a line bisecting Wing V . . . 33 2-6 Sections in Figure 2-4 illustrating Denver Basin structure on the...25 5-1 Average Formation Thicknesses Under Wing V Flights .. .. ... 68 7/8 SECTION 1 INTRODUCTION In 1975 a magnitude 6.0 (ML) earthquake

  18. Hazard assessment of long-period ground motions for the Nankai Trough earthquakes

    Science.gov (United States)

    Maeda, T.; Morikawa, N.; Aoi, S.; Fujiwara, H.

    2013-12-01

    We evaluate a seismic hazard for long-period ground motions associated with the Nankai Trough earthquakes (M8~9) in southwest Japan. Large interplate earthquakes occurring around the Nankai Trough have caused serious damages due to strong ground motions and tsunami; most recent events were in 1944 and 1946. Such large interplate earthquake potentially causes damages to high-rise and large-scale structures due to long-period ground motions (e.g., 1985 Michoacan earthquake in Mexico, 2003 Tokachi-oki earthquake in Japan). The long-period ground motions are amplified particularly on basins. Because major cities along the Nankai Trough have developed on alluvial plains, it is therefore important to evaluate long-period ground motions as well as strong motions and tsunami for the anticipated Nankai Trough earthquakes. The long-period ground motions are evaluated by the finite difference method (FDM) using 'characterized source models' and the 3-D underground structure model. The 'characterized source model' refers to a source model including the source parameters necessary for reproducing the strong ground motions. The parameters are determined based on a 'recipe' for predicting strong ground motion (Earthquake Research Committee (ERC), 2009). We construct various source models (~100 scenarios) giving the various case of source parameters such as source region, asperity configuration, and hypocenter location. Each source region is determined by 'the long-term evaluation of earthquakes in the Nankai Trough' published by ERC. The asperity configuration and hypocenter location control the rupture directivity effects. These parameters are important because our preliminary simulations are strongly affected by the rupture directivity. We apply the system called GMS (Ground Motion Simulator) for simulating the seismic wave propagation based on 3-D FDM scheme using discontinuous grids (Aoi and Fujiwara, 1999) to our study. The grid spacing for the shallow region is 200 m and

  19. Displaced rocks, strong motion, and the mechanics of shallow faulting associated with the 1999 Hector Mine, California, earthquake

    Science.gov (United States)

    Michael, Andrew J.; Ross, Stephanie L.; Stenner, Heidi D.

    2002-01-01

    The paucity of strong-motion stations near the 1999 Hector Mine earthquake makes it impossible to make instrumental studies of key questions about near-fault strong-motion patterns associated with this event. However, observations of displaced rocks allow a qualitative investigation of these problems. By observing the slope of the desert surface and the frictional coefficient between these rocks and the desert surface, we estimate the minimum horizontal acceleration needed to displace the rocks. Combining this information with observations of how many rocks were displaced in different areas near the fault, we infer the level of shaking. Given current empirical shaking attenuation relationships, the number of rocks that moved is slightly lower than expected; this implies that slightly lower than expected shaking occurred during the Hector Mine earthquake. Perhaps more importantly, stretches of the fault with 4 m of total displacement at the surface displaced few nearby rocks on 15?? slopes, suggesting that the horizontal accelerations were below 0.2g within meters of the fault scarp. This low level of shaking suggests that the shallow parts of this rupture did not produce strong accelerations. Finally, we did not observe an increased incidence of displaced rocks along the fault zone itself. This suggests that, despite observations of fault-zone-trapped waves generated by aftershocks of the Hector Mine earthquake, such waves were not an important factor in controlling peak ground acceleration during the mainshock.

  20. Development of Earthquake Ground Motion Input for Preclosure Seismic Design and Postclosure Performance Assessment of a Geologic Repository at Yucca Mountain, NV

    Energy Technology Data Exchange (ETDEWEB)

    I. Wong

    2004-11-05

    This report describes a site-response model and its implementation for developing earthquake ground motion input for preclosure seismic design and postclosure assessment of the proposed geologic repository at Yucca Mountain, Nevada. The model implements a random-vibration theory (RVT), one-dimensional (1D) equivalent-linear approach to calculate site response effects on ground motions. The model provides results in terms of spectral acceleration including peak ground acceleration, peak ground velocity, and dynamically-induced strains as a function of depth. In addition to documenting and validating this model for use in the Yucca Mountain Project, this report also describes the development of model inputs, implementation of the model, its results, and the development of earthquake time history inputs based on the model results. The purpose of the site-response ground motion model is to incorporate the effects on earthquake ground motions of (1) the approximately 300 m of rock above the emplacement levels beneath Yucca Mountain and (2) soil and rock beneath the site of the Surface Facilities Area. A previously performed probabilistic seismic hazard analysis (PSHA) (CRWMS M&O 1998a [DIRS 103731]) estimated ground motions at a reference rock outcrop for the Yucca Mountain site (Point A), but those results do not include these site response effects. Thus, the additional step of applying the site-response ground motion model is required to develop ground motion inputs that are used for preclosure and postclosure purposes.

  1. OPTICAL FLOW FOR GLACIER MOTION ESTIMATION

    Directory of Open Access Journals (Sweden)

    C. Vogel

    2012-07-01

    Full Text Available Quantitative measurements of glacier flow over time are an important ingredient for glaciological research, for example to determine the mass balances and the evolution of glaciers. Measuring glacier flow in multi-temporal images involves the estimation of a dense set of corresponding points, which in turn define the flow vectors. Furthermore glaciers exhibit rather difficult radiometry, since their surface usually contains homogeneous areas as well as weak texture and contrast. To date glacier flow is usually observed by manually measuring a sparse set of correspondences, which is labor-intensive and often yields rather irregular point distributions, with the associated problems of interpolating over large areas. In the present work we propose to densely compute motion vectors at every pixel, by using recent robust methods for optic flow computation. Determining the optic flow, i.e. the dense deformation field between two images of a dynamic scene, has been a classic, long-standing research problem in computer vision and image processing. Sophisticated methods exist to optimally balance data fidelity with smoothness of the motion field. Depending on the strength of the local image gradients these methods yield a smooth trade-off between matching and interpolation, thereby avoiding the somewhat arbitrary decision which discrete anchor points to measure, while at the same time mitigating the problem of gross matching errors. We evaluate our method by comparing with manually measured point wise ground truth.

  2. Earthquake shaking hazard estimates and exposure changes in the conterminous United States

    Science.gov (United States)

    Jaiswal, Kishor S.; Petersen, Mark D.; Rukstales, Kenneth S.; Leith, William S.

    2015-01-01

    A large portion of the population of the United States lives in areas vulnerable to earthquake hazards. This investigation aims to quantify population and infrastructure exposure within the conterminous U.S. that are subjected to varying levels of earthquake ground motions by systematically analyzing the last four cycles of the U.S. Geological Survey's (USGS) National Seismic Hazard Models (published in 1996, 2002, 2008 and 2014). Using the 2013 LandScan data, we estimate the numbers of people who are exposed to potentially damaging ground motions (peak ground accelerations at or above 0.1g). At least 28 million (~9% of the total population) may experience 0.1g level of shaking at relatively frequent intervals (annual rate of 1 in 72 years or 50% probability of exceedance (PE) in 50 years), 57 million (~18% of the total population) may experience this level of shaking at moderately frequent intervals (annual rate of 1 in 475 years or 10% PE in 50 years), and 143 million (~46% of the total population) may experience such shaking at relatively infrequent intervals (annual rate of 1 in 2,475 years or 2% PE in 50 years). We also show that there is a significant number of critical infrastructure facilities located in high earthquake-hazard areas (Modified Mercalli Intensity ≥ VII with moderately frequent recurrence interval).

  3. Tsunami Prediction and Earthquake Parameters Estimation in the Red Sea

    KAUST Repository

    Sawlan, Zaid A

    2012-12-01

    Tsunami concerns have increased in the world after the 2004 Indian Ocean tsunami and the 2011 Tohoku tsunami. Consequently, tsunami models have been developed rapidly in the last few years. One of the advanced tsunami models is the GeoClaw tsunami model introduced by LeVeque (2011). This model is adaptive and consistent. Because of different sources of uncertainties in the model, observations are needed to improve model prediction through a data assimilation framework. Model inputs are earthquake parameters and topography. This thesis introduces a real-time tsunami forecasting method that combines tsunami model with observations using a hybrid ensemble Kalman filter and ensemble Kalman smoother. The filter is used for state prediction while the smoother operates smoothing to estimate the earthquake parameters. This method reduces the error produced by uncertain inputs. In addition, state-parameter EnKF is implemented to estimate earthquake parameters. Although number of observations is small, estimated parameters generates a better tsunami prediction than the model. Methods and results of prediction experiments in the Red Sea are presented and the prospect of developing an operational tsunami prediction system in the Red Sea is discussed.

  4. Estimation of source parameters and scaling relations for moderate size earthquakes in North-West Himalaya

    Science.gov (United States)

    Kumar, Vikas; Kumar, Dinesh; Chopra, Sumer

    2016-10-01

    The scaling relation and self similarity of earthquake process have been investigated by estimating the source parameters of 34 moderate size earthquakes (mb 3.4-5.8) occurred in the NW Himalaya. The spectral analysis of body waves of 217 accelerograms recorded at 48 sites have been carried out using in the present analysis. The Brune's ω-2 model has been adopted for this purpose. The average ratio of the P-wave corner frequency, fc(P), to the S-wave corner frequency, fc(S), has been found to be 1.39 with fc(P) > fc(S) for 90% of the events analyzed here. This implies the shift in the corner frequency in agreement with many other similar studies done for different regions. The static stress drop values for all the events analyzed here lie in the range 10-100 bars average stress drop value of the order of 43 ± 19 bars for the region. This suggests the likely estimate of the dynamic stress drop, which is 2-3 times the static stress drop, is in the range of about 80-120 bars. This suggests the relatively high seismic hazard in the NW Himalaya as high frequency strong ground motions are governed by the stress drop. The estimated values of stress drop do not show significant variation with seismic moment for the range 5 × 1014-2 × 1017 N m. This observation along with the cube root scaling of corner frequencies suggests the self similarity of the moderate size earthquakes in the region. The scaling relation between seismic moment and corner frequency Mo fc3 = 3.47 ×1016Nm /s3 estimated in the present study can be utilized to estimate the source dimension given the seismic moment of the earthquake for the hazard assessment. The present study puts the constrains on the important parameters stress drop and source dimension required for the synthesis of strong ground motion from the future expected earthquakes in the region. Therefore, the present study is useful for the seismic hazard and risk related studies for NW Himalaya.

  5. Report of Earthquake Drills with Experiences of Ground Motion in Childcare for Young Children, Japan

    Science.gov (United States)

    Yamada, N.

    2013-12-01

    After the Great East Japan Earthquake of 2011, this disaster has become one of the opportunities to raise awareness of earthquake and tsunami disaster prevention, and the improvement of disaster prevention education is to be emphasized. The influences of these bring the extension to the spatial axis in Japan, and also, it is important to make a development of the education with continuous to the expansion of time axes. Although fire or earthquake drills as the disaster prevention education are often found in Japan, the children and teachers only go from school building to outside. Besides, only the shortness of the time to spend for the drill often attracts attention. The complementary practice education by the cooperation with experts such as the firefighting is practiced, but the verification of the effects is not enough, and it is the present conditions that do not advance to the study either. Although it is expected that improvement and development of the disaster prevention educations are accomplished in future, there are a lot of the problems. Our target is construction and utilization of material contributing to the education about "During the strong motion" in case of the earthquake which may experience even if wherever of Japan. One of the our productions is the handicraft shaking table to utilize as teaching tools of the education to protect the body which is not hurt at the time of strong motion. This made much of simplicity than high reproduction of the earthquake ground motions. We aimed to helping the disaster prevention education including not only the education for young children but also for the school staff and their parents. In this report, the focusing on a way of the non-injured during the time of the earthquake ground motion, and adopting activity of the play, we are going to show the example of the framework of earthquake disaster prevention childcare through the virtual experience. This presentation has a discussion as a practice study with

  6. Recent development of the earthquake strong motion-intensity catalog and intensity prediction equations for Iran

    Science.gov (United States)

    Zare, Mehdi

    2017-07-01

    This study aims to develop a new earthquake strong motion-intensity catalog as well as intensity prediction equations for Iran based on the available data. For this purpose, all the sites which had both recorded strong motion and intensity values throughout the region were first searched. Then, the data belonging to the 306 identified sites were processed, and the results were compiled as a new strong motion-intensity catalog. Based on this new catalog, two empirical equations between the values of intensity and the ground motion parameters (GMPs) for the Iranian earthquakes were calculated. At the first step, earthquake "intensity" was considered as a function of five independent GMPs including "Log (PHA)," "moment magnitude (MW)," "distance to epicenter," "site type," and "duration," and a multiple stepwise regression was calculated. Regarding the correlations between the parameters and the effectiveness coefficients of the predictors, the Log (PHA) was recognized as the most effective parameter on the earthquake "intensity," while the parameter "site type" was removed from the equations since it was determines as the least significant variable. Then, at the second step, a simple ordinary least squares (OLS) regression was fitted only between the parameters intensity and the Log (PHA) which resulted in more over/underestimated intensity values comparing to the results of the multiple intensity-GMPs regression. However, for rapid response purposes, the simple OLS regression may be more useful comparing to the multiple regression due to its data availability and simplicity. In addition, according to 50 selected earthquakes, an empirical relation between the macroseismic intensity (I0) and MW was developed.

  7. Effect of the surface geology on strong ground motions due to the 2016 Central Tottori Earthquake, Japan

    Science.gov (United States)

    Kagawa, Takao; Noguchi, Tatsuya; Yoshida, Shohei; Yamamoto, Shinji

    2017-08-01

    On October 21, 2016, an earthquake with Japan Meteorological Agency (JMA) magnitude 6.6 hit the central part of Tottori Prefecture, Japan. This paper demonstrates two notable effects of the surface geology on strong ground motions due to the earthquake. One is a predominant period issue observed over a large area. A seismic intensity of 6 lower on the JMA scale was registered at three sites in the disaster area. However, the peak ground acceleration ranged from 0.3 to 1.4 G at the three sites because of the varying peak periods of observed strong ground motions. The spectral properties of the observations also reflect the damage around the sites. Three-component microtremors were observed in the area; the predominant ground period distributions based on horizontal to vertical spectral ratios were provided by the authors. The peak periods of the strong motion records agree well with predominant periods estimated from microtremor observations at a rather hard site; however, the predominant periods of the microtremors are slightly shorter than those of the main shock at the other two soft sites. We checked the nonlinear effect at the sites by comparing the site responses to small events and the main shock. The peak periods of the main shock were longer than those of the weak motions at the sites. This phenomenon indicates a nonlinear site effect due to large ground motions caused by the main shock. A horizontal component of the accelerogram showed rather pulsating swings that indicate cyclic mobility behavior, especially at a site close to a pond shore; ground subsidence of 20 cm was observed around the site. The peak periods of weak motions agree well with those of the microtremor observations. This implies an important issue that the predominant periods estimated by microtremors are not sufficient to estimate the effect of surface geology for disaster mitigation. We have to estimate the predominant periods under large ground motions considering the nonlinear site

  8. Kinematic Earthquake Ground‐Motion Simulations on Listric Normal Faults

    KAUST Repository

    Passone, Luca

    2017-11-28

    Complex finite-faulting source processes have important consequences for near-source ground motions, but empirical ground-motion prediction equations still lack near-source data and hence cannot fully capture near-fault shaking effects. Using a simulation-based approach, we study the effects of specific source parameterizations on near-field ground motions where empirical data are limited. Here, we investigate the effects of fault listricity through near-field kinematic ground-motion simulations. Listric faults are defined as curved faults in which dip decreases with depth, resulting in a concave upward profile. The listric profiles used in this article are built by applying a specific shape function and varying the initial dip and the degree of listricity. Furthermore, we consider variable rupture speed and slip distribution to generate ensembles of kinematic source models. These ensembles are then used in a generalized 3D finite-difference method to compute synthetic seismograms; the corresponding shaking levels are then compared in terms of peak ground velocities (PGVs) to quantify the effects of breaking fault planarity. Our results show two general features: (1) as listricity increases, the PGVs decrease on the footwall and increase on the hanging wall, and (2) constructive interference of seismic waves emanated from the listric fault causes PGVs over two times higher than those observed for the planar fault. Our results are relevant for seismic hazard assessment for near-fault areas for which observations are scarce, such as in the listric Campotosto fault (Italy) located in an active seismic area under a dam.

  9. Control grid motion estimation for efficient application of optical flow

    CERN Document Server

    Zwart, Christine M

    2012-01-01

    Motion estimation is a long-standing cornerstone of image and video processing. Most notably, motion estimation serves as the foundation for many of today's ubiquitous video coding standards including H.264. Motion estimators also play key roles in countless other applications that serve the consumer, industrial, biomedical, and military sectors. Of the many available motion estimation techniques, optical flow is widely regarded as most flexible. The flexibility offered by optical flow is particularly useful for complex registration and interpolation problems, but comes at a considerable compu

  10. Comparison of the inelastic response of steel building frames to strong earthquake and underground nuclear explosion ground motion

    Energy Technology Data Exchange (ETDEWEB)

    Murray, R.C.; Tokarz, F.J.

    1976-06-30

    Analytic studies were made of the adequacy of simulating earthquake effects at the Nevada Test Site for structural testing purposes. It is concluded that underground nuclear explosion ground motion will produce inelastic behavior and damage comparable to that produced by strong earthquakes. The generally longer duration of earthquakes compared with underground nuclear explosions does not appear to significantly affect the structural behavior of the building frames considered. A comparison of maximum ductility ratios, maximum story drifts, and maximum displacement indicate similar structural behavior for both types of ground motion. Low yield (10 - kt) underground nuclear explosions are capable of producing inelastic behavior in large structures. Ground motion produced by underground nuclear explosions can produce inelastic earthquake-like effects in large structures and could be used for testing large structures in the inelastic response regime. The Nevada Test Site is a feasible earthquake simulator for testing large structures.

  11. Seismic Source Process and Strong Ground Motion of 1920-Haiyuan Earthquake

    Science.gov (United States)

    Xu, X.; Zhang, Z.; Chen, X.

    2016-12-01

    The 16 December 1920 Haiyuan earthquake (M=7.8 8.3), which occurred near Gan-yanchi along the Haiyuan fault, was one of the largest devastating intraplate earthquakes in China and even in the world. The maximum epicentral intensity reached XI degree. Deng et al. (1989) found nearly 237km surface rupture and 10-11m maximum sinistral strike-slip dislocation in their geological survey. The seismogenic fault (Haiyuan fault) which is located in the northeast Tibetan Plateau, is extremely complex due to the crustal deformation. Many researchers have studied this earthquake and the seismogenic fault by magnetotelluric sounding, deep seismic reflection profile, LiDAR, GPS, InSAR and trenching, etc. However, Because of few seismic recordings available in Haiyuan earthquake, the detailed rupture mechanisms and hazard distribution need to further scientifically analyze. In order to figure out the rupture mechanism of 1920 Haiyuan earthquake, we use two popular methods to model the earthquake source. One is the characterized source model which is based on asperity model. This model can summarize the main features of the rupture process and more in-deep research. Another one is the dynamic rupture model which is based on earthquake source physics. The method can simulate the process of earthquake rupture initiation, extension and termination. Zhang et al. (2014) have studied the 3-D dynamic rupture process on non-planar fault using 3D curved-grid finite-difference method (CG-FDM) which is flexible in modeling a fault with complex geometry and have successfully simulated the dynamic rupture of Wenchuan earthquake. In this work, we build reasonable kinematic and dynamic models based on previous investigations including tectonic stress, friction parameters, co-seismic displacement, and so on. Then, the strong ground motion of Haiyuan earthquake is simulated by CG-FDM. Finally, we analyze the synthetic intensity distribution and the effect on the stress distribution around this

  12. Estimating Source Duration for Moderate and Large Earthquakes in Taiwan

    Science.gov (United States)

    Chang, Wen-Yen; Hwang, Ruey-Der; Ho, Chien-Yin; Lin, Tzu-Wei

    2017-04-01

    Estimating Source Duration for Moderate and Large Earthquakes in Taiwan Wen-Yen Chang1, Ruey-Der Hwang2, Chien-Yin Ho3 and Tzu-Wei Lin4 1 Department of Natural Resources and Environmental Studies, National Dong Hwa University, Hualien, Taiwan, ROC 2Department of Geology, Chinese Culture University, Taipei, Taiwan, ROC 3Department of Earth Sciences, National Cheng Kung University, Tainan, Taiwan, ROC 4Seismology Center, Central Weather Bureau, Taipei, Taiwan, ROC ABSTRACT To construct a relationship between seismic moment (M0) and source duration (t) was important for seismic hazard in Taiwan, where earthquakes were quite active. In this study, we used a proposed inversion process using teleseismic P-waves to derive the M0-t relationship in the Taiwan region for the first time. Fifteen earthquakes with MW 5.5-7.1 and focal depths of less than 40 km were adopted. The inversion process could simultaneously determine source duration, focal depth, and pseudo radiation patterns of direct P-wave and two depth phases, by which M0 and fault plane solutions were estimated. Results showed that the estimated t ranging from 2.7 to 24.9 sec varied with one-third power of M0. That is, M0 is proportional to t**3, and then the relationship between both of them was M0=0.76*10**23(t)**3 , where M0 in dyne-cm and t in second. The M0-t relationship derived from this study was very close to those determined from global moderate to large earthquakes. For further understanding the validity in the derived relationship, through the constructed relationship of M0-, we inferred the source duration of the 1999 Chi-Chi (Taiwan) earthquake with M0=2-5*10**27 dyne-cm (corresponding to Mw = 7.5-7.7) to be approximately 29-40 sec, in agreement with many previous studies for source duration (28-42 sec).

  13. Near-Fault Strong Ground Motions during the 2016 Kumamoto, Japan, Earthquake

    Science.gov (United States)

    Iwata, T.; Asano, K.

    2016-12-01

    The 2016 Kumamoto mainshock (Mw7.0) produced a surface ruptured fault of about 20km long with maximum 2m offset, and identified as a surface ruptured event. Two strong motion records were observed near the surface ruptured fault at Mashiki town hall and Nishihara village hall. We investigated characteristics of those strong ground motions. As the acceleration records consisted of the baseline errors caused by nonzero initial acceleration and tilting of the accelerograph, we carefully removed the baseline errors (c.f. Chiu, 2001, Boore and Bommer, 2005) so as to obtain velocity and displacements. The observed permanent displacements were about 1.2m in horizontal direction and about 0.7m sinking in vertical direction at Mashiki town hall, and about 1.7m and 1.8m, respectively, at Nishihara village hall. Those permanent displacements almost coincide to results by GNSS and InSAR analysis (e.g., GSI, 2016). It takes about only 3 s to reach the permanent displacement. Somerville (2003) pointed out that ground motions from earthquakes producing large surface ruptures appeared to have systematically weaker ground motions than ground motions from earthquakes whose rupture were confined to the subsurface using the Ground Motion Prediction Equation (GMPE) for response spectra (Abrahamson and Silva, 1997). We calculated the response spectra of those records, compared them to the GMPE with the same manner and found two records were systematically larger than the expected from the GMPE in the period range of 0.3 s to 5 s. We need to re-consider the working hypothesis that the near-fault ground motions are weaker and to separate the near-fault and site effects on ground motions. Strong motions in the longer period range would be mainly caused by the near-fault (near-field term) effect.We used the acceleration data of the Kumamoto seismic intensity information network, provided by JMA.

  14. Crustal Stress in the Flinders Ranges, South Australia, From Earthquake First Motion Data

    Science.gov (United States)

    Cummins, P. R.; Balfour, N.; Love, D.

    2010-12-01

    We have used data recorded by a temporary seismograph deployment to infer constraints on the state of crustal stress in the Flinders Ranges in south-central Australia. Previous stress estimates for the region have been poorly constrained due to the lack of large events and limited station coverage for focal mechanisms. New data allowed 65 events with 544 first motions to be used in a stress inversion to estimate the principal stress directions and stress ratio.While our initial inversion suggested that stress in the region was not homogeneous, we found that discarding data for events in the top 2km of the crust resulted in a well-constrained stress orientation that is consistent with the assumption of homogeneous stress throughout the Flinders Ranges. We speculate that the need to screen out shallow events may be due to the presence in the shallow crust of either: (1) small-scale velocity heterogeneity that would bias the ray parameter estimates, or (2) heterogeneity in the stress field itself, possibly due to the influence of the relatively pronounced topographic relief. The stress derived from earthquakes in the Flinders Ranges show an oblique reverse faulting stress regime, which contrasts with the pure thrust and pure strike slip regimes suggested by earlier studies. However, the roughly E-W direction of maximum horizontal compressive stress we obtain supports the conclusion of virtually all previous studies that the Flinders Ranges are undergoing E-W compression due to orogenic events at the boundaries of the Australian and Indian Plates.

  15. Conditional shape models for cardiac motion estimation

    DEFF Research Database (Denmark)

    Metz, Coert; Baka, Nora; Kirisli, Hortense

    2010-01-01

    alignment of pre-operative CTA data with intra-operative X-ray imaging. Due to a trend towards prospective electrocardiogram gating techniques, 4D imaging data, from which motion information could be extracted, is not commonly available. The prediction of motion from shape information is thus relevant...

  16. Strong ground motion in Port-au-Prince, Haiti, during the M7.0 12 January 2010 Haiti earthquake

    Science.gov (United States)

    Hough, Susan E; Given, Doug; Taniguchi, Tomoyo; Altidor, J.R.; Anglade, Dieuseul; Mildor, S-L.

    2011-01-01

    No strong motion records are available for the 12 January 2010 M7.0 Haiti earthquake. We use aftershock recordings as well as detailed considerations of damage to estimate the severity and distribution of mainshock shaking in Port-au-Prince. Relative to ground motions at a hard - rock reference site, peak accelerations are amplified by a factor of approximately 2 at sites on low-lying deposits in central Port-au-Prince and by a factor of 2.5 - 3.5 on a steep foothill ridge in the southern Port-au-Prince metropolitan region. The observed amplification along the ridge cannot be explained by sediment - induced amplification , but is consistent with predicted topographic amplification by a steep, narrow ridge. Although damage was largely a consequence of poor construction , the damage pattern inferred from analysis of remote sensing imagery provides evidence for a correspondence between small-scale (0.1 - 1.0 km) topographic relief and high damage. Mainshock shaking intensity can be estimated crudely from a consideration of macroseismic effects . We further present detailed, quantitative analysis of the marks left on a tile floor by an industrial battery rack displaced during the mainshock, at the location where we observed the highest weak motion amplifications. Results of this analysis indicate that mainshock shaking was significantly higher at this location (~0.5 g , MMI VIII) relative to the shaking in parts of Port-au-Prince that experienced light damage. Our results further illustrate how observations of rigid body horizontal displacement during earthquakes can be used to estimate peak ground accelerations in the absence of instrumental data .

  17. Real-time performance of probabilistic, first-motion earthquake mechanisms to improve tsunami early-warning

    Science.gov (United States)

    Lomax, Anthony; Michelni, Alberto; Bernardi, Fabrizio; Scognamiglio, Laura

    2017-04-01

    The first tsunami warning messages are typically based on simple earthquake parameters: epicenter location, hypocenter depth, and magnitude. The addition of early information on the faulting mechanism can enable more reliable estimates of seafloor uplift, tsunami excitation, tsunami potential and impact, and earlier, real-time tsunami scenario forecasting. Full-waveform, centroid moment tensor solutions (CMT) are typically available in 3-15min for local/near-regional earthquakes and in 10-30min for regional/teleseismic distances. In contrast, classic, P first-motion (FM) focal-mechanisms can be available within 3min for local/near-regional events and in 5-10 min for regional/teleseismic distances. We present fmamp, a robust, probabilistic, adaptive grid-search, FM mechanism determination procedure which generates a comprehensive set of "acceptable" FM mechanisms and related uncertainties. This FM solution, combined with fast magnitude estimates such as Mwp, forms a CMT proxy for rapid source characterization and analysis before a definitive, waveform CMT is available. Currently, fmamp runs in real-time in Early-est*, the module for rapid earthquake detection, location and analysis at the INGV tsunami alert center (CAT, "Centro di Allerta Tsunami"), part of the Italian, candidate Tsunami Watch Provider. We show the real-time performance of fmamp and compare its speed and accuracy to CMT results. For large earthquakes in areas of sparse seismic station coverage, fmamp mechanisms are typically available in 5-10min, while CMT results take 10-30min. The fmamp solutions usually agree with CMT results for larger events, but sometimes differ, due to insufficient or noisy FM readings, or real difference between the FM mechanism, representing the faulting at the hypocenter, and the CMT mechanism representing some average, centroid faulting. * http://early-est.alomax.net, http://early-est.rm.ingv.it, http://alomax.free.fr/posters/early-est

  18. Structure-specific scalar intensity measures for near-source and ordinary earthquake ground motions

    Science.gov (United States)

    Luco, N.; Cornell, C.A.

    2007-01-01

    Introduced in this paper are several alternative ground-motion intensity measures (IMs) that are intended for use in assessing the seismic performance of a structure at a site susceptible to near-source and/or ordinary ground motions. A comparison of such IMs is facilitated by defining the "efficiency" and "sufficiency" of an IM, both of which are criteria necessary for ensuring the accuracy of the structural performance assessment. The efficiency and sufficiency of each alternative IM, which are quantified via (i) nonlinear dynamic analyses of the structure under a suite of earthquake records and (ii) linear regression analysis, are demonstrated for the drift response of three different moderate- to long-period buildings subjected to suites of ordinary and of near-source earthquake records. One of the alternative IMs in particular is found to be relatively efficient and sufficient for the range of buildings considered and for both the near-source and ordinary ground motions. ?? 2007, Earthquake Engineering Research Institute.

  19. Decoupling the structure from the ground motion during earthquakes by employing friction pendulums

    Science.gov (United States)

    Gillich, G. R.; Iancu, V.; Gillich, N.; Korka, Z. I.; Chioncel, C. P.; Hatiegan, C.

    2018-01-01

    Avoiding dynamic loads on structures during earthquakes is an actual issue since seismic actions can harm or destroy the built environment. Several attempts to prevent this are possible, the essence being to decouple the structure from the ground motion during earthquakes and preventing in this way large deflections and high accelerations. A common approach is the use of friction pendulums, with cylindrical or spherical surfaces but not limited to that, inserted between the ground and the structure, respectively between the pillar and the superstructure. This type of bearings permits small pendulum motion and in this way, earthquake-induced displacements that occur in the bearings are not integrally transmitted to the structure. The consequence is that the structure is subject to greatly reduced lateral loads and shaking movements. In the experiments, conducted to prove the efficiency of the friction pendulums, we made use of an own designed and manufactured shaking table. Two types of sliding surfaces are analyzed, one polynomial of second order (i.e. circular) and one of a superior order. For both pendulum types, analytical models were developed. The results have shown that the structure is really decoupled from the ground motion and has a similar behaviour as that described by the analytic model.

  20. Performance of Irikura's Recipe Rupture Model Generator in Earthquake Ground Motion Simulations as Implemented in the Graves and Pitarka Hybrid Approach.

    Energy Technology Data Exchange (ETDEWEB)

    Pitarka, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-11-22

    We analyzed the performance of the Irikura and Miyake (2011) (IM2011) asperity-­ based kinematic rupture model generator, as implemented in the hybrid broadband ground-­motion simulation methodology of Graves and Pitarka (2010), for simulating ground motion from crustal earthquakes of intermediate size. The primary objective of our study is to investigate the transportability of IM2011 into the framework used by the Southern California Earthquake Center broadband simulation platform. In our analysis, we performed broadband (0 -­ 20Hz) ground motion simulations for a suite of M6.7 crustal scenario earthquakes in a hard rock seismic velocity structure using rupture models produced with both IM2011 and the rupture generation method of Graves and Pitarka (2016) (GP2016). The level of simulated ground motions for the two approaches compare favorably with median estimates obtained from the 2014 Next Generation Attenuation-­West2 Project (NGA-­West2) ground-­motion prediction equations (GMPEs) over the frequency band 0.1–10 Hz and for distances out to 22 km from the fault. We also found that, compared to GP2016, IM2011 generates ground motion with larger variability, particularly at near-­fault distances (<12km) and at long periods (>1s). For this specific scenario, the largest systematic difference in ground motion level for the two approaches occurs in the period band 1 – 3 sec where the IM2011 motions are about 20 – 30% lower than those for GP2016. We found that increasing the rupture speed by 20% on the asperities in IM2011 produced ground motions in the 1 – 3 second bandwidth that are in much closer agreement with the GMPE medians and similar to those obtained with GP2016. The potential implications of this modification for other rupture mechanisms and magnitudes are not yet fully understood, and this topic is the subject of ongoing study.

  1. ToF camera ego-motion estimation

    CSIR Research Space (South Africa)

    Ratshidaho, T

    2012-10-01

    Full Text Available We present three approaches for ego-motion estimation using Time-of-Flight (ToF) camera data. Ego-motion is defined as a process of estimating a camera’s pose (position and orientation) relative to some initial pose using the camera’s image...

  2. Vehicle ego-motion estimation with geometric algebra

    NARCIS (Netherlands)

    Mark, W. van der; Fontijne, D.; Dorst, L.; Groen, F.C.A.

    2003-01-01

    A method for estimating ego-motion with vehicle mounted stereo cameras is presented. This approach is based on finding corresponding features in stereo images and tracking them between succeeding stereo frames. Our approach estimates stereo ego-motion with geometric algebra techniques. Starting with

  3. Estimation of the global regularity of a multifractional Brownian motion

    DEFF Research Database (Denmark)

    Lebovits, Joachim; Podolskij, Mark

    This paper presents a new estimator of the global regularity index of a multifractional Brownian motion. Our estimation method is based upon a ratio statistic, which compares the realized global quadratic variation of a multifractional Brownian motion at two different frequencies. We show...

  4. Real-time damage estimations of 2016 Kumamoto earthquakes extrapolated by the Japan Real-time Information System for earthquake (J-RISQ)

    Science.gov (United States)

    Shohei, N.; Nakamura, H.; Takahashi, I.; Fujiwara, H.

    2016-12-01

    It is crucial to develop methods grasping the situation soon after the earthquake, both in terms of supporting initial reactions, and enhancing social systems more resilient. For those reasons, we have been developing J-RISQ. Promptly after an earthquake, it estimates damages by combining methods for predicting ground motion using subsurface data, information about population and buildings, damage assessment methods for building using different fragility functions, and real-time observation data obtained by NIED, municipalities and JMA. In this study, we describe about estimations of 2016 Kumamoto earthquakes extrapolated by J-RISQ. In 2016, Kumamoto have faced 2 large jolts, the foreshock (M6.5) occurred on April 14, the main shock (M7.3) came on April 16. J-RISQ published a first report in 29 seconds after the foreshock and generated a total of seven reports within 10 minutes. Finally, it estimated that the number of completely collapsed buildings was between 5,000 and 14,000. In case of the main shock, a first report in 29 seconds, then 8 reports within 11 minutes. Finally, estimated numbers of completely collapsed buildings was between 15,000 and 38,000. The count of completely collapsed residences is approximately 8,300 according to the announcement by FDMA at July 19. In this regard, J-RISQ seems to be overestimated, however, the spatial distribution of estimation indicates a belt of destructive area adjacent to Mashiki town, and this result is correspond approximately to actual damaged area. For verification, we have performed field investigations of building damage in Kumamoto. On the other hand, the damage after the main shock includes the effect of the foreshock, so we are going to develop estimation methods considering about reduction of building caused by continuous earthquakes. *This work was supported by the CSTI through the Cross-ministerial Strategic Innovation Promotion Program (SIP), titled "Enhancement of societal resiliency against natural

  5. Motion of an Antarctic glacier by repeated tidally modulated earthquakes

    Science.gov (United States)

    Zoet, Lucas K.; Anandakrishnan, Sridhar; Alley, Richard B.; Nyblade, Andrew A.; Wiens, Douglas A.

    2012-09-01

    Between debris-laden glacial ice and bedrock, basal seismicity can develop that yields information about bed properties, stress distribution, outburst flooding, and crevassing and calving. Basal seismicity in response to glacial motion is linked to variations in both stress and lubrication of bedrock by water and till. Here we analyse data from the Transantarctic Mountains Seismic Experiment array in 2002-2003 to investigate seismic behaviour at David Glacier, a large outlet glacier that drains 4% of East Antarctica's ice sheet into the Ross Sea. We identify about 20,000 seismic events that are larger in magnitude and duration than typical for glacial sources and repeat at regular intervals of about 25min. These events are consistent with stick-slip behaviour of debris-laden ice moving over a single obstacle of rough bedrock, modulated by relatively small stress changes from the ocean tides. In the years before and after the interval of repeating events, seismic events with irregular and generally longer intervals were detected at the same location, and are consistent with combined stick-slip and continuous sliding of the subglacial interface. We suggest that the observed transitions in seismicity patterns capture the dynamic behaviour of the ice stream, and that--despite lower ice-flow velocities--sliding in the stick-slip regime enhances subglacial erosion.

  6. Earthquake stress drops, ambient tectonic stresses and stresses that drive plate motions

    Science.gov (United States)

    Hanks, T.C.

    1977-01-01

    A variety of geophysical observations suggests that the upper portion of the lithosphere, herein referred to as the elastic plate, has long-term material properties and frictional strength significantly greater than the lower lithosphere. If the average frictional stress along the non-ridge margin of the elastic plate is of the order of a kilobar, as suggested by the many observations of the frictional strength of rocks at mid-crustal conditions of pressure and temperature, the only viable mechanism for driving the motion of the elastic plate is a basal shear stress of several tens of bars. Kilobars of tectonic stress are then an ambient, steady condition of the earth's crust and uppermost mantle. The approximate equality of the basal shear stress and the average crustal earthquake stress drop, the localization of strain release for major plate margin earthquakes, and the rough equivalence of plate margin slip rates and gross plate motion rates suggest that the stress drops of major plate margin earthquakes are controlled by the elastic release of the basal shear stress in the vicinity of the plate margin, despite the existence of kilobars of tectonic stress existing across vertical planes parallel to the plate margin. If the stress differences available to be released at the time of faulting are distributed in a random, white fasbion with a mean-square value determined by the average earthquake stress drop, the frequency of occurrence of constant stress drop earthquakes will be proportional to reciprocal faulting area, in accordance with empirically known frequency of occurrence statistics. ?? 1977 Birkha??user Verlag.

  7. Methodology for earthquake rupture rate estimates of fault networks: example for the western Corinth rift, Greece

    Science.gov (United States)

    Chartier, Thomas; Scotti, Oona; Lyon-Caen, Hélène; Boiselet, Aurélien

    2017-10-01

    Modeling the seismic potential of active faults is a fundamental step of probabilistic seismic hazard assessment (PSHA). An accurate estimation of the rate of earthquakes on the faults is necessary in order to obtain the probability of exceedance of a given ground motion. Most PSHA studies consider faults as independent structures and neglect the possibility of multiple faults or fault segments rupturing simultaneously (fault-to-fault, FtF, ruptures). The Uniform California Earthquake Rupture Forecast version 3 (UCERF-3) model takes into account this possibility by considering a system-level approach rather than an individual-fault-level approach using the geological, seismological and geodetical information to invert the earthquake rates. In many places of the world seismological and geodetical information along fault networks is often not well constrained. There is therefore a need to propose a methodology relying on geological information alone to compute earthquake rates of the faults in the network. In the proposed methodology, a simple distance criteria is used to define FtF ruptures and consider single faults or FtF ruptures as an aleatory uncertainty, similarly to UCERF-3. Rates of earthquakes on faults are then computed following two constraints: the magnitude frequency distribution (MFD) of earthquakes in the fault system as a whole must follow an a priori chosen shape and the rate of earthquakes on each fault is determined by the specific slip rate of each segment depending on the possible FtF ruptures. The modeled earthquake rates are then compared to the available independent data (geodetical, seismological and paleoseismological data) in order to weight different hypothesis explored in a logic tree.The methodology is tested on the western Corinth rift (WCR), Greece, where recent advancements have been made in the understanding of the geological slip rates of the complex network of normal faults which are accommodating the ˜ 15 mm yr-1 north

  8. The ratio of injured to fatalities in earthquakes, estimated from intensity and building properties

    Science.gov (United States)

    Wyss, M.; Trendafiloski, G.

    2009-04-01

    We estimate the number of fatalities (Fat) within less than an hour of any significant earthquake worldwide as a first order assessment of the extent of a possible disaster and distribute this information to anyone who needs it. However, the number of injured people (Inj) is more directly useful for planning rescue and relief operations, and is indispensable for a proper response of the health-care system. Thus, we attempt to estimate both of these parameters. In the literature the assumption is made that the ratio R=Inj/Fat may be constant and close to three. We reject this notion and propose that R depends chiefly on two parameters. (1) R depends on the resistance of the built environment to strong ground motions. In the industrialized world, the median of all earthquakes we could find for which both parameters are known since 1970 is R(med, 26 events)=50; in the 23 events since 1980 it is 60. In the developing world, R(med)=2.5, derived from 55 events (except 6 special cases) since 1970. We conclude that the better building quality in the industrialized world increases the probability for a person not to die in a strong earthquake by more than a factor 10. (2) In addition, R depends on the intensity of shaking (I on the modified Mercally Scale). It is obvious that small nearby and large distant earthquakes cause only relatively low intensities (for example VI) that cause minor damage to buildings, resulting in zero fatalities, but some people are injured. In such cases R approaches infinity. The six special cases excluded from the sample used above for representing the developing world were of this type and their R(med)=15. For example an M7.3 earthquake with an epicenter near Martinique, but at 145 km depth has been powerful enough to have injured 100 people, but it caused only 1 fatality, resulting in R=100. An extreme case on the opposite end of the possibility is the Bam earthquake of December 2003, which occurred at unusually shallow depth directly beneath

  9. Remo Dance Motion Estimation with Markerless Motion Capture Using The Optical Flow Method

    Directory of Open Access Journals (Sweden)

    Neny Kurniati

    2016-03-01

    Full Text Available Motion capture has been developed and applied in various fields, one of them is dancing. Remo dance is a dance from East Java that tells the struggle of a prince who fought on the battlefield. Remo dancer does not use body-tight costume. He wears a few costume pieces and accessories, so required a motion detection method that can detect limb motion which does not damage the beauty of the costumes and does not interfere motion of the dancer. The method is Markerless Motion Capture. Limbs motions are partial behavior. This means that all limbs do not move simultaneously, but alternately. It required motion tracking to detect parts of the body moving and where the direction of motion. Optical flow is a method that is suitable for the above conditions. Moving body parts will be detected by the bounding box. A bounding box differential value between frames can determine the direction of the motion and how far the object is moving. The optical flow method is simple and does not require a monochrome background. This method does not use complex feature extraction process so it can be applied to real-time motion capture. Performance of motion detection with optical flow method is determined by the value of the ratio between the area of the blob and the area of the bounding box. Estimate coordinates are not necessarily like original coordinates, but if the chart of estimate motion similar to the chart of the original motion, it means motion estimation it can be said to have the same motion with the original. Keywords: Motion Capture, Markerless, Remo Dance, Optical Flow

  10. On the modeling of strong motion parameters and correlation with historical macroseismic data: an application to the 1915 Avezzano earthquake

    Directory of Open Access Journals (Sweden)

    G. Longhi

    1995-06-01

    Full Text Available This article describes the results of a ground motion modeling study of the 1915 Avezzano earthquake. The goal was to test assuinptions regarding the rupture process of this earthquake by attempting to model the damage to historical monuments and populated habitats during the earthquake. The methodology used combines stochastic and deterministic modeling techniques to synthesize strong ground motion, starting from a simple characterization of the earthquake source on an extended fault plane. The stochastic component of the methodology is used to simulate high-frequency ground motion oscillations. The envelopes of these synthetic waveforms, however, are simulated in a deterministic way based on the isochron formulation for the calculation of radiated seismic energy. Synthetic acceleration time histories representative of ground motion experienced at the towns of Avezzano, Celano, Ortucchio, and Sora are then analyzed in terms of the damage to historical buildings at these sites. The article also discusses how the same methodology can be adapted to efficiently evaluate various strong motion parameters such as duration and amplitude of ground shaking, at several hundreds of surface sites and as a function of rupture process. The usefulness of such a technique is illustrated through the inodeling of intensity data from the Avezzano earthquake. One of the most interesting results is that it is possible to distinguish between different rupture scenarios for the 1915 earthquake based on the goodness of fit of theoretical intensities to observed values.

  11. Development of a web-based simulator for estimating motion errors in linear motion stages

    Science.gov (United States)

    Khim, G.; Oh, J.-S.; Park, C.-H.

    2017-08-01

    This paper presents a web-based simulator for estimating 5-DOF motion errors in the linear motion stages. The main calculation modules of the simulator are stored on the server computer. The clients uses the client software to send the input parameters to the server and receive the computed results from the server. By using the simulator, we can predict performances such as 5-DOF motion errors, bearing and table stiffness by entering the design parameters in a design step before fabricating the stages. Motion errors are calculated using the transfer function method from the rail form errors which is the most dominant factor on the motion errors. To verify the simulator, the predicted motion errors are compared to the actually measured motion errors in the linear motion stage.

  12. Source process of the 2016 Kumamoto earthquake (Mj7.3) inferred from kinematic inversion of strong-motion records

    Science.gov (United States)

    Yoshida, Kunikazu; Miyakoshi, Ken; Somei, Kazuhiro; Irikura, Kojiro

    2017-05-01

    In this study, we estimated source process of the 2016 Kumamoto earthquake from strong-motion data by using the multiple-time window linear kinematic waveform inversion method to discuss generation of strong motions and to explain crustal deformation pattern with a seismic source inversion model. A four-segment fault model was assumed based on the aftershock distribution, active fault traces, and interferometric synthetic aperture radar data. Three western segments were set to be northwest-dipping planes, and the most eastern segment under the Aso caldera was examined to be a southeast-dipping plane. The velocity structure models used in this study were estimated by using waveform modeling of moderate earthquakes that occurred in the source region. We applied a two-step approach of the inversions of 20 strong-motion datasets observed by K-NET and KiK-net by using band-pass-filtered strong-motion data at 0.05-0.5 Hz and then at 0.05-1.0 Hz. The rupture area of the fault plane was determined by applying the criterion of Somerville et al. (Seismol Res Lett 70:59-80, 1999) to the inverted slip distribution. From the first-step inversion, the fault length was trimmed from 52 to 44 km, whereas the fault width was kept at 18 km. The trimmed rupture area was not changed in the second-step inversion. The source model obtained from the two-step approach indicated 4.7 × 1019 Nm of the total moment release and 1.8 m average slip of the entire fault with a rupture area of 792 km2. Large slip areas were estimated in the seismogenic zone and in the shallow part corresponding to the surface rupture that occurred during the Mj7.3 mainshock. The areas of the high peak moment rate correlated roughly with those of large slip; however, the moment rate functions near the Earth surface have low peak, bell shape, and long duration. These subfaults with long-duration moment release are expected to cause weak short-period ground motions. We confirmed that the southeast dipping of the most

  13. Paleo-earthquake magnitudes estimation based on multiple observations

    Science.gov (United States)

    Hintersberger, E.; Decker, K.

    2016-12-01

    Paleoearthquake magnitudes play an important role in the assessment of surface rupture hazard, especially in intraplate regions with low seismicity, where paleoearthquake magnitudes are generally larger than those of historical earthquakes. In general, paleoearthquake magnitudes are based either on surface rupture length or on surface displacement observed at trenching sites. Several correlations link observed surface displacement to a certain magnitude, but combining more than one observation is still not well established. We present a method based on a probabilistic approach by Biasi and Weldon (2006) to combine several observations to better constrain the possible paleo-earthquake magnitude range. Assuming the single-observation probability density functions (PDF) independent of each other, the joint PDF for all observed surface displacements is the product of all single-observation PDFs.Using surface displacement data for earthquakes with known magnitudes, we combined the PDFs for randomly selected "observations" into one joint PDF for an increasing number of "observations". The resultant range of most probable magnitudes confirms the instrumentally derived magnitude. In addition, the associated uncertainties decrease rapidly with an optimum of 4 to 6 observation points. The magnitude PDFs are dominated by the largest observed displacement, especially with respect to the lowest possible magnitude.In total, we can show that this approach seems to be a suitable method to combine observations from different locations to one magnitude value accounting for the natural variances of observed along-strike surface displacement. In addition, the resultant PDFs can be used as a direct input for hazard-related probabilistic calculations. Reference: Biasi, G.P. & Weldon, R.J., (2006). Estimating surface rupture length and magnitude of paleoearthquakes from point measurements of rupture displacement. Bulletin of the Seismological Society of America 96, 1612-1623.

  14. Bayesian Estimation of Source Parameters and Associated Coulomb Failure Stress Changes for the 2005 Fukuoka (Japan) Earthquake

    KAUST Repository

    Dutta, Rishabh

    2017-12-20

    Several researchers have studied the source parameters of the 2005 Fukuoka (northwestern Kyushu Island, Japan) earthquake (MW 6.6) using teleseismic, strong motion and geodetic data. However, in all previous studies, errors of the estimated fault solutions have been neglected, making it impossible to assess the reliability of the reported solutions. We use Bayesian inference to estimate the location, geometry and slip parameters of the fault and their uncertainties using Interferometric Synthetic Aperture Radar (InSAR) and Global Positioning System (GPS) data. The offshore location of the earthquake makes the fault parameter estimation challenging, with geodetic data coverage mostly to the southeast of the earthquake. To constrain the fault parameters, we use a priori constraints on the magnitude of the earthquake and the location of the fault with respect to the aftershock distribution and find that the estimated fault slip ranges from 1.5 m to 2.5 m with decreasing probability. The marginal distributions of the source parameters show that the location of the western end of the fault is poorly constrained by the data whereas that of the eastern end, located closer to the shore, is better resolved. We propagate the uncertainties of the fault model and calculate the variability of Coulomb failure stress changes for the nearby Kego fault, located directly below Fukuoka city, showing that the mainshock increased stress on the fault and brought it closer to failure.

  15. Assessment of strain effect of strong-motion (focus zones of earthquakes on earth's surface displacement

    Directory of Open Access Journals (Sweden)

    Kh.L. Khamidov

    2017-01-01

    Full Text Available Strain effect of focal zones on fore-seismic displacements of earth's surface is studied in the paper for real conditions of focus zones of the earthquakes. The width of the interval of maximum displacements is determined by the conditions of potential focus of tectonic earthquake. The solution of elastic problem for half-space with soft inclusion is used. Calculations are conducted also by empirical formulas, obtained for similar stress states. Possible radius of the zone of maximum revelation of strain anomaly is determined on the basis of the growth of rupture scale and change in heterogeneity volume. It is shown that obtained expression covers a wider range of magnitude variations with consideration of the interval of scale change in upcoming rupture-forming zone. In the example of Tashkent (1966 and Gazli (1984 strong ground motions, an analysis of possible strains occurrence on the Earth's surface was conducted.

  16. Human joint motion estimation for electromyography (EMG)-based dynamic motion control.

    Science.gov (United States)

    Zhang, Qin; Hosoda, Ryo; Venture, Gentiane

    2013-01-01

    This study aims to investigate a joint motion estimation method from Electromyography (EMG) signals during dynamic movement. In most EMG-based humanoid or prosthetics control systems, EMG features were directly or indirectly used to trigger intended motions. However, both physiological and nonphysiological factors can influence EMG characteristics during dynamic movements, resulting in subject-specific, non-stationary and crosstalk problems. Particularly, when motion velocity and/or joint torque are not constrained, joint motion estimation from EMG signals are more challenging. In this paper, we propose a joint motion estimation method based on muscle activation recorded from a pair of agonist and antagonist muscles of the joint. A linear state-space model with multi input single output is proposed to map the muscle activity to joint motion. An adaptive estimation method is proposed to train the model. The estimation performance is evaluated in performing a single elbow flexion-extension movement in two subjects. All the results in two subjects at two load levels indicate the feasibility and suitability of the proposed method in joint motion estimation. The estimation root-mean-square error is within 8.3% ∼ 10.6%, which is lower than that being reported in several previous studies. Moreover, this method is able to overcome subject-specific problem and compensate non-stationary EMG properties.

  17. Systematic difference between first-motion and waveform-inversion solutions for shallow offshore earthquakes due to a low-angle dipping slab

    Science.gov (United States)

    Takemura, Shunsuke; Shiomi, Katsuhiko; Kimura, Takeshi; Saito, Tatsuhiko

    2016-08-01

    Systematic difference between first-motion and waveform-inversion solutions for shallow offshore earthquakes was examined by using the seismograms of the 2016 Off Mie ( Mw 5.8) earthquake occurred at a depth of 14 km southeast off of the Kii peninsula, central Japan. Observed seismograms illustrated first arrivals with an apparent velocity of 7.2 km/s, which is faster than crustal P waves. The apparent velocity and polarization pattern of the first arrivals were reproduced by a finite-difference method simulation incorporating the three-dimensional Philippine Sea slab. The first arrivals consist of P waves radiated downward from the source, passing the oceanic Moho as head waves. Thus, a first-motion analysis, assuming a one-dimensional structure, causes incorrect estimations of the focal mechanisms and hypocenter depths, which tend to be deeper than the actual ones. Our result possibly indicates that the seismicity above the oceanic Moho was underestimated in the previous catalogs.

  18. Source parameters estimation of 2003 Bam earthquake Mw 6.5 ...

    Indian Academy of Sciences (India)

    We determine the source parameters for 2003 (Mw 6.5) Bam, Iran, earthquake using an empirical. Green's function summation approach to model ground motions recorded by two strong motion stations at approximately 45km epicentral distance. We introduce a genetic algorithm technique to optimize the fit to observed ...

  19. Accurate and Robust Ego-Motion Estimation using Expectation Maximization

    NARCIS (Netherlands)

    Dubbelman, G.; Mark, W. van der; Groen, F.C.A.

    2008-01-01

    A novel robust visual-odometry technique, called EM-SE(3) is presented and compared against using the random sample consensus (RANSAC) for ego-motion estimation. In this contribution, stereo-vision is used to generate a number of minimal-set motion hypothesis. By using EM-SE(3), which involves

  20. Explaining extreme ground motion in Osaka basin during the 2011 Tohoku earthquake

    Science.gov (United States)

    Tsai, Victor C.; Bowden, Daniel C.; Kanamori, Hiroo

    2017-07-01

    Despite being 770 km away from the epicenter, observed ground motions due to the Tohoku earthquake in the Osaka Basin were unexpectedly large, with an amplification of more than a factor of 20 compared to immediately outside the basin, and including 2.7 m peak-to-peak roof displacements at one high-rise building. The local ground motions exceeded expectations based on standard computations of site response by a factor of 3, predicted frequencies of peak acceleration were off by at least 50%, and such discrepancies have not yet been explained quantitatively. Here we show that utilizing semianalytic theory for surface-wave amplification, we are able to accurately predict both the amplitudes and frequencies of large ground amplification in the Osaka Basin using only knowledge of the local one-dimensional structure. Comparison between this simple prediction and observed amplification was not expected to be so favorable and suggests that simple one-dimensional surface-wave site amplification factors can be useful in the absence of full three-dimensional wave propagation simulations. Such surface-wave amplification factors can be included in addition to the standard measures of site-specific site amplification and should help explain strong ground motion variability in future large earthquakes that shake Osaka Basin and elsewhere in the world.

  1. Three-dimensional ground-motion simulations of earthquakes for the Hanford area, Washington

    Science.gov (United States)

    Frankel, Arthur; Thorne, Paul; Rohay, Alan

    2014-01-01

    This report describes the results of ground-motion simulations of earthquakes using three-dimensional (3D) and one-dimensional (1D) crustal models conducted for the probabilistic seismic hazard assessment (PSHA) of the Hanford facility, Washington, under the Senior Seismic Hazard Analysis Committee (SSHAC) guidelines. The first portion of this report demonstrates that the 3D seismic velocity model for the area produces synthetic seismograms with characteristics (spectral response values, duration) that better match those of the observed recordings of local earthquakes, compared to a 1D model with horizontal layers. The second part of the report compares the response spectra of synthetics from 3D and 1D models for moment magnitude (M) 6.6–6.8 earthquakes on three nearby faults and for a dipping plane wave source meant to approximate regional S-waves from a Cascadia great earthquake. The 1D models are specific to each site used for the PSHA. The use of the 3D model produces spectral response accelerations at periods of 0.5–2.0 seconds as much as a factor of 4.5 greater than those from the 1D models for the crustal fault sources. The spectral accelerations of the 3D synthetics for the Cascadia plane-wave source are as much as a factor of 9 greater than those from the 1D models. The differences between the spectral accelerations for the 3D and 1D models are most pronounced for sites with thicker supra-basalt sediments and for stations with earthquakes on the Rattlesnake Hills fault and for the Cascadia plane-wave source.

  2. Using SW4 for 3D Simulations of Earthquake Strong Ground Motions: Application to Near-Field Strong Motion, Building Response, Basin Edge Generated Waves and Earthquakes in the San Francisco Bay Are

    Science.gov (United States)

    Rodgers, A. J.; Pitarka, A.; Petersson, N. A.; Sjogreen, B.; McCallen, D.; Miah, M.

    2016-12-01

    Simulation of earthquake ground motions is becoming more widely used due to improvements of numerical methods, development of ever more efficient computer programs (codes), and growth in and access to High-Performance Computing (HPC). We report on how SW4 can be used for accurate and efficient simulations of earthquake strong motions. SW4 is an anelastic finite difference code based on a fourth order summation-by-parts displacement formulation. It is parallelized and can run on one or many processors. SW4 has many desirable features for seismic strong motion simulation: incorporation of surface topography; automatic mesh generation; mesh refinement; attenuation and supergrid boundary conditions. It also has several ways to introduce 3D models and sources (including Standard Rupture Format for extended sources). We are using SW4 to simulate strong ground motions for several applications. We are performing parametric studies of near-fault motions from moderate earthquakes to investigate basin edge generated waves and large earthquakes to provide motions to engineers study building response. We show that 3D propagation near basin edges can generate significant amplifications relative to 1D analysis. SW4 is also being used to model earthquakes in the San Francisco Bay Area. This includes modeling moderate (M3.5-5) events to evaluate the United States Geologic Survey's 3D model of regional structure as well as strong motions from the 2014 South Napa earthquake and possible large scenario events. Recently SW4 was built on a Commodity Technology Systems-1 (CTS-1) at LLNL, new systems for capacity computing at the DOE National Labs. We find SW4 scales well and runs faster on these systems compared to the previous generation of LINUX clusters.

  3. Sensitivity of Reliability Estimates in Partially Damaged RC Structures subject to Earthquakes, using Reduced Hysteretic Models

    DEFF Research Database (Denmark)

    Iwankiewicz, R.; Nielsen, Søren R. K.; Skjærbæk, P. S.

    The subject of the paper is the investigation of the sensitivity of structural reliability estimation by a reduced hysteretic model for a reinforced concrete frame under an earthquake excitation.......The subject of the paper is the investigation of the sensitivity of structural reliability estimation by a reduced hysteretic model for a reinforced concrete frame under an earthquake excitation....

  4. Estimation of seismic ground motions using deterministic approach for major cities of Gujarat

    Directory of Open Access Journals (Sweden)

    J. Shukla

    2012-06-01

    Full Text Available A deterministic seismic hazard analysis has been carried out for various sites of the major cities (Ahmedabad, Surat, Bhuj, Jamnagar and Junagadh of the Gujarat region in India to compute the seismic hazard exceeding a certain level in terms of peak ground acceleration (PGA and to estimate maximum possible PGA at each site at bed rock level. The seismic sources in Gujarat are very uncertain and recurrence intervals of regional large earthquakes are not well defined. Because the instrumental records of India specifically in the Gujarat region are far from being satisfactory for modeling the seismic hazard using the probabilistic approach, an attempt has been made in this study to accomplish it through the deterministic approach. In this regard, all small and large faults of the Gujarat region were evaluated to obtain major fault systems. The empirical relations suggested by earlier researchers for the estimation of maximum magnitude of earthquake motion with various properties of faults like length, surface area, slip rate, etc. have been applied to those faults to obtain the maximum earthquake magnitude. For the analysis, seven different ground motion attenuation relations (GMARs of strong ground motion have been utilized to calculate the maximum horizontal ground accelerations for each major city of Gujarat. Epistemic uncertainties in the hazard computations are accounted for within a logic-tree framework by considering the controlling parameters like b-value, maximum magnitude and ground motion attenuation relations (GMARs. The corresponding deterministic spectra have been prepared for each major city for the 50th and 84th percentiles of ground motion occurrence. These deterministic spectra are further compared with the specified spectra of Indian design code IS:1893-Part I (2002 to validate them for further practical use. Close examination of the developed spectra reveals that the expected ground motion values become high for the

  5. Estimation of seismic ground motions using deterministic approach for major cities of Gujarat

    Science.gov (United States)

    Shukla, J.; Choudhury, D.

    2012-06-01

    A deterministic seismic hazard analysis has been carried out for various sites of the major cities (Ahmedabad, Surat, Bhuj, Jamnagar and Junagadh) of the Gujarat region in India to compute the seismic hazard exceeding a certain level in terms of peak ground acceleration (PGA) and to estimate maximum possible PGA at each site at bed rock level. The seismic sources in Gujarat are very uncertain and recurrence intervals of regional large earthquakes are not well defined. Because the instrumental records of India specifically in the Gujarat region are far from being satisfactory for modeling the seismic hazard using the probabilistic approach, an attempt has been made in this study to accomplish it through the deterministic approach. In this regard, all small and large faults of the Gujarat region were evaluated to obtain major fault systems. The empirical relations suggested by earlier researchers for the estimation of maximum magnitude of earthquake motion with various properties of faults like length, surface area, slip rate, etc. have been applied to those faults to obtain the maximum earthquake magnitude. For the analysis, seven different ground motion attenuation relations (GMARs) of strong ground motion have been utilized to calculate the maximum horizontal ground accelerations for each major city of Gujarat. Epistemic uncertainties in the hazard computations are accounted for within a logic-tree framework by considering the controlling parameters like b-value, maximum magnitude and ground motion attenuation relations (GMARs). The corresponding deterministic spectra have been prepared for each major city for the 50th and 84th percentiles of ground motion occurrence. These deterministic spectra are further compared with the specified spectra of Indian design code IS:1893-Part I (2002) to validate them for further practical use. Close examination of the developed spectra reveals that the expected ground motion values become high for the Kachchh region i.e. Bhuj

  6. Estimation of the global regularity of a multifractional Brownian motion

    OpenAIRE

    Lebovits, Joachim; Podolskij, Mark

    2016-01-01

    This paper presents a new estimator of the global regularity index of a multifractional Brownian motion. Our estimation method is based upon a ratio statistic, which compares the realized global quadratic variation of a multifractional Brownian motion at two different frequencies. We show that a logarithmic transformation of this statistic converges in probability to the minimum of the Hurst functional parameter, which is, under weak assumptions, identical to the global regularity index of th...

  7. Seismic Site Characterizations and Earthquake Loss Estimation Analyses for K-12 Schools in Washington State

    Science.gov (United States)

    Cakir, R.; Walsh, T. J.; Hayashi, K.; Norman, D. K.; Lau, T.; Scott, S.

    2016-12-01

    Washington State has the second-highest earthquake risk in the U.S. after only California, and major earthquakes in western Washington in 1946, 1949, 1965, and 2001 killed 15 people and caused billions of dollars' worth of property damage. Washington State has not been exempt from earthquake damage to school buildings. The mission of The Washington Department of Natural Resources-Division of Geology and Earth Resources is to "reduce or eliminate risks to life and property from natural hazards." We conducted active and passive seismic surveys, and estimated shear-wave velocity (Vs) profiles, then determined NEHRP soil classifications using calculated Vs30m values at public schools in Thurston, Grays Harbor, Walla Walla, Chelan and Okanogan counties, Washington. We used active and passive seismic surveys: 1D and 2D MASW and MAM, P- and S-wave refraction, horizontal-to-vertical spectral ratio (H/V), and 2-Station SPAC (2ST-SPAC) surveys to measure Vs and Vp at shallow (0-70m) and Vs at greater (10 to 500 or 10 -3000 meters) depths at the sites, respectively. We then ran Ground Penetrating Radar (GPR) surveys along each seismic line to check possible horizontal subsurface variations between the survey line and the actual location of the school buildings. These survey results were then used for calculations of Vs30m to determine the NEHRP site classifications at school sites. These site classes were also used for determining soil amplification effects on the ground motions affecting structural damage estimations of the school buildings. These seismic site characterization results associated with structural engineering evaluations were then used as inputs in FEMA Hazus-Advanced Engineering Building Module (AEBM) analysis to provide estimated casualties, nonstructural, and structural losses. The final AEBM loss estimation along with the more detailed structural evaluations will help school districts assess the earthquake performance of school buildings in order to

  8. Ubiquitous human upper-limb motion estimation using wearable sensors.

    Science.gov (United States)

    Zhang, Zhi-Qiang; Wong, Wai-Choong; Wu, Jian-Kang

    2011-07-01

    Human motion capture technologies have been widely used in a wide spectrum of applications, including interactive game and learning, animation, film special effects, health care, navigation, and so on. The existing human motion capture techniques, which use structured multiple high-resolution cameras in a dedicated studio, are complicated and expensive. With the rapid development of microsensors-on-chip, human motion capture using wearable microsensors has become an active research topic. Because of the agility in movement, upper-limb motion estimation has been regarded as the most difficult problem in human motion capture. In this paper, we take the upper limb as our research subject and propose a novel ubiquitous upper-limb motion estimation algorithm, which concentrates on modeling the relationship between upper-arm movement and forearm movement. A link structure with 5 degrees of freedom (DOF) is proposed to model the human upper-limb skeleton structure. Parameters are defined according to Denavit-Hartenberg convention, forward kinematics equations are derived, and an unscented Kalman filter is deployed to estimate the defined parameters. The experimental results have shown that the proposed upper-limb motion capture and analysis algorithm outperforms other fusion methods and provides accurate results in comparison to the BTS optical motion tracker.

  9. A Motion Estimation Algorithm Using DTCWT and ARPS

    Directory of Open Access Journals (Sweden)

    Unan Y. Oktiawati

    2013-09-01

    Full Text Available In this paper, a hybrid motion estimation algorithm utilizing the Dual Tree Complex Wavelet Transform (DTCWT and the Adaptive Rood Pattern Search (ARPS block is presented. The proposed algorithm first transforms each video sequence with DTCWT. The frame n of the video sequence is used as a reference input and the frame n+2 is used to find the motion vector. Next, the ARPS block search algorithm is carried out and followed by an inverse DTCWT. The motion compensation is then carried out on each inversed frame n and motion vector. The results show that PSNR can be improved for mobile device without depriving its quality. The proposed algorithm also takes less memory usage compared to the DCT-based algorithm. The main contribution of this work is a hybrid wavelet-based motion estimation algorithm for mobile devices. Other contribution is the visual quality scoring system as used in section 6.

  10. Ground motion prediction and earthquake scenarios in the volcanic region of Mt. Etna (Southern Italy

    Science.gov (United States)

    Langer, Horst; Tusa, Giuseppina; Luciano, Scarfi; Azzaro, Raffaela

    2013-04-01

    One of the principal issues in the assessment of seismic hazard is the prediction of relevant ground motion parameters, e. g., peak ground acceleration, radiated seismic energy, response spectra, at some distance from the source. Here we first present ground motion prediction equations (GMPE) for horizontal components for the area of Mt. Etna and adjacent zones. Our analysis is based on 4878 three component seismograms related to 129 seismic events with local magnitudes ranging from 3.0 to 4.8, hypocentral distances up to 200 km, and focal depth shallower than 30 km. Accounting for the specific seismotectonic and geological conditions of the considered area we have divided our data set into three sub-groups: (i) Shallow Mt. Etna Events (SEE), i.e., typically volcano-tectonic events in the area of Mt. Etna having a focal depth less than 5 km; (ii) Deep Mt. Etna Events (DEE), i.e., events in the volcanic region, but with a depth greater than 5 km; (iii) Extra Mt. Etna Events (EEE), i.e., purely tectonic events falling outside the area of Mt. Etna. The predicted PGAs for the SEE are lower than those predicted for the DEE and the EEE, reflecting their lower high-frequency energy content. We explain this observation as due to the lower stress drops. The attenuation relationships are compared to the ones most commonly used, such as by Sabetta and Pugliese (1987)for Italy, or Ambraseys et al. (1996) for Europe. Whereas our GMPEs are based on small earthquakes, the magnitudes covered by the two above mentioned attenuation relationships regard moderate to large magnitudes (up to 6.8 and 7.9, respectively). We show that the extrapolation of our GMPEs to magnitues beyond the range covered by the data is misleading; at the same time also the afore mentioned relationships fail to predict ground motion parameters for our data set. Despite of these discrepancies, we can exploit our data for setting up scenarios for strong earthquakes for which no instrumental recordings are

  11. Update of the Graizer-Kalkan ground-motion prediction equations for shallow crustal continental earthquakes

    Science.gov (United States)

    Graizer, Vladimir; Kalkan, Erol

    2015-01-01

    A ground-motion prediction equation (GMPE) for computing medians and standard deviations of peak ground acceleration and 5-percent damped pseudo spectral acceleration response ordinates of maximum horizontal component of randomly oriented ground motions was developed by Graizer and Kalkan (2007, 2009) to be used for seismic hazard analyses and engineering applications. This GMPE was derived from the greatly expanded Next Generation of Attenuation (NGA)-West1 database. In this study, Graizer and Kalkan’s GMPE is revised to include (1) an anelastic attenuation term as a function of quality factor (Q0) in order to capture regional differences in large-distance attenuation and (2) a new frequency-dependent sedimentary-basin scaling term as a function of depth to the 1.5-km/s shear-wave velocity isosurface to improve ground-motion predictions for sites on deep sedimentary basins. The new model (GK15), developed to be simple, is applicable to the western United States and other regions with shallow continental crust in active tectonic environments and may be used for earthquakes with moment magnitudes 5.0–8.0, distances 0–250 km, average shear-wave velocities 200–1,300 m/s, and spectral periods 0.01–5 s. Directivity effects are not explicitly modeled but are included through the variability of the data. Our aleatory variability model captures inter-event variability, which decreases with magnitude and increases with distance. The mixed-effects residuals analysis shows that the GK15 reveals no trend with respect to the independent parameters. The GK15 is a significant improvement over Graizer and Kalkan (2007, 2009), and provides a demonstrable, reliable description of ground-motion amplitudes recorded from shallow crustal earthquakes in active tectonic regions over a wide range of magnitudes, distances, and site conditions.

  12. ESTIMATION OF 3-D STRUCTURE AND EVALUATION OF SEISMIC RESPONSE PROPERTIES OF A LANDSLIDE BLOCK BY MICRO-EARTHQUAKE OBSERVATION

    Science.gov (United States)

    Mori, Shinichiro; Otake, Hidenori

    This paper demonstrates the efficiency of micro-earthquake observation for estimation of 3-D structure of a landslide block and evaluation of seismic response properties of a landslide site, showing an example of such an observation conducted at a national famous landslide area at Choja in Kochi Prefecture, Japan. First, we show that it is quite difficult to explore the landslide site in terms of underground S-wave velocity structure by conventional microtremor measurement because of extremely low level of ambient vibration. Next, we show that a three-day observation of micro-earthquake is effective for obtaining some recognizable micro-earthquake motions at the landslide site. Finally, we demonstrate that predominant frequencies specified according to the spectral amplification of the micro-earthquakes can be obtained at three observation points locating inside of the landslide block, and that depths of a sliding plane estimated by multiple reflection theory for one-dimensional soil column with both the predominant frequencies and the S-wave velocities obtained through multi-channel surface wave exploration agree with actual ones referred from a literature with 15% error.

  13. Deconvolution effect of near-fault earthquake ground motions on stochastic dynamic response of tunnel-soil deposit interaction systems

    Directory of Open Access Journals (Sweden)

    K. Hacıefendioğlu

    2012-04-01

    Full Text Available The deconvolution effect of the near-fault earthquake ground motions on the stochastic dynamic response of tunnel-soil deposit interaction systems are investigated by using the finite element method. Two different earthquake input mechanisms are used to consider the deconvolution effects in the analyses: the standard rigid-base input and the deconvolved-base-rock input model. The Bolu tunnel in Turkey is chosen as a numerical example. As near-fault ground motions, 1999 Kocaeli earthquake ground motion is selected. The interface finite elements are used between tunnel and soil deposit. The mean of maximum values of quasi-static, dynamic and total responses obtained from the two input models are compared with each other.

  14. Estimating tropical vertical motion profile shapes from satellite observations

    Science.gov (United States)

    Back, L. E.; Handlos, Z.

    2013-12-01

    The vertical structure of tropical deep convection strongly influences interactions with larger scale circulations and climate. This research focuses on investigating this vertical structure and its relationship with mesoscale tropical weather states. We test the hypothesis that vertical motion shape varies in association with weather state type. We estimate mean state vertical motion profile shapes for six tropical weather states defined using cloud top pressure and optical depth properties from the International Satellite Cloud Climatology Project. The relationship between vertical motion and the dry static energy budget are utilized to set up a regression analysis that empirically determines two modes of variability in vertical motion from reanalysis data. We use these empirically determined modes, this relationship and surface convergence to estimate vertical motion profile shape from observations of satellite retrievals of rainfall and surface convergence. We find that vertical motion profile shapes vary systematically between different tropical weather states. The "isolated systems" regime exhibits a more ''bottom-heavy'' profile shape compared to the convective/thick cirrus and vigorous deep convective regimes, with maximum upward vertical motion occurring in the lower troposphere rather than the middle to upper troposphere. The variability we observe with our method does not coincide with that expected based on conventional ideas about how stratiform rain fraction and vertical motion are related.

  15. The effect of a sedimentary wedge on earthquake ground motions: The influence of eastern U.S. Atlantic Coastal Plain strata

    Science.gov (United States)

    Pratt, Thomas; Magnani, Beatrice

    2017-04-01

    Coastal regions of the eastern U.S. are underlain by a wedge of partially consolidated Atlantic Coastal Plain (ACP) marine sedimentary strata overlying a bedrock of crystalline or indurated sedimentary rocks. The ACP strata extend more than 200 km inland, tapering landward from as much as 1 km near the coast. Unconsolidated, shallow sedimentary strata strongly influence earthquake ground motions due to low seismic impedance and strong reflections from the bedrock contact. Site response estimates primarily determine high-frequency amplifications from shear-wave velocities in the upper 30 m (Vs30), but thicker sedimentary sequences can increase longer-period ground motions important to large structures. Here we use data from continental-scale seismic experiments that span the ACP (e.g. Eastern North America Margin [ENAM], Earthscope Transportable Array) to examine the influence of ACP strata on earthquake ground motions. We use teleseismic and regional earthquake recordings to compute spectral ratios relative to bedrock sites. Thin ACP strata produce fundamental resonance peaks at high frequencies (>5 Hz), but the fundamental peaks decrease to about 0.45 Hz as the sediments thicken to about 500 m. Amplitudes of the fundamental resonance peaks decrease as the strata thicken, but even coastal sites show amplification factors as great as 5. In addition, we use the frequency of the resonance peaks to invert for an average velocity function within the ACP strata. A smaller array within the city of Washington, DC, which is underlain by a wedge 0- to 270-m-thick ACP strata, shows large amplifications at frequencies of 0.7 to 5 Hz. These amplifications likely contributed to the widespread damage to the city during the relatively modest, M5.8 Virginia earthquake in 2011. This work confirms amplification of short-period ground motions by thin ACP strata, and documents longer-period amplifications caused by thick sedimentary sequences beneath coastal regions of the eastern U.S.

  16. Ground motion in the presence of complex topography: Earthquake and ambient noise sources

    Science.gov (United States)

    Hartzell, Stephen; Meremonte, Mark; Ramírez-Guzmán, Leonardo; McNamara, Daniel

    2014-01-01

    To study the influence of topography on ground motion, eight seismic recorders were deployed for a period of one year over Poverty Ridge on the east side of the San Francisco Bay Area, California. This location is desirable because of its proximity to local earthquake sources and the significant topographic relief of the array (439 m). Topographic amplification is evaluated as a function of frequency using a variety of methods, including reference‐site‐based spectral ratios and single‐station horizontal‐to‐vertical spectral ratios using both shear waves from earthquakes and ambient noise. Field observations are compared with the predicted ground motion from an accurate digital model of the topography and a 3D local velocity model. Amplification factors from the theoretical calculations are consistent with observations. The fundamental resonance of the ridge is prominently observed in the spectra of data and synthetics; however, higher‐frequency peaks are also seen primarily for sources in line with the major axis of the ridge, perhaps indicating higher resonant modes. Excitations of lateral ribs off of the main ridge are also seen at frequencies consistent with their dimensions. The favored directions of resonance are shown to be transverse to the major axes of the topographic features.

  17. Seismic microzonation of the city of Elche (Spain) for earthquake loss estimation

    Science.gov (United States)

    Agea-Medina, Noelia; Galiana-Merino, Juan Jose; Navarro, Manuel; Molina-Palacios, Sergio; Rosa-Herranz, Julio; Soler-Llorens, Juan Luis

    2017-04-01

    Elche town is located in the SE of the Alicante province (Southeast of Spain). This part of Spain is one of the most hazardous zones from the viewpoint of the seismic hazard. The current seismic normative assigns a PGA value of 0.20g (return period of 475 years) to this city being the maximum 0.23g in the city of Jacarilla (Alicante). The urban area comprises more than 20000 buildings with an important number constructed without seismic considerations. Therefore, a correct seismic microzonation will let us to establish the shear wave velocity, predominant periods and dispersion curves needed to compute accurately the ground motions scenarios in the city for an earthquake loss estimation (ELE). We have tested several techniques: multichannel analysis of surface waves (MASW) and spatial autocorrelation (SPAC) and calibrated the results with geotechnical information. The dispersion curves were obtained in different wavelength ranges and finally the 1-D Vs model was computed for each final dispersion curve using an iterative process. Additionally, a map of predominant periods has been obtained for the city. The sensitivity of the results according to the used techniques and the recording instruments has been analysed and its influence when computing earthquake damage has been addressed.

  18. Physically-Based Ground Motion Prediction and Validation A Case Study: Mid-sized Marmara Sea Earthquakes

    Science.gov (United States)

    Mert, A.

    2015-12-01

    In this study we have two main purposes. The first one is to simulate five midsize earthquakes (Mw≈5.0) recorded in the Marmara region, which has a geologically complex and heterogeneous crustal structure. We synthesize ground motion for the full wave train on three components, and applied a 'physics based' solution of earthquake rupture. The simulation methodology is based on the studies by Hutchings et al. (2007), Scognamiglio and Hutchings (2009). For each earthquake, we synthesized seismograms using by 500 different rupture scenarios that were generated by Monte Carlo selection of parameters within the range. Synthetic ground motion is a major challenge for seismic hazard assessment studies. Especially after the adoption of performance-based design approach with the Earthquake resistant design of engineering structures. To compute realistic time histories for different locations around Marmara region can be helpful for engineering design, retrofitting the existing structures, hazard and risk management studies and developing new seismic codes and standards.The second purpose is to validate synthetic seismograms with real seismograms. We follow the methodology presented by Anderson (2003) for validation. This methodology proposes a similarity score based on averages of the quality of fit measuring ground motion characteristics and uses a suite of measurements. Namely, the synthetics are compared to real data by ten representative ground motion criteria. The applicability of Empirical Green's functions methodology and physics based solution of earthquake rupture had been assessed in terms of modeling in complex geologic structure. Because the methodology produces source and site specific synthetic ground motion time histories and goodness-of-fit scores of obtained synthetics is between 'fair' to 'good' range based on Anderson's score, we concluded that it can be tried to produce ground motion that has not previously been recorded during catastrophic earthquake

  19. Validation of Broadband Ground Motion Simulations for Japanese Crustal Earthquakes by the Recipe

    Science.gov (United States)

    Iwaki, A.; Maeda, T.; Morikawa, N.; Miyake, H.; Fujiwara, H.

    2015-12-01

    The Headquarters for Earthquake Research Promotion (HERP) of Japan has organized the broadband ground motion simulation method into a standard procedure called the "recipe" (HERP, 2009). In the recipe, the source rupture is represented by the characterized source model (Irikura and Miyake, 2011). The broadband ground motion time histories are computed by a hybrid approach: the 3-D finite-difference method (Aoi et al. 2004) and the stochastic Green's function method (Dan and Sato, 1998; Dan et al. 2000) for the long- (> 1 s) and short-period (sites are well reproduced by the simulations. Then we evaluate 5% damped pseudo acceleration spectra (PSA) in the framework of the SCEC Broadband Platform (BBP) validation (Dreger et al. 2015). The validation results are generally acceptable in the period range 0.1 - 10 s, whereas those in the shortest period range (0.01-0.1 s) are less satisfactory. We also evaluate the simulations with the 1-D velocity structure models used in the SCEC BBP validation exercise. Although the goodness-of-fit parameters for PSA do not significantly differ from those for the 3-D velocity structure model, noticeable differences in velocity waveforms are observed. Our results suggest the importance of 1) well-constrained 3-D velocity structure model for broadband ground motion simulations and 2) evaluation of time series of ground motion as well as response spectra.

  20. Survey of strong motion earthquake effects on thermal power plants in California with emphasis on piping systems. Volume 2, Appendices

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, J.D. [Stevenson and Associates, Cleveland, OH (United States)

    1995-11-01

    Volume 2 of the ``Survey of Strong Motion Earthquake Effects on Thermal Power Plants in California with Emphasis on Piping Systems`` contains Appendices which detail the detail design and seismic response of several power plants subjected to strong motion earthquakes. The particular plants considered include the Ormond Beach, Long Beach and Seal Beach, Burbank, El Centro, Glendale, Humboldt Bay, Kem Valley, Pasadena and Valley power plants. Included is a typical power plant piping specification and photographs of typical power plant piping specification and photographs of typical piping and support installations for the plants surveyed. Detailed piping support spacing data are also included.

  1. Motion Estimation and Compensation Strategies in Dynamic Computerized Tomography

    Science.gov (United States)

    Hahn, Bernadette N.

    2017-12-01

    A main challenge in computerized tomography consists in imaging moving objects. Temporal changes during the measuring process lead to inconsistent data sets, and applying standard reconstruction techniques causes motion artefacts which can severely impose a reliable diagnostics. Therefore, novel reconstruction techniques are required which compensate for the dynamic behavior. This article builds on recent results from a microlocal analysis of the dynamic setting, which enable us to formulate efficient analytic motion compensation algorithms for contour extraction. Since these methods require information about the dynamic behavior, we further introduce a motion estimation approach which determines parameters of affine and certain non-affine deformations directly from measured motion-corrupted Radon-data. Our methods are illustrated with numerical examples for both types of motion.

  2. Estimation of earthquake source parameters in the Kachchh seismic ...

    Indian Academy of Sciences (India)

    Durgada Nagamani

    2017-07-25

    Jul 25, 2017 ... Earthquake source parameters and crustal Q0 values for the 138 selected local events of (Mw:2.5−4.4) the 2001 Bhuj earthquake sequence have been computed through inversion modelling of S-waves from three-component broadband seismometer data. SEISAN software has been used to locate the ...

  3. Ground-Motion Simulations of the 2008 Ms8.0 Wenchuan, China, Earthquake Using Empirical Green's Function Method

    Science.gov (United States)

    Zhang, W.; Zhang, Y.; Yao, X.

    2010-12-01

    On May 12, 2008, a huge earthquake with magnitude Ms8.0 occurred in the Wenhuan, Sichuan Province of China. This event was the most devastating earthquake in the mainland of China since the 1976 M7.8 Tangshan earthquake. It resulted in tremendous losses of life and property. There were about 90,000 persons killed. Due to occur in the mountainous area, this great earthquake and the following thousands aftershocks also caused many other geological disasters, such as landslide, mud-rock flow and “quake lakes” which formed by landslide-induced reservoirs. This earthquake occurred along the Longmenshan fault, as the result of motion on a northeast striking reverse fault or thrust fault on the northwestern margin of the Sichuan Basin. The earthquake's epicenter and focal-mechanism are consistent with it having occurred as the result of movement on the Longmenshan fault or a tectonically related fault. The earthquake reflects tectonic stresses resulting from the convergence of crustal material slowly moving from the high Tibetan Plateau, to the west, against strong crust underlying the Sichuan Basin and southeastern China. In this study, we simulate the near-field strong ground motions of this great event based on the empirical Green’s function method (EGF). Referring to the published inversion source models, at first, we assume that there are three asperities on the rupture area and choose three different small events as the EGFs. Then, we identify the parameters of the source model using a genetic algorithm (GA). We calculate the synthetic waveforms based on the obtained source model and compare with the observed records. Our result shows that for most of the synthetic waveforms agree very well with the observed ones. The result proves the validity and the stability of the method. Finally, we forward the near-field strong ground motions near the source region and try to explain the damage distribution caused by the great earthquake.

  4. Estimation of Seismic Loss for a Portfolio of Buildings under Bidirectional Horizontal Ground Motions due to a Scenario Cascadia Event

    Directory of Open Access Journals (Sweden)

    Taojun Liu

    2017-10-01

    Full Text Available Earthquake ground motions induced by a scenario event are spatially (partially correlated and (partially coherent. Simulated ground motion records can be used to carry out nonlinear inelastic time history analysis for a portfolio of buildings to estimate the seismic loss, which is advantageous as there is no need to develop and apply empirical ground motion prediction equations and the ductility demand rules, or to search the scenario-compatible recorded records at selected sites that may not exist. Further, if the structures being considered are sensitive to the orientation of the excitation, multiple-component ground motion records are needed. For the simulation of such ground motion records, previous studies have shown that correlation and coherency between any pair of ground motion components need to be incorporated. In this study, the seismic loss of a portfolio of hypothetical buildings in downtown Vancouver under bidirectional horizontal ground motions due to a scenario Cascadia event is estimated by using simulated bidirectional ground motion records that include realistic correlation and coherency characteristics. The hysteretic behaviors of the buildings are described by bidirectional Bouc–Wen model. The results show that the use of unidirectional ground motions and single-degree-of-freedom system structural model may underestimate the aggregated seismic loss.

  5. Within-Event and Between-Events Ground Motion Variability from Earthquake Rupture Scenarios

    Science.gov (United States)

    Crempien, Jorge G. F.; Archuleta, Ralph J.

    2017-09-01

    Measurement of ground motion variability is essential to estimate seismic hazard. Over-estimation of variability can lead to extremely high annual hazard estimates of ground motion exceedance. We explore different parameters that affect the variability of ground motion such as the spatial correlations of kinematic rupture parameters on a finite fault and the corner frequency of the moment-rate spectra. To quantify the variability of ground motion, we simulate kinematic rupture scenarios on several vertical strike-slip faults and compute ground motion using the representation theorem. In particular, for the entire suite of rupture scenarios, we quantify the within-event and the between-events ground motion variability of peak ground acceleration (PGA) and response spectra at several periods, at 40 stations—all approximately at an equal distance of 20 and 50 km from the fault. Both within-event and between-events ground motion variability increase when the slip correlation length on the fault increases. The probability density functions of ground motion tend to truncate at a finite value when the correlation length of slip decreases on the fault, therefore, we do not observe any long-tail distribution of peak ground acceleration when performing several rupture simulations for small correlation lengths. Finally, for a correlation length of 6 km, the within-event and between-events PGA log-normal standard deviations are 0.58 and 0.19, respectively, values slightly smaller than those reported by Boore et al. (Earthq Spectra, 30(3):1057-1085, 2014). The between-events standard deviation is consistently smaller than the within-event for all correlations lengths, a feature that agrees with recent ground motion prediction equations.

  6. A comparison of two methods for earthquake source inversion using strong motion seismograms

    Directory of Open Access Journals (Sweden)

    G. C. Beroza

    1994-06-01

    Full Text Available In this paper we compare two time-domain inversion methods that have been widely applied to the problem of modeling earthquake rupture using strong-motion seismograms. In the multi-window method, each point on the fault is allowed to rupture multiple times. This allows flexibility in the rupture time and hence the rupture velocity. Variations in the slip-velocity function are accommodated by variations in the slip amplitude in each time-window. The single-window method assumes that each point on the fault ruptures only once, when the rupture front passes. Variations in slip amplitude are allowed and variations in rupture velocity are accommodated by allowing the rupture time to vary. Because the multi-window method allows greater flexibility, it has the potential to describe a wider range of faulting behavior; however, with this increased flexibility comes an increase in the degrees of freedom and the solutions are comparatively less stable. We demonstrate this effect using synthetic data for a test model of the Mw 7.3 1992 Landers, California earthquake, and then apply both inversion methods to the actual recordings. The two approaches yield similar fits to the strong-motion data with different seismic moments indicating that the moment is not well constrained by strong-motion data alone. The slip amplitude distribution is similar using either approach, but important differences exist in the rupture propagation models. The single-window method does a better job of recovering the true seismic moment and the average rupture velocity. The multi-window method is preferable when rise time is strongly variable, but tends to overestimate the seismic moment. Both methods work well when the rise time is constant or short compared to the periods modeled. Neither approach can recover the temporal details of rupture propagation unless the distribution of slip amplitude is constrained by independent data.

  7. Uncertainty, variability, and earthquake physics in ground‐motion prediction equations

    Science.gov (United States)

    Baltay, Annemarie S.; Hanks, Thomas C.; Abrahamson, Norm A.

    2017-01-01

    Residuals between ground‐motion data and ground‐motion prediction equations (GMPEs) can be decomposed into terms representing earthquake source, path, and site effects. These terms can be cast in terms of repeatable (epistemic) residuals and the random (aleatory) components. Identifying the repeatable residuals leads to a GMPE with reduced uncertainty for a specific source, site, or path location, which in turn can yield a lower hazard level at small probabilities of exceedance. We illustrate a schematic framework for this residual partitioning with a dataset from the ANZA network, which straddles the central San Jacinto fault in southern California. The dataset consists of more than 3200 1.15≤M≤3 earthquakes and their peak ground accelerations (PGAs), recorded at close distances (R≤20  km). We construct a small‐magnitude GMPE for these PGA data, incorporating VS30 site conditions and geometrical spreading. Identification and removal of the repeatable source, path, and site terms yield an overall reduction in the standard deviation from 0.97 (in ln units) to 0.44, for a nonergodic assumption, that is, for a single‐source location, single site, and single path. We give examples of relationships between independent seismological observables and the repeatable terms. We find a correlation between location‐based source terms and stress drops in the San Jacinto fault zone region; an explanation of the site term as a function of kappa, the near‐site attenuation parameter; and a suggestion that the path component can be related directly to elastic structure. These correlations allow the repeatable source location, site, and path terms to be determined a priori using independent geophysical relationships. Those terms could be incorporated into location‐specific GMPEs for more accurate and precise ground‐motion prediction.

  8. Simulation of strong ground motion parameters of the 1 June 2013 Gulf of Suez earthquake, Egypt

    Science.gov (United States)

    Toni, Mostafa

    2017-06-01

    This article aims to simulate the ground motion parameters of the moderate magnitude (ML 5.1) June 1, 2013 Gulf of Suez earthquake, which represents the largest instrumental earthquake to be recorded in the middle part of the Gulf of Suez up to now. This event was felt in all cities located on both sides of the Gulf of Suez, with minor damage to property near the epicenter; however, no casualties were observed. The stochastic technique with the site-dependent spectral model is used to simulate the strong ground motion parameters of this earthquake in the cities located at the western side of the Gulf of Suez and north Red Sea namely: Suez, Ain Sokhna, Zafarana, Ras Gharib, and Hurghada. The presence of many tourist resorts and the increase in land use planning in the considered cities represent the motivation of the current study. The simulated parameters comprise the Peak Ground Acceleration (PGA), Peak Ground Velocity (PGV), and Peak Ground Displacement (PGD), in addition to Pseudo Spectral Acceleration (PSA). The model developed for ground motion simulation is validated by using the recordings of three accelerographs installed around the epicenter of the investigated earthquake. Depending on the site effect that has been determined in the investigated areas by using geotechnical data (e.g., shear wave velocities and microtremor recordings), the investigated areas are classified into two zones (A and B). Zone A is characterized by higher site amplification than Zone B. The ground motion parameters are simulated at each zone in the considered areas. The results reveal that the highest values of PGA, PGV, and PGD are observed at Ras Gharib city (epicentral distance ∼ 11 km) as 67 cm/s2, 2.53 cm/s, and 0.45 cm respectively for Zone A, and as 26.5 cm/s2, 1.0 cm/s, and 0.2 cm respectively for Zone B, while the lowest values of PGA, PGV, and PGD are observed at Suez city (epicentral distance ∼ 190 km) as 3.0 cm/s2, 0.2 cm/s, and 0.05 cm/s respectively for Zone A

  9. Using the Charleston, SC earthquake of 1886 to develop new models for estimating future earthquake damage

    Science.gov (United States)

    Miner, Krystle Sunbow

    In 1886, a magnitude 7.3 earthquake occurred near Charleston, South Carolina. This earthquake produced extensive damage in the city and surrounding region. Because earthquake damage on the Charleston Peninsula is so well documented, there is an opportunity to use this information to develop better models of damage in future earthquakes. This project uses GIS and HAZUS to test the usefulness of new geological, geotechnical, and seismological data in describing actual building damage in 1886. A detailed catalog of building damage was mapped spatially in order to make comparisons to surface geology, elevation, fill depth, liquefaction susceptibility, soil type, and site amplitude within a small area at the southern tip of the Charleston Peninsula. Despite a large sample size of structures included in the area of interest, we do not have records for buildings in the most vulnerable regions of the study area. More information is needed to fill in the holes so that correlations can be resolved with confidence. Since the timing of an earthquake is unpredictable, preemptive preparations are needed so a city can best survive the earthquake. Therefore, the results of this study can be used to make city-planning recommendations and enhance community awareness programs so that Charleston can better prepare itself for the next large earthquake.

  10. Consistency-based respiratory motion estimation in rotational angiography.

    Science.gov (United States)

    Unberath, Mathias; Aichert, André; Achenbach, Stephan; Maier, Andreas

    2017-09-01

    Rotational coronary angiography enables 3D reconstruction but suffers from intra-scan cardiac and respiratory motion. While gating handles cardiac motion, respiratory motion requires compensation. State-of-the-art algorithms rely on 3D-2D registration that depends on initial reconstructions of sufficient quality. We propose a compensation method that is applied directly in projection domain. It overcomes the need for reconstruction and thus complements the state-of-the-art. Virtual single-frame background subtraction based on vessel segmentation and spectral deconvolution yields non-truncated images of the contrasted lumen. This allows motion compensation based on data consistency conditions. We compensate craniocaudal shifts by optimizing epipolar consistency to (a) devise an image-based surrogate for cardiac motion and (b) compensate for respiratory motion. We validate our approach in two numerical phantom studies and three clinical cases. Correlation of the image-based surrogate for cardiac motion with the ECG-based ground truth was excellent yielding a Pearson correlation of 0.93 ± 0.04. Considering motion compensation, the target error measure decreased by 98% and 69%, respectively, for the phantom experiments while for the clinical cases the same figure of merit improved by 46 ± 21%. The proposed method is entirely image-based and accurately estimates craniocaudal shifts due to respiration and cardiac contraction. Future work will investigate experimental trajectories and possibilities for simplification of the single-frame subtraction pipeline. © 2016 American Association of Physicists in Medicine.

  11. Adaptive Motion Estimation Processor for Autonomous Video Devices

    Directory of Open Access Journals (Sweden)

    Dias T

    2007-01-01

    Full Text Available Motion estimation is the most demanding operation of a video encoder, corresponding to at least 80% of the overall computational cost. As a consequence, with the proliferation of autonomous and portable handheld devices that support digital video coding, data-adaptive motion estimation algorithms have been required to dynamically configure the search pattern not only to avoid unnecessary computations and memory accesses but also to save energy. This paper proposes an application-specific instruction set processor (ASIP to implement data-adaptive motion estimation algorithms that is characterized by a specialized datapath and a minimum and optimized instruction set. Due to its low-power nature, this architecture is highly suitable to develop motion estimators for portable, mobile, and battery-supplied devices. Based on the proposed architecture and the considered adaptive algorithms, several motion estimators were synthesized both for a Virtex-II Pro XC2VP30 FPGA from Xilinx, integrated within an ML310 development platform, and using a StdCell library based on a 0.18 μm CMOS process. Experimental results show that the proposed architecture is able to estimate motion vectors in real time for QCIF and CIF video sequences with a very low-power consumption. Moreover, it is also able to adapt the operation to the available energy level in runtime. By adjusting the search pattern and setting up a more convenient operating frequency, it can change the power consumption in the interval between 1.6 mW and 15 mW.

  12. Rupture dynamics and ground motions from earthquakes in 2-D heterogeneous media

    KAUST Repository

    Bydlon, Samuel A.

    2015-03-21

    ©2015. American Geophysical Union. All Rights Reserved. We perform 2-D simulations of earthquakes on rough faults in media with random heterogeneities (with von Karman distribution) to study the effects of geometric and material heterogeneity on the rupture process and resulting high-frequency ground motions in the near-fault region (out to ∼20km). Variations in slip and rupture velocity can arise from material heterogeneity alone but are dominantly controlled by fault roughness. Scattering effects become appreciable beyond ∼3km from the fault. Near-fault scattering extends the duration of incoherent, high-frequency ground motions and, at least in our 2-D simulations, elevates root-mean-square accelerations (i.e., Arias intensity) with negligible reduction in peak velocities. We also demonstrate that near-fault scattering typically occurs in the power law tail of the power spectral density function, quantified by the Hurst exponent and another parameter combining standard deviation and correlation length. Key Points Fault roughness, not material heterogeneity, dominates rupture process Introduce parameter that can be used to quantify near-fault scattering Scattering affects the duration and amplitude of high-frequency ground motions

  13. Spatial modeling for estimation of earthquakes economic loss in West Java

    Science.gov (United States)

    Retnowati, Dyah Ayu; Meilano, Irwan; Riqqi, Akhmad; Hanifa, Nuraini Rahma

    2017-07-01

    Indonesia has a high vulnerability towards earthquakes. The low adaptive capacity could make the earthquake become disaster that should be concerned. That is why risk management should be applied to reduce the impacts, such as estimating the economic loss caused by hazard. The study area of this research is West Java. The main reason of West Java being vulnerable toward earthquake is the existence of active faults. These active faults are Lembang Fault, Cimandiri Fault, Baribis Fault, and also Megathrust subduction zone. This research tries to estimates the value of earthquakes economic loss from some sources in West Java. The economic loss is calculated by using HAZUS method. The components that should be known are hazard (earthquakes), exposure (building), and the vulnerability. Spatial modeling is aimed to build the exposure data and make user get the information easier by showing the distribution map, not only in tabular data. As the result, West Java could have economic loss up to 1,925,122,301,868,140 IDR ± 364,683,058,851,703.00 IDR, which is estimated from six earthquake sources with maximum possibly magnitude. However, the estimation of economic loss value in this research is the worst case earthquakes occurrence which is probably over-estimated.

  14. Estimation of strong ground motion in broad-frequency band based on a seismic source scaling model and an empirical Green's function technique

    Directory of Open Access Journals (Sweden)

    K. Kamae

    1994-06-01

    Full Text Available We introduce a generalized method for simulating strong ground motion from large earthquakes by summing subevent records to follow the ?2 law. The original idea of the method is based on a constant stress parameter between the target event and the subevent. It is applicable to a case where both events have a different stress drop after some manipulation. However, the simulation for a very large earthquake from a small event with this method has inevitably some deficiencies of spectral amplitudes in the intermediate frequency range deviating f`rom the ?2 model, although the high and low frequency motions match the scaling. We improve the simulation algorithm so as not to make spectral sags, introducing self-similar distribution of subfaults with different sizes in the fault plane, so-called fractal composite faulting model. We show successful simulations for intermediate-sized earthquakes (MJMA = 5.0, 6.0 and 6.1, the large aftershocks of the 1983 Akita-Oki earthquake. using the records of smaller aftershocks (MJMA = 3.9 and 5.0 as an empirical Green's function. Further, we attempted to estimate strong ground motion for the 1946 Nankai earthquake with Mw 8.2, using the records of a MJMA 5.1 earthquake occurring near the source region of the mainshock. We found that strong ground motions simulated for the fractal composite faulting model with two asperities radiating significantly high frequency motions matched well the observed data such as the near-field displacement record, the source spectrum estimated from the teleseismic record, and the seismic intensity distribution during the 1946 Nankai earthquake.

  15. Motion estimation under location uncertainty for turbulent fluid flows

    Science.gov (United States)

    Cai, Shengze; Mémin, Etienne; Dérian, Pierre; Xu, Chao

    2018-01-01

    In this paper, we propose a novel optical flow formulation for estimating two-dimensional velocity fields from an image sequence depicting the evolution of a passive scalar transported by a fluid flow. This motion estimator relies on a stochastic representation of the flow allowing to incorporate naturally a notion of uncertainty in the flow measurement. In this context, the Eulerian fluid flow velocity field is decomposed into two components: a large-scale motion field and a small-scale uncertainty component. We define the small-scale component as a random field. Subsequently, the data term of the optical flow formulation is based on a stochastic transport equation, derived from the formalism under location uncertainty proposed in Mémin (Geophys Astrophys Fluid Dyn 108(2):119-146, 2014) and Resseguier et al. (Geophys Astrophys Fluid Dyn 111(3):149-176, 2017a). In addition, a specific regularization term built from the assumption of constant kinetic energy involves the very same diffusion tensor as the one appearing in the data transport term. Opposite to the classical motion estimators, this enables us to devise an optical flow method dedicated to fluid flows in which the regularization parameter has now a clear physical interpretation and can be easily estimated. Experimental evaluations are presented on both synthetic and real world image sequences. Results and comparisons indicate very good performance of the proposed formulation for turbulent flow motion estimation.

  16. Earthquakes

    Science.gov (United States)

    ... earthquake occurs in a populated area, it may cause property damage, injuries, and even deaths. If you live in a coastal area, there is the possibility of a tsunami. Damage from earthquakes can also lead to floods or fires. Although there are no guarantees of ...

  17. WHITTIER NARROWS, CALIFORNIA EARTHQUAKE OF OCTOBER 1, 1987-PRELIMINARY ASSESSMENT OF STRONG GROUND MOTION RECORDS.

    Science.gov (United States)

    Brady, A.G.; Etheredge, E.C.; Porcella, R.L.

    1988-01-01

    More than 250 strong-motion accelerograph stations were triggered by the Whittier Narrows, California earthquake of 1 October 1987. Considering the number of multichannel structural stations in the area of strong shaking, this set of records is one of the more significant in history. Three networks, operated by the U. S. Geological Survey, the California Division of Mines and Geology, and the University of Southern California produced the majority of the records. The excellent performance of the instruments in these and the smaller arrays is attributable to the quality of the maintenance programs. Readiness for a magnitude 8 event is directly related to these maintenance programs. Prior to computer analysis of the analog film records, a number of important structural resonant modes can be identified, and frequencies and simple mode shapes have been scaled.

  18. 3-D velocity structure model for long-period ground motion simulation of the hypothetical Nankai Earthquake

    Science.gov (United States)

    Kagawa, T.; Petukhin, A.; Koketsu, K.; Miyake, H.; Murotani, S.; Tsurugi, M.

    2010-12-01

    Three dimensional velocity structure model of southwest Japan is provided to simulate long-period ground motions due to the hypothetical subduction earthquakes. The model is constructed from numerous physical explorations conducted in land and offshore areas and observational study of natural earthquakes. Any available information is involved to explain crustal structure and sedimentary structure. Figure 1 shows an example of cross section with P wave velocities. The model has been revised through numbers of simulations of small to middle earthquakes as to have good agreement with observed arrival times, amplitudes, and also waveforms including surface waves. Figure 2 shows a comparison between Observed (dash line) and simulated (solid line) waveforms. Low velocity layers have added on seismological basement to reproduce observed records. The thickness of the layer has been adjusted through iterative analysis. The final result is found to have good agreement with the results from other physical explorations; e.g. gravity anomaly. We are planning to make long-period (about 2 to 10 sec or longer) simulations of ground motion due to the hypothetical Nankai Earthquake with the 3-D velocity structure model. As the first step, we will simulate the observed ground motions of the latest event occurred in 1946 to check the source model and newly developed velocity structure model. This project is partly supported by Integrated Research Project for Long-Period Ground Motion Hazard Maps by Ministry of Education, Culture, Sports, Science and Technology (MEXT). The ground motion data used in this study were provided by National Research Institute for Earth Science and Disaster Prevention Disaster (NIED). Figure 1 An example of cross section with P wave velocities Figure 2 Observed (dash line) and simulated (solid line) waveforms due to a small earthquake

  19. Human motion estimation with multiple frequency modulated continuous wave radars

    NARCIS (Netherlands)

    van Dorp, P.; Groen, F.C.A.

    2010-01-01

    Human motion estimation is an important issue in automotive, security or home automation applications. Radar systems are well suited for this because they are robust, are independent of day or night conditions and have accurate range and speed domain. The human response in a radar range-speed-time

  20. Estimating Distances To Objects From Motion In Images

    Science.gov (United States)

    Sridhar, B.; Suorsa, R.; Hussien, B.

    1996-01-01

    In developmental method of estimating distances between moving platform and nearby stationary objects, positions of objects relative to moving platform deduced from apparent motions of those objects in images generated by video camera affixed to platform. Estimates enhanced by use of extended Kalman filter. Developed for use in controlling military helicopters in low-altitude evasive maneuvers, also potentially applicable in robotics and in autonomous navigation of vehicles in general.

  1. Low-Frequency Seismic Ground Motion At The Pier Positions Of The Planned Messina Straits Bridge For A Realistic Earthquake Scenario

    Science.gov (United States)

    Gusev, A. A.; Pavlov, V.; Romanelli, F.; Panza, G.

    2008-07-01

    We estimated longer-period (period T>0.5 s) components of the ground motion at the piers of the planned Messina straits bridge. As the shortest fault-to-site distance is only 3-5 km, the kinematic earthquake rupture process has to be described in a realistic way and thus, the causative fault is represented by a dense grid of subfaults. To model the 1908 event, we assume a Mw = 7 earthquake, with a 40×20 km rectangular fault, and pure reverse dip-slip. The horizontal upper side of the rectangle is at 3-km depth, and the N corner of the rectangle is just between the piers. For the fault nucleation point, the least favorable place is assumed and a randomized rupture velocity is used in a particular run. In a typical simulation, the fault motion is initially represented by the time history of slip in each of the subfaults and by the distribution of the final seismic moment among the subsources (forming "asperities"), both generated as lognormal random functions. The time histories are then filtered in order to fit a chosen source spectral model. The parameters that are conditioning the random functions can be based on the bulk of published fault inversions, or reproduced from an earlier successful attempt to simulate ground motions in the epicentral zone of the 1994, M = 6.7 Northridge, California, earthquake. In the second step of calculations, the Green functions (for each subfault and pier combination) are calculated for a layered halfspace model of the pier foundation stratigraphy, using an advanced Green function calculator, that allows an accurate calculation over the entire relevant frequency band including static terms. Finally, the 3-components of the strong ground motion are obtained at the two piers through convolution and summation over the different subsources. We compare a set of response horizontal velocity spectra (PRV) obtained from our calculations with a reference PRV that is considered as a reasonable upper bound for the possible ground motion near

  2. Assessing the impact of Syrian refugees on earthquake fatality estimations in southeast Turkey

    Science.gov (United States)

    Wilson, Bradley; Paradise, Thomas

    2018-01-01

    The influx of millions of Syrian refugees into Turkey has rapidly changed the population distribution along the Dead Sea Rift and East Anatolian fault zones. In contrast to other countries in the Middle East where refugees are accommodated in camp environments, the majority of displaced individuals in Turkey are integrated into local cities, towns, and villages - placing stress on urban settings and increasing potential exposure to strong earthquake shaking. Yet displaced populations are often unaccounted for in the census-based population models used in earthquake fatality estimations. This study creates a minimally modeled refugee gridded population model and analyzes its impact on semi-empirical fatality estimations across southeast Turkey. Daytime and nighttime fatality estimates were produced for five fault segments at earthquake magnitudes 5.8, 6.4, and 7.0. Baseline fatality estimates calculated from census-based population estimates for the study area varied in scale from tens to thousands of fatalities, with higher death totals in nighttime scenarios. Refugee fatality estimations were analyzed across 500 semi-random building occupancy distributions. Median fatality estimates for refugee populations added non-negligible contributions to earthquake fatalities at four of five fault locations, increasing total fatality estimates by 7-27 %. These findings communicate the necessity of incorporating refugee statistics into earthquake fatality estimations in southeast Turkey and the ongoing importance of placing environmental hazards in their appropriate regional and temporal context.

  3. Empirical ground-motion relations for subduction-zone earthquakes and their application to Cascadia and other regions

    Science.gov (United States)

    Atkinson, G.M.; Boore, D.M.

    2003-01-01

    Ground-motion relations for earthquakes that occur in subduction zones are an important input to seismic-hazard analyses in many parts of the world. In the Cascadia region (Washington, Oregon, northern California, and British Columbia), for example, there is a significant hazard from megathrust earthquakes along the subduction interface and from large events within the subducting slab. These hazards are in addition to the hazard from shallow earthquakes in the overlying crust. We have compiled a response spectra database from thousands of strong-motion recordings from events of moment magnitude (M) 5-8.3 occurring in subduction zones around the world, including both interface and in-slab events. The 2001 M 6.8 Nisqually and 1999 M 5.9 Satsop earthquakes are included in the database, as are many records from subduction zones in Japan (Kyoshin-Net data), Mexico (Guerrero data), and Central America. The size of the database is four times larger than that available for previous empirical regressions to determine ground-motion relations for subduction-zone earthquakes. The large dataset enables improved determination of attenuation parameters and magnitude scaling, for both interface and in-slab events. Soil response parameters are also better determined by the data. We use the database to develop global ground-motion relations for interface and in-slab earthquakes, using a maximum likelihood regression method. We analyze regional variability of ground-motion amplitudes across the global database and find that there are significant regional differences. In particular, amplitudes in Cascadia differ by more than a factor of 2 from those in Japan for the same magnitude, distance, event type, and National Earthquake Hazards Reduction Program (NEHRP) soil class. This is believed to be due to regional differences in the depth of the soil profile, which are not captured by the NEHRP site classification scheme. Regional correction factors to account for these differences are

  4. Overview of the relations earthquake source parameters and the specification of strong ground motion for design purposes

    Energy Technology Data Exchange (ETDEWEB)

    Bernreuter, D.L.

    1977-08-01

    One of the most important steps in the seismic design process is the specification of the appropriate ground motion to be input into the design analysis. From the point-of-view of engineering design analysis, the important parameters are peak ground acceleration, spectral shape and peak spectral levels. In a few cases, ground displacement is a useful parameter. The earthquake is usually specified by giving its magnitude and either the epicentral distance or the distance of the closest point on the causitive fault to the site. Typically, the appropriate ground motion parameters are obtained using the specified magnitude and distance in equations obtained from regression analysis among the appropriate variables. Two major difficulties with such an approach are: magnitude is not the best parameter to use to define the strength of an earthquake, and little near-field data is available to establish the appropriate form for the attenuation of the ground motion with distance, source size and strength. These difficulties are important for designing a critical facility; i.e., one for which a very low risk of exceeding the design ground motion is required. Examples of such structures are nuclear power plants, schools and hospitals. for such facilities, a better understanding of the relation between the ground motion and the important earthquake source parameters could be very useful for several reasons.

  5. Magnitude estimation using the first three seconds P-wave amplitude in earthquake early warning

    Science.gov (United States)

    Wu, Yih-Min; Zhao, Li

    2006-08-01

    Pd is the peak amplitude of displacement in the first three seconds after the arrival of the P wave. We investigated the attenuation of Pd with the hypocentral distance R in southern California as a function of magnitude M, and obtained the following relationship: log (Pd) = -3.463 + 0.729 × M - 1.374 × log (R) +/- 0.305. Given an earthquake location determined by the P-wave arrival times at stations close to the epicenter, this relationship can be used to define a so-called ``Pd magnitude'' of earthquakes. Our result shows that for earthquakes in southern California the Pd magnitudes agree with the catalog magnitudes with a standard deviation of 0.18 for events less than magnitude 6.5. Therefore, Pd is a robust measurement for estimating the magnitudes of earthquakes and has practical application in earthquake early warning systems.

  6. Safe-Taipei a Program Project for Strong Motions, Active Faults, and Earthquakes in the Taipei Metropolitan Area

    Science.gov (United States)

    Wang, Jeen-Hwa

    Strong collision between the Eurasian and Philippine Sea Plates causes high seismicity in the Taiwan region, which is often attacked by large earthquakes. Several cities, including three mega-cities, i.e., Taipei, Taichung, and Kaoshung, have been constructed on western Taiwan, where is lying on thick sediments. These cities, with a high-population density, are usually a regional center of culture, economics, and politics. Historically, larger-sized earthquakes, e.g. the 1935 Hsingchu—Taichung earthquake and the 1999 Chi—Chi earthquake, often caused serious damage on the cities. Hence, urban seismology must be one of the main subjects of Taiwan's seismological community. Since 2005, a program project, sponsored by Academia Sinica, has been launched to investigate seismological problems in the Taipei Metropolitan Area. This program project is performed during the 2005—2007 period. The core research subjects are: (1) the deployment of the Taipei Down-hole Seismic Array; (2) the properties of earthquakes and active faults in the area; (3) the seismogenic-zone structures, including the 3-D velocity and Q structures, of the area; (4) the characteristics of strong-motions and sites affects; and (5) strong-motion prediction. In addition to academic goals, the results obtained from the program project will be useful for seismic hazard mitigation not only for the area but also for others.

  7. 8 March 2010 Elazığ-Kovancilar (Turkey) Earthquake: observations on ground motions and building damage

    Science.gov (United States)

    Akkar, Sinan; Aldemir, A.; Askan, A.; Bakir, S.; Canbay, E.; Demirel, I.O.; Erberik, M.A.; Gulerce, Z.; Gulkan, Polat; Kalkan, Erol; Prakash, S.; Sandikkaya, M.A.; Sevilgen, V.; Ugurhan, B.; Yenier, E.

    2011-01-01

    An earthquake of MW = 6.1 occurred in the Elazığ region of eastern Turkey on 8 March 2010 at 02:32:34 UTC. The United States Geological Survey (USGS) reported the epicenter of the earthquake as 38.873°N-39.981°E with a focal depth of 12 km. Forty-two people lost their lives and 137 were injured during the event. The earthquake was reported to be on the left-lateral strike-slip east Anatolian fault (EAF), which is one of the two major active fault systems in Turkey. Teams from the Earthquake Engineering Research Center of the Middle East Technical University (EERC-METU) visited the earthquake area in the aftermath of the mainshock. Their reconnaissance observations were combined with interpretations of recorded ground motions for completeness. This article summarizes observations on building and ground damage in the area and provides a discussion of the recorded motions. No significant observations in terms of geotechnical engineering were made.

  8. Ground Motion Prediction for M7+ scenarios on the San Andreas Fault using the Virtual Earthquake Approach

    Science.gov (United States)

    Denolle, M.; Dunham, E. M.; Prieto, G.; Beroza, G. C.

    2013-05-01

    There is no clearer example of the increase in hazard due to prolonged and amplified shaking in sedimentary, than the case of Mexico City in the 1985 Michoacan earthquake. It is critically important to identify what other cities might be susceptible to similar basin amplification effects. Physics-based simulations in 3D crustal structure can be used to model and anticipate those effects, but they rely on our knowledge of the complexity of the medium. We propose a parallel approach to validate ground motion simulations using the ambient seismic field. We compute the Earth's impulse response combining the ambient seismic field and coda-wave enforcing causality and symmetry constraints. We correct the surface impulse responses to account for the source depth, mechanism and duration using a 1D approximation of the local surface-wave excitation. We call the new responses virtual earthquakes. We validate the ground motion predicted from the virtual earthquakes against moderate earthquakes in southern California. We then combine temporary seismic stations on the southern San Andreas Fault and extend the point source approximation of the Virtual Earthquake Approach to model finite kinematic ruptures. We confirm the coupling between source directivity and amplification in downtown Los Angeles seen in simulations.

  9. Monitoring postseismic motion of the frontal wedge after 2011 Tohoku Earthquake by across-trench acoustic ranging

    Science.gov (United States)

    Yamamoto, Ryusuke; Hino, Ryota; Kido, Motoyuki; Honsho, Chie

    2017-04-01

    After the occurrence of the 2011 Tohoku Earthquake causing > 50 m coseismic slip at the shallowest portion of the plate boundary (e.g. Iinuma et al., 2012, JGR), evident postseismic deformation has been observed by seafloor geodetic observations. Fast postseismic displacement rates observed by GPS/Acoustic (GPS/A) measurements both on the landward- and oceanward-slopes of the Japan Trench can be by viscoelastic relaxation induced by the mainshock (e.g. Sun et al., 2014, Nature; Watanabe et al., 2014, GRL; Tomita et al., 2015, GRL). However, the prevalence of the viscoelastic relaxation makes it difficult to evaluate behavior of the shallow megathrust after the massive coseismic slip based on the available GPS/A data. It is expected that the relative motion of the frontal wedge against the incoming oceanic plate reflects the motion of the shallow plate boundary fault and we have been carried out seafloor acoustic ranging observations across the Japan Trench to monitor it. Acoustic ranging measures two-way travel times between a pair of precision acoustic transponders placed on the seafloor. By repeating the measurements and after correcting for sound speed fluctuations, temporal change of measured travel time is converted to change of the baseline length. We have deployed instruments to make long-term continuous acoustic ranging across the Japan Trench, since 2013. Osada et al. (2014, JpGU) estimated the precision of the baseline length measurement to be several mm/year for 1 km baseline and proved that our acoustic ranging technique is capable of detecting seafloor motion at a rate of cm/year, equivalent to the expected rate of relative motions across the Japan Trench. Yamamoto et al. (2016, JpGU) reported no significant changes of the baseline lengths across the trench axis and suggested absence of afterslip on the shallow fault in the area. In this paper, we show results of most recent deployment from September 2015 to September 2016 at the same region. In this

  10. Review of variations in Mw < 7 earthquake motions on position and TEC (Mw = 6.5 Aegean Sea earthquake sample)

    Science.gov (United States)

    Yildirim, Omer; Inyurt, Samed; Mekik, Cetin

    2016-02-01

    Turkey is a country located in the middle latitude zone, where tectonic activity is intensive. Recently, an earthquake of magnitude 6.5 Mw occurred offshore in the Aegean Sea on 24 May 2014 at 09:25 UTC, which lasted about 40 s. The earthquake was also felt in Greece, Romania, and Bulgaria in addition to Turkey. In recent years, ionospheric anomaly detection studies have been carried out because of seismicity with total electron content (TEC) computed from the global navigation satellite system's (GNSS) signal delays and several interesting findings have been published. In this study, both TEC and positional variations have been examined separately following a moderate size earthquake in the Aegean Sea. The correlation of the aforementioned ionospheric variation with the positional variation has also been investigated. For this purpose, a total of 15 stations was used, including four continuously operating reference stations in Turkey (CORS-TR) and stations in the seismic zone (AYVL, CANA, IPSA, and YENC), as well as international GNSS service (IGS) and European reference frame permanent network (EPN) stations. The ionospheric and positional variations of the AYVL, CANA, IPSA, and YENC stations were examined using Bernese v5.0 software. When the precise point positioning TEC (PPP-TEC) values were examined, it was observed that the TEC values were approximately 4 TECU (total electron content unit) above the upper-limit TEC value at four stations located in Turkey, 3 days before the earthquake at 08:00 and 10:00 UTC. At the same stations, on the day before the earthquake at 06:00, 08:00, and 10:00 UTC, the TEC values were approximately 5 TECU below the lower-limit TEC value. The global ionosphere model TEC (GIM-TEC) values published by the Centre for Orbit Determination in Europe (CODE) were also examined. Three days before the earthquake, at all stations, it was observed that the TEC values in the time period between 08:00 and 10:00 UTC were approximately 2 TECU

  11. Estimation of Ship Motions Using Closed-Form Expressions

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher; Mansour, A.E.; Olsen, Anders Smærup

    2004-01-01

    A semi-analytical approach is used to derive frequency response functions for the wave-induced motions for monohull ships. The results are given as closed-form expressions and the required input information for the procedure is restricted to the main dimensions: Length, breadth, draught, block...... coefficient together with speed and heading. The formulas make it simple to obtain quick estimates of the wave-induced motions and accelerations in the conceptual design phase and to perform a sensitivity study of the variation with main dimensions and operational profile....

  12. Ground Motion Simulations of Scenario Earthquake Ruptures of the Hayward Fault

    Science.gov (United States)

    Aagaard, B.; Graves, R.; Larsen, S.; Ma, S.; Rodgers, A.; Brocher, T.; Graymer, R.; Harris, R.; Lienkaemper, J.; Ponce, D.; Schwartz, D.; Simpson, R.; Spudich, P.; Dreger, D.; Petersson, A.; Boatwright, J.

    2008-12-01

    We compute ground motions in the San Francisco Bay area for a suite of 35 magnitude 6.7--7.2 scenario earthquake ruptures involving the Hayward fault. The suite of scenarios encompasses variability in rupture length, hypocenter, distribution of slip, rupture speed, and rise time. The five rupture lengths include the Hayward fault and portions thereof, as well as combined rupture of the Hayward and Rodgers Creek faults and the Hayward and Calaveras faults. For most rupture lengths, we consider three hypocenters, yielding north-to-south rupture, bilateral rupture, and south-to-north rupture. We also consider multiple random realizations of the slip distribution, accounting for creeping patches (Funning et al., 2007) either through simple assumptions about how creep reduces coseismic slip or a slip-predictable approach. The kinematic rupture models include local variations in rupture speed and use a ray-tracing algorithm to propagate the rupture front. Although we are not attempting to simulate the 1868 Hayward fault earthquake in detail, a few of the scenarios are designed to have source parameters that might be similar to this event. This collaborative effort involves four modeling groups, using different wave propagation codes and domains of various sizes and resolutions, computing long-period (T > 1--2 s) or broadband (T > 0.1 s) synthetic ground motions for overlapping subsets of the suite of scenarios. The simulations incorporate the 3-D geologic structure as described by the USGS 3-D Geologic Model (Jachens et al., 2006; Watt et al., 2007) and USGS Bay Area Velocity Model (Brocher et al., 2007). The simulations illustrate the dramatic increase in intensity of shaking for a magnitude 7.0 bilateral rupture of the entire Hayward fault compared with a magnitude 6.8 bilateral rupture of the southern two-thirds of the fault; the area subjected to shaking stronger than MMI VII increases from about 10% to more than 40% of the San Francisco Bay urban area. For a given

  13. Identifying the unique ground motion signatures of supershear earthquakes - The one-two punch effect on high-rise buildings

    Science.gov (United States)

    Rosakis, A.; Mello, M.; Bhat, H.; Krishnan, S.; Kanamori, H.

    2011-12-01

    Directly studying earthquakes presents a host of insurmountable difficulties, the least of which is our inability to trigger earthquakes of various magnitudes at will and the lack of means of scrutinizing the behavior at depth while the quake propagates. We have developed techniques to produce miniature (or surrogate) laboratory earthquakes and follow their progress with high-speed imaging tools. Our laboratory quakes mimic actual ones, and have allowed us to demonstrate the existence of ruptures of super-shear or intersonic rupture speeds. The propagating fronts of such supershear ruptures feature a Mach-cone of shear shock waves similar to that of supersonic aircraft. For earthquake ruptures transitioning from sub-Rayleigh to supershear rupture speeds, this unusual shear Mach cone feature is also followed by a trailing Rayleigh disturbance which is all that remains of the old sub-Rayleigh rupture after transition is complete. Each propagating disturbance contributes to the unique ground motion signature in the near field. We refer to this as a one-two punch scenario. In particular, ground motion associated with passage of the shear Mach features a dominant fault-parallel velocity component while ground motion from the trailing Rayleigh field is characterized by a dominant fault-normal velocity component (characteristic of common, sub-shear earthquake ruptures). Appropriate scaling of the laboratory ground velocity measurements are used to shake 3-D numerical models of high-rise buildings (located in near fault locations) with hypothetical supershear and sub-Rayleigh earthquakes with unexpected implication to building safety and seismic hazard analysis.

  14. Combined UAVSAR and GPS Estimates of Fault Slip for the M 6.0 South Napa Earthquake

    Science.gov (United States)

    Donnellan, A.; Parker, J. W.; Hawkins, B.; Hensley, S.; Jones, C. E.; Owen, S. E.; Moore, A. W.; Wang, J.; Pierce, M. E.; Rundle, J. B.

    2014-12-01

    Combined UAVSAR and GPS Estimates of Fault Slip for the M 6.0 South Napa Earthquake Andrea Donnellan, Jay Parker, Brian Hawkins, Scott Hensley, Cathleen Jones, Susan Owen, Angelyn Moore Jet Propulsion Laboratory, California Institute of Technology Marlon Pierce, Jun Wang Indiana University John Rundle University of California, Davis The South Napa to Santa Rosa area has been observed with NASA's UAVSAR since late 2009 as part of an experiment to monitor areas identified as having a high probability of an earthquake. The M 6.0 South Napa earthquake occurred on 24 August 2014. The area was flown 29 May 2014 preceeding the earthquake, and again on 29 August 2014, five days after the earthquake. The UAVSAR results show slip on a single fault at the south end of the rupture near the epicenter of the event. The rupture branches out into multiple faults further north near the Napa area. A combined inversion of rapid GPS results and the unwrapped UAVSAR interferogram indicate nearly pure strike slip motion. Using this assumption, the UAVSAR data show horizontal right-lateral slip across the fault of 19 cm at the south end of the rupture and increasing to 70 cm northward over a distance of 6.5 km. The joint inversion indicates slip of ~30 cm on a network of sub-parallel faults is concentrated in a zone about 17 km long. The lower depths of the faults are 5-8.5 km. The eastern two sub-parallel faults break the surface, while three faults to the west are buried at depths ranging from 2-6 km with deeper depths to the north and west. The geodetic moment release is equivalent to a M 6.1 event. Additional ruptures are observed in the interferogram, but the inversions suggest that they represent superficial slip that does not contribute to the overall moment release.

  15. Automated Motion Estimation for 2D Cine DENSE MRI

    Science.gov (United States)

    Gilliam, Andrew D.; Epstein, Frederick H.

    2013-01-01

    Cine displacement encoding with stimulated echoes (DENSE) is a magnetic resonance (MR) method that directly encodes tissue displacement into MR phase images. This technique has successfully interrogated many forms of tissue motion, but is most commonly used to evaluate cardiac mechanics. Currently, motion analysis from cine DENSE images requires manually delineated anatomical structures. An automated analysis would improve measurement throughput, simplify data interpretation, and potentially access important physiological information during the MR exam. In this article, we present the first fully automated solution for the estimation of tissue motion and strain from 2D cine DENSE data. Results using both simulated and human cardiac cine DENSE data indicate good agreement between the automated algorithm and the standard semi-manual analysis method. PMID:22575669

  16. Estimation of earthquake source parameters in the Kachchh seismic ...

    Indian Academy of Sciences (India)

    SEISAN software has been used to locate the identified local earthquakes, which were recorded at least three or more stations of the Kachchh seismological network. Three component spectra of S-wave are being inverted by using the Levenberg–Marquardt non-linear inversion technique, wherein the inversion scheme is ...

  17. A global building inventory for earthquake loss estimation and risk management

    Science.gov (United States)

    Jaiswal, K.; Wald, D.; Porter, K.

    2010-01-01

    We develop a global database of building inventories using taxonomy of global building types for use in near-real-time post-earthquake loss estimation and pre-earthquake risk analysis, for the U.S. Geological Survey's Prompt Assessment of Global Earthquakes for Response (PAGER) program. The database is available for public use, subject to peer review, scrutiny, and open enhancement. On a country-by-country level, it contains estimates of the distribution of building types categorized by material, lateral force resisting system, and occupancy type (residential or nonresidential, urban or rural). The database draws on and harmonizes numerous sources: (1) UN statistics, (2) UN Habitat's demographic and health survey (DHS) database, (3) national housing censuses, (4) the World Housing Encyclopedia and (5) other literature. ?? 2010, Earthquake Engineering Research Institute.

  18. Joint framework for motion validity and estimation using block overlap.

    Science.gov (United States)

    Santoro, Michael; AlRegib, Ghassan; Altunbasak, Yucel

    2013-04-01

    This paper presents a block-overlap-based validity metric for use as a measure of motion vector (MV) validity and to improve the quality of the motion field. In contrast to other validity metrics in the literature, the proposed metric is not sensitive to image features and does not require the use of neighboring MVs or manual thresholds. Using a hybrid de-interlacer, it is shown that the proposed metric outperforms other block-based validity metrics in the literature. To help regularize the ill-posed nature of motion estimation, the proposed validity metric is also used as a regularizer in an energy minimization framework to determine the optimal MV. Experimental results show that the proposed energy minimization framework outperforms several existing motion estimation methods in the literature in terms of MV and interpolation quality. For interpolation quality, our algorithm outperforms all other block-based methods as well as several complex optical flow methods. In addition, it is one of the fastest implementations at the time of this writing.

  19. Probability estimates of seismic event occurrence compared to health hazards - Forecasting Taipei's Earthquakes

    Science.gov (United States)

    Fung, D. C. N.; Wang, J. P.; Chang, S. H.; Chang, S. C.

    2014-12-01

    Using a revised statistical model built on past seismic probability models, the probability of different magnitude earthquakes occurring within variable timespans can be estimated. The revised model is based on Poisson distribution and includes the use of best-estimate values of the probability distribution of different magnitude earthquakes recurring from a fault from literature sources. Our study aims to apply this model to the Taipei metropolitan area with a population of 7 million, which lies in the Taipei Basin and is bounded by two normal faults: the Sanchaio and Taipei faults. The Sanchaio fault is suggested to be responsible for previous large magnitude earthquakes, such as the 1694 magnitude 7 earthquake in northwestern Taipei (Cheng et. al., 2010). Based on a magnitude 7 earthquake return period of 543 years, the model predicts the occurrence of a magnitude 7 earthquake within 20 years at 1.81%, within 79 years at 6.77% and within 300 years at 21.22%. These estimates increase significantly when considering a magnitude 6 earthquake; the chance of one occurring within the next 20 years is estimated to be 3.61%, 79 years at 13.54% and 300 years at 42.45%. The 79 year period represents the average lifespan of the Taiwan population. In contrast, based on data from 2013, the probability of Taiwan residents experiencing heart disease or malignant neoplasm is 11.5% and 29%. The inference of this study is that the calculated risk that the Taipei population is at from a potentially damaging magnitude 6 or greater earthquake occurring within their lifetime is just as great as of suffering from a heart attack or other health ailments.

  20. Vertical motions in Thailand after the 2004 Sumatra-Andaman Earthquake from GPS observations and its geophysical modelling

    Science.gov (United States)

    Satirapod, C.; Trisirisatayawong, I.; Fleitout, L.; Garaud, J. D.; Simons, W. J. F.

    2013-04-01

    Following previous findings from ongoing GPS research in Thailand since 2004 we continue to exploit the GPS technique to monitor and model land motions induced by the Sumatra-Andaman Earthquake. Our latest results show that up to the end of 2010, Thailand has been co-seismically displaced and is subsequently undergoing a post-seismic horizontal deformation with total displacements (co-seismic plus post-seismic) ranging from 10.5 to 74.7 cm. We observed the largest horizontal displacements in the southern part of Thailand and moderate and small displacements in the central and northern parts. In addition to horizontal displacements throughout Thailand, continuous GPS measurements show that large parts of Thailand are subsiding at rates up to 1 cm/yr. It is the first time that such vertical post-seismic deformations at large distances (650-1500 km away from the Earthquake's epicentre) have been recorded. We have investigated the physical processes leading to the observed subsidence. While after-slip on the subduction interface induces negligible or even slightly positive vertical motions, relaxation in the asthenosphere is associated with a sizable subsidence. Predictions from a 3D finite element model feature an asthenosphere with an effective viscosity of the order of 3 \\midast 1018 Pas, fit the horizontal post-seismic data and the observed subsidence well. This model is then used to predict the subsidence over the whole seismic cycle. The subsidence should go on with a diminishing rate through the next two decades and its final magnitude should not exceed 10 cm in the Bangkok area.The post-seismic subsidence makes it difficult to identify other geophysical signals, particularly sea level rise, when observed from tide gauge data and thus there is a need for reliable estimation of subsidence velocities. This phenomenon may also worsen coastal erosion and flooding from sea water and so cause a considerable impact on the socio-economic development of coastal and low

  1. SSI-bridge : soil bridge interaction during long-duration earthquake motions.

    Science.gov (United States)

    2014-09-01

    The seismic response of a complete soil-bridge system during shallow, crustal and subduction zone earthquakes is the topic of this report. Specifically, the effects of earthquake duration on the seismic performance of soil-bridge systems are examined...

  2. A methodology to estimate earthquake effects on fractures intersecting canister holes

    Energy Technology Data Exchange (ETDEWEB)

    La Pointe, P.; Wallmann, P.; Thomas, A.; Follin, S. [Golder Assocites Inc. (Sweden)

    1997-03-01

    A literature review and a preliminary numerical modeling study were carried out to develop and demonstrate a method for estimating displacements on fractures near to or intersecting canister emplacement holes. The method can be applied during preliminary evaluation of candidate sites prior to any detailed drilling or underground excavation, utilizing lineament maps and published regression relations between surface rupture trace length and earthquake magnitude, rupture area and displacements. The calculated displacements can be applied to lineament traces which are assumed to be faults and may be the sites for future earthquakes. Next, a discrete fracture model is created for secondary faulting and jointing in the vicinity of the repository. These secondary fractures may displace due to the earthquake on the primary faults. The three-dimensional numerical model assumes linear elasticity and linear elastic fracture mechanics which provides a conservative displacement estimate, while still preserving realistic fracture patterns. Two series of numerical studies were undertaken to demonstrate how the methodology could be implemented and how results could be applied to questions regarding site selection and performance assessment. The first series illustrates how earthquake damage to a hypothetical repository for a specified location (Aespoe) could be estimated. A second series examined the displacements induced by earthquakes varying in magnitude from 6.0 to 8.2 as a function of how close the earthquake was in relation to the repository. 143 refs, 25 figs, 7 tabs.

  3. Source and ground-motion parameters of the 2011 Lorca earthquake; Parametros de la fuente y del movimiento del suelo del terremoto de Lorca de 2011

    Energy Technology Data Exchange (ETDEWEB)

    Alguacil de la Blanca, G.; Vidal Sanchez, F.; Stich, D.; Mancilla Perez, F. L.; Lopez Comino, J. A.; Morales Soto, J.; Navarro Bernal, M.

    2012-07-01

    113 events of the Lorca seismic series has been relocated by using Double difference algorithm and data from both temporary and permanent seismic networks. Relocations yield shallow hypo central distribution of aftershocks with a {approx}5 km long, NE-SW trending, placed SW of the mainshock, suggesting a SW propagating rupture along the Alhama de Murcia fault. Similar oblique reverse faulting mechanism has been obtained for three largest events. Source parameters of these three earthquakes have been estimated. Horizontal ground motion was estimated at 11 city points whose local structure was known by SPAC experiments. A set of ground motion parameters (PGA, PGV, AI, CAV, SI, SA and SV) here calculated, have higher values at these points respect to the ones at LOR station. All parameter values are also above the expected values for Euro -Mediterranean earthquakes with local intensity VIII (EMS). Nevertheless, SD values are unusually short and less than the reference ones. Higher values of the response spectra of acceleration and velocity are given for periods of less than 0.7 s, with maximum spectral acceleration at 0.15 s and velocity at 0.5 s. The elastic input energy spectrum is well connected to the shake destructiveness in each place. Equivalent velocity > 60 cm/s is found in almost all sites and > 100 cm/s (for periods 0.3 to 0.6 s) in someone. Factors such as proximity, and focal mechanism and ground response characteristics explain the high ground motion parameter values obtained in Lorca sites and show the great influence of the source and site conditions on the characteristics of strong ground motion in the vicinity of the rupture. (Author) 68 refs.

  4. An Alternative Estimate of the Motion of the Capricorn Plate

    Science.gov (United States)

    Burris, S. G.; Gordon, R. G.

    2013-12-01

    Diffuse plate boundaries cover ~15% of Earth's surface and can exceed 1000 km in across-strike width. Deforming oceanic lithosphere in the equatorial Indian Ocean accommodates the motion between the India and Capricorn plates and serves as their mutual diffuse plate boundary. This deforming lithosphere lies between the Central Indian Ridge to the west and the Sumatra trench to the east; the plates diverge to the west of ≈74°E and converge to the east of it. Many data have shown that the pole of rotation between the India and Capricorn plates lies within this diffuse plate boundary [1,2]. Surprisingly, however, the recently estimated angular velocity in the MORVEL global set of angular velocities [3] places this pole of rotation north of prior poles by several degrees, and north of the diffuse plate boundary. The motion between the India and Capricorn plates can only be estimated indirectly by differencing the motion of the India plate relative to the Somalia plate, on the one hand, and the motion of the Capricorn plate relative to Somalia plate, on the other. While the MORVEL India-Somalia angular velocity is similar to prior estimates, the MORVEL Capricorn-Somalia pole of rotation lies northwest of its predecessors. The difference is not caused by new transform azimuth data incorporated into MORVEL or by the new application of a correction to spreading rates for outward displacement. Instead the difference appears to be caused by a few anomalous spreading rates near the northern end of the Capricorn-Somalia plate boundary along the Central Indian Ridge. Rejecting these data leads to consistency with prior results. Implications for the motion of the Capricorn plate relative to Australia will be discussed. [1] DeMets, C., R. G. Gordon, and J.-Y. Royer, 2005. Motion between the Indian, Capricorn, and Somalian plates since 20 Ma: implications for the timing and magnitude of distributed deformation in the equatorial Indian ocean, Geophys. J. Int., 161, 445-468. [2

  5. Optimized order estimation for autoregressive models to predict respiratory motion.

    Science.gov (United States)

    Dürichen, Robert; Wissel, Tobias; Schweikard, Achim

    2013-11-01

    To successfully ablate moving tumors in robotic radio-surgery, it is necessary to compensate for motion of inner organs caused by respiration. This can be achieved by tracking the body surface and correlating the external movement with the tumor position as it is implemented in the CyberKnife[Formula: see text] Synchrony system. Tracking errors, originating from system immanent time delays, are typically reduced by time series prediction. Many prediction algorithms exploit autoregressive (AR) properties of the signal. Estimating the optimal model order [Formula: see text] for these algorithms constitutes a challenge often solved via grid search or prior knowledge about the signal. Aiming at a more efficient approach instead, this study evaluates the Akaike information criterion (AIC), the corrected AIC, and the Bayesian information criterion (BIC) on the first minute of the respiratory signal. Exemplarily, we evaluated the approach for a least mean square (LMS) and a wavelet-based LMS (wLMS) predictor. Analyzing 12 motion traces, orders estimated by AIC had the highest prediction accuracy for both prediction algorithms. Extending the investigations to 304 real motion traces, the prediction error of wLMS using AIC was found to decrease significantly by 85.1 % of the data compared to the original implementation The overall results suggest that using AIC to estimate the model order [Formula: see text] for prediction algorithms based on AR properties is a valid method which avoids intensive grid search and leads to high prediction accuracy.

  6. Fast Registration of Remotely Sensed Images for Earthquake Damage Estimation

    Directory of Open Access Journals (Sweden)

    Kasaei Shohreh

    2006-01-01

    Full Text Available Analysis of the multispectral remotely sensed images of the areas destroyed by an earthquake is proved to be a helpful tool for destruction assessments. The performance of such methods is highly dependant on the preprocess that registers the two shots before and after an event. In this paper, we propose a new fast and reliable change detection method for remotely sensed images and analyze its performance. The experimental results show the efficiency of the proposed algorithm.

  7. Strong ground motion in the Taipei basin from the 1999 Chi-Chi, Taiwan, earthquake

    Science.gov (United States)

    Fletcher, Joe B.; Wen, K.-L.

    2005-01-01

    The Taipei basin, located in northwest Taiwan about 160 km from the epicenter of the Chi-Chi earthquake, is a shallow, triangular-shaped basin filled with low-velocity fluvial deposits. There is a strong velocity contrast across the basement interface of about 600 m/sec at a depth of about 600-700 m in the deeper section of the basin, suggesting that ground motion should be amplified at sites in the basin. In this article, the ground-motion recordings are analyzed to determine the effect of the basin both in terms of amplifications expected from a 1D model of the sediments in the basin and in terms of the 3D structure of the basin. Residuals determined for peak acceleration from attenuation curves are more positive (amplified) in the basin (average of 5.3 cm/ sec2 compared to - 24.2 cm/sec2 for those stations outside the basin and between 75 and 110 km from the surface projection of the faulted area, a 40% increase in peak ground acceleration). Residuals for peak velocity are also significantly more positive at stations in the basin (31.8 cm/sec compared to 20.0 cm/sec out). The correlation of peak motion with depth to basement, while minor in peak acceleration, is stronger in the peak velocities. Record sections of ground motion from stations in and around the Taipei basin show that the largest long-period arrival, which is coherent across the region, is strongest on the vertical component and has a period of about 10-12 sec. This phase appears to be a Rayleigh wave, probably associated with rupture at the north end of the Chelungpu fault. Records of strong motion from stations in and near the basin have an additional, higher frequency signal: nearest the deepest point in the basin, the signal is characterized by frequencies of about 0.3 - 0.4 Hz. These frequencies are close to simple predictions using horizontal layers and the velocity structure of the basin. Polarizations of the S wave are mostly coherent across the array, although there are significant

  8. Amplification of Earthquake Ground Motions in Washington, DC, and Implications for Hazard Assessments in Central and Eastern North America

    Science.gov (United States)

    Pratt, Thomas L.; Horton, J. Wright; Muñoz, Jessica; Hough, Susan E.; Chapman, Martin C.; Olgun, C. Guney

    2017-12-01

    The extent of damage in Washington, DC, from the 2011 Mw 5.8 Mineral, VA, earthquake was surprising for an epicenter 130 km away; U.S. Geological Survey "Did-You-Feel-It" reports suggest that Atlantic Coastal Plain and other unconsolidated sediments amplified ground motions in the city. We measure this amplification relative to bedrock sites using earthquake signals recorded on a temporary seismometer array. The spectral ratios show strong amplification in the 0.7 to 4 Hz frequency range for sites on sediments. This range overlaps with resonant frequencies of buildings in the city as inferred from their heights, suggesting amplification at frequencies to which many buildings are vulnerable to damage. Our results emphasize that local amplification can raise moderate ground motions to damaging levels in stable continental regions, where low attenuation extends shaking levels over wide areas and unconsolidated deposits on crystalline metamorphic or igneous bedrock can result in strong contrasts in near-surface material properties.

  9. Motion visualization and estimation for flapping wing systems

    Science.gov (United States)

    Hsu, Tzu-Sheng Shane; Fitzgerald, Timothy; Nguyen, Vincent Phuc; Patel, Trisha; Balachandran, Balakumar

    2017-04-01

    Studies of fluid-structure interactions associated with flexible structures such as flapping wings require the capture and quantification of large motions of bodies that may be opaque. As a case study, motion capture of a free flying Manduca sexta, also known as hawkmoth, is considered by using three synchronized high-speed cameras. A solid finite element (FE) representation is used as a reference body and successive snapshots in time of the displacement fields are reconstructed via an optimization procedure. One of the original aspects of this work is the formulation of an objective function and the use of shadow matching and strain-energy regularization. With this objective function, the authors penalize the projection differences between silhouettes of the captured images and the FE representation of the deformed body. The process and procedures undertaken to go from high-speed videography to motion estimation are discussed, and snapshots of representative results are presented. Finally, the captured free-flight motion is also characterized and quantified.

  10. An Estimation of Earthquake Impact to Population in Makassar by Probabilistic Approach

    Directory of Open Access Journals (Sweden)

    Bambang Sunardi

    2016-12-01

    Full Text Available Makassar is one of Indonesian big cities with rapid growth rate, but not totally safe from earthquake hazard. This condition led study on affected population by earthquakes in this city are important to do. This paper estimated the population of Makassar City threatened by the probabilistic earthquake hazard. In this current study, earthquake hazard in the forms of peak ground acceleration (PGA and spectral acceleration,  estimated by using Probabilistic Seismic Hazards Analysis (PSHA. The PSHA result then overlaid with administration map and population data to obtain distribution and percentage of population threatened by the probabilistic earthquake hazard. The results showed the smallest value of ground acceleration located in the south-west (Tamalate sub district, further north increased and reached the highest value in the northeast (Biring Kanaya sub district. Both Tamalate and Biringkanaya can be classified as rural area with low population density.  The urban area of Makassar, which is the concentration of population, located in the centre of Makassar, got the middle earthquake hazard.

  11. Estimated damage and loss scenarios for future major earthquakes in Luzon, Philippines

    Science.gov (United States)

    Pacchiani, F.; Wyss, M.

    2012-04-01

    The northernmost and biggest island of the Philippines, Luzon, is bordered both west and east by active subduction zones and, on land, the island is cut by numerous fault systems. These active systems regularly generate major earthquakes that shake the island. The largest historical earthquake was a magnitude M=8 and the last major catastrophic event was the July 16, 1990, Ms 7.8 event, that caused over 2,400 fatalities, injured over 3,500 and destroyed over 100,000 houses. Such catastrophic earthquakes will unfortunately repeat in the future and in an attempt to predict these events it has been found that for Luzon a time of increased probability (TIP) for such an earthquake exists. Considering these facts, it is of interest to evaluate the destruction and losses this event could eventually cause. We have analyzed the historical seismicity and constructed different loss scenarios. With QLARM2, a loss estimation algorithm used in real-time mode for over 10 years, we simulated the various plausible scenarios for a major earthquake (M>7) on Luzon. Results show that such an earthquake affects the majority of the island's inhabitants. As an example, for a M=7.4 earthquake, 12 km deep and 30 km from the capital city Manila, the overall maximum mean damage to be expected is 4.5 and the maximum intensity is X in the epicentral area. In terms of fatalities, QLARM2 allows to obtain first order estimates. Preliminary results suggest a conservative mean estimate of expected fatalities of 6,000, and a maximum of 18,000, values that can vary greatly, depending on location and magnitude of the future earthquake. Due to its position along the ring-of-fire and in light of our computations, Luzon will continue to be shaken by catastrophic earthquakes and should continue its effort to mitigate earthquake risk. This is particularly true for Manila, an agglomeration of over 11 million people, directly affected by the earthquake hazard.

  12. Pixel-By Estimation of Scene Motion in Video

    Science.gov (United States)

    Tashlinskii, A. G.; Smirnov, P. V.; Tsaryov, M. G.

    2017-05-01

    The paper considers the effectiveness of motion estimation in video using pixel-by-pixel recurrent algorithms. The algorithms use stochastic gradient decent to find inter-frame shifts of all pixels of a frame. These vectors form shift vectors' field. As estimated parameters of the vectors the paper studies their projections and polar parameters. It considers two methods for estimating shift vectors' field. The first method uses stochastic gradient descent algorithm to sequentially process all nodes of the image row-by-row. It processes each row bidirectionally i.e. from the left to the right and from the right to the left. Subsequent joint processing of the results allows compensating inertia of the recursive estimation. The second method uses correlation between rows to increase processing efficiency. It processes rows one after the other with the change in direction after each row and uses obtained values to form resulting estimate. The paper studies two criteria of its formation: gradient estimation minimum and correlation coefficient maximum. The paper gives examples of experimental results of pixel-by-pixel estimation for a video with a moving object and estimation of a moving object trajectory using shift vectors' field.

  13. The SCEC-USGS Dynamic Earthquake Rupture Code Verification Exercise: Regular and Extreme Ground Motion

    Science.gov (United States)

    Harris, R.; Barall, M.; Archuleta, R. J.; Aagaard, B.; Ampuero, J. P.; Andrews, D. J.; Cruz-Atienza, V. M.; Dalguer Gudiel, L. A.; Day, S. M.; Duan, B.; Dunham, E. M.; Ely, G. P.; Gabriel, A. A.; Kaneko, Y.; Kase, Y.; Lapusta, N.; Ma, S.; Noda, H.; Oglesby, D. D.; Olsen, K. B.; Roten, D.; Song, S.

    2010-12-01

    We summarize recent progress by the SCEC-USGS Dynamic Rupture Code Verification Group, that examines if SCEC and USGS researchers’ spontaneous-rupture computer codes agree when computing benchmark scenarios for dynamic earthquake rupture. Our latest benchmarks are ‘regular’ dynamic ruptures on a vertical strike-slip fault and on a normal fault, at a range of resolutions, and, ‘extreme’ dynamic ruptures on a normal fault. The ‘extreme’ dynamic ruptures were designed as complete stress-drop, supershear ruptures that would be most likely to produce maximum possible ground motions. These simulated ruptures could be thought of as very unlikely, but still possible. Among the 2009 ‘extreme’ dynamic rupture benchmarks were those targeted to test two simplified versions of the Andrews et al. [BSSA, 2007] numerical simulations for hypothesized maximum-possible ground motion at a site near Yucca Mountain. To test the Andrews et al. methodology, we constructed a benchmark for a planar dipping normal-fault set in a medium where the off-fault response was designated to be elastic (TPV12), and another benchmark where the off-fault response was designated to be plastic (TPV13). Although most of our group’s previous benchmarks have concentrated on 3D solutions, both the TPV12 and TPV13 benchmarks were offered with both 2D and 3D options, partly because the Andrews et al. study was conducted in 2D, and partly because it is important to understand the differences and similarities among 2D and 3D rupture propagation and ground motion predictions. Seven researchers’ codes participated in the TPV12 2D benchmark test, seven participated in the TPV12 3D test, six participated in the TPV13 2D benchmark test, and four participated in the TPV13 3D test. Our findings were similar to those hypothesized in the Andrews et al. publication. At a proposed site for a nuclear waste repository, that was modeled to be 1-km from the fault, at 300 m depth, our 2D elastic benchmark

  14. Hazus® estimated annualized earthquake losses for the United States

    Science.gov (United States)

    Jaiswal, Kishor; Bausch, Doug; Rozelle, Jesse; Holub, John; McGowan, Sean

    2017-01-01

    Large earthquakes can cause social and economic disruption that can be unprecedented to any given community, and the full recovery from these impacts may or may not always be achievable. In the United States (U.S.), the 1994 M6.7 Northridge earthquake in California remains the third costliest disaster in U.S. history; and it was one of the most expensive disasters for the federal government. Internationally, earthquakes in the last decade alone have claimed tens of thousands of lives and caused hundreds of billions of dollars of economic impact throughout the globe (~90 billion U.S. dollars (USD) from 2008 M7.9 Wenchuan China, ~20 billion USD from 2010 M8.8 Maule earthquake in Chile, ~220 billion USD from 2011 M9.0 Tohoku Japan earthquake, ~25 billion USD from 2011 M6.3 Christchurch New Zealand, and ~22 billion USD from 2016 M7.0 Kumamoto Japan). Recent earthquakes show a pattern of steadily increasing damages and losses that are primarily due to three key factors: (1) significant growth in earthquake-prone urban areas, (2) vulnerability of the older building stock, including poorly engineered non-ductile concrete buildings, and (3) an increased interdependency in terms of supply and demand for the businesses that operate among different parts of the world. In the United States, earthquake risk continues to grow with increased exposure of population and development even though the earthquake hazard has remained relatively stable except for the regions of induced seismic activity. Understanding the seismic hazard requires studying earthquake characteristics and locales in which they occur, while understanding the risk requires an assessment of the potential damage from earthquake shaking to the built environment and to the welfare of people—especially in high-risk areas. Estimating the varying degree of earthquake risk throughout the United States is critical for informed decision-making on mitigation policies, priorities, strategies, and funding levels in the

  15. Rapid Estimation of Macroseismic Intensity for On-site Earthquake Early Warning in Italy from Early Radiated Energ

    Science.gov (United States)

    Emolo, A.; Zollo, A.; Brondi, P.; Picozzi, M.; Mucciarelli, M.

    2015-12-01

    Earthquake Early Warning System (EEWS) are effective tools for the risk mitigation in active seismic regions. Recently, a feasibility study of a nation-wide earthquake early warning systems has been conducted for Italy considering the RAN Network and the EEW software platform PRESTo. This work showed that a reliable estimations in terms of magnitude and epicentral localization would be available within 3-4 seconds after the first P-wave arrival. On the other hand, given the RAN's density, a regional EEWS approach would result in a Blind Zone (BZ) of 25-30 km in average. Such BZ dimension would provide lead-times greater than zero only for events having magnitude larger than 6.5. Considering that in Italy also smaller events are capable of generating great losses both in human and economic terms, as dramatically experienced during the recent 2009 L'Aquila (ML 5.9) and 2012 Emilia (ML 5.9) earthquakes, it has become urgent to develop and test on-site approaches. The present study is focused on the development of a new on-site EEW metodology for the estimation of the macroseismic intensity at a target site or area. In this analysis we have used a few thousands of accelerometric traces recorded by RAN related to the largest earthquakes (ML>4) occurred in Italy in the period 1997-2013. The work is focused on the integral EW parameter Squared Velocity Integral (IV2) and on its capability to predict the peak ground velocity PGV and the Housner Intensity IH, as well as from these latters we parameterized a new relation between IV2 and the Macroseismic Intensity. To assess the performance of the developed on-site EEW relation, we used data of the largest events occurred in Italy in the last 6 years recorded by the Osservatorio Sismico delle Strutture, as well as on the recordings of the moderate earthquake reported by INGV Strong Motion Data. The results shows that the macroseismic intensity values predicted by IV2 and the one estimated by PGV and IH are in good agreement.

  16. Simulated ground motion in Santa Clara Valley, California, and vicinity from M≥6.7 scenario earthquakes

    Science.gov (United States)

    Harmsen, Stephen C.; Hartzell, Stephen

    2008-01-01

    Models of the Santa Clara Valley (SCV) 3D velocity structure and 3D finite-difference software are used to predict ground motions from scenario earthquakes on the San Andreas (SAF), Monte Vista/Shannon, South Hayward, and Calaveras faults. Twenty different scenario ruptures are considered that explore different source models with alternative hypocenters, fault dimensions, and rupture velocities and three different velocity models. Ground motion from the full wave field up to 1 Hz is exhibited as maps of peak horizontal velocity and pseudospectral acceleration at periods of 1, 3, and 5 sec. Basin edge effects and amplification in sedimentary basins of the SCV are observed that exhibit effects from shallow sediments with relatively low shear-wave velocity (330 m/sec). Scenario earthquakes have been simulated for events with the following magnitudes: (1) M 6.8–7.4 Calaveras sources, (2) M 6.7–6.9 South Hayward sources, (3) M 6.7 Monte Vista/Shannon sources, and (4) M 7.1–7.2 Peninsula segment of the SAF sources. Ground motions are strongly influenced by source parameters such as rupture velocity, rise time, maximum depth of rupture, hypocenter, and source directivity. Cenozoic basins also exert a strong influence on ground motion. For example, the Evergreen Basin on the northeastern side of the SCV is especially responsive to 3–5-sec energy from most scenario earthquakes. The Cupertino Basin on the southwestern edge of the SCV tends to be highly excited by many Peninsula and Monte Vista fault scenarios. Sites over the interior of the Evergreen Basin can have long-duration coda that reflect the trapping of seismic energy within this basin. Plausible scenarios produce predominantly 5-sec wave trains with greater than 30 cm/sec sustained ground-motion amplitude with greater than 30 sec duration within the Evergreen Basin.

  17. Surface structure feature matching algorithm for cardiac motion estimation.

    Science.gov (United States)

    Zhang, Zhengrui; Yang, Xuan; Tan, Cong; Guo, Wei; Chen, Guoliang

    2017-12-20

    Cardiac diseases represent the leading cause of sudden death worldwide. During the development of cardiac diseases, the left ventricle (LV) changes obviously in structure and function. LV motion estimation plays an important role for diagnosis and treatment of cardiac diseases. To estimate LV motion accurately for cine magnetic resonance (MR) cardiac images, we develop an algorithm by combining point set matching with surface structure features of myocardium. The structure features of myocardial wall are described by estimating the normal directions of points locating on the myocardium contours using an approximation approach. The Gaussian mixture model (GMM) of structure features is used to represent LV structure feature distribution. A new cost function is defined to represent the differences between two Gaussian mixture models, which are the GMM of structure features and the GMM of positions of two point sets. To optimize the cost function, its gradient is derived to use the Quasi-Newton (QN). Furthermore, to resolve the dis-convergence issue of Quasi-Newton for high-dimensional parameter space, Stochastic Gradient Descent (SGD) is used and SGD gradient is derived. Finally, the new cost function is solved by optimization combining SGD with QN. With the closed form expression of gradient, this paper provided a computationally efficient registration algorithm. Three public datasets are employed to verify the performance of our algorithm, including cardiac MR image sequences acquired from 33 subjects, 14 inter-subject heart cases, and the data obtained in MICCAI 2009s 3D Segmentation Challenge for Clinical Applications. We compare our results with those of the other point set registration methods for LV motion estimation. The obtained results demonstrate that our algorithm shows inherent statistical robustness, due to the combination of SGD and Quasi-Newton optimization. Furthermore, our method is shown to outperform other point set matching methods in the

  18. Distribution of Ground Motions for the 2008 Mw5.4 Chino Hills Earthquake

    Science.gov (United States)

    Yong, A.; Hough, S. E.; Wills, C. J.; Wald, D. J.

    2008-12-01

    The 29 July 2008 Mw5.4 Chino Hills earthquake was widely felt throughout the greater Los Angeles region. Over 40,000 people filled out the Community Internet Intensity Map (CIIM), also known as the "Did You Feel It?" questionnaire, and the ShakeMap for the event is constrained by amplitudes from over 500 stations. The CIIM responses provide Modified Mercalli Intensity (MMI) values for 802 Zip codes. Due to the dense population of the greater Los Angeles region, intensity values averaged within Zip codes provide good spatial correlation to the location of the actual reporting sites. We use a least-squares approach to fit the average MMI to a standard functional form, MMI = A - Br - C log r (where r represents distance from the observation site to the epicenter and A, B and C are constants), and calculate the residuals. The distribution of average intensities clusters closely around the curve of the equation, corroborating the conclusion (e.g., Atkinson and Wald, SRL, 2006) that CIIM intensities provide a consistent measure of earthquake ground motions. A comparison of CIIM intensities and instrumentally determined ShakeMap intensities reveals generally good correspondence, but suggests a tendency for ShakeMap intensities to be higher at basin sites. We conclude that the ShakeMap intensities reflect long-period amplification, whereas observed intensities were more controlled by higher frequency accelerations. Where both the CIIM map and ShakeMap show systematic variations, the distributions show a strong correlation with near-surface geological structure, as well as with basin depth. Our preliminary conclusions are: 1) as expected, intensities are lower at hard rock sites; 2) intensities are systematically higher in the deepest parts of the basin and significantly lower in shallow regions. Intensities are systematically lower to the west of the Newport-Inglewood fault correlating with subtle topographic relief and shallower basin depths; 3) there is a suggestion that

  19. Isoseismal map of the 2015 Nepal earthquake and its relationships with ground-motion parameters, distance and magnitude

    Science.gov (United States)

    Prajapati, Sanjay K.; Dadhich, Harendra K.; Chopra, Sumer

    2017-01-01

    A devastating earthquake of Mw 7.8 struck central Nepal on 25th April, 2015 (6:11:25 UT) which resulted in more than ∼9000 deaths, and destroyed millions of houses. Standing buildings, roads and electrical installations worth 25-30 billions of dollars are reduced to rubbles. The earthquake was widely felt in the northern parts of India and moderate damage have been observed in the northern part of UP and Bihar region of India. Maximum intensity IX, according to the USGS report, was observed in the meizoseismal zone, surrounding the Kathmandu region. In the present study, we have compiled available information from the print, electronic media and various reports of damages and other effects caused by the event, and interpreted them to obtain Modified Mercalli Intensities (MMI) at over 175 locations spread over Nepal and surrounding Indian and Tibet region. We have also obtained a number of strong motion recordings from India and Nepal seismic network and developed an empirical relationship between the MMI and peak ground acceleration (PGA), peak ground velocity (PGV). We have used least square regression technique to derive the empirical relation between the MMI and ground motion parameters and compared them with the empirical relationships available for other regions of the world. Further, seismic intensity information available for historical earthquakes, which have occurred in the Nepal Himalaya along with the present intensity data has been utilized for developing an attenuation relationship for the studied region using two step regression analyses. The derived attenuation relationship is useful for assessing damage of a potential future large earthquake (earthquake scenario-based planning purposes) in the region.

  20. Developing and Testing the Automated Post-Event Earthquake Loss Estimation and Visualisation (APE-ELEV) Technique

    OpenAIRE

    Astoul, Anthony; Filliter, Christopher; Mason,Eric; Rau-Chaplin, Andrew; Shridhar, Kunal; Varghese, Blesson; Varshney, Naman

    2013-01-01

    An automated, real-time, multiple sensor data source relying and globally applicable earthquake loss model and visualiser is desirable for post-event earthquake analysis. To achieve this there is a need to support rapid data ingestion, loss estimation and integration of data from multiple data sources and rapid visualisation at multiple geographic levels. In this paper, the design and development of the Automated Post-Event Earthquake Loss Estimation and Visualisation (APE-ELEV) system for re...

  1. Shape estimation of gastrointestinal polyps using motion information

    Science.gov (United States)

    Ruano, Josue; Martinez, Fabio; Gomez, Martin; Romero, Eduardo

    2013-11-01

    Polyp size quanti cation is currently the main variable for deciding the patient treatment during an endoscopic procedure. Nowadays, the polyp size is estimated by an expert, even when using devices that are provided with calibrated grids. As such estimation is highly subjective, automatic approaches have come to be appealing but also challenging because the polyp shape and appearance variability, the di erent types of motion present during the capture and the specular highlight noise. This work presents a novel approach to automatically estimate gastrointestinal polyp shapes in a video endoscopic sequence using spatiotemporal information. For doing so, a local spatio temporal descriptor is built up to obtain an initial segmentation since the polyp is the region with more movement. Then, an initial polyp manual segmentation outlines a region of interest (RoI) in the rst frame of the sequence and used as a reference for the polyp tracking during the sequence. Afterward, an exhaustive cross-correlation of the initial shape is carried out along the sequence and fused with the motion descriptor to re ne the original segmentation. The proposed approach was evaluated in 15 real video sequences achieving an average DSC score of 0:67% .

  2. Evaluation of Soil-Structure Interaction on the Seismic Response of Liquid Storage Tanks under Earthquake Ground Motions

    Directory of Open Access Journals (Sweden)

    Mostafa Farajian

    2017-03-01

    Full Text Available Soil-structure interaction (SSI could affect the seismic response of structures. Since liquid storage tanks are vital structures and must continue their operation under severe earthquakes, their seismic behavior should be studied. Accordingly, the seismic response of two types of steel liquid storage tanks (namely, broad and slender, with aspect ratios of height to radius equal to 0.6 and 1.85 founded on half-space soil is scrutinized under different earthquake ground motions. For a better comparison, the six considered ground motions are classified, based on their pulse-like characteristics, into two groups, named far and near fault ground motions. To model the liquid storage tanks, the simplified mass-spring model is used and the liquid is modeled as two lumped masses known as sloshing and impulsive, and the interaction of fluid and structure is considered using two coupled springs and dashpots. The SSI effect, also, is considered using a coupled spring and dashpot. Additionally, four types of soils are used to consider a wide variety of soil properties. To this end, after deriving the equations of motion, MATLAB programming is employed to obtain the time history responses. Results show that although the SSI effect leads to a decrease in the impulsive displacement, overturning moment, and normalized base shear, the sloshing (or convective displacement is not affected by such effects due to its long period.

  3. Towards Estimating the Magnitude of Earthquakes from EM Data Collected from the Subduction Zone

    Science.gov (United States)

    Heraud, J. A.

    2016-12-01

    During the past three years, magnetometers deployed in the Peruvian coast have been providing evidence that the ULF pulses received are indeed generated at the subduction or Benioff zone. Such evidence was presented at the AGU 2015 Fall meeting, showing the results of triangulation of pulses from two magnetometers located in the central area of Peru, using data collected during a two-year period. The process has been extended in time, only pulses associated with the occurrence of earthquakes and several pulse parameters have been used to estimate a function relating the magnitude of the earthquake with the value of a function generated with those parameters. The results shown, including an animated data video, are a first approximation towards the estimation of the magnitude of an earthquake about to occur, based on electromagnetic pulses that originated at the subduction zone. During the past three years, magnetometers deployed in the Peruvian coast have been providing evidence that the ULF pulses received are indeed generated at the subduction or Benioff zone. Such evidence was presented at the AGU 2015 Fall meeting, showing the results of triangulation of pulses from two magnetometers located in the central area of Peru, using data collected during a two-year period. The process has been extended in time, only pulses associated with the occurrence of earthquakes have been used and several pulse parameters have been used to estimate a function relating the magnitude of the earthquake with the value of a function generated with those parameters. The results shown, including an animated data video, are a first approximation towards the estimation of the magnitude of an earthquake about to occur, based on electromagnetic pulses that originated at the subduction zone.

  4. Dense motion field estimation from myocardial boundary displacements.

    Science.gov (United States)

    Morais, Pedro; Queirós, Sandro; Ferreira, Adriano; Rodrigues, Nuno F; Baptista, Maria J; D'hooge, Jan; Vilaça, João L; Barbosa, Daniel

    2016-09-01

    Minimally invasive cardiovascular interventions guided by multiple imaging modalities are rapidly gaining clinical acceptance for the treatment of several cardiovascular diseases. These images are typically fused with richly detailed pre-operative scans through registration techniques, enhancing the intra-operative clinical data and easing the image-guided procedures. Nonetheless, rigid models have been used to align the different modalities, not taking into account the anatomical variations of the cardiac muscle throughout the cardiac cycle. In the current study, we present a novel strategy to compensate the beat-to-beat physiological adaptation of the myocardium. Hereto, we intend to prove that a complete myocardial motion field can be quickly recovered from the displacement field at the myocardial boundaries, therefore being an efficient strategy to locally deform the cardiac muscle. We address this hypothesis by comparing three different strategies to recover a dense myocardial motion field from a sparse one, namely, a diffusion-based approach, thin-plate splines, and multiquadric radial basis functions. Two experimental setups were used to validate the proposed strategy. First, an in silico validation was carried out on synthetic motion fields obtained from two realistic simulated ultrasound sequences. Then, 45 mid-ventricular 2D sequences of cine magnetic resonance imaging were processed to further evaluate the different approaches. The results showed that accurate boundary tracking combined with dense myocardial recovery via interpolation/diffusion is a potentially viable solution to speed up dense myocardial motion field estimation and, consequently, to deform/compensate the myocardial wall throughout the cardiac cycle. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  5. Comparing population exposure to multiple Washington earthquake scenarios for prioritizing loss estimation studies

    Science.gov (United States)

    Wood, Nathan J.; Ratliff, Jamie L.; Schelling, John; Weaver, Craig S.

    2014-01-01

    Scenario-based, loss-estimation studies are useful for gauging potential societal impacts from earthquakes but can be challenging to undertake in areas with multiple scenarios and jurisdictions. We present a geospatial approach using various population data for comparing earthquake scenarios and jurisdictions to help emergency managers prioritize where to focus limited resources on data development and loss-estimation studies. Using 20 earthquake scenarios developed for the State of Washington (USA), we demonstrate how a population-exposure analysis across multiple jurisdictions based on Modified Mercalli Intensity (MMI) classes helps emergency managers understand and communicate where potential loss of life may be concentrated and where impacts may be more related to quality of life. Results indicate that certain well-known scenarios may directly impact the greatest number of people, whereas other, potentially lesser-known, scenarios impact fewer people but consequences could be more severe. The use of economic data to profile each jurisdiction’s workforce in earthquake hazard zones also provides additional insight on at-risk populations. This approach can serve as a first step in understanding societal impacts of earthquakes and helping practitioners to efficiently use their limited risk-reduction resources.

  6. Rupture process and strong ground motions of the 2007 Niigataken Chuetsu-Oki earthquake -Directivity pulses striking the Kashiwazaki-Kariwa Nuclear Power Plant-

    Science.gov (United States)

    Irikura, K.; Kagawa, T.; Miyakoshi, K.; Kurahashi, S.

    2007-12-01

    The Niigataken Chuetsu-Oki earthquake occurred on July 16, 2007, northwest-off Kashiwazaki in Niigata Prefecture, Japan, causing severe damages of ten people dead, about 1300 injured, about 1000 collapsed houses and major lifelines suspended. In particular, strong ground motions from the earthquake struck the Kashiwazaki-Kariwa nuclear power plant (hereafter KKNPP), triggering a fire at an electric transformer and other problems such as leakage of water containing radioactive materials into air and the sea, although the radioactivity levels of the releases are as low as those of the radiation which normal citizens would receive from the natural environment in a year. The source mechanism of this earthquake is a reverse fault, but whether it is the NE-SW strike and NW dip or the SW-NE strike and SE dip are still controversial from the aftershock distribution and geological surveys near the source. Results of the rupture processes inverted by using the GPS and SAR data, tsunami data and teleseismic data so far did not succeed in determining which fault planes moved. Strong ground motions were recorded at about 390 stations by the K-NET of NIED including the stations very close to the source area. There was the KKNPP which is probably one of buildings and facilities closest to the source area. They have their own strong motion network with 22 three-components' accelerographs locating at ground-surface, underground, buildings and basements of reactors. The PGA attenuation-distance relationships made setting the fault plane estimated from the GPS data generally follow the empirical relations in Japan, for example, Fukushima and Tanaka (1990) and Si and Midorikawa (1999), even if either fault plane, SE dip or NW dip, is assumed. However, the strong ground motions in the site of the KKNPP had very large accelerations and velocities more than those expected from the empirical relations. The surface motions there had the PGA of more than 1200 gals and even underground

  7. Trench motion-controlled slab morphology and stress variations: Implications for the isolated 2015 Bonin Islands deep earthquake

    Science.gov (United States)

    Yang, Ting; Gurnis, Michael; Zhan, Zhongwen

    2017-07-01

    The subducted old and cold Pacific Plate beneath the young Philippine Sea Plate at the Izu-Bonin trench over the Cenozoic hosts regional deep earthquakes. We investigate slab morphology and stress regimes under different trench motion histories with mantle convection models. Viscosity, temperature, and deviatoric stress are inherently heterogeneous within the slab, which we link to the occurrence of isolated earthquakes. Models expand on previous suggestions that observed slab morphology variations along the Izu-Bonin subduction zone, exhibited as shallow slab dip angles in the north and steeper dip angles in the south, are mainly due to variations in the rate of trench retreat from the north (where it is fast) to the south (where it is slow). Geodynamic models consistent with the regional plate tectonics, including oceanic plate age, plate convergence rate, and trench motion history, reproduce the seismologically observed principal stress direction and slab morphology. We suggest that the isolated 680 km deep, 30 May 2015 Mw 7.9 Bonin Islands earthquake, which lies east of the well-defined Benioff zone and has its principal compressional stress direction oriented toward the tip of the previously defined Benioff zone, can be explained by Pacific slab buckling in response to the slow trench retreat.

  8. Geological and seismological survey for new design-basis earthquake ground motion of Kashiwazaki-Kariwa NPS

    Science.gov (United States)

    Takao, M.; Mizutani, H.

    2009-05-01

    At about 10:13 on July 16, 2007, a strong earthquake named 'Niigata-ken Chuetsu-oki Earthquake' of Mj6.8 on Japan Meteorological Agencyfs scale occurred offshore Niigata prefecture in Japan. However, all of the nuclear reactors at Kashiwazaki-Kariwa Nuclear Power Station (KKNPS) in Niigata prefecture operated by Tokyo Electric Power Company shut down safely. In other words, automatic safety function composed of shutdown, cooling and containment worked as designed immediately after the earthquake. During the earthquake, the peak acceleration of the ground motion exceeded the design-basis ground motion (DBGM), but the force due to the earthquake applied to safety-significant facilities was about the same as or less than the design basis taken into account as static seismic force. In order to assess anew the safety of nuclear power plants, we have evaluated a new DBGM after conducting geomorphological, geological, geophysical, seismological survey and analyses. [Geomorphological, Geological and Geophysical survey] In the land area, aerial photograph interpretation was performed at least within the 30km radius to extract geographies that could possibly be tectonic reliefs as a geomorphological survey. After that, geological reconnaissance was conducted to confirm whether the extracted landforms are tectonic reliefs or not. Especially we carefully investigated Nagaoka Plain Western Boundary Fault Zone (NPWBFZ), which consists of Kakuda-Yahiko fault, Kihinomiya fault and Katakai fault, because NPWBFZ is the one of the active faults which have potential of Mj8 class in Japan. In addition to the geological survey, seismic reflection prospecting of approximate 120km in total length was completed to evaluate the geological structure of the faults and to assess the consecutiveness of the component faults of NPWBFZ. As a result of geomorphological, geological and geophysical surveys, we evaluated that the three component faults of NPWBFZ are independent to each other from the

  9. Ground motions from the 2015 Mw 7.8 Gorkha, Nepal, earthquake constrained by a detailed assessment of macroseismic data

    Science.gov (United States)

    Martin, Stacey; Hough, Susan E.; Hung, Charleen

    2015-01-01

    To augment limited instrumental recordings of the Mw 7.8 Gorkha, Nepal, earthquake on 25 April 2015 (Nepali calendar: 12 Baisakh 2072, Bikram Samvat), we collected 3831 detailed media and first-person accounts of macroseismic effects that include sufficiently detailed information to assign intensities. The resulting intensity map reveals the distribution of shaking within and outside of Nepal, with the key result that shaking intensities throughout the near-field region only exceeded intensity 8 on the 1998 European Macroseismic Scale (EMS-98) in rare instances. Within the Kathmandu Valley, intensities were generally 6–7 EMS. This surprising (and fortunate) result can be explained by the nature of the mainshock ground motions, which were dominated by energy at periods significantly longer than the resonant periods of vernacular structures throughout the Kathmandu Valley. Outside of the Kathmandu Valley, intensities were also generally lower than 8 EMS, but the earthquake took a heavy toll on a number of remote villages, where many especially vulnerable masonry houses collapsed catastrophically in 7–8 EMS shaking. We further reconsider intensities from the 1833 earthquake sequence and conclude that it occurred on the same fault segment as the Gorkha earthquake.

  10. Fast-coding robust motion estimation model in a GPU

    Science.gov (United States)

    García, Carlos; Botella, Guillermo; de Sande, Francisco; Prieto-Matias, Manuel

    2015-02-01

    Nowadays vision systems are used with countless purposes. Moreover, the motion estimation is a discipline that allow to extract relevant information as pattern segmentation, 3D structure or tracking objects. However, the real-time requirements in most applications has limited its consolidation, considering the adoption of high performance systems to meet response times. With the emergence of so-called highly parallel devices known as accelerators this gap has narrowed. Two extreme endpoints in the spectrum of most common accelerators are Field Programmable Gate Array (FPGA) and Graphics Processing Systems (GPU), which usually offer higher performance rates than general propose processors. Moreover, the use of GPUs as accelerators involves the efficient exploitation of any parallelism in the target application. This task is not easy because performance rates are affected by many aspects that programmers should overcome. In this paper, we evaluate OpenACC standard, a programming model with directives which favors porting any code to a GPU in the context of motion estimation application. The results confirm that this programming paradigm is suitable for this image processing applications achieving a very satisfactory acceleration in convolution based problems as in the well-known Lucas & Kanade method.

  11. Shear Wave Velocity and Site Amplification Factors for 25 Strong-Motion Instrument Stations Affected by the M5.8 Mineral, Virginia, Earthquake of August 23, 2011

    Science.gov (United States)

    Kayen, Robert E.; Carkin, Brad A.; Corbett, Skye C.; Zangwill, Aliza; Estevez, Ivan; Lai, Lena

    2015-01-01

    Vertical one-dimensional shear wave velocity (Vs) profiles are presented for 25 strong-motion instrument sites along the Mid-Atlantic eastern seaboard, Piedmont region, and Appalachian region, which surround the epicenter of the M5.8 Mineral, Virginia, Earthquake of August 23, 2011. Testing was performed at sites in Pennsylvania, Maryland, West Virginia, Virginia, the District of Columbia, North Carolina, and Tennessee. The purpose of the study is to determine the detailed site velocity profile, the average velocity in the upper 30 meters of the profile (VS,30), the average velocity for the entire profile (VS,Z), and the National Earthquake Hazards Reduction Program (NEHRP) site classification. The Vs profiles are estimated using a non-invasive continuous-sine-wave method for gathering the dispersion characteristics of surface waves. A large trailer-mounted active source was used to shake the ground during the testing and produce the surface waves. Shear wave velocity profiles were inverted from the averaged dispersion curves using three independent methods for comparison, and the root-mean square combined coefficient of variation (COV) of the dispersion and inversion calculations are estimated for each site.

  12. A long source area of the 1906 Colombia-Ecuador earthquake estimated from observed tsunami waveforms

    Science.gov (United States)

    Yamanaka, Yusuke; Tanioka, Yuichiro; Shiina, Takahiro

    2017-12-01

    The 1906 Colombia-Ecuador earthquake induced both strong seismic motions and a tsunami, the most destructive earthquake in the history of the Colombia-Ecuador subduction zone. The tsunami propagated across the Pacific Ocean, and its waveforms were observed at tide gauge stations in countries including Panama, Japan, and the USA. This study conducted slip inverse analysis for the 1906 earthquake using these waveforms. A digital dataset of observed tsunami waveforms at the Naos Island (Panama) and Honolulu (USA) tide gauge stations, where the tsunami was clearly observed, was first produced by consulting documents. Next, the two waveforms were applied in an inverse analysis as the target waveform. The results of this analysis indicated that the moment magnitude of the 1906 earthquake ranged from 8.3 to 8.6. Moreover, the dominant slip occurred in the northern part of the assumed source region near the coast of Colombia, where little significant seismicity has occurred, rather than in the southern part. The results also indicated that the source area, with significant slip, covered a long distance, including the southern, central, and northern parts of the region.[Figure not available: see fulltext.

  13. Ground Motion Selection and Scaling for the Seismic Investigation of the Concrete Gravity Dams for Near Fault Earthquakes

    Science.gov (United States)

    Arici, Y.; Bybordiani, M.

    2016-12-01

    The use of time histories for the seismic design and analysis of dams is becoming increasingly common given the state of the art of the computational tools for assessing the seismic demands on these systems. Determination of the ground motions that will be used in time history analysis is a crucial task since the results usually show a wide variability in the required quantity due to the stochastic nature of the applied earthquake record. In order to reduce this variability and predict the "true" demand related to the seismic hazard conditions of the site, the ground motions are usually carefully selected and subjected to scaling procedures. A separate but equally important goal in this regard is to obtain the required demand with a small number of representative motions reducing the considerable analysis workload for these large systems. In this regard, the common ground motion scaling techniques are evaluated in this study in a robust dam-foundation-reservoir interaction (DFRI) setting for determining the efficiency and accuracy of the scaling techniques for predicting the target demands for concrete gravity dams. A large ensemble of ground motions were used on a range of systems with different canyon geometries and moduli ratios in order to consider the effect of the soil-structure interaction (SSI) on the motion selection for concrete gravity dams. The frequency response of different systems and their interaction with the frequency content of the ground motions were henceforth considered. The required number of ground motions for consistent and efficient analyses of such systems was investigated considering different engineering demand parameters on the dam systems. The choice of EDP, and the corresponding effect of the scaling procedure on the analyses were evaluated in order to provide guidelines on the scaling of the ground motions for the seismic analyses of these systems.

  14. Using Internet reports for early estimates of the final death toll of earthquake-generated tsunami: the March 11, 2011, Tohoku, Japan, earthquake

    Directory of Open Access Journals (Sweden)

    Zhongliang Wu

    2011-06-01

    Full Text Available A retrospective case study was conducted for the March 11, 2011, earthquake that occurred off the east Pacific coast of Tohoku, Japan, with reference to the Sumatra-Andaman earthquake and Indian Ocean tsunami on December 26, 2004. The regularities of the temporal variations of the number of deaths reported through the Internet is used to make an early stage quick-and-rough estimate to assist in the emergency decision making, and to continue the revision of the estimate as new data comes in. The quick-and-rough estimate of the final fatalities that was obtained on the second day after the earthquake is shown to agree with the final reported fatalities to within an order of magnitude. This also has an added advantage over other estimation models, in that the estimates can be updated with new data as they become available.

  15. Broadband Strong Ground Motion Simulation For a Potential Mw 7.1 Earthquake on The Enriquillo Fault in Haiti

    Science.gov (United States)

    Douilly, R.; Mavroeidis, G. P.; Calais, E.

    2015-12-01

    The devastating 2010 Haiti earthquake showed the need to be more vigilant toward mitigation for future earthquakes in the region. Previous studies have shown that this earthquake did not occur on the Enriquillo Fault, the main plate boundary fault running through the heavily populated Port-au-Prince region, but on the nearby and previously unknown Léogâne transpressional fault. Slip on that fault has increased stresses on the Enriquillo Fault mostly in the region closer to Port-au-Prince, the most populated city of the country. Here we investigate the ground shaking level in this region if a rupture similar to the Mw 7.0 2010 Haiti earthquake occurred on the Enriquillo fault. We use a finite element method and assumptions on regional stress to simulate low frequency dynamic rupture propagation for a 53 km long segment. We introduce some heterogeneity by creating two slip patches with shear traction 10% greater than the initial shear traction on the fault. The final slip distribution is similar in distribution and magnitude to previous finite fault inversions for the 2010 Haiti earthquake. The high-frequency ground motion components are calculated using the specific barrier model, and the hybrid synthetics are obtained by combining the low-frequencies (f 1Hz) from the stochastic simulation using matched filtering at a crossover frequency of 1 Hz. The average horizontal peak ground acceleration, computed at several sites of interest through Port-au-Prince, has a value of 0.35g. We also compute response spectra at those sites and compare them to the spectra from the microzonation study.

  16. First-passage Probability Estimation of an Earthquake Response of Seismically Isolated Containment Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Hahm, Dae-Gi [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Kwan-Soon [Dongguk University, Seoul (Korea, Republic of); Koh, Hyun-Moo [Seoul National Univ., Seoul (Korea, Republic of)

    2008-10-15

    The awareness of a seismic hazard and risk is being increased rapidly according to the frequent occurrences of the huge earthquakes such as the 2008 Sichuan earthquake which caused about 70,000 confirmed casualties and a 20 billion U.S. dollars economic loss. Since an earthquake load contains various uncertainties naturally, the safety of a structural system under an earthquake excitation has been assessed by probabilistic approaches. In many structural applications for a probabilistic safety assessment, it is often regarded that the failure of a system will occur when the response of the structure firstly crosses the limit barrier within a specified interval of time. The determination of such a failure probability is usually called the 'first-passage problem' and has been extensively studied during the last few decades. However, especially for the structures which show a significant nonlinear dynamic behavior, an effective and accurate method for the estimation of such a failure probability is not fully established yet. In this study, we presented a new approach to evaluate the first-passage probability of an earthquake response of seismically isolated structures. The proposed method is applied to the seismic isolation system for the containment buildings of a nuclear power plant. From the numerical example, we verified that the proposed method shows accurate results with more efficient computational efforts compared to the conventional approaches.

  17. Fault geometry, rupture dynamics and ground motion from potential earthquakes on the North Anatolian Fault under the Sea of Marmara

    KAUST Repository

    Oglesby, David D.

    2012-03-01

    Using the 3-D finite-element method, we develop dynamic spontaneous rupture models of earthquakes on the North Anatolian Fault system in the Sea of Marmara, Turkey, considering the geometrical complexity of the fault system in this region. We find that the earthquake size, rupture propagation pattern and ground motion all strongly depend on the interplay between the initial (static) regional pre-stress field and the dynamic stress field radiated by the propagating rupture. By testing several nucleation locations, we observe that those far from an oblique normal fault stepover segment (near Istanbul) lead to large through-going rupture on the entire fault system, whereas nucleation locations closer to the stepover segment tend to produce ruptures that die out in the stepover. However, this pattern can change drastically with only a 10° rotation of the regional stress field. Our simulations also reveal that while dynamic unclamping near fault bends can produce a new mode of supershear rupture propagation, this unclamping has a much smaller effect on the speed of the peak in slip velocity along the fault. Finally, we find that the complex fault geometry leads to a very complex and asymmetric pattern of near-fault ground motion, including greatly amplified ground motion on the insides of fault bends. The ground-motion pattern can change significantly with different hypocentres, even beyond the typical effects of directivity. The results of this study may have implications for seismic hazard in this region, for the dynamics and ground motion of geometrically complex faults, and for the interpretation of kinematic inverse rupture models.

  18. Natural Time, Nowcasting and the Physics of Earthquakes: Estimation of Seismic Risk to Global Megacities

    Science.gov (United States)

    Rundle, John B.; Luginbuhl, Molly; Giguere, Alexis; Turcotte, Donald L.

    2017-11-01

    Natural Time ("NT") refers to the concept of using small earthquake counts, for example of M > 3 events, to mark the intervals between large earthquakes, for example M > 6 events. The term was first used by Varotsos et al. (2005) and later by Holliday et al. (2006) in their studies of earthquakes. In this paper, we discuss ideas and applications arising from the use of NT to understand earthquake dynamics, in particular by use of the idea of nowcasting. Nowcasting differs from forecasting, in that the goal of nowcasting is to estimate the current state of the system, rather than the probability of a future event. Rather than focus on an individual earthquake faults, we focus on a defined local geographic region surrounding a particular location. This local region is considered to be embedded in a larger regional setting from which we accumulate the relevant statistics. We apply the nowcasting idea to the practical development of methods to estimate the current state of risk for dozens of the world's seismically exposed megacities, defined as cities having populations of over 1 million persons. We compute a ranking of these cities based on their current nowcast value, and discuss the advantages and limitations of this approach. We note explicitly that the nowcast method is not a model, in that there are no free parameters to be fit to data. Rather, the method is simply a presentation of statistical data, which the user can interpret. Among other results, we find, for example, that the current nowcast ranking of the Los Angeles region is comparable to its ranking just prior to the January 17, 1994 Northridge earthquake.

  19. Benefits of multidisciplinary collaboration for earthquake casualty estimation models: recent case studies

    Science.gov (United States)

    So, E.

    2010-12-01

    Earthquake casualty loss estimation, which depends primarily on building-specific casualty rates, has long suffered from a lack of cross-disciplinary collaboration in post-earthquake data gathering. An increase in our understanding of what contributes to casualties in earthquakes involve coordinated data-gathering efforts amongst disciplines; these are essential for improved global casualty estimation models. It is evident from examining past casualty loss models and reviewing field data collected from recent events, that generalized casualty rates cannot be applied globally for different building types, even within individual countries. For a particular structure type, regional and topographic building design effects, combined with variable material and workmanship quality all contribute to this multi-variant outcome. In addition, social factors affect building-specific casualty rates, including social status and education levels, and human behaviors in general, in that they modify egress and survivability rates. Without considering complex physical pathways, loss models purely based on historic casualty data, or even worse, rates derived from other countries, will be of very limited value. What’s more, as the world’s population, housing stock, and living and cultural environments change, methods of loss modeling must accommodate these variables, especially when considering casualties. To truly take advantage of observed earthquake losses, not only do damage surveys need better coordination of international and national reconnaissance teams, but these teams must integrate difference areas of expertise including engineering, public health and medicine. Research is needed to find methods to achieve consistent and practical ways of collecting and modeling casualties in earthquakes. International collaboration will also be necessary to transfer such expertise and resources to the communities in the cities which most need it. Coupling the theories and findings from

  20. Evaluating a kinematic method for generating broadband ground motions for great subduction zone earthquakes: Application to the 2003 Mw 8.3 Tokachi‐Oki earthquake

    Science.gov (United States)

    Wirth, Erin A.; Frankel, Arthur; Vidale, John E.

    2017-01-01

    We compare broadband synthetic seismograms with recordings of the 2003 Mw">MwMw 8.3 Tokachi‐Oki earthquake to evaluate a compound rupture model, in which slip on the fault consists of multiple high‐stress‐drop asperities superimposed on a background slip distribution with longer rise times. Low‐frequency synthetics (1  Hz">>1  Hz>1  Hz) stochastic synthetics using a matched filter at 1 Hz. We show that this compound rupture model and overall approach accurately reproduces waveform envelopes and observed response spectral accelerations (SAs) from the Tokachi‐Oki event. We find that sufficiently short subfault rise times (i.e., ∼1  Hz∼1  Hz. This is achieved by either (1) including distinct subevents with short rise times, as may be suggested by the Tokachi‐Oki data, or (2) imposing a fast‐slip velocity over the entire rupture area. We also include a systematic study on the effects of varying several kinematic rupture parameters. We find that simulated strong ground motions are sensitive to the average rupture velocity and coherence of the rupture front, with more coherent ruptures yielding higher response SAs. We also assess the effects of varying the average slip velocity and the character (i.e., area, magnitude, and location) of high‐stress‐drop subevents. Even in the absence of precise constraints on these kinematic rupture parameters, our simulations still reproduce major features in the Tokachi‐Oki earthquake data, supporting its accuracy in modeling future large earthquakes.

  1. Motion estimation for video coding efficient algorithms and architectures

    CERN Document Server

    Chakrabarti, Indrajit; Chatterjee, Sumit Kumar

    2015-01-01

    The need of video compression in the modern age of visual communication cannot be over-emphasized. This monograph will provide useful information to the postgraduate students and researchers who wish to work in the domain of VLSI design for video processing applications. In this book, one can find an in-depth discussion of several motion estimation algorithms and their VLSI implementation as conceived and developed by the authors. It records an account of research done involving fast three step search, successive elimination, one-bit transformation and its effective combination with diamond search and dynamic pixel truncation techniques. Two appendices provide a number of instances of proof of concept through Matlab and Verilog program segments. In this aspect, the book can be considered as first of its kind. The architectures have been developed with an eye to their applicability in everyday low-power handheld appliances including video camcorders and smartphones.

  2. Site effect on strong-motion records of the 2011 Mw9.0 Tohoku earthquake in Japan

    Directory of Open Access Journals (Sweden)

    Li Heng

    2011-08-01

    Full Text Available Strong-motion site effect was checked for four sites at comparable epicentral distances from the March 11, 2011 Mw9.0 Tohoku earthquake in Japan. The result showed that site condition had a significant impact on peak acceleration, and on maximal amplitude and characteristic period of its response spectrum. Shorter-period seismic waves were amplified mainly in shallower soils, while longer-period waves in deeper soft rocks and soils, where the characteristic periods of response spectra were longer than those on ground surface.

  3. Empirical Assessment of Nonlinear Seismic Demand of Mainshock-Aftershock Ground Motion Sequences for Japanese Earthquakes

    Directory of Open Access Journals (Sweden)

    Katsuichiro eGoda

    2015-06-01

    Full Text Available This study investigates the effects of earthquake types, magnitudes, and hysteretic behavior on the peak and residual ductility demands of inelastic single-degree-of-freedom systems and evaluates the effects of major aftershocks on the nonlinear structural responses. An extensive dataset of real mainshock-aftershock sequences for Japanese earthquakes is developed. The constructed dataset is large, compared with previous datasets of similar kinds, and includes numerous sequences from the 2011 Tohoku earthquake, facilitating an investigation of spatial aspects of the aftershock effects. The empirical assessment of peak and residual ductility demands of numerous inelastic systems having different vibration periods, yield strengths, and hysteretic characteristics indicates that the increase in seismic demand measures due to aftershocks occurs rarely but can be significant. For a large mega-thrust subduction earthquake, a critical factor for major aftershock damage is the spatial occurrence process of aftershocks.

  4. 3D Dynamic Rupture process ans Near Source Ground Motion Simulation Using the Discrete Element Method: Application to the 1999 Chi-chi and 2000 Tottori Earthquakes

    Science.gov (United States)

    Dalguer Gudiel, L. A.; Irikura, K.

    2001-12-01

    weakening friction model is used). The choice of these parameters used for the simulation of the dynamic rupture of a fault is a delicate issue, still subject of debate. Assuming that the effective stress to slip is the stress drop, we do not need to know the absolute level of the stress, therefore, the initial stress could be assumed to be in the zero level. Then, for the assumption of a slip weakening friction law, we need to define the stress drop, the strength excess and the critical slip along the fault. The direct estimation of these source parameters from observations are not feasible, the closest information about the source that we have is the results of the kinematic waveform inversion given by the slip distribution along the fault. In this context, we use the Discrete Element Method (DEM) to solve the elastodynamic equation of the continuous medium assuming the slip distribution obtained by kinematic fault model as a boundary condition along the fault. The result of this calculation is the shear stress distribution in space and time. From the shear stress function we can estimate approximately the dynamic source parameters given by the stress drop, strength excess and critical slip along the fault. These parameters are used to simulate the rupture process and near source ground motion. The results obtained closely match the observed ground motion records of the two earthquakes in study.

  5. Slip distribution of the 1973 Nemuro-oki earthquake estimated from the re-examined geodetic data

    Science.gov (United States)

    Nishimura, T.

    2009-11-01

    Geodetic data, including leveling, tide-gauge, triangulation/trilateration, and repeated EDM data, from eastern Hokkaido, Japan, were re-examined to clarify the crustal deformation associated with the 1973 Nemuro-oki earthquake. We inverted the geodetic data to estimate the slip distribution on the interface of the subducting Pacific plate. The estimated coseismic slip, potentially including afterslip, showed a patch of large slip (i.e., an asperity) near the epicenter of the mainshock. The moment magnitude of the Nemuro-oki earthquake was estimated to be 8.0 from the geodetic data, which is comparable to the 2003 Mw = 8.0 Tokachi-oki earthquake. The estimated slip distribution suggests a 50 km-long gap in the coseismic slip between the 1973 Nemuro-oki and the 2003 Tokachi-oki earthquakes. The slip area of the 2004 Mw = 7.0 Kushiro-oki earthquake, estimated from GPS data, was located at the northwestern edge of the Nemuro-oki earthquake, which implies that the area may have acted as a barrier during the Nemuro-oki earthquake. The postseismic deformation observed by leveling and tide-gauge measurements suggests that the afterslip of the Nemuro-oki earthquake occurred at least in a western and northern (i.e., deeper) extension of the asperity on the plate interface.

  6. Ground Motions versus Geotechnical and Structural Damage in the February 2011 Christchurch Earthquake

    OpenAIRE

    Smyrou, E; Tasiopoulou, P; Bal, I.E; Gazetas, G.

    2011-01-01

    The Mw = 6.3 Christchurch earthquake was a surprising and unusual event which occurred in an unknown fault that had already been awakened by the September 2010 stronger earthquake, and it had a strong thrust component and a steeply dipping plane. This paper has attempted to identify quantifiable parameters that could provide better insight to seismologists and engineers who try to systematically investigate the reasons behind the structural and soil failures that occurred in the February shaking

  7. Estimating nonrigid motion from inconsistent intensity with robust shape features

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wenyang [Department of Bioengineering, University of California, Los Angeles, California 90095 (United States); Ruan, Dan, E-mail: druan@mednet.ucla.edu [Department of Bioengineering, University of California, Los Angeles, California 90095 (United States); Department of Radiation Oncology, University of California, Los Angeles, California 90095 (United States); Department of Biomedical Physics, University of California, Los Angeles, California 90095 (United States)

    2013-12-15

    Purpose: To develop a nonrigid motion estimation method that is robust to heterogeneous intensity inconsistencies amongst the image pairs or image sequence. Methods: Intensity and contrast variations, as in dynamic contrast enhanced magnetic resonance imaging, present a considerable challenge to registration methods based on general discrepancy metrics. In this study, the authors propose and validate a novel method that is robust to such variations by utilizing shape features. The geometry of interest (GOI) is represented with a flexible zero level set, segmented via well-behaved regularized optimization. The optimization energy drives the zero level set to high image gradient regions, and regularizes it with area and curvature priors. The resulting shape exhibits high consistency even in the presence of intensity or contrast variations. Subsequently, a multiscale nonrigid registration is performed to seek a regular deformation field that minimizes shape discrepancy in the vicinity of GOIs. Results: To establish the working principle, realistic 2D and 3D images were subject to simulated nonrigid motion and synthetic intensity variations, so as to enable quantitative evaluation of registration performance. The proposed method was benchmarked against three alternative registration approaches, specifically, optical flow, B-spline based mutual information, and multimodality demons. When intensity consistency was satisfied, all methods had comparable registration accuracy for the GOIs. When intensities among registration pairs were inconsistent, however, the proposed method yielded pronounced improvement in registration accuracy, with an approximate fivefold reduction in mean absolute error (MAE = 2.25 mm, SD = 0.98 mm), compared to optical flow (MAE = 9.23 mm, SD = 5.36 mm), B-spline based mutual information (MAE = 9.57 mm, SD = 8.74 mm) and mutimodality demons (MAE = 10.07 mm, SD = 4.03 mm). Applying the proposed method on a real MR image sequence also provided

  8. Estimating Fault Displacement from the 1999 Hector Mine Earthquake Using LIDAR

    Science.gov (United States)

    Borsa, A. A.; Minster, J.; Hudnut, K. W.

    2001-12-01

    The 1999 Hector Mine Earthquake generated visible surface faulting along almost 60km of sparsely vegetated, undeveloped desert terrain. Six months after the earthquake, the entire length of the Hector Mine fault zone was mapped with a scanning laser altimeter as part of a joint experiment between the U.S. Geological Survey, the Southern California Earthquake Center and the commercial firm, Aerotec LLC. This data set has recently been recalibrated and validated with respect to GPS-measured ground control to provide a high-resolution, geodetic-quality digital elevation model (DEM) that can be used for applications requiring precise knowledge of the faulted terrain within a half-kilometer swath along the Hector Mine surface rupture. We show the various methods of calibration used and the improvements to the DEM that result. We then use this recalibrated DEM to estimate vertical and horizontal displacement at several diagnostic locations along the fault. Having a quantitative representation of the post-earthquake faulted terrain allows us to bring signal-processing techniques to bear on this problem, and we compare our results to those made by the USGS using conventional surveying techniques and to recently published Hector Mine displacement estimates from InSAR.

  9. Comparison of the sand liquefaction estimated based on codes and practical earthquake damage phenomena

    Science.gov (United States)

    Fang, Yi; Huang, Yahong

    2017-12-01

    Conducting sand liquefaction estimated based on codes is the important content of the geotechnical design. However, the result, sometimes, fails to conform to the practical earthquake damages. Based on the damage of Tangshan earthquake and engineering geological conditions, three typical sites are chosen. Moreover, the sand liquefaction probability was evaluated on the three sites by using the method in the Code for Seismic Design of Buildings and the results were compared with the sand liquefaction phenomenon in the earthquake. The result shows that the difference between sand liquefaction estimated based on codes and the practical earthquake damage is mainly attributed to the following two aspects: The primary reasons include disparity between seismic fortification intensity and practical seismic oscillation, changes of groundwater level, thickness of overlying non-liquefied soil layer, local site effect and personal error. Meanwhile, although the judgment methods in the codes exhibit certain universality, they are another reason causing the above difference due to the limitation of basic data and the qualitative anomaly of the judgment formulas.

  10. Evaluation of earthquake ground motions for aseismatic design of high rise buildings in Tokyo bay area. Tokyo wangan ni okeru koso kenchikubutsu no taishin sekkei yo nyuryoku jishindo hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Ota, T.; Shima, E.; Niwa, M.; Ikeura, T. (Kajima Inst. of Construction Technology, Tokyo (Japan)); Takemura, M. (Kajima Corp., Tokyo (Japan))

    1991-08-30

    A proposal is made on the evaluation method for design input ground motions, which is based on the examples of earthquake ground motions evaluated using fault models and is supported by the concept for future design earthquake ground motions. The features of this evaluation method are to designate earthquakes to be considered and evaluate the ground motions in the applicable site employing fault models. Waveform synthesis method is used where uneven sliding on the fault surface in the earthquake site is taken into consideration. A method of evaluating ground motions in the site using fault models is employed in lieu of the conventional method which is used for aseismatic design input ground motions for high rise buildings, and an example is given quoting the case of reclaimed land and alluvial ground at Yokohama City, Japan. The studied earthquakes are hypothetical recurrence of 1923 southern Kanto earthquake and hypothetical earthquake in Tokai region, and the evaluation of the ground motions is made by waveform synthesis method using fault models for which records of medium scale ground motions obtained near those sites are used. The maximum ground accelerations of about 330Gal and 115Gal, and the maximum velocities of about 40cm/s and 20cm/s are obtained for the hypothetical southern Kanto earthquake and the hypothetical earthquake in Tokai region, respectively. 32 refs., 16 figs., 3 tabs.

  11. A database of instrumentally recorded ground motion intensity measurements from induced earthquakes in Oklahoma and Kansas

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The database contains uniformly processed ground motion intensity measurements (peak horizontal ground motions and 5-percent-damped pseudospectral accelerations for...

  12. Integrating landslide and liquefaction hazard and loss estimates with existing USGS real-time earthquake information products

    Science.gov (United States)

    Allstadt, Kate E.; Thompson, Eric M.; Hearne, Mike; Nowicki Jessee, M. Anna; Zhu, J.; Wald, David J.; Tanyas, Hakan

    2017-01-01

    The U.S. Geological Survey (USGS) has made significant progress toward the rapid estimation of shaking and shakingrelated losses through their Did You Feel It? (DYFI), ShakeMap, ShakeCast, and PAGER products. However, quantitative estimates of the extent and severity of secondary hazards (e.g., landsliding, liquefaction) are not currently included in scenarios and real-time post-earthquake products despite their significant contributions to hazard and losses for many events worldwide. We are currently running parallel global statistical models for landslides and liquefaction developed with our collaborators in testing mode, but much work remains in order to operationalize these systems. We are expanding our efforts in this area by not only improving the existing statistical models, but also by (1) exploring more sophisticated, physics-based models where feasible; (2) incorporating uncertainties; and (3) identifying and undertaking research and product development to provide useful landslide and liquefaction estimates and their uncertainties. Although our existing models use standard predictor variables that are accessible globally or regionally, including peak ground motions, topographic slope, and distance to water bodies, we continue to explore readily available proxies for rock and soil strength as well as other susceptibility terms. This work is based on the foundation of an expanding, openly available, case-history database we are compiling along with historical ShakeMaps for each event. The expected outcome of our efforts is a robust set of real-time secondary hazards products that meet the needs of a wide variety of earthquake information users. We describe the available datasets and models, developments currently underway, and anticipated products. 

  13. Reference trajectory generation for rehabilitation robots: complementary limb motion estimation.

    Science.gov (United States)

    Vallery, Heike; van Asseldonk, Edwin H F; Buss, Martin; van der Kooij, Herman

    2009-02-01

    For gait rehabilitation robots, an important question is how to ensure stable gait, while avoiding any interaction forces between robot and human in case the patient walks correctly. To achieve this, the definition of "correct" gait needs to adapted both to the individual patient and to the situation. Recently, we proposed a method for online trajectory generation that can be applied for hemiparetic subjects. Desired states for one (disabled) leg are generated online based on the movements of the other (sound) leg. An instantaneous mapping between legs is performed by exploiting physiological interjoint couplings. This way, the patient generates the reference motion for the affected leg autonomously. The approach, called Complementary Limb Motion Estimation (CLME), is implemented on the LOPES gait rehabilitation robot and evaluated with healthy subjects in two different experiments. In a previously described study, subjects walk only with one leg, while the robot's other leg acts as a fake prosthesis, to simulate complete loss of function in one leg. This study showed that CLME ensures stable gait. In a second study, to be presented in this paper, healthy subjects walk with both their own legs to assess the interference with self-determined walking. Evaluation criteria are: Power delivered to the joints by the robot, electromyography (EMG) distortions, and kinematic distortions, all compared to zero torque control, which is the baseline of minimum achievable interference. Results indicate that interference of the robot is lower with CLME than with a fixed reference trajectory, mainly in terms of lowered exchanged power and less alteration of EMG. This implies that subjects can walk more naturally with CLME, and they are assisted less by the robot when it is not needed. Future studies with patients are yet to show whether these properties of CLME transfer to the clinical domain.

  14. Three-Dimensional Finite Difference Simulation of Ground Motions from the August 24, 2014 South Napa Earthquake

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, Arthur J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Univ. of California, Berkeley, CA (United States); Dreger, Douglas S. [Univ. of California, Berkeley, CA (United States); Pitarka, Arben [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-06-15

    We performed three-dimensional (3D) anelastic ground motion simulations of the South Napa earthquake to investigate the performance of different finite rupture models and the effects of 3D structure on the observed wavefield. We considered rupture models reported by Dreger et al. (2015), Ji et al., (2015), Wei et al. (2015) and Melgar et al. (2015). We used the SW4 anelastic finite difference code developed at Lawrence Livermore National Laboratory (Petersson and Sjogreen, 2013) and distributed by the Computational Infrastructure for Geodynamics. This code can compute the seismic response for fully 3D sub-surface models, including surface topography and linear anelasticity. We use the 3D geologic/seismic model of the San Francisco Bay Area developed by the United States Geological Survey (Aagaard et al., 2008, 2010). Evaluation of earlier versions of this model indicated that the structure can reproduce main features of observed waveforms from moderate earthquakes (Rodgers et al., 2008; Kim et al., 2010). Simulations were performed for a domain covering local distances (< 25 km) and resolution providing simulated ground motions valid to 1 Hz.

  15. Motion estimation and compensation for coronary artery and myocardium in cardiac CT

    Science.gov (United States)

    Tang, Qiulin; Matthews, James; Razeto, Marco; Linde, Jesper J.; Nakanishi, Satoru

    2015-03-01

    Motion blurring is still a challenge for cardiac CT imaging. A new motion estimation (ME) and motion compensation method is developed for cardiac CT. The proposed method estimates motion of entire heart, and then applies motion compensation. Therefore, the proposed method reduces motion artifacts not only in coronary artery region as most other methods did, but also reduces motion blurring in myocardium region. In motion compensated reconstruction, we use the Fourier transfer method proposed by Pack et al to obtain a series of partial images, and then warp and sum together to obtain final motion compensated images. The robustness and performance of the proposed method was verified with data from 10 patients and improvements in sharpness of both coronary arteries and myocardium were obtained.

  16. Compressive Video Recovery Using Block Match Multi-Frame Motion Estimation Based on Single Pixel Cameras

    Directory of Open Access Journals (Sweden)

    Sheng Bi

    2016-03-01

    Full Text Available Compressive sensing (CS theory has opened up new paths for the development of signal processing applications. Based on this theory, a novel single pixel camera architecture has been introduced to overcome the current limitations and challenges of traditional focal plane arrays. However, video quality based on this method is limited by existing acquisition and recovery methods, and the method also suffers from being time-consuming. In this paper, a multi-frame motion estimation algorithm is proposed in CS video to enhance the video quality. The proposed algorithm uses multiple frames to implement motion estimation. Experimental results show that using multi-frame motion estimation can improve the quality of recovered videos. To further reduce the motion estimation time, a block match algorithm is used to process motion estimation. Experiments demonstrate that using the block match algorithm can reduce motion estimation time by 30%.

  17. Real-Time Earthquake Intensity Estimation Using Streaming Data Analysis of Social and Physical Sensors

    Science.gov (United States)

    Kropivnitskaya, Yelena; Tiampo, Kristy F.; Qin, Jinhui; Bauer, Michael A.

    2017-06-01

    Earthquake intensity is one of the key components of the decision-making process for disaster response and emergency services. Accurate and rapid intensity calculations can help to reduce total loss and the number of casualties after an earthquake. Modern intensity assessment procedures handle a variety of information sources, which can be divided into two main categories. The first type of data is that derived from physical sensors, such as seismographs and accelerometers, while the second type consists of data obtained from social sensors, such as witness observations of the consequences of the earthquake itself. Estimation approaches using additional data sources or that combine sources from both data types tend to increase intensity uncertainty due to human factors and inadequate procedures for temporal and spatial estimation, resulting in precision errors in both time and space. Here we present a processing approach for the real-time analysis of streams of data from both source types. The physical sensor data is acquired from the U.S. Geological Survey (USGS) seismic network in California and the social sensor data is based on Twitter user observations. First, empirical relationships between tweet rate and observed Modified Mercalli Intensity (MMI) are developed using data from the M6.0 South Napa, CAF earthquake that occurred on August 24, 2014. Second, the streams of both data types are analyzed together in simulated real-time to produce one intensity map. The second implementation is based on IBM InfoSphere Streams, a cloud platform for real-time analytics of big data. To handle large processing workloads for data from various sources, it is deployed and run on a cloud-based cluster of virtual machines. We compare the quality and evolution of intensity maps from different data sources over 10-min time intervals immediately following the earthquake. Results from the joint analysis shows that it provides more complete coverage, with better accuracy and higher

  18. Linear Motion Blur Parameter Estimation in Noisy Images Using Fuzzy Sets and Power Spectrum

    OpenAIRE

    Moghaddam Mohsen Ebrahimi; Jamzad Mansour

    2007-01-01

    Motion blur is one of the most common causes of image degradation. Restoration of such images is highly dependent on accurate estimation of motion blur parameters. To estimate these parameters, many algorithms have been proposed. These algorithms are different in their performance, time complexity, precision, and robustness in noisy environments. In this paper, we present a novel algorithm to estimate direction and length of motion blur, using Radon transform and fuzzy set concepts. The most...

  19. The Italian Project S2 - Task 4:Near-fault earthquake ground motion simulation in the Sulmona alluvial basin

    Science.gov (United States)

    Stupazzini, M.; Smerzini, C.; Cauzzi, C.; Faccioli, E.; Galadini, F.; Gori, S.

    2009-04-01

    Recently the Italian Department of Civil Protection (DPC), in cooperation with Istituto Nazionale di Geofisica e Vulcanologia (INGV) has promoted the 'S2' research project (http://nuovoprogettoesse2.stru.polimi.it/) aimed at the design, testing and application of an open-source code for seismic hazard assessment (SHA). The tool envisaged will likely differ in several important respects from an existing international initiative (Open SHA, Field et al., 2003). In particular, while "the OpenSHA collaboration model envisions scientists developing their own attenuation relationships and earthquake rupture forecasts, which they will deploy and maintain in their own systems", the main purpose of S2 project is to provide a flexible computational tool for SHA, primarily suited for the needs of DPC, which not necessarily are scientific needs. Within S2, a crucial issue is to make alternative approaches available to quantify the ground motion, with emphasis on the near field region. The SHA architecture envisaged will allow for the use of ground motion descriptions other than those yielded by empirical attenuation equations, for instance user generated motions provided by deterministic source and wave propagation simulations. In this contribution, after a brief presentation of Project S2, we intend to illustrate some preliminary 3D scenario simulations performed in the alluvial basin of Sulmona (Central Italy), as an example of the type of descriptions that can be handled in the future SHA architecture. In detail, we selected some seismogenic sources (from the DISS database), believed to be responsible for a number of destructive historical earthquakes, and derive from them a family of simplified geometrical and mechanical source models spanning across a reasonable range of parameters, so that the extent of the main uncertainties can be covered. Then, purely deterministic (for frequencies Journal of Seismology, 1, 237-251. Field, E.H., T.H. Jordan, and C.A. Cornell (2003

  20. Effect Of Long-Period Earthquake Ground Motions On Nonlinear Vibration Of Shells With Variable Thickness

    Science.gov (United States)

    Abdikarimov, R.; Bykovtsev, A.; Khodzhaev, D.; Research Team Of Geotechnical; Structural Engineers

    2010-12-01

    Long-period earthquake ground motions (LPEGM) with multiple oscillations have become a crucial consideration in seismic hazard assessment because of the rapid increase of tall buildings and special structures (SP).Usually, SP refers to innovative long-span structural systems. More specifically, they include many types of structures, such as: geodesic showground; folded plates; and thin shells. As continuation of previous research (Bykovtsev, Abdikarimov, Khodzhaev 2003, 2010) analysis of nonlinear vibrations (NV) and dynamic stability of SP simulated as shells with variable rigidity in geometrically nonlinear statement will be presented for two cases. The first case will represent NV example of a viscoelastic orthotropic cylindrical shell with radius R, length L and variable thickness h=h(x,y). The second case will be NV example of a viscoelastic shell with double curvature, variable thickness, and bearing the concentrated masses. In both cases we count, that the SP will be operates under seismic load generated by LPEGM with multiple oscillations. For different seismic loads simulations, Bykovtsev’s Model and methodology was used for generating LPEGM time history. The methodology for synthesizing LPEGM from fault with multiple segmentations was developed by Bykovtev (1978-2010) and based on 3D-analytical solutions by Bykovtsev-Kramarovskii (1987&1989) constructed for faults with multiple segmentations. This model is based on a kinematics description of displacement function on the fault and included in consideration of all possible combinations of 3 components of vector displacement (two slip vectors and one tension component). The opportunities to take into consideration fault segmentations with both shear and tension vector components of displacement on the fault plane provide more accurate LPEGM evaluations. Radiation patterns and directivity effects were included in the model and more physically realistic results for simulated LPEGM were considered. The

  1. W-phase estimation of first-order rupture distribution for megathrust earthquakes

    Science.gov (United States)

    Benavente, Roberto; Cummins, Phil; Dettmer, Jan

    2014-05-01

    Estimating the rupture pattern for large earthquakes during the first hour after the origin time can be crucial for rapid impact assessment and tsunami warning. However, the estimation of coseismic slip distribution models generally involves complex methodologies that are difficult to implement rapidly. Further, while model parameter uncertainty can be crucial for meaningful estimation, they are often ignored. In this work we develop a finite fault inversion for megathrust earthquakes which rapidly generates good first order estimates and uncertainties of spatial slip distributions. The algorithm uses W-phase waveforms and a linear automated regularization approach to invert for rupture models of some recent megathrust earthquakes. The W phase is a long period (100-1000 s) wave which arrives together with the P wave. Because it is fast, has small amplitude and a long-period character, the W phase is regularly used to estimate point source moment tensors by the NEIC and PTWC, among others, within an hour of earthquake occurrence. We use W-phase waveforms processed in a manner similar to that used for such point-source solutions. The inversion makes use of 3 component W-phase records retrieved from the Global Seismic Network. The inverse problem is formulated by a multiple time window method, resulting in a linear over-parametrized problem. The over-parametrization is addressed by Tikhonov regularization and regularization parameters are chosen according to the discrepancy principle by grid search. Noise on the data is addressed by estimating the data covariance matrix from data residuals. The matrix is obtained by starting with an a priori covariance matrix and then iteratively updating the matrix based on the residual errors of consecutive inversions. Then, a covariance matrix for the parameters is computed using a Bayesian approach. The application of this approach to recent megathrust earthquakes produces models which capture the most significant features of

  2. Investigation of the frequency content of ground motions recorded during strong Vrancea earthquakes, based on deterministic and stochastic indices

    CERN Document Server

    Craifaleanu, Iolanda-Gabriela

    2013-01-01

    The paper presents results from a recent study in progress, involving an extensive analysis, based on several deterministic and stochastic indices, of the frequency content of ground motions recorded during strong Vrancea seismic events. The study, continuing those initiated by Lungu et al. in the early nineties, aims to better reveal the characteristics of the analyzed ground motions. Over 300 accelerograms, recorded during the strong Vrancea seismic events mentioned above and recently re-digitized, are used in the study. Various analytical estimators of the frequency content, such as those based on Fourier spectra, power spectral density, response spectra and peak ground motion values are evaluated and compared. The results are correlated and validated by using the information provided by various spectral bandwidth measures, as the Vanmarcke and the Cartwright and Longuet-Higgins indices. The capacity of the analyzed estimators to describe the frequency content of the analyzed ground motions is assessed com...

  3. Tissue motion in blood velocity estimation and its simulation

    DEFF Research Database (Denmark)

    Schlaikjer, Malene; Torp-Pedersen, Søren; Jensen, Jørgen Arendt

    1998-01-01

    . The motion due to the heart, when the volunteer was asked to hold his breath, gave a peak velocity of 4.2±1.7 mm/s. The movement of the carotid artery wall due to changing blood pressure had a peak velocity of 8.9±3.7 mm/s over the cardiac cycle. The variations are due to differences in heart rhythm......Determination of blood velocities for color flow mapping systems involves both stationary echo cancelling and velocity estimation. Often the stationary echo cancelling filter is the limiting factor in color flow mapping and the optimization and further development of this filter is crucial...... to the improvement of color flow imaging. Optimization based on in-vivo data is difficult since the blood and tissue signals cannot be accurately distinguished and the correct extend of the vessel under investigation is often unknown. This study introduces a model for the simulation of blood velocity data in which...

  4. Estimating Mandibular Motion Based on Chin Surface Targets During Speech

    Science.gov (United States)

    Green, Jordan R.; Wilson, Erin M.; Wang, Yu-Tsai; Moore, Christopher A.

    2009-01-01

    Purpose The movement of the jaw during speech and chewing has frequently been studied by tracking surface landmarks on the chin. However, the extent to which chin motions accurately represent those of the underlying mandible remains in question. In this investigation, the movements of a pellet attached to the incisor of the mandible were compared with those of pellets attached to different regions of the chin. Method Ten healthy talkers served as participants. Three speaking contexts were recorded from each participant: word, sentence, and paragraph. Chin position errors were estimated by computing the standard distance between the mandibular incisor pellet and the chin pellets. Results Relative to the underlying mandible, chin pellets moved with an average absolute and relative error of 0.81 mm and 7.30%, respectively. The movements of chin and mandibular pellets were tightly coupled in time. Conclusion The chin tracking errors observed in this investigation are considered acceptable for descriptive studies of oromotor behavior, particularly in situations where mandibular placements are not practical (e.g., young children or edentulous adults). The observed amount of error, however, may not be tolerable for fine-grained analyses of mandibular biomechanics. Several guidelines are provided for minimizing error associated with tracking surface landmarks on the chin. PMID:17675597

  5. Dislocation motion and the microphysics of flash heating and weakening of faults during earthquakes

    NARCIS (Netherlands)

    Spagnuolo, Elena; Plümper, Oliver; Violay, Marie; Cavallo, Andrea; Di Toro, Giulio

    2016-01-01

    Earthquakes are the result of slip along faults and are due to the decrease of rock frictional strength (dynamic weakening) with increasing slip and slip rate. Friction experiments simulating the abrupt accelerations (>>10 m/s2), slip rates (~1 m/s), and normal stresses (>>10 MPa) expected at the

  6. Application of seismogram synthesis to the study of earthquake source from strong motion records

    Directory of Open Access Journals (Sweden)

    M. Campiello

    1994-06-01

    Full Text Available We present the results of an analysis of the Michoacan and Landers earthquakes to constrain the kinematic description of the rupture process. The example of the Michoacan earthquake shows that a crack type model is better a dislocation model to describe the displacement in the vicinity of the fault. We also show that this in contradiction with the fact that the faulting appears to be a complex process. We attribute this complexity to instabilities in crack growth. The June 28, Landers earthquake offers an exceptional opportunity to apply a new inversion technique to a major strike slip event. We model the rupture evolution including local differences in slip durations and variations in rupture velocity. The slip distribution shows that this event consists of a series of regions of high slip (sub-events separated by regions of relative low slip. Our inversion favors the hypothesis that the duration of the slip at each point is of the order of the duration of the rupture of each sub-event and is consistent with a crack type process occurring during each sub-event. For such a large earthquake, the slip duration is however smaller than the total rupture duration.

  7. Predecessors of the giant 1960 Chile earthquake

    Science.gov (United States)

    Cisternas, M.; Atwater, B.F.; Torrejon, F.; Sawai, Y.; Machuca, G.; Lagos, M.; Eipert, A.; Youlton, C.; Salgado, I.; Kamataki, T.; Shishikura, M.; Rajendran, C.P.; Malik, J.K.; Rizal, Y.; Husni, M.

    2005-01-01

    It is commonly thought that the longer the time since last earthquake, the larger the next earthquake's slip will be. But this logical predictor of earthquake size, unsuccessful for large earthquakes on a strike-slip fault, fails also with the giant 1960 Chile earthquake of magnitude 9.5 (ref. 3). Although the time since the preceding earthquake spanned 123 years (refs 4, 5), the estimated slip in 1960, which occurred on a fault between the Nazca and South American tectonic plates, equalled 250-350 years' worth of the plate motion. Thus the average interval between such giant earthquakes on this fault should span several centuries. Here we present evidence that such long intervals were indeed typical of the last two millennia. We use buried soils and sand layers as records of tectonic subsidence and tsunami inundation at an estuary midway along the 1960 rupture. In these records, the 1960 earthquake ended a recurrence interval that had begun almost four centuries before, with an earthquake documented by Spanish conquistadors in 1575. Two later earthquakes, in 1737 and 1837, produced little if any subsidence or tsunami at the estuary and they therefore probably left the fault partly loaded with accumulated plate motion that the 1960 earthquake then expended. ?? 2005 Nature Publishing Group.

  8. Predecessors of the giant 1960 Chile earthquake

    Science.gov (United States)

    Cisternas, Marco; Atwater, Brian F.; Torrejón, Fernando; Sawai, Yuki; Machuca, Gonzalo; Lagos, Marcelo; Eipert, Annaliese; Youlton, Cristián; Salgado, Ignacio; Kamataki, Takanobu; Shishikura, Masanobu; Rajendran, C. P.; Malik, Javed K.; Rizal, Yan; Husni, Muhammad

    2005-09-01

    It is commonly thought that the longer the time since last earthquake, the larger the next earthquake's slip will be. But this logical predictor of earthquake size, unsuccessful for large earthquakes on a strike-slip fault, fails also with the giant 1960 Chile earthquake of magnitude 9.5 (ref. 3). Although the time since the preceding earthquake spanned 123years (refs 4, 5), the estimated slip in 1960, which occurred on a fault between the Nazca and South American tectonic plates, equalled 250-350years' worth of the plate motion. Thus the average interval between such giant earthquakes on this fault should span several centuries. Here we present evidence that such long intervals were indeed typical of the last two millennia. We use buried soils and sand layers as records of tectonic subsidence and tsunami inundation at an estuary midway along the 1960 rupture. In these records, the 1960 earthquake ended a recurrence interval that had begun almost four centuries before, with an earthquake documented by Spanish conquistadors in 1575. Two later earthquakes, in 1737 and 1837, produced little if any subsidence or tsunami at the estuary and they therefore probably left the fault partly loaded with accumulated plate motion that the 1960 earthquake then expended.

  9. An atlas of ShakeMaps for selected global earthquakes

    Science.gov (United States)

    Allen, Trevor I.; Wald, David J.; Hotovec, Alicia J.; Lin, Kuo-Wan; Earle, Paul S.; Marano, Kristin D.

    2008-01-01

    An atlas of maps of peak ground motions and intensity 'ShakeMaps' has been developed for almost 5,000 recent and historical global earthquakes. These maps are produced using established ShakeMap methodology (Wald and others, 1999c; Wald and others, 2005) and constraints from macroseismic intensity data, instrumental ground motions, regional topographically-based site amplifications, and published earthquake-rupture models. Applying the ShakeMap methodology allows a consistent approach to combine point observations with ground-motion predictions to produce descriptions of peak ground motions and intensity for each event. We also calculate an estimated ground-motion uncertainty grid for each earthquake. The Atlas of ShakeMaps provides a consistent and quantitative description of the distribution and intensity of shaking for recent global earthquakes (1973-2007) as well as selected historic events. As such, the Atlas was developed specifically for calibrating global earthquake loss estimation methodologies to be used in the U.S. Geological Survey Prompt Assessment of Global Earthquakes for Response (PAGER) Project. PAGER will employ these loss models to rapidly estimate the impact of global earthquakes as part of the USGS National Earthquake Information Center's earthquake-response protocol. The development of the Atlas of ShakeMaps has also led to several key improvements to the Global ShakeMap system. The key upgrades include: addition of uncertainties in the ground motion mapping, introduction of modern ground-motion prediction equations, improved estimates of global seismic-site conditions (VS30), and improved definition of stable continental region polygons. Finally, we have merged all of the ShakeMaps in the Atlas to provide a global perspective of earthquake ground shaking for the past 35 years, allowing comparison with probabilistic hazard maps. The online Atlas and supporting databases can be found at http://earthquake.usgs.gov/eqcenter/shakemap/atlas.php/.

  10. Joint inversion of teleseismic and strong motion data for the rupture process of the 2008 Wenchuan, China, earthquake

    Science.gov (United States)

    Koketsu, Kazuki; Hikima, Kazuhito; Yokota, Yusuke; Wang, Zifa

    2010-05-01

    The 2008 Wenchuan, China, earthquake, that is the largest and deadliest earthquake of the world for 2008, occurred on May 12, 2008 (local time). We first obtained teleseismic data observed at stations of FDSN from IRIS DMC, and carried out preliminary point sources analyses of them using the algorithm of Kikuchi and Kanamori (1991). The results of these analyses and aftershock distribution by USGS indicate low-angle dip slips in the southern half and high-angle strike slips in the northern half. Some surface fault investigations (e.g., Hao et al., 2009) suggest two parallel fault traces in the southern half, but only the one closer to the Sichuan basin should be related to the source fault of the earthquake, because the other cannot be of low angle. Accordingly, we defined a fault system consisting of two single-trace segments. The strike and dip angles for the southern and northern segments are respectively given to be (228, 35) and (232, 65) based on the results of the point source analyses. We next used strong motion data observed by the Institute of Engineering Mechanics of the China Earthquake Administration, and then carried out a joint finite source inversion of them and the teleseismic data mentioned above. We adopted the Green's functions of Kohketsu (1985) and Kikuchi and Kanamori (1991). We also used the inverse algorithm of Yoshida et al. (1996) with the revisions of Hikima and Koketsu (2005), and the location of the hypocenter determined by USGS (103.33E, 30.99N, depth 12 km) as a rupture initiation point. The resultant slip distribution indicates the first asperity with the largest reverse-faulting slip of about 7 m and the second asperity with a strike slip of about 3 m to be located in the southern and northern segments, respectively. The total seismic moment is 1.0 x 10**21 Nm, which corresponds to a moment magnitude (Mw) of 7.9. Significant slips appear in a 250 km long region (10,000 km**2) of the source fault, and these length and area are close

  11. Intensity Estimation Using the MSK-64 and EMS-98 Scales for Selected Historical Earthquakes

    Science.gov (United States)

    Labak, P.; Hammerl, C.

    2002-12-01

    Two different approaches for the comparison of the intensity estimation using the MSK-64 and EMS-98 scales are presented for historical earthquakes: 1) a direct comparison of the scales; 2) intensity estimation for selected historical earthquakes using the both scales. The scales are directly compared in the graphic forms. First, the graphic form of the EMS-98 was constructed. The effects on humans, and objects and nature were displayed in the form of tables. The tables include the size of the effects for all intensities. The definition of damage to buildings was displayed in the form of vulnerability class vs. damage grade table for each intensity degree separately. The MSK-64 scale was re-arranged into the same form as the EMS-98 scale. Then the classification of buildings, definitions of quantities and damage grades were compared. Finally, the effects on people, effects on objects and nature, and damage to buildings were compared separately. The effects, which are used only in one of the scales, and the effects, which are used in the both scales were identified. The cases where the differences in the intensity estimation can reach up to one degree are shown and discussed. The situations where the intensity estimation can be done using only one of the scales are also shown and discussed. The graphic forms of the MSK-64 and EMS-98 scales enable us to identify how the observed effects correspond to the defined effects for an intensity degree. Intensity estimations using the both scales were compared for the January 15, 1858 Zilina (Slovakia) and January 25, 1348 Friuli earthquakes. Examples of different intensity estimations using the both scales are given.

  12. Estimation of peak ground accelerations for Mexican subduction zone earthquakes using neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Silvia R; Romo, Miguel P; Mayoral, Juan M [Instituto de Ingenieria, Universidad Nacional Autonoma de Mexico, Mexico D.F. (Mexico)

    2007-01-15

    An extensive analysis of the strong ground motion Mexican data base was conducted using Soft Computing (SC) techniques. A Neural Network NN is used to estimate both orthogonal components of the horizontal (PGAh) and vertical (PGAv) peak ground accelerations measured at rock sites during Mexican subduction zone earthquakes. The work discusses the development, training, and testing of this neural model. Attenuation phenomenon was characterized in terms of magnitude, epicentral distance and focal depth. Neural approximators were used instead of traditional regression techniques due to their flexibility to deal with uncertainty and noise. NN predictions follow closely measured responses exhibiting forecasting capabilities better than those of most established attenuation relations for the Mexican subduction zone. Assessment of the NN, was also applied to subduction zones in Japan and North America. For the database used in this paper the NN and the-better-fitted- regression approach residuals are compared. [Spanish] Un analisis exhaustivo de la base de datos mexicana de sismos fuertes se llevo a cabo utilizando tecnicas de computo aproximado, SC (soft computing). En particular, una red neuronal, NN, es utilizada para estimar ambos componentes ortogonales de la maxima aceleracion horizontal del terreno, PGAh, y la vertical, PGAv, medidas en sitios en roca durante terremotos generados en la zona de subduccion de la Republica Mexicana. El trabajo discute el desarrollo, entrenamiento, y prueba de este modelo neuronal. El fenomeno de atenuacion fue caracterizado en terminos de la magnitud, la distancia epicentral y la profundidad focal. Aproximaciones neuronales fueron utilizadas en lugar de tecnicas de regresion tradicionales por su flexibilidad para tratar con incertidumbre y ruido en los datos. La NN sigue de cerca la respuesta medida exhibiendo capacidades predictivas mejores que las mostradas por muchas de las relaciones de atenuacion establecidas para la zona de

  13. Regional earthquake loss estimation in the Autonomous Province of Bolzano - South Tyrol (Italy)

    Science.gov (United States)

    Huttenlau, Matthias; Winter, Benjamin

    2013-04-01

    Beside storm events geophysical events cause a majority of natural hazard losses on a global scale. However, in alpine regions with a moderate earthquake risk potential like in the study area and thereupon connected consequences on the collective memory this source of risk is often neglected in contrast to gravitational and hydrological hazards processes. In this context, the comparative analysis of potential disasters and emergencies on a national level in Switzerland (Katarisk study) has shown that earthquakes are the most serious source of risk in general. In order to estimate the potential losses of earthquake events for different return periods and loss dimensions of extreme events the following study was conducted in the Autonomous Province of Bolzano - South Tyrol (Italy). The applied methodology follows the generally accepted risk concept based on the risk components hazard, elements at risk and vulnerability, whereby risk is not defined holistically (direct, indirect, tangible and intangible) but with the risk category losses on buildings and inventory as a general risk proxy. The hazard analysis is based on a regional macroseismic scenario approach. Thereby, the settlement centre of each community (116 communities) is defined as potential epicentre. For each epicentre four different epicentral scenarios (return periods of 98, 475, 975 and 2475 years) are calculated based on the simple but approved and generally accepted attenuation law according to Sponheuer (1960). The relevant input parameters to calculate the epicentral scenarios are (i) the macroseismic intensity and (ii) the focal depth. The considered macroseismic intensities are based on a probabilistic seismic hazard analysis (PSHA) of the Italian earthquake catalogue on a community level (Dipartimento della Protezione Civile). The relevant focal depth are considered as a mean within a defined buffer of the focal depths of the harmonized earthquake catalogues of Italy and Switzerland as well as

  14. Subpopulation-based correspondence modelling for improved respiratory motion estimation in the presence of inter-fraction motion variations

    Science.gov (United States)

    Wilms, Matthias; Werner, René; Yamamoto, Tokihiro; Handels, Heinz; Ehrhardt, Jan

    2017-07-01

    Correspondence modelling between low-dimensional breathing signals and internal organ motion is a prerequisite for application of advanced techniques in radiotherapy of moving targets. Patient-specific correspondence models can, for example, be built prior to treatment based on a planning 4D CT and simultaneously acquired breathing signals. Reliability of pre-treatment-built models depends, however, on the degree of patient-specific inter-fraction motion variations. This study investigates whether motion estimation accuracy in the presence of inter-fraction motion variations can be improved using correspondence models that incorporate motion information from different patients. The underlying assumption is that inter-patient motion variations resemble patient-specific inter-fraction motion variations for subpopulations of patients with similar breathing characteristics. The hypothesis is tested by integrating a sparse manifold clustering approach into a regression-based correspondence modelling framework that allows for automated identification of patient subpopulations. The evaluation is based on a total of 73 lung 4D CT data sets, including two cohorts of patients with repeat 4D CT scans (cohort 1: 14 patients; cohort 2: ten patients). The results are consistent for both cohorts: The subpopulation-based modelling approach outperforms general population modelling (models built on all data sets available) as well as pre-treatment-built models trained on only the patient-specific motion information. The results thereby support the hypothesis and illustrate the potential of subpopulation-based correspondence modelling.

  15. Mantle Attenuation Estimated from Regional and Teleseismic P-waves of Deep Earthquakes and Surface Explosions

    Science.gov (United States)

    Ichinose, G.; Woods, M.; Dwyer, J.

    2014-03-01

    We estimated the network-averaged mantle attenuation t*(total) of 0.5 s beneath the North Korea test site (NKTS) by use of P-wave spectra and normalized spectral stacks from the 25 May 2009 declared nuclear test (mb 4.5; IDC). This value was checked using P-waves from seven deep (580-600 km) earthquakes (4.8 North Korea. These earthquakes are 200-300 km from the NKTS, within 200 km of the Global Seismic Network seismic station in Mudanjiang, China (MDJ) and the International Monitoring System primary arrays at Ussuriysk, Russia (USRK) and Wonju, Republic of Korea (KSRS). With the deep earthquakes, we split the t*(total) ray path into two segments: a t*(u), that represents the attenuation of the up-going ray from the deep hypocenters to the local-regional receivers, and t*(d), that represents the attenuation along the down-going ray to teleseismic receivers. The sum of t*(u) and t*(d) should be equal to t*(total), because they both share coincident ray paths. We estimated the upper-mantle attenuation t*(u) of 0.1 s at stations MDJ, USRK, and KSRS from individual and stacks of normalized P-wave spectra. We then estimated the average lower-mantle attenuation t*(d) of 0.4 s using stacked teleseismic P-wave spectra. We finally estimated a network average t*(total) of 0.5 s from the stacked teleseismic P-wave spectra from the 2009 nuclear test, which confirms the equality with the sum of t*(u) and t*(d). We included constraints on seismic moment, depth, and radiation pattern by using results from a moment tensor analysis and corner frequencies from modeling of P-wave spectra recorded at local distances. We also avoided finite-faulting effects by excluding earthquakes with complex source time functions. We assumed ω2 source models for earthquakes and explosions. The mantle attenuation beneath the NKTS is clearly different when compared with the network-averaged t* of 0.75 s for the western US and is similar to values of approximately 0.5 s for the Semipalatinsk test site

  16. Hardware architecture design of a fast global motion estimation method

    Science.gov (United States)

    Liang, Chaobing; Sang, Hongshi; Shen, Xubang

    2015-12-01

    VLSI implementation of gradient-based global motion estimation (GME) faces two main challenges: irregular data access and high off-chip memory bandwidth requirement. We previously proposed a fast GME method that reduces computational complexity by choosing certain number of small patches containing corners and using them in a gradient-based framework. A hardware architecture is designed to implement this method and further reduce off-chip memory bandwidth requirement. On-chip memories are used to store coordinates of the corners and template patches, while the Gaussian pyramids of both the template and reference frame are stored in off-chip SDRAMs. By performing geometric transform only on the coordinates of the center pixel of a 3-by-3 patch in the template image, a 5-by-5 area containing the warped 3-by-3 patch in the reference image is extracted from the SDRAMs by burst read. Patched-based and burst mode data access helps to keep the off-chip memory bandwidth requirement at the minimum. Although patch size varies at different pyramid level, all patches are processed in term of 3x3 patches, so the utilization of the patch-processing circuit reaches 100%. FPGA implementation results show that the design utilizes 24,080 bits on-chip memory and for a sequence with resolution of 352x288 and frequency of 60Hz, the off-chip bandwidth requirement is only 3.96Mbyte/s, compared with 243.84Mbyte/s of the original gradient-based GME method. This design can be used in applications like video codec, video stabilization, and super-resolution, where real-time GME is a necessity and minimum memory bandwidth requirement is appreciated.

  17. Estimating the Maximum Possible Earthquake Magnitude Using Extreme Value Methodology : the Groningen Case

    NARCIS (Netherlands)

    Beirlant, J.; Kijko, Andrzej; Reykens, Tom; Einmahl, John

    2017-01-01

    The area-characteristic, maximum possible earthquake magnitude TM is required by the earthquake engineering community, disaster management agencies and the insurance industry. The Gutenberg-Richter law predicts that earthquake magnitudes M follow a truncated exponential distribution. In the

  18. Processed seismic motion records from earthquakes (1982--1993): Recorded at Scotty`s Castle, California

    Energy Technology Data Exchange (ETDEWEB)

    Lum, P K; Honda, K K

    1993-10-01

    The 8mm data tape contains the processed seismic data of earthquakes recorded at Scotty`s Castle, California. The seismic data were recorded by seismographs maintained by the DOE/NV in Southern Nevada. Four files were generated from each seismic recorder. They are ``Uncorrected acceleration time histories, 2. corrected acceleration, velocity and displacement time histories, 3. original recording, and 4. Fourier amplitude spectra of acceleration.

  19. Simulation of strong ground motion for the 25 April 2015 Nepal (Gorkha) Mw 7.8 earthquake using the SCEC broadband platform

    Science.gov (United States)

    M. C., Raghucharan; Somala, Surendra Nadh

    2017-07-01

    The 25th April 2015 Nepal (Gorkha) earthquake has been introduced into the SCEC BBP v15.3, and validation simulations are run using EXSIM methodology with the strong ground motion data of the earthquake. Synthetic seismograms are generated along with the response spectra for engineering applications. Goodness-of-fit metrics have been computed from response spectra for 14 stations located in the Central Indo-Gangetic Plains (CIGP). Plots of residuals are made as a function of hypocentral distance for various time periods. Spatial distribution of residuals as well as average residuals for all stations for the horizontal components are computed. The results demonstrate that there was a good match between the actual data and synthetics generated by the broadband platform. Finally, four of the widely used ground motion prediction equations around the world are chosen to compare how they predict the synthetics for Gorkha earthquake in CIGP.

  20. Evaluation of the evolving stress field of the Yellowstone volcanic plateau, 1988 to 2010, from earthquake first-motion inversions

    Science.gov (United States)

    Russo, E.; Waite, G. P.; Tibaldi, A.

    2017-03-01

    Although the last rhyolite eruption occurred around 70 ka ago, the silicic Yellowstone volcanic field is still considered active due to high hydrothermal and seismic activity and possible recent magma intrusions. Geodetic measurements document complex deformation patterns in crustal strain and seismic activity likewise reveal spatial and temporal variations in the stress field. We use earthquake data recorded between 1988 and 2010 to investigate these variations and their possible causes in more detail. Earthquake relocations and a set of 369 well-constrained, double-couple, focal mechanism solutions were computed. Events were grouped according to location and time to investigate trends in faulting. The majority of the events have normal-faulting solutions, subordinate strike-slip kinematics, and very rarely, reverse motions. The dominant direction of extension throughout the 0.64 Ma Yellowstone caldera is nearly ENE, consistent with the perpendicular direction of alignments of volcanic vents within the caldera, but our study also reveals spatial and temporal variations. Stress-field solutions for different areas and time periods were calculated from earthquake focal mechanism inversion. A well-resolved rotation of σ3 was found, from NNE-SSW near the Hebgen Lake fault zone, to ENE-WSW near Norris Junction. In particular, the σ3 direction changed throughout the years around Norris Geyser Basin, from being ENE-WSW, as calculated in the study by Waite and Smith (2004), to NNE-SSW, while the other σ3 directions are mostly unchanged over time. The presence of ;chocolate tablet; structures, with two sets of nearly perpendicular normal faults, was identified in many stages of the deformation history both in the Norris Geyser Basin area and inside the caldera.

  1. Survey of strong motion earthquake effects on thermal power plants in California with emphasis on piping systems. Volume 1, Main report

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, J.D. [Stevenson and Associates, Cleveland, OH (United States)

    1995-11-01

    Since 1982, there has been a major effort expended to evaluate the susceptibility of nuclear Power plant equipment to failure and significant damage during seismic events. This was done by making use of data on the performance of electrical and mechanical equipment in conventional power plants and other similar industrial facilities during strong motion earthquakes. This report is intended as an extension of the seismic experience data collection effort and a compilation of experience data specific to power plant piping and supports designed and constructed US power piping code requirements which have experienced strong motion earthquakes. Eight damaging (Richter Magnitude 7.7 to 5.5) California earthquakes and their effects on 8 power generating facilities in use natural gas and California were reviewed. All of these facilities were visited and evaluated. Seven fossel-fueled (dual use natural gas and oil) and one nuclear fueled plants consisting of a total of 36 individual boiler or reactor units were investigated. Peak horizontal ground accelerations that either had been recorded on site at these facilities or were considered applicable to these power plants on the basis of nearby recordings ranged between 0.20g and 0.5lg with strong motion durations which varied from 3.5 to 15 seconds. Most US nuclear power plants are designed for a safe shutdown earthquake peak ground acceleration equal to 0.20g or less with strong motion durations which vary from 10 to 15 seconds.

  2. Visualization of strong around motion calculated from the numerical simulation of Hyogo-ken Nanbu earthquake; Suchi simulation de miru Hyogoken nanbu jishin no kyoshindo

    Energy Technology Data Exchange (ETDEWEB)

    Furumura, T. [Hokkaido Univ. of Education, Sapporo (Japan); Koketsu, K. [The University of Tokyo, Tokyo (Japan). Earthquake Research Institute

    1996-10-01

    Hyogo-ken Nanbu earthquake with a focus in the Akashi straits has given huge earthquake damages in and around Awaji Island and Kobe City in 1995. It is clear that the basement structure, which is steeply deepened at Kobe City from Rokko Mountains towards the coast, and the focus under this related closely to the local generation of strong ground motion. Generation process of the strong ground motion was discussed using 2D and 3D numerical simulation methods. The 3D pseudospectral method was used for the calculation. Space of 51.2km{times}25.6km{times}25.6km was selected for the calculation. This space was discretized with the lattice interval of 200m. Consequently, it was found that the basement structure with a steeply deepened basement, soft and weak geological structure thickly deposited on the basement, and earthquake faults running under the boundary of base rock and sediments related greatly to the generation of strong ground motion. Numerical simulation can be expected to predict the strong ground motion by shallow earthquakes. 9 refs., 7 figs.

  3. Source characteristics of moderate-to-strong earthquakes in the Nantou area, Taiwan: insight from strong ground motion simulations

    Science.gov (United States)

    Wen, Yi-Ying; Chao, Shen-Yu; Yen, Yin-Tung; Wen, Strong

    2017-09-01

    In Taiwan, the Nantou area is a seismically active region where several moderate events have occurred, causing some disasters during the past century. Here, we applied the strong ground motion simulation with the empirical Green's function method to investigate the source characteristics for the eight moderate blind-fault events that struck the Nantou area in 1999 and 2013. The results show that for these Nantou events, a high stress drop and focal depth dependence were noted, which might be related to the immature buried fault in this area. From the viewpoint of seismic hazard prevention and preparation, future earthquake scenarios that include high stress drop should be applied to more analyses, especially the moderate-to-large events originating from the immature blind faulting.[Figure not available: see fulltext.

  4. Testing earthquake source inversion methodologies

    KAUST Repository

    Page, Morgan T.

    2011-01-01

    Source Inversion Validation Workshop; Palm Springs, California, 11-12 September 2010; Nowadays earthquake source inversions are routinely performed after large earthquakes and represent a key connection between recorded seismic and geodetic data and the complex rupture process at depth. The resulting earthquake source models quantify the spatiotemporal evolution of ruptures. They are also used to provide a rapid assessment of the severity of an earthquake and to estimate losses. However, because of uncertainties in the data, assumed fault geometry and velocity structure, and chosen rupture parameterization, it is not clear which features of these source models are robust. Improved understanding of the uncertainty and reliability of earthquake source inversions will allow the scientific community to use the robust features of kinematic inversions to more thoroughly investigate the complexity of the rupture process and to better constrain other earthquakerelated computations, such as ground motion simulations and static stress change calculations.

  5. Directional topographic site response at Tarzana observed in aftershocks of the 1994 Northridge, California, earthquake: Implications for mainshock motions

    Science.gov (United States)

    Spudich, P.; Hellweg, M.; Lee, W.H.K.

    1996-01-01

    The Northridge earthquake caused 1.78 g acceleration in the east-west direction at a site in Tarzana, California, located about 6 km south of the mainshock epicenter. The accelerograph was located atop a hill about 15-m high, 500-m long, and 130-m wide, striking about N78??E. During the aftershock sequence, a temporary array of 21 three-component geophones was deployed in six radial lines centered on the accelerograph, with an average sensor spacing of 35 m. Station COO was located about 2 m from the accelerograph. We inverted aftershock spectra to obtain average relative site response at each station as a function of direction of ground motion. We identified a 3.2-Hz resonance that is a transverse oscillation of the hill (a directional topographic effect). The top/base amplification ratio at 3.2 Hz is about 4.5 for horizontal ground motions oriented approximately perpendicular to the long axis of the hill and about 2 for motions parallel to the hill. This resonance is seen most strongly within 50 m of COO. Other resonant frequencies were also observed. A strong lateral variation in attenuation, probably associated with a fault, caused substantially lower motion at frequencies above 6 Hz at the east end of the hill. There may be some additional scattered waves associated with the fault zone and seen at both the base and top of the hill, causing particle motions (not spectral ratios) at the top of the hill to be rotated about 20?? away from the direction transverse to the hill. The resonant frequency, but not the amplitude, of our observed topographic resonance agrees well with theory, even for such a low hill. Comparisons of our observations with theoretical results indicate that the 3D shape of the hill and its internal structure are important factors affecting its response. The strong transverse resonance of the hill does not account for the large east-west mainshock motions. Assuming linear soil response, mainshock east-west motions at the Tarzana accelerograph

  6. Reevaluation of the macroseismic effects of the 1887 Sonora, Mexico earthquake and its magnitude estimation

    Science.gov (United States)

    Suárez, Gerardo; Hough, Susan E.

    2008-01-01

    The Sonora, Mexico, earthquake of 3 May 1887 occurred a few years before the start of the instrumental era in seismology. We revisit all available accounts of the earthquake and assign Modified Mercalli Intensities (MMI), interpreting and analyzing macroseismic information using the best available modern methods. We find that earlier intensity assignments for this important earthquake were unjustifiably high in many cases. High intensity values were assigned based on accounts of rock falls, soil failure or changes in the water table, which are now known to be very poor indicators of shaking severity and intensity. Nonetheless, reliable accounts reveal that light damage (intensity VI) occurred at distances of up to ~200 km in both Mexico and the United States. The resulting set of 98 reevaluated intensity values is used to draw an isoseismal map of this event. Using the attenuation relation proposed by Bakun (2006b), we estimate an optimal moment magnitude of Mw7.6. Assuming this magnitude is correct, a fact supported independently by documented rupture parameters assuming standard scaling relations, our results support the conclusion that northern Sonora as well as the Basin and Range province are characterized by lower attenuation of intensities than California. However, this appears to be at odds with recent results that Lg attenuation in the Basin and Range province is comparable to that in California.

  7. Fast Estimate of Rupture Process of Large Earthquakes via Real Time Hi-net Data

    Science.gov (United States)

    Wang, D.; Kawakatsu, H.; Mori, J. J.

    2014-12-01

    We developed a real time system based on Hi-net seismic array that can offer fast and reliable source information, for example, source extent and rupture velocity, for earthquakes that occur at distance of roughly 30°- 85°with respect to the array center. We perform continuous grid search on a Hi-net real time data stream to identify possible source locations (following Nishida, K., Kawakatsu, H., and S. Obara, 2008). Earthquakes that occurred off the bright area of the array (30°- 85°with respect to the array center) will be ignored. Once a large seismic event is identified successfully, back-projection will be implemented to trace the source propagation and energy radiation. Results from extended global GRiD-MT and real time W phase inversion will be combined for the better identification of large seismic events. The time required is mainly due to the travel time from the epicenter to the array stations, so we can get the results between 6 to 13 min depending on the epicenter distances. This system can offer fast and robust estimates of earthquake source information, which will be useful for disaster mitigation, such as tsunami evacuation, emergency rescue, and aftershock hazard evaluation.

  8. Ground motion simulation for the 23 August 2011, Mineral, Virginia earthquake using physics-based and stochastic broadband methods

    Science.gov (United States)

    Sun, Xiaodan; Hartzell, Stephen; Rezaeian, Sanaz

    2015-01-01

    Three broadband simulation methods are used to generate synthetic ground motions for the 2011 Mineral, Virginia, earthquake and compare with observed motions. The methods include a physics‐based model by Hartzell et al. (1999, 2005), a stochastic source‐based model by Boore (2009), and a stochastic site‐based model by Rezaeian and Der Kiureghian (2010, 2012). The ground‐motion dataset consists of 40 stations within 600 km of the epicenter. Several metrics are used to validate the simulations: (1) overall bias of response spectra and Fourier spectra (from 0.1 to 10 Hz); (2) spatial distribution of residuals for GMRotI50 peak ground acceleration (PGA), peak ground velocity, and pseudospectral acceleration (PSA) at various periods; (3) comparison with ground‐motion prediction equations (GMPEs) for the eastern United States. Our results show that (1) the physics‐based model provides satisfactory overall bias from 0.1 to 10 Hz and produces more realistic synthetic waveforms; (2) the stochastic site‐based model also yields more realistic synthetic waveforms and performs superiorly for frequencies greater than about 1 Hz; (3) the stochastic source‐based model has larger bias at lower frequencies (spatial distribution of GMRotI50 residuals shows that there is no obvious pattern with distance in the simulation bias, but there is some azimuthal variability. The comparison between synthetics and GMPEs shows similar fall‐off with distance for all three models, comparable PGA and PSA amplitudes for the physics‐based and stochastic site‐based models, and systematic lower amplitudes for the stochastic source‐based model at lower frequencies (<0.5  Hz).

  9. Test suite for image-based motion estimation of the brain and tongue

    Science.gov (United States)

    Ramsey, Jordan; Prince, Jerry L.; Gomez, Arnold D.

    2017-03-01

    Noninvasive analysis of motion has important uses as qualitative markers for organ function and to validate biomechanical computer simulations relative to experimental observations. Tagged MRI is considered the gold standard for noninvasive tissue motion estimation in the heart, and this has inspired multiple studies focusing on other organs, including the brain under mild acceleration and the tongue during speech. As with other motion estimation approaches, using tagged MRI to measure 3D motion includes several preprocessing steps that affect the quality and accuracy of estimation. Benchmarks, or test suites, are datasets of known geometries and displacements that act as tools to tune tracking parameters or to compare different motion estimation approaches. Because motion estimation was originally developed to study the heart, existing test suites focus on cardiac motion. However, many fundamental differences exist between the heart and other organs, such that parameter tuning (or other optimization) with respect to a cardiac database may not be appropriate. Therefore, the objective of this research was to design and construct motion benchmarks by adopting an "image synthesis" test suite to study brain deformation due to mild rotational accelerations, and a benchmark to model motion of the tongue during speech. To obtain a realistic representation of mechanical behavior, kinematics were obtained from finite-element (FE) models. These results were combined with an approximation of the acquisition process of tagged MRI (including tag generation, slice thickness, and inconsistent motion repetition). To demonstrate an application of the presented methodology, the effect of motion inconsistency on synthetic measurements of head- brain rotation and deformation was evaluated. The results indicated that acquisition inconsistency is roughly proportional to head rotation estimation error. Furthermore, when evaluating non-rigid deformation, the results suggest that

  10. 3D ground‐motion simulations of Mw 7 earthquakes on the Salt Lake City segment of the Wasatch fault zone: Variability of long‐period (T≥1  s) ground motions and sensitivity to kinematic rupture parameters

    Science.gov (United States)

    Moschetti, Morgan P.; Hartzell, Stephen; Ramirez-Guzman, Leonardo; Frankel, Arthur; Angster, Stephen J.; Stephenson, William J.

    2017-01-01

    We examine the variability of long‐period (T≥1  s) earthquake ground motions from 3D simulations of Mw 7 earthquakes on the Salt Lake City segment of the Wasatch fault zone, Utah, from a set of 96 rupture models with varying slip distributions, rupture speeds, slip velocities, and hypocenter locations. Earthquake ruptures were prescribed on a 3D fault representation that satisfies geologic constraints and maintained distinct strands for the Warm Springs and for the East Bench and Cottonwood faults. Response spectral accelerations (SA; 1.5–10 s; 5% damping) were measured, and average distance scaling was well fit by a simple functional form that depends on the near‐source intensity level SA0(T) and a corner distance Rc:SA(R,T)=SA0(T)(1+(R/Rc))−1. Period‐dependent hanging‐wall effects manifested and increased the ground motions by factors of about 2–3, though the effects appeared partially attributable to differences in shallow site response for sites on the hanging wall and footwall of the fault. Comparisons with modern ground‐motion prediction equations (GMPEs) found that the simulated ground motions were generally consistent, except within deep sedimentary basins, where simulated ground motions were greatly underpredicted. Ground‐motion variability exhibited strong lateral variations and, at some sites, exceeded the ground‐motion variability indicated by GMPEs. The effects on the ground motions of changing the values of the five kinematic rupture parameters can largely be explained by three predominant factors: distance to high‐slip subevents, dynamic stress drop, and changes in the contributions from directivity. These results emphasize the need for further characterization of the underlying distributions and covariances of the kinematic rupture parameters used in 3D ground‐motion simulations employed in probabilistic seismic‐hazard analyses.

  11. Ground-motion site effects from multimethod shear-wave velocity characterization at 16 seismograph stations deployed for aftershocks of the August 2011 Mineral, Virginia earthquake

    Science.gov (United States)

    Stephenson, William J.; Odum, Jackson K.; McNamara, Daniel E.; Williams, Robert A.; Angster, Stephen J

    2014-01-01

    We characterize shear-wave velocity versus depth (Vs profile) at 16 portable seismograph sites through the epicentral region of the 2011 Mw 5.8 Mineral (Virginia, USA) earthquake to investigate ground-motion site effects in the area. We used a multimethod acquisition and analysis approach, where active-source horizontal shear (SH) wave reflection and refraction as well as active-source multichannel analysis of surface waves (MASW) and passive-source refraction microtremor (ReMi) Rayleigh wave dispersion were interpreted separately. The time-averaged shear-wave velocity to a depth of 30 m (Vs30), interpreted bedrock depth, and site resonant frequency were estimated from the best-fit Vs profile of each method at each location for analysis. Using the median Vs30 value (270–715 m/s) as representative of a given site, we estimate that all 16 sites are National Earthquake Hazards Reduction Program (NEHRP) site class C or D. Based on a comparison of simplified mapped surface geology to median Vs30 at our sites, we do not see clear evidence for using surface geologic units as a proxy for Vs30 in the epicentral region, although this may primarily be because the units are similar in age (Paleozoic) and may have similar bulk seismic properties. We compare resonant frequencies calculated from ambient noise horizontal:vertical spectral ratios (HVSR) at available sites to predicted site frequencies (generally between 1.9 and 7.6 Hz) derived from the median bedrock depth and average Vs to bedrock. Robust linear regression of HVSR to both site frequency and Vs30 demonstrate moderate correlation to each, and thus both appear to be generally representative of site response in this region. Based on Kendall tau rank correlation testing, we find that Vs30 and the site frequency calculated from average Vs to median interpreted bedrock depth can both be considered reliable predictors of weak-motion site effects in the epicentral region.

  12. Imaging of the First Five Seconds in the Rupture Process of the 2008 Iwate-Miyagi Nairiku (Inland, Japan) Earthquake From the Local Strong-motion Records

    Science.gov (United States)

    Takenaka, H.; Yamamoto, Y.

    2008-12-01

    From local P-wave records we can get not only point information on earthquake source such as hypocenter location or magnitude but also plane information such as fault plane or asperity distribution. As an effective method for imaging asperity on fault plane in the initial stage of the rupture, we introduced a backprojection technique using near-source P-wave records to map the "radiation strength" on the fault planes, where high radiation strength zones are considered to be "asperity", for the 2005 West off Fukuoka earthquake (Mw6.6) (Yamamoto and Takenaka, 2006), the 2007 Noto-hanto earthquake (Mw6.7) (Yamamoto and Takenaka, 2007) and the 2007 Niigataken Chuetsu-oki earthquake (Mw6.6) (Takenaka et al., 2008). In this study we apply this method to the 2008 Iwate-Miyagi Nairiku (Inland, Japan) earthquake (Mw6.8), which occurred on 14 June 2008 (JST) in north Japan, to image the first 5 seconds of the rupture process from the local strong- motion records (K-NET and KiK-net). Using the hypocenter by JMA (depth of 7.8 km) and the fault plane by the F-net CMT (strike: N186, dip: 47), from the imaging the asperity area is then found to be located updidward and strikeward (southward) a little away from the hypocenter on the fault plane. The line passing the hypocenter and the imaged asperity area is pointing to Ichinoseki city. In the presentation we show the imaging results with discussion on the relation to the observed strong ground motion. [Acknowledgements] We used the strong-motion records supplied by the National Institute for Earth Science and Disaster Prevention (NIED; K-NET, KiK-net, F-net), and the mainshock hypocenter determined by the Japan Meteorological Agency (JMA). This study is partially supported by "Special Project for Earthquake Disaster Mitigation in Metropolitan Tokyo Area".

  13. The October 20, 2006 Manyas (ML=5.2 and October 24, 2006 Gemlik (ML=5.2 earthquakes in the Marmara region (NW Turkey: ground motion characteristics

    Directory of Open Access Journals (Sweden)

    Esref Yalcinkaya

    2015-03-01

    Full Text Available In this study, we analyze the ground motion characteristics of October 20, 2006 Manyas (ML=5.2 and October 24, 2006 Gemlik (ML=5.2 earthquakes. Both earthquakes occurred on the southern branch of the North Anatolian Fault Zone in Marmara region, which has a lower seismic hazard relative to the northern branch. The two events are the largest earthquakes on the southern branch recorded by a modern and vast seismological network; therefore their records are valuable to evaluate seismic risk of the region and the understanding of physics of wave propagation. The analysis show that the attenuation of PGAs is very similar for two earthquakes, but they are not represented by the empirical relation obtained for earthquakes occurred on the northern branch. The waveforms of the Gemlik earthquake recorded by BYTNet array indicate an EW rupture orientation with right-lateral slip which fits to the general character of the southern branch. Ground motions at the stations located within basin are strongly influenced by the presence of locally induced surface waves resulting in lengthening of significant shaking duration with respect to a nearby ridge site. Surface wave characteristics are very similar for the Manyas and Gemlik earthquakes, but variations are observed on components which may be related to 3D basin geometry. Resonance frequencies of the surface waves generated within basin are very close to the 1D site resonances at the stations obtained from H/V ratios of S waves. The resonance frequency is about 0.2 Hz within the large Bursa Plain, whereas it increases to about 0.9 Hz within the smaller Gemlik Plain.

  14. Tracking using motion estimation with physically motivated inter-region constraints

    KAUST Repository

    Arif, Omar

    2014-09-01

    We propose a method for tracking structures (e.g., ventricles and myocardium) in cardiac images (e.g., magnetic resonance) by propagating forward in time a previous estimate of the structures using a new physically motivated motion estimation scheme. Our method estimates motion by regularizing only within structures so that differing motions among different structures are not mixed. It simultaneously satisfies the physical constraints at the interface between a fluid and a medium that the normal component of the fluid\\'s motion must match the normal component of the medium\\'s motion and the No-Slip condition, which states that the tangential velocity approaches zero near the interface. We show that these conditions lead to partial differential equations with Robin boundary conditions at the interface, which couple the motion between structures. We show that propagating a segmentation across frames using our motion estimation scheme leads to more accurate segmentation than traditional motion estimation that does not use physical constraints. Our method is suited to interactive segmentation, prominently used in commercial applications for cardiac analysis, where segmentation propagation is used to predict a segmentation in the next frame. We show that our method leads to more accurate predictions than a popular and recent interactive method used in cardiac segmentation. © 2014 IEEE.

  15. Estimating the 2008 Quetame (Colombia) earthquake source parameters from seismic data and InSAR measurements

    Science.gov (United States)

    Dicelis, Gabriel; Assumpção, Marcelo; Kellogg, James; Pedraza, Patricia; Dias, Fábio

    2016-12-01

    Seismic waveforms and geodetic measurements (InSAR) were used to determine the location, focal mechanism and coseismic surface displacements of the Mw 5.9 earthquake which struck the center of Colombia on May 24, 2008. We determined the focal mechanism of the main event using teleseismic P wave arrivals and regional waveform inversion for the moment tensor. We relocated the best set of aftershocks (30 events) with magnitudes larger than 2.0 recorded from May to June 2008 by a temporary local network as well as by stations of the Colombia national network. We successfully estimated coseismic deformation using SAR interferometry, despite distortion in some areas of the interferogram by atmospheric noise. The deformation was compared to synthetic data for rectangular dislocations in an elastic half-space. Nine source parameters (strike, dip, length, width, strike-slip deformation, dip-slip deformation, latitude shift, longitude shift, and minimum depth) were inverted to fit the observed changes in line-of-sight (LOS) toward the satellite four derived parameters were also estimated (rake, average slip, maximum depth and seismic moment). The aftershock relocation, the focal mechanism and the coseismic dislocation model agree with a right-lateral strike-slip fault with nodal planes oriented NE-SW and NW-SE. We use the results of the waveform inversion, radar interferometry and aftershock relocations to identify the high-angle NE-SW nodal plane as the primary fault. The inferred subsurface rupture length is roughly 11 km, which is consistent with the 12 km long distribution of aftershocks. This coseismic model can provide insights on earthquake mechanisms and seismic hazard assessments for the area, including the 8 million residents of Colombia's nearby capital city Bogota. The 2008 Quetame earthquake appears to be associated with the northeastward "escape" of the North Andean block, and it may help to illuminate how margin-parallel shear slip is partitioned in the

  16. Moment Tensors and their Uncertainties for M3 Earthquakes in the Geysers, California, from Waveform Modeling and First Motions

    Science.gov (United States)

    Guilhem, A.; Dreger, D. S.; Hutchings, L. J.; Johnson, L.

    2012-12-01

    We investigate moment tensor solutions and their uncertainties for magnitude (M) ~3 earthquakes located in the northwest Geysers geothermal field, California. We are exploiting an unusual opportunity where data for M~3 events have been recorded by three different networks and have moment tensor solutions calculated by three different methods. We solve for both deviatoric and full moment tensor solutions. The data sets include local short-period instruments (4.5 Hz) of the 30 stations of the Lawrence Berkeley National Laboratory (LBNL), with which we obtain waveform inversion solutions at relatively high frequencies (i.e., up to 2.5 Hz), and regionally distributed broadband stations operated by the Berkeley Seismological Laboratory (BSL), with which are used to provide waveform inversion solutions with data filtered at longer periods (i.e., > 10 sec). We also utilize the LBNL data to obtain moment tensor solutions by fitting the P-wave first motions. The USGS, LBNL, and BSL obtain different event locations, utilize different velocity models, and analyze different frequency bands and wave types (i.e., body waves for LBNL method and primarily surface waves for the BSL analysis). Preliminary results indicate that the BSL and LBNL waveform modeling analyses give similar results in terms of nodal plane characteristics, moment magnitude, and moment tensor decomposition. Analysis of the P-wave first motions recorded by LBNL stations can illuminate complexities in the source processes when compared to waveform moment tensor solutions. We discuss uncertainties in the source inversions that use broadband and/or short-period waveform modeling, and in the source inversions from first motions only. We also combine the different datasets and compare their individual importance as they can help illustrate the complex source processes happening in the Geysers. This study introduces the possibility to interpret the seismic sources as complex processes in which both shear and tensile

  17. Fast Identification of Near-Trench Earthquakes Along the Mexican Subduction Zone Based on Characteristics of Ground Motion in Mexico City

    Science.gov (United States)

    Perez-Campos, X.; Singh, S. K.; Arroyo, D.; Rodríguez, Q.; Iglesias, A.

    2015-12-01

    The disastrous 1985 Michoacan earthquake gave rise to a seismic alert system for Mexico City which became operational in 1991. Initially limited to earthquakes along the Guerrero coast, the system now has a much wider coverage. Also, the 2004 Sumatra earthquake exposed the need for a tsunami early warning along the Mexican subduction zone. A fast identification of near-trench earthquakes along this zone may be useful in issuing a reliable early tsunami alert. The confusion caused by low PGA for the magnitude of an earthquake, leading to "missed" seismic alert, would be averted if its near-trench origin can be quickly established. It may also help reveal the spatial extent and degree of seismic coupling on the near-trench portion of the plate interface. This would lead to a better understanding of tsunami potential and seismic hazard along the Mexican subduction zone. We explore three methods for quick detection of near-trench earthquakes, testing them on recordings of 65 earthquakes at station CU in Mexico City (4.8 ≤Mw≤8.0; 270≤R≤615 km). The first method is based on the ratio of total to high-frequency energy, ER (Shapiro et al., 1998). The second method is based on parameter Sa*(6) which is the pseudo-acceleration response spectrum with 5% damping, Sa, at 6 s normalized by the PGA. The third parameter is the PGA residual, RESN, at CU, with respect to a newly-derived ground motion prediction equation at CU for coastal shallow-dipping thrust earthquakes following a bayesian approach. Since the near-trench earthquakes are relatively deficient in high-frequency radiation, we expect ER and Sa*(6) to be relatively large and RESN to be negative for such events. Tests on CU recordings show that if ER ≥ 100 and/or Sa*(6) ≥ 0.70, then the earthquake is near trench; for these events RESN ≤ 0. Such an event has greater tsunami potential. Few misidentifications and missed events are most probably a consequence of poor location, although unusual depth and source

  18. Citizen earthquake alert using near real time PGA estimation from a local array combining a variety of accelerometric instruments

    Science.gov (United States)

    Melis, Nikolaos S.; Konstantinou, Konstantinos; Kalogeras, Ioannis; Sokos, Efthimios; Tselentis, G.-Akis

    2017-04-01

    It is of a great importance to assess rapidly the intensity of a felt event in a highly populated environment. Rapid and reliable information plays a key role to decision making responses, by performing correctly the first steps after a felt ground shaking. Thus, it is important to accurately respond to urgent societal demand using reliable information. A strong motion array is under deployment and trial operation in the area of Patras, Greece. It combines: (a) standard accelerometric stations operated by the National Observatory of Athens, Institute of Geodynamics (NOA), (b) QCN-type USB MEMS acceleration sensors deployed in schools and (c) P-alert MEMS acceleration devices deployed in public sector buildings as well as in private dwellings. The array intends to cover the whole city of Patras and the populated suburbs. All instruments are operating in near real time and they are linked to a combined Earthworm - SeisComP3 server at NOA, Athens. Rapid intensity estimation can be also performed by the P-alert accelerometers locally, but the performance of a near real time intensity estimation system is under operation at NOA. The procedure is based on observing the maximum PGA value at each instrument and empirically estimate the corresponding intensity. The values are also fed to a SeisComP3 based ShakeMap procedure that is served at NOA and uses the scwfparam module of SeisComP3. Earthquake activity has been recorded so far from the western Corinth Gulf, the Ionian Islands and Achaia-Elia area, western Peloponnesus. The first phase involves correlation tests of collocated instruments and assessment of their performance to low intensity as well as to strongly felt events in the Patras city area. Steps of expanding the array are also under consideration, in order to cover the wider area of northwestern Peloponnesus and Ionian islands.

  19. Earthquake Damage - General

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — An earthquake is the motion or trembling of the ground produced by sudden displacement of rock in the Earth's crust. Earthquakes result from crustal strain,...

  20. Identifying Active Faults by Improving Earthquake Locations with InSAR Data and Bayesian Estimation: The 2004 Tabuk (Saudi Arabia) Earthquake Sequence

    KAUST Repository

    Xu, Wenbin

    2015-02-03

    A sequence of shallow earthquakes of magnitudes ≤5.1 took place in 2004 on the eastern flank of the Red Sea rift, near the city of Tabuk in northwestern Saudi Arabia. The earthquakes could not be well located due to the sparse distribution of seismic stations in the region, making it difficult to associate the activity with one of the many mapped faults in the area and thus to improve the assessment of seismic hazard in the region. We used Interferometric Synthetic Aperture Radar (InSAR) data from the European Space Agency’s Envisat and ERS‐2 satellites to improve the location and source parameters of the largest event of the sequence (Mw 5.1), which occurred on 22 June 2004. The mainshock caused a small but distinct ∼2.7  cm displacement signal in the InSAR data, which reveals where the earthquake took place and shows that seismic reports mislocated it by 3–16 km. With Bayesian estimation, we modeled the InSAR data using a finite‐fault model in a homogeneous elastic half‐space and found the mainshock activated a normal fault, roughly 70 km southeast of the city of Tabuk. The southwest‐dipping fault has a strike that is roughly parallel to the Red Sea rift, and we estimate the centroid depth of the earthquake to be ∼3.2  km. Projection of the fault model uncertainties to the surface indicates that one of the west‐dipping normal faults located in the area and oriented parallel to the Red Sea is a likely source for the mainshock. The results demonstrate how InSAR can be used to improve locations of moderate‐size earthquakes and thus to identify currently active faults.

  1. Estimation of damage and human losses due to earthquakes worldwide - QLARM strategy and experience

    Science.gov (United States)

    Trendafiloski, G.; Rosset, P.; Wyss, M.; Wiemer, S.; Bonjour, C.; Cua, G.

    2009-04-01

    Within the framework of the IMRPOVE project, we are constructing our second-generation loss estimation tool QLARM (earthQuake Loss Assessment for Response and Mitigation). At the same time, we are upgrading the input data to be used in real-time and scenario mode. The software and databases will be open to all scientific users. The estimates include: (1) total number of fatalities and injured, (2) casualties by settlement, (3) percent of buildings in five damage grades in each settlement, (4) a map showing mean damage by settlement, and (5) functionality of large medical facilities. We present here our strategy and progress so far in constructing and calibrating the new tool. The QLARM worldwide database of the elements-at-risk consists of point and discrete city models with the following parameters: (1) Soil amplification factors; (2) distribution of building stock and population into vulnerability classes of the European Macroseismic Scale (EMS-98); (3) most recent population numbers by settlement or district; (4) information regarding medical facilities where available. We calculate the seismic demand in terms of (a) macroseismic (seismic intensity) or (b) instrumental (PGA) parameters. Attenuation relationships predicting both parameters will be used for different regions worldwide, considering the tectonic regime and wave propagation characteristics. We estimate damage and losses using: (i) vulnerability models pertinent to EMS-98 vulnerability classes; (ii) building collapse rates pertinent to different regions worldwide; and, (iii) casualty matrices pertinent to EMS-98 vulnerability classes. We also provide approximate estimates for the functionality of large medical facilities considering their structural, non-structural damage and loss-of-function of the medical equipment and installations. We calibrate the QLARM database and the loss estimation tool using macroseismic observations and information regarding damage and human losses from past earthquakes

  2. Characterizing the Kathmandu Valley sediment response through strong motion recordings of the 2015 Gorkha earthquake sequence

    Science.gov (United States)

    Rajaure, S.; Asimaki, D.; Thompson, E. M.; Hough, S.; Martin, S.; Ampuero, J. P.; Dhital, M. R.; Inbal, A.; Takai, N.; Shigefuji, M.; Bijukchhen, S.; Ichiyanagi, M.; Sasatani, T.; Paudel, L.

    2017-09-01

    We analyze strong motion records and high-rate GPS measurements of the M 7.8 Gorkha mainshock, M 7.3 Dolakha, and two moderate aftershock events recorded at four stations on the Kathmandu basin sediments, and one on rock-outcrop. Recordings on soil from all four events show systematic amplification relative to the rock site at multiple frequencies in the 0.1-2.5 Hz frequency range, and de-amplification of higher frequencies (>2.5-10 Hz). The soil-to-rock amplification ratios for the M 7.8 and M 7.3 events have lower amplitude and frequency peaks relative to the ratios of the two moderate events, effects that could be suggestive of nonlinear site response. Further, comparisons to ground motion prediction equations show that 1) both soil and rock mainshock recordings were severely depleted of high frequencies, and 2) the depletion at high frequencies is not present in the aftershocks. These observations indicate that the high frequency deamplification is additionally related to characteristics of the source that are not captured by simplified ground motion prediction equations, and allude to seismic hazard analysis models being revised - possibly by treating isolated high frequency radiation sources separately from long period components to capture large magnitude near-source events such as the 2015 Gorkha mainshock.

  3. Characterizing the Kathmandu Valley sediment response through strong motion recordings of the 2015 Gorkha earthquake sequence

    Science.gov (United States)

    Rajaure, S.; Asimaki, Domniki; Thompson, Eric; Hough, Susan E.; Martin, Stacey; Ampuero, J.P.; Dhital, M.R.; Inbal, A; Takai, N; Shigefuji, M.; Bijukchhen, S; Ichiyanagi, M; Sasatani, T; Paudel, L

    2017-01-01

    We analyze strong motion records and high-rate GPS measurements of the M 7.8 Gorkha mainshock, M 7.3 Dolakha, and two moderate aftershock events recorded at four stations on the Kathmandu basin sediments, and one on rock-outcrop. Recordings on soil from all four events show systematic amplification relative to the rock site at multiple frequencies in the 0.1–2.5 Hz frequency range, and de-amplification of higher frequencies ( >2.5–10 Hz). The soil-to-rock amplification ratios for the M 7.8 and M 7.3 events have lower amplitude and frequency peaks relative to the ratios of the two moderate events, effects that could be suggestive of nonlinear site response. Further, comparisons to ground motion prediction equations show that 1) both soil and rock mainshock recordings were severely depleted of high frequencies, and 2) the depletion at high frequencies is not present in the aftershocks. These observations indicate that the high frequency deamplification is additionally related to characteristics of the source that are not captured by simplified ground motion prediction equations, and allude to seismic hazard analysis models being revised – possibly by treating isolated high frequency radiation sources separately from long period components to capture large magnitude near-source events such as the 2015 Gorkha mainshock.

  4. Effectiveness of external respiratory surrogates for in vivo liver motion estimation

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Kai-Hsiang; Ho, Ming-Chih; Yeh, Chi-Chuan; Chen, Yu-Chien; Lian, Feng-Li; Lin, Win-Li; Yen, Jia-Yush; Chen, Yung-Yaw [Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei 10041, Taiwan (China); Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei 10617, Taiwan (China); Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Institute of Biomedical Engineering, National Taiwan University, Taipei 10041, Taiwan (China); Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Department of Electrical Engineering and Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei 10617, Taiwan (China)

    2012-08-15

    Purpose: Due to low frame rate of MRI and high radiation damage from fluoroscopy and CT, liver motion estimation using external respiratory surrogate signals seems to be a better approach to track liver motion in real-time for liver tumor treatments in radiotherapy and thermotherapy. This work proposes a liver motion estimation method based on external respiratory surrogate signals. Animal experiments are also conducted to investigate related issues, such as the sensor arrangement, multisensor fusion, and the effective time period. Methods: Liver motion and abdominal motion are both induced by respiration and are proved to be highly correlated. Contrary to the difficult direct measurement of the liver motion, the abdominal motion can be easily accessed. Based on this idea, our study is split into the model-fitting stage and the motion estimation stage. In the first stage, the correlation between the surrogates and the liver motion is studied and established via linear regression method. In the second stage, the liver motion is estimated by the surrogate signals with the correlation model. Animal experiments on cases of single surrogate signal, multisurrogate signals, and long-term surrogate signals are conducted and discussed to verify the practical use of this approach. Results: The results show that the best single sensor location is at the middle of the upper abdomen, while multisurrogate models are generally better than the single ones. The estimation error is reduced from 0.6 mm for the single surrogate models to 0.4 mm for the multisurrogate models. The long-term validity of the estimation models is quite satisfactory within the period of 10 min with the estimation error less than 1.4 mm. Conclusions: External respiratory surrogate signals from the abdomen motion produces good performance for liver motion estimation in real-time. Multisurrogate signals enhance estimation accuracy, and the estimation model can maintain its accuracy for at least 10 min. This

  5. Nowcasting Earthquakes

    Science.gov (United States)

    Rundle, J. B.; Donnellan, A.; Grant Ludwig, L.; Turcotte, D. L.; Luginbuhl, M.; Gail, G.

    2016-12-01

    Nowcasting is a term originating from economics and finance. It refers to the process of determining the uncertain state of the economy or markets at the current time by indirect means. We apply this idea to seismically active regions, where the goal is to determine the current state of the fault system, and its current level of progress through the earthquake cycle. In our implementation of this idea, we use the global catalog of earthquakes, using "small" earthquakes to determine the level of hazard from "large" earthquakes in the region. Our method does not involve any model other than the idea of an earthquake cycle. Rather, we define a specific region and a specific large earthquake magnitude of interest, ensuring that we have enough data to span at least 20 or more large earthquake cycles in the region. We then compute the earthquake potential score (EPS) which is defined as the cumulative probability distribution P(nearthquakes in the region. From the count of small earthquakes since the last large earthquake, we determine the value of EPS = P(nestimate of the level of progress through the earthquake cycle in the defined region at the current time.

  6. Inferring Peak Ground Acceleration (PGA) from observed building damage and EO-derived exposure development to develop rapid loss estimates following the April 2015 Nepal earthquake.

    Science.gov (United States)

    Huyck, C. K.

    2016-12-01

    The April 25th 7.8 Gorkha earthquake in Nepal occurred in an area with very few seismic stations. Ground motions were estimated primarily by Ground Motion Prediction Equations (GMPEs) over a very large region, with a very high degree of uncertainty. Accordingly, initial fatality estimates and their distribution was highly uncertain, with a 65% chance of fatalities ranging from 1,000 to 100,000. With an aim to developing estimates of: 1) the number of buildings damaged by category (slight, moderate, extensive, complete), 2) fatalities and their distribution, and 3) rebuilding costs, researchers at ImageCat have developed a preliminary inferred Peak Ground Acceleration product in %g (PGA). The inferred PGA is determined by using observations of building collapse from the National Geospatial Agency and building exposure estimates derived from EO data to determine the percentage of buildings collapsed in key locations. The percentage of building collapse is adjusted for accuracy and cross referenced with composite building damage functions for 4 development patterns in Nepal: 1) sparsely populated, 2) rural, 3) dense development, and 4) urban development to yield an inferred PGA. Composite damage functions are derived from USGS Pager collapse fragility functions (Jaiswal et al., 2011) and are weighted by building type frequencies developed by ImageCat. The PGA is interpolated to yield a surface. An initial estimate of the fatalities based on ATC 13 (Rojan and Sharpe, 1985) using these PGA yields an estimate of: Extensively damaged or destroyed buildings: 225,000 to 450,000 Fatalities: 8,700 to 22,000, with a mean estimate of 15,700. The total number of displaced persons is estimated between 1 and 2 million. Rebuilding costs for building damage only are estimated to be between 2 and 3 billion USD. The inferred PGA product is recommended for use solely in loss estimation processes.

  7. On an outline of investigation results of earthquake damage estimation for Akita prefecture; Akitaken jishin higai sotei chosa kekka no gaiyo ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Nogoshi, M. [Akita University, Akita (Japan). College of Education

    1997-05-27

    This paper reports an outline of investigation results of earthquake damage estimation carried out in Akita Prefecture. The basic policy for this investigation consists of the following: (1) an indication on existence of a blank area in the Akita off-coast earthquake shall be viewed so importantly that a fault model is set to estimate damages; (2) because most of the earthquakes in history of Akita Prefecture are inland earthquakes with magnitude of about M=7, four earthquakes in the past shall be adopted as the set model; and (3) the central Sea of Japan earthquake in 1983 was an earthquake occurred in the Sea of Japan side and caused a great deal of damages to Akita Prefecture, and its epicenter model and damages were investigated in detail, hence these data shall be utilized in verifying the procedure and method for estimating damages studied in the present investigation. This paper reports finally estimated human damages. With an assumed earthquake as strong as the Tencho earthquake in the year of 830, more than 1000 deaths will occur in the city of Akita; with an earthquake in the scale of the Noshiro earthquake in 1694, more than 50 deaths will be counted in the city of Noshiro; one as strong as the Rikuu earthquake in 1896 will cause about 300 deaths in the cities of Yokote and Omagari, respectively; one with the scale of the 1914 Goushu earthquake will result in about 300 people to be killed in the city of Omagari and about 200 people in the city of Yuzawa; and an earthquake estimated to occur in the blank area off the Akita coast will force 33% of the residents of the Kisakata town to be evacuated from their homes. 1 fig.

  8. Estimates of source parameters of M4.9 Kharsali earthquake using waveform modelling

    Science.gov (United States)

    Paul, Ajay; Kumar, Naresh

    2010-10-01

    This paper presents the computation of time series of the 22 July 2007 M 4.9 Kharsali earthquake. It occurred close to the Main Central Thrust (MCT) where seismic gap exists. The main shock and 17 aftershocks were located by closely spaced eleven seismograph stations in a network that involved VSAT based real-time seismic monitoring. The largest aftershock of M 3.5 and other aftershocks occurred within a small volume of 4 × 4 km horizontal extent and between depths of 10 and 14 km. The values of seismic moment ( M ∘) determined using P-wave spectra and Brune's model based on f 2 spectral shape ranges from 1018 to 1023 dyne-cm. The initial aftershocks occurred at greater depth compared to the later aftershocks. The time series of ground motion have been computed for recording sites using geometric ray theory and Green's function approach. The method for computing time series consists in integrating the far-field contributions of Green's function for a number of distributed point source. The generated waveforms have been compared with the observed ones. It has been inferred that the Kharsali earthquake occurred due to a northerly dipping low angle thrust fault at a depth of 14 km taking strike N279°E, dip 14° and rake 117°. There are two regions on the fault surface which have larger slip amplitudes (asperities) and the rupture which has been considered as circular in nature initiated from the asperity at a greater depth shifting gradually upwards. The two asperities cover only 10% of the total area of the causative fault plane. However, detailed seismic imaging of these two asperities can be corroborated with structural heterogeneities associated with causative fault to understand how seismogenesis is influenced by strong or weak structural barriers in the region.

  9. Dislocation Motion and the Microphysics of Flash Heating and Weakening of Faults during Earthquakes

    Directory of Open Access Journals (Sweden)

    Elena Spagnuolo

    2016-07-01

    Full Text Available Earthquakes are the result of slip along faults and are due to the decrease of rock frictional strength (dynamic weakening with increasing slip and slip rate. Friction experiments simulating the abrupt accelerations (>>10 m/s2, slip rates (~1 m/s, and normal stresses (>>10 MPa expected at the passage of the earthquake rupture along the front of fault patches, measured large fault dynamic weakening for slip rates larger than a critical velocity of 0.01–0.1 m/s. The dynamic weakening corresponds to a decrease of the friction coefficient (defined as the ratio of shear stress vs. normal stress up to 40%–50% after few millimetres of slip (flash weakening, almost independently of rock type. The microstructural evolution of the sliding interfaces with slip may yield hints on the microphysical processes responsible for flash weakening. At the microscopic scale, the frictional strength results from the interaction of micro- to nano-scale surface irregularities (asperities which deform during fault sliding. During flash weakening, the visco-plastic and brittle work on the asperities results in abrupt frictional heating (flash heating and grain size reduction associated with mechano-chemical reactions (e.g., decarbonation in CO2-bearing minerals such as calcite and dolomite; dehydration in water-bearing minerals such as clays, serpentine, etc. and phase transitions (e.g., flash melting in silicate-bearing rocks. However, flash weakening is also associated with grain size reduction down to the nanoscale. Using focused ion beam scanning and transmission electron microscopy, we studied the micro-physical mechanisms associated with flash heating and nanograin formation in carbonate-bearing fault rocks. Experiments were conducted on pre-cut Carrara marble (99.9% calcite cylinders using a rotary shear apparatus at conditions relevant to seismic rupture propagation. Flash heating and weakening in calcite-bearing rocks is associated with a shock-like stress

  10. Ground motion in the presence of complex Topography II: Earthquake sources and 3D simulations

    Science.gov (United States)

    Hartzell, Stephen; Ramirez-Guzman, Leonardo; Meremonte, Mark; Leeds, Alena L.

    2017-01-01

    Eight seismic stations were placed in a linear array with a topographic relief of 222 m over Mission Peak in the east San Francisco Bay region for a period of one year to study topographic effects. Seventy‐two well‐recorded local earthquakes are used to calculate spectral amplitude ratios relative to a reference site. A well‐defined fundamental resonance peak is observed with individual station amplitudes following the theoretically predicted progression of larger amplitudes in the upslope direction. Favored directions of vibration are also seen that are related to the trapping of shear waves within the primary ridge dimensions. Spectral peaks above the fundamental one are also related to topographic effects but follow a more complex pattern. Theoretical predictions using a 3D velocity model and accurate topography reproduce many of the general frequency and time‐domain features of the data. Shifts in spectral frequencies and amplitude differences, however, are related to deficiencies of the model and point out the importance of contributing factors, including the shear‐wave velocity under the topographic feature, near‐surface velocity gradients, and source parameters.

  11. Simulation of strong ground motion parameters of the 1 June 2013 Gulf of Suez earthquake, Egypt

    Directory of Open Access Journals (Sweden)

    Mostafa Toni

    2017-06-01

    The results reveal that the highest values of PGA, PGV, and PGD are observed at Ras Gharib city (epicentral distance ∼ 11 km as 67 cm/s2, 2.53 cm/s, and 0.45 cm respectively for Zone A, and as 26.5 cm/s2, 1.0 cm/s, and 0.2 cm respectively for Zone B, while the lowest values of PGA, PGV, and PGD are observed at Suez city (epicentral distance ∼ 190 km as 3.0 cm/s2, 0.2 cm/s, and 0.05 cm/s respectively for Zone A, and as 1.3 cm/s2, 0.1 cm/s, and 0.024 cm respectively for Zone B. Also the highest PSA values are observed in Ras Gharib city as 200 cm/s2 and 78 cm/s2 for Zone A and Zone B respectively, while the lowest PSA values are observed in Suez city as 7 cm/s2 and 3 cm/s2 for Zone A and Zone B respectively. These results show a good agreement with the earthquake magnitude, epicentral distances, and site characterizations as well.

  12. After the damages: Lessons learned from recent earthquakes for ground-motion prediction and seismic hazard assessment (C.F. Gauss Lecture)

    Science.gov (United States)

    Cotton, Fabrice

    2017-04-01

    Recent damaging earthquakes (e.g. Japan 2011, Nepal 2014, Italy 2016) and associated ground-shaking (ground-motion) records challenge the engineering models used to quantify seismic hazard. The goal of this presentation is to present the lessons learned from these recent events and discuss their implications for ground-motion prediction and probabilistic seismic hazard assessment. The following points will be particularly addressed: 1) Recent observations clearly illustrate the dependency of ground-shaking on earthquake source related factors (e.g. fault properties and geometry, earthquake depth, directivity). The weaknesses of classical models and the impact of these factors on hazard evaluation will be analysed and quantified. 2) These observations also show that events of similar magnitude and style of faulting are producing ground-motions which are highly variable. We will analyse this variability and show that the exponential growth of recorded data give a unique opportunity to quantify regional or between-events shaking variations. Indeed, most seismic-hazard evaluations do not consider the regional specificities of earthquake or wave-propagation properties. There is little guidance in the literature on how this should be done and we will show that this challenge is interdisciplinary, as structural geology, neotectonic and tomographic images can provide key understanding of these regional variations. 3) One of the key lessons of recent earthquakes is that extreme hazard scenarios and ground-shaking are difficult to predict. In other words, we need to mobilize "scientific imagination" and define new strategies based on the latest research results to capture epistemic uncertainties and integrate them in engineering seismology projects. We will discuss these strategies and show an example of their implementation to develop new seismic hazard maps of Europe (Share and Sera FP7 projects) and Germany.

  13. Maximum Likelihood Estimation of Monocular Optical Flow Field for Mobile Robot Ego-Motion

    Directory of Open Access Journals (Sweden)

    Huajun Liu

    2016-01-01

    Full Text Available This paper presents an optimized scheme of monocular ego-motion estimation to provide location and pose information for mobile robots with one fixed camera. First, a multi-scale hyper-complex wavelet phase-derived optical flow is applied to estimate micro motion of image blocks. Optical flow computation overcomes the difficulties of unreliable feature selection and feature matching of outdoor scenes; at the same time, the multi-scale strategy overcomes the problem of road surface self-similarity and local occlusions. Secondly, a support probability of flow vector is defined to evaluate the validity of the candidate image motions, and a Maximum Likelihood Estimation (MLE optical flow model is constructed based not only on image motion residuals but also their distribution of inliers and outliers, together with their support probabilities, to evaluate a given transform. This yields an optimized estimation of inlier parts of optical flow. Thirdly, a sampling and consensus strategy is designed to estimate the ego-motion parameters. Our model and algorithms are tested on real datasets collected from an intelligent vehicle. The experimental results demonstrate the estimated ego-motion parameters closely follow the GPS/INS ground truth in complex outdoor road scenarios.

  14. Update earthquake risk assessment in Cairo, Egypt

    Science.gov (United States)

    Badawy, Ahmed; Korrat, Ibrahim; El-Hadidy, Mahmoud; Gaber, Hanan

    2017-07-01

    The Cairo earthquake (12 October 1992; m b = 5.8) is still and after 25 years one of the most painful events and is dug into the Egyptians memory. This is not due to the strength of the earthquake but due to the accompanied losses and damages (561 dead; 10,000 injured and 3000 families lost their homes). Nowadays, the most frequent and important question that should rise is "what if this earthquake is repeated today." In this study, we simulate the same size earthquake (12 October 1992) ground motion shaking and the consequent social-economic impacts in terms of losses and damages. Seismic hazard, earthquake catalogs, soil types, demographics, and building inventories were integrated into HAZUS-MH to produce a sound earthquake risk assessment for Cairo including economic and social losses. Generally, the earthquake risk assessment clearly indicates that "the losses and damages may be increased twice or three times" in Cairo compared to the 1992 earthquake. The earthquake risk profile reveals that five districts (Al-Sahel, El Basateen, Dar El-Salam, Gharb, and Madinat Nasr sharq) lie in high seismic risks, and three districts (Manshiyat Naser, El-Waily, and Wassat (center)) are in low seismic risk level. Moreover, the building damage estimations reflect that Gharb is the highest vulnerable district. The analysis shows that the Cairo urban area faces high risk. Deteriorating buildings and infrastructure make the city particularly vulnerable to earthquake risks. For instance, more than 90 % of the estimated buildings damages are concentrated within the most densely populated (El Basateen, Dar El-Salam, Gharb, and Madinat Nasr Gharb) districts. Moreover, about 75 % of casualties are in the same districts. Actually, an earthquake risk assessment for Cairo represents a crucial application of the HAZUS earthquake loss estimation model for risk management. Finally, for mitigation, risk reduction, and to improve the seismic performance of structures and assure life safety

  15. Estimating earthquake-induced failure probability and downtime of critical facilities.

    Science.gov (United States)

    Porter, Keith; Ramer, Kyle

    2012-01-01

    Fault trees have long been used to estimate failure risk in earthquakes, especially for nuclear power plants (NPPs). One interesting application is that one can assess and manage the probability that two facilities - a primary and backup - would be simultaneously rendered inoperative in a single earthquake. Another is that one can calculate the probabilistic time required to restore a facility to functionality, and the probability that, during any given planning period, the facility would be rendered inoperative for any specified duration. A large new peer-reviewed library of component damageability and repair-time data for the first time enables fault trees to be used to calculate the seismic risk of operational failure and downtime for a wide variety of buildings other than NPPs. With the new library, seismic risk of both the failure probability and probabilistic downtime can be assessed and managed, considering the facility's unique combination of structural and non-structural components, their seismic installation conditions, and the other systems on which the facility relies. An example is offered of real computer data centres operated by a California utility. The fault trees were created and tested in collaboration with utility operators, and the failure probability and downtime results validated in several ways.

  16. EARTHQUAKE RESPONSE ANALYSIS OF A VIADUCT WITH HORIZONTAL FORCE DISTRIBUTED STRUCTURE USING STRONG MOTION OBSERVED DURING THE 2011 OFF THE PACIFIC COAST OF TOHOKU EARTHQUAKE

    Science.gov (United States)

    Kataoka, Shojiro; Nagaya, Kazuhiro; Yabe, Masaaki; Matsuoka, Kazunari; Kaneko, Masahiro

    Dynamic analysis is widely used for the seismic design of the bridge with horizontal force distributed structure in recent years. There is few research on dynamic analysis of such bridges using real earthquake data. In this research, we carried out dynamic analysis using accelerograms recorded during the 2011 off the Pacific coast of Tohoku earthquake (Mw9.0). The analytical earthquake response shows a good agreement with the observed response when colliding and friction forces acted between sideblocks and shoes are taken into account.

  17. Evaluation of the conservativeness of the methodology for estimating earthquake-induced movements of fractures intersecting canisters

    Energy Technology Data Exchange (ETDEWEB)

    La Pointe, Paul R.; Cladouhos, Trenton T. [Golder Associates Inc., Las Vegas, NV (United States); Outters, Nils; Follin, Sven [Golder Grundteknik KB, Stockholm (Sweden)

    2000-04-01

    This study evaluates the parameter sensitivity and the conservativeness of the methodology outlined in TR 99-03. Sensitivity analysis focuses on understanding how variability in input parameter values impacts the calculated fracture displacements. These studies clarify what parameters play the greatest role in fracture movements, and help define critical values of these parameters in terms of canister failures. The thresholds or intervals of values that lead to a certain level of canister failure calculated in this study could be useful for evaluating future candidate sites. Key parameters include: 1. magnitude/frequency of earthquakes; 2. the distance of the earthquake from the canisters; 3. the size and aspect ratio of fractures intersecting canisters; and 4. the orientation of the fractures. The results of this study show that distance and earthquake magnitude are the most important factors, followed by fracture size. Fracture orientation is much less important. Regression relations were developed to predict induced fracture slip as a function of distance and either earthquake magnitude or slip on the earthquake fault. These regression relations were validated by using them to estimate the number of canister failures due to single damaging earthquakes at Aberg, and comparing these estimates with those presented in TR 99-03. The methodology described in TR 99-03 employs several conservative simplifications in order to devise a numerically feasible method to estimate fracture movements due to earthquakes outside of the repository over the next 100,000 years. These simplifications include: 1. fractures are assumed to be frictionless and cohesionless; 2. all energy transmitted to the fracture by the earthquake is assumed to produce elastic deformation of the fracture; no energy is diverted into fracture propagation; and 3. shielding effects of other fractures between the earthquake and the fracture are neglected. The numerical modeling effectively assumes that the

  18. Variable disparity-motion estimation based fast three-view video coding

    Science.gov (United States)

    Bae, Kyung-Hoon; Kim, Seung-Cheol; Hwang, Yong Seok; Kim, Eun-Soo

    2009-02-01

    In this paper, variable disparity-motion estimation (VDME) based 3-view video coding is proposed. In the encoding, key-frame coding (KFC) based motion estimation and variable disparity estimation (VDE) for effectively fast three-view video encoding are processed. These proposed algorithms enhance the performance of 3-D video encoding/decoding system in terms of accuracy of disparity estimation and computational overhead. From some experiments, stereo sequences of 'Pot Plant' and 'IVO', it is shown that the proposed algorithm's PSNRs is 37.66 and 40.55 dB, and the processing time is 0.139 and 0.124 sec/frame, respectively.

  19. The range split-spectrum method for ionosphere estimation applied to the 2008 Kyrgyzstan earthquake

    Science.gov (United States)

    Gomba, Giorgio; Eineder, Michael

    2015-04-01

    L-band remote sensing systems, like the future Tandem-L mission, are disrupted by the ionized upper part of the atmosphere called ionosphere. The ionosphere is a region of the upper atmosphere composed by gases that are ionized by the solar radiation. The extent of the effects induced on a SAR measurement is given by the electron density integrated along the radio-wave paths and on its spatial variations. The main effect of the ionosphere on microwaves is to cause an additional delay, which introduces a phase difference between SAR measurements modifying the interferometric phase. The objectives of the Tandem-L mission are the systematic monitoring of dynamic Earth processes like Earth surface deformations, vegetation structure, ice and glacier changes and ocean surface currents. The scientific requirements regarding the mapping of surface deformation due to tectonic processes, earthquakes, volcanic cycles and anthropogenic factors demand deformation measurements; namely one, two or three dimensional displacement maps with resolutions of a few hundreds of meters and accuracies of centimeter to millimeter level. Ionospheric effects can make impossible to produce deformation maps with such accuracy and must therefore be estimated and compensated. As an example of this process, the implementation of the range split-spectrum method proposed in [1,2] will be presented and applied to an example dataset. The 2008 Kyrgyzstan Earthquake of October 5 is imaged by an ALOS PALSAR interferogram; a part from the earthquake, many fringes due to strong ionospheric variations can also be seen. The compensated interferogram shows how the ionosphere-related fringes were successfully estimated and removed. [1] Rosen, P.A.; Hensley, S.; Chen, C., "Measurement and mitigation of the ionosphere in L-band Interferometric SAR data," Radar Conference, 2010 IEEE , vol., no., pp.1459,1463, 10-14 May 2010 [2] Brcic, R.; Parizzi, A.; Eineder, M.; Bamler, R.; Meyer, F., "Estimation and

  20. Comparison between scaling law and nonparametric Bayesian estimate for the recurrence time of strong earthquakes

    Science.gov (United States)

    Rotondi, R.

    2009-04-01

    According to the unified scaling theory the probability distribution function of the recurrence time T is a scaled version of a base function and the average value of T can be used as a scale parameter for the distribution. The base function must belong to the scale family of distributions: tested on different catalogues and for different scale levels, for Corral (2005) the (truncated) generalized gamma distribution is the best model, for German (2006) the Weibull distribution. The scaling approach should overcome the difficulty of estimating distribution functions over small areas but theorical limitations and partial instability of the estimated distributions have been pointed out in the literature. Our aim is to analyze the recurrence time of strong earthquakes that occurred in the Italian territory. To satisfy the hypotheses of independence and identical distribution we have evaluated the times between events that occurred in each area of the Database of Individual Seismogenic Sources and then we have gathered them by eight tectonically coherent regions, each of them dominated by a well characterized geodynamic process. To solve problems like: paucity of data, presence of outliers and uncertainty in the choice of the functional expression for the distribution of t, we have followed a nonparametric approach (Rotondi (2009)) in which: (a) the maximum flexibility is obtained by assuming that the probability distribution is a random function belonging to a large function space, distributed as a stochastic process; (b) nonparametric estimation method is robust when the data contain outliers; (c) Bayesian methodology allows to exploit different information sources so that the model fitting may be good also to scarce samples. We have compared the hazard rates evaluated through the parametric and nonparametric approach. References Corral A. (2005). Mixing of rescaled data and Bayesian inference for earthquake recurrence times, Nonlin. Proces. Geophys., 12, 89

  1. Using needle orientation sensing as surrogate signal for respiratory motion estimation in percutaneous interventions.

    Science.gov (United States)

    Abayazid, Momen; Kato, Takahisa; Silverman, Stuart G; Hata, Nobuhiko

    2018-01-01

    To develop and evaluate an approach to estimate the respiratory-induced motion of lesions in the chest and abdomen. The proposed approach uses the motion of an initial reference needle inserted into a moving organ to estimate the lesion (target) displacement that is caused by respiration. The needles position is measured using an inertial measurement unit (IMU) sensor externally attached to the hub of an initially placed reference needle. Data obtained from the IMU sensor and the target motion are used to train a learning-based approach to estimate the position of the moving target. An experimental platform was designed to mimic respiratory motion of the liver. Liver motion profiles of human subjects provided inputs to the experimental platform. Variables including the insertion angle, target depth, target motion velocity and target proximity to the reference needle were evaluated by measuring the error of the estimated target position and processing time. The mean error of estimation of the target position ranged between 0.86 and 1.29 mm. The processing maximum training and testing time was 5 ms which is suitable for real-time target motion estimation using the needle position sensor. The external motion of an initially placed reference needle inserted into a moving organ can be used as a surrogate, measurable and accessible signal to estimate in real-time the position of a moving target caused by respiration; this technique could then be used to guide the placement of subsequently inserted needles directly into the target.

  2. Real Time Earthquake Information System in Japan

    Science.gov (United States)

    Doi, K.; Kato, T.

    2003-12-01

    An early earthquake notification system in Japan had been developed by the Japan Meteorological Agency (JMA) as a governmental organization responsible for issuing earthquake information and tsunami forecasts. The system was primarily developed for prompt provision of a tsunami forecast to the public with locating an earthquake and estimating its magnitude as quickly as possible. Years after, a system for a prompt provision of seismic intensity information as indices of degrees of disasters caused by strong ground motion was also developed so that concerned governmental organizations can decide whether it was necessary for them to launch emergency response or not. At present, JMA issues the following kinds of information successively when a large earthquake occurs. 1) Prompt report of occurrence of a large earthquake and major seismic intensities caused by the earthquake in about two minutes after the earthquake occurrence. 2) Tsunami forecast in around three minutes. 3) Information on expected arrival times and maximum heights of tsunami waves in around five minutes. 4) Information on a hypocenter and a magnitude of the earthquake, the seismic intensity at each observation station, the times of high tides in addition to the expected tsunami arrival times in 5-7 minutes. To issue information above, JMA has established; - An advanced nationwide seismic network with about 180 stations for seismic wave observation and about 3,400 stations for instrumental seismic intensity observation including about 2,800 seismic intensity stations maintained by local governments, - Data telemetry networks via landlines and partly via a satellite communication link, - Real-time data processing techniques, for example, the automatic calculation of earthquake location and magnitude, the database driven method for quantitative tsunami estimation, and - Dissemination networks, via computer-to-computer communications and facsimile through dedicated telephone lines. JMA operationally

  3. MuSeSe - A multisensor armchair for unobtrusive vital sign estimation and motion artifact analysis.

    Science.gov (United States)

    Antink, Christoph Hoog; Leonhardt, Steffen; Schulz, Florian; Walter, Marian

    2017-07-01

    Unobtrusive vital sign estimation with sensors integrated into objects of everyday living can substantially advance the field of remote monitoring. At the same time, motion artifacts cause severe problems and have to be dealt with. Here, the fusion of multimodal sensor data is a promising approach. In this paper, we present an armchair equipped with capacitively coupled electrocardiogram, two types of ballistocardiographic sensors, photoplethysmographic and two high-frequency impedance sensors. In addition, a video-based sensor for motion analysis is integrated. Using a defined motion protocol, the feasibility of the system is demonstrated in a self-experimentation. Moreover, the influence of different movements on different modalities is analyzed. Finally, robust beat-to-beat interval estimation demonstrates the benefits of multimodal sensor fusion for vital sign estimation in the presence of motion artifacts.

  4. Re-estimation of Motion and Reconstruction for Distributed Video Coding

    DEFF Research Database (Denmark)

    Luong, Huynh Van; Raket, Lars Lau; Forchhammer, Søren

    2014-01-01

    Transform domain Wyner-Ziv (TDWZ) video coding is an efficient approach to distributed video coding (DVC), which provides low complexity encoding by exploiting the source statistics at the decoder side. The DVC coding efficiency depends mainly on side information and noise modeling. This paper...... proposes a motion re-estimation technique based on optical flow to improve side information and noise residual frames by taking partially decoded information into account. To improve noise modeling, a noise residual motion re-estimation technique is proposed. Residual motion compensation with motion...... re-estimation (MORE) are integrated in the SING TDWZ codec, which uses side information and noise learning. For Wyner-Ziv frames using GOP size 2, the MORE codec significantly improves the TDWZ coding efficiency with an average (Bjøntegaard) PSNR improvement of 2.5 dB and up to 6 dB improvement...

  5. Motion Estimation Using the Firefly Algorithm in Ultrasonic Image Sequence of Soft Tissue

    Directory of Open Access Journals (Sweden)

    Chih-Feng Chao

    2015-01-01

    Full Text Available Ultrasonic image sequence of the soft tissue is widely used in disease diagnosis; however, the speckle noises usually influenced the image quality. These images usually have a low signal-to-noise ratio presentation. The phenomenon gives rise to traditional motion estimation algorithms that are not suitable to measure the motion vectors. In this paper, a new motion estimation algorithm is developed for assessing the velocity field of soft tissue in a sequence of ultrasonic B-mode images. The proposed iterative firefly algorithm (IFA searches for few candidate points to obtain the optimal motion vector, and then compares it to the traditional iterative full search algorithm (IFSA via a series of experiments of in vivo ultrasonic image sequences. The experimental results show that the IFA can assess the vector with better efficiency and almost equal estimation quality compared to the traditional IFSA method.

  6. Linear Motion Blur Parameter Estimation in Noisy Images Using Fuzzy Sets and Power Spectrum

    Directory of Open Access Journals (Sweden)

    Moghaddam Mohsen Ebrahimi

    2007-01-01

    Full Text Available Motion blur is one of the most common causes of image degradation. Restoration of such images is highly dependent on accurate estimation of motion blur parameters. To estimate these parameters, many algorithms have been proposed. These algorithms are different in their performance, time complexity, precision, and robustness in noisy environments. In this paper, we present a novel algorithm to estimate direction and length of motion blur, using Radon transform and fuzzy set concepts. The most important advantage of this algorithm is its robustness and precision in noisy images. This method was tested on a wide range of different types of standard images that were degraded with different directions (between and and motion lengths (between and pixels. The results showed that the method works highly satisfactory for SNR dB and supports lower SNR compared with other algorithms.

  7. Motion Estimation Utilizing Range Detection-Enhanced Visual Odometry

    Science.gov (United States)

    Friend, Paul Russell (Inventor); Chen, Qi (Inventor); Chang, Hong (Inventor); Morris, Daniel Dale (Inventor); Graf, Jodi Seaborn (Inventor)

    2016-01-01

    A motion determination system is disclosed. The system may receive a first and a second camera image from a camera, the first camera image received earlier than the second camera image. The system may identify corresponding features in the first and second camera images. The system may receive range data comprising at least one of a first and a second range data from a range detection unit, corresponding to the first and second camera images, respectively. The system may determine first positions and the second positions of the corresponding features using the first camera image and the second camera image. The first positions or the second positions may be determined by also using the range data. The system may determine a change in position of the machine based on differences between the first and second positions, and a VO-based velocity of the machine based on the determined change in position.

  8. Can landslide-prone slope response to strong shaking be inferred from weak motion data? First answer from 2009 L'Aquila earthquake

    Science.gov (United States)

    Del Gaudio, Vincenzo; Wasowski, Janusz

    2010-05-01

    The complexity of factors controlling the dynamic response of marginally stable slopes and the scarcity of direct ground motion recordings acquired on landslide-prone areas make it difficult to evaluate the role of site response in seismic landslide triggering. A long term accelerometric monitoring, conducted at a tectonically and geomorphologically active site of Abruzzo in Central Italy (Caramanico Terme) has provided interesting evidence of amplification with a pronounced directional character parallel to the local slope direction on a landslide consisting of colluvial deposits overlying mudstone substratum. However, until 2008, these observations were based only on recordings of events of low to moderate magnitude. The 6.3 Mw earthquake that on 6 April 2009 hit L'Aquila, 60 km from Caramanico, allowed to test whether these previous findings hold true also for the landslide site response at higher shaking levels. The comparison of the 2009 mainshock recordings of the accelerometric station located on the landslide (CAR2) to those from two nearby stations, one sited on soft soils similar to landslide substratum (CAR1) and the other on colluvial material (CAR5), showed relative amplifications (in terms of peak horizontal acceleration PHA) very close to the average values estimated from smaller events (about 1.5 and 1.0 relatively to CAR1 and CAR5, respectively). The similarity of PHA observed on colluvium, regardless of its involvement in landsliding, confirmed that, in terms of total shaking energy, the main factor controlling amplification is the impedance contrast between colluvium and mudstone substratum. The comparison between the station on landslide and a reference station on rock (CAR4) showed a relative amplification increasing with magnitude, probably because of the stronger response of the rock site to the higher frequencies prevailing in wavetrains coming from nearby small sources. This suggests that in such cases amplification assessments based on

  9. Simultaneous estimation of earthquake source parameters and crustal Q value from broadband data of selected aftershocks of the 2001 M w 7.7 Bhuj earthquake

    Science.gov (United States)

    Saha, A.; Lijesh, S.; Mandal, P.

    2012-12-01

    This paper presents the simultaneous estimation of source parameters and crustal Q values for small to moderate-size aftershocks ( M w 2.1-5.1) of the M_{w }7.7 2001 Bhuj earthquake. The horizontal-component S-waves of 144 well located earthquakes (2001-2010) recorded at 3-10 broadband seismograph sites in the Kachchh Seismic Zone, Gujarat, India are analyzed, and their seismic corner frequencies, long-period spectral levels and crustal Q values are simultaneously estimated by inverting the horizontal component of the S-wave displacement spectrum using the Levenberg-Marquardt nonlinear inversion technique, wherein the inversion scheme is formulated based on the ω-square source spectral model. The static stress drops (Δ σ) are then calculated from the corner frequency and seismic moment. The estimated source parameters suggest that the seismic moment ( M 0) and source radius ( r) of aftershocks are varying from 1.12 × 1012 to 4.00 × 1016 N-m and 132.57 to 513.20 m, respectively. Whereas, estimated stress drops (Δ σ) and multiplicative factor ( E mo) values range from 0.01 to 20.0 MPa and 1.05 to 3.39, respectively. The corner frequencies are found to be ranging from 2.36 to 8.76 Hz. The crustal S-wave quality factor varies from 256 to 1882 with an average of 840 for the Kachchh region, which agrees well with the crustal Q value of the seismically active New Madrid region, USA. Our estimated stress drop values are quite large compared to the other similar size Indian intraplate earthquakes, which can be attributed to the presence of crustal mafic intrusives and aqueous fluids in the lower crust as revealed by the earlier tomographic study of the region.

  10. Estimating Fallout Building Attributes from Architectural Features and Global Earthquake Model (GEM) Building Descriptions

    Energy Technology Data Exchange (ETDEWEB)

    Dillon, Michael B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kane, Staci R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-03-01

    A nuclear explosion has the potential to injure or kill tens to hundreds of thousands (or more) of people through exposure to fallout (external gamma) radiation. Existing buildings can protect their occupants (reducing fallout radiation exposures) by placing material and distance between fallout particles and individuals indoors. Prior efforts have determined an initial set of building attributes suitable to reasonably assess a given building’s protection against fallout radiation. The current work provides methods to determine the quantitative values for these attributes from (a) common architectural features and data and (b) buildings described using the Global Earthquake Model (GEM) taxonomy. These methods will be used to improve estimates of fallout protection for operational US Department of Defense (DoD) and US Department of Energy (DOE) consequence assessment models.

  11. Dual Respiratory and Cardiac Motion Estimation in PET Imaging: Methods Design and Quantitative Evaluation.

    Science.gov (United States)

    Feng, Tao; Wang, Jizhe; Tsui, Benjamin M W

    2018-02-05

    The goal of this study is to develop and evaluate four post-reconstruction respiratory and cardiac (R&C) motion vector field (MVF) estimation methods for cardiac 4D PET data. In Method 1, the dual R&C motions were estimated directly from the dual R&C gated images. In Methods 2, respiratory motion (RM) and cardiac motion (CM) were separately estimated from the respiratory gated only and cardiac gated only images. The effects of RM on CM estimation were modeled in Method 3 by applying an image-based RM correction on the cardiac gated images before CM estimation, the effects of CM on RM estimation were neglected. Methods 4 iteratively models the mutual effects of RM and CM during dual R&C motion estimations. Realistic simulation data were generated for quantitative evaluation of four methods. Almost noise-free PET projection data were generated from the 4D XCAT phantom with realistic R&C MVF using Monte Carlo simulation. Poisson noise was added to the scaled projection data to generate additional datasets of 2 more different noise levels. All the projection data were reconstructed using a 4D image reconstruction method to obtain dual R&C gated images. The four dual R&C MVF estimation methods were applied to the dual R&C gated images and the accuracy of motion estimation was quantitatively evaluated using the root mean square error (RMSE) of the estimated MVFs. Results show that among the 4 estimation methods, Methods 2 performed the worst for noise-free case while Method 1 performed the worst for noisy cases in terms of quantitative accuracy of the estimated MVF. Methods 4 and 3 showed comparable results and achieved RMSE lower by up to 35% than that in Method 1 for noisy cases. In conclusion, we have developed and evaluated 4 different post-reconstruction R&C MVF estimation methods for use in 4D PET imaging. Comparison of the performance of four methods on simulated data indicates separate R&C estimation with modeling of RM before CM estimation (Method 3) to be the

  12. Estimate of airborne release of plutonium from Babcock and Wilcox plant as a result of severe wind hazard and earthquake

    Energy Technology Data Exchange (ETDEWEB)

    Mishima, J.; Schwendiman, L.C.; Ayer, J.E.

    1978-10-01

    As part of an interdisciplinary study to evaluate the potential radiological consequences of wind hazard and earthquake upon existing commercial mixed oxide fuel fabrication plants, the potential mass airborne releases of plutonium (source terms) from such events are estimated. The estimated souce terms are based upon the fraction of enclosures damaged to three levels of severity (crush, puncture penetrate, and loss of external filter, in order of decreasing severity), called damage ratio, and the airborne release if all enclosures suffered that level of damage. The discussion of damage scenarios and source terms is divided into wind hazard and earthquake scenarios in order of increasing severity. The largest airborne releases from the building were for cases involving the catastrophic collapse of the roof over the major production areas--wind hazard at 110 mph and earthquakes with peak ground accelerations of 0.20 to 0.29 g. Wind hazards at higher air velocities and earthquakes with higher ground acceleration do not result in significantly greater source terms. The source terms were calculated as additional mass of respirable particles released with time up to 4 days; and, under these assumptions, approximately 98% of the mass of material of concern is made airborne from 2 h to 4 days after the event. The overall building source terms from the damage scenarios evaluated are shown in a table. The contribution of individual areas to the overall building source term is presented in order of increasing severity for wind hazard and earthquake.

  13. Different motion cues are used to estimate time-to-arrival for frontoparallel and looming trajectories

    Science.gov (United States)

    Calabro, Finnegan J.; Beardsley, Scott A.; Vaina, Lucia M.

    2012-01-01

    Estimation of time-to-arrival for moving objects is critical to obstacle interception and avoidance, as well as to timing actions such as reaching and grasping moving objects. The source of motion information that conveys arrival time varies with the trajectory of the object raising the question of whether multiple context-dependent mechanisms are involved in this computation. To address this question we conducted a series of psychophysical studies to measure observers’ performance on time-to-arrival estimation when object trajectory was specified by angular motion (“gap closure” trajectories in the frontoparallel plane), looming (colliding trajectories, TTC) or both (passage courses, TTP). We measured performance of time-to-arrival judgments in the presence of irrelevant motion, in which a perpendicular motion vector was added to the object trajectory. Data were compared to models of expected performance based on the use of different components of optical information. Our results demonstrate that for gap closure, performance depended only on the angular motion, whereas for TTC and TTP, both angular and looming motion affected performance. This dissociation of inputs suggests that gap closures are mediated by a separate mechanism than that used for the detection of time-to-collision and time-to-passage. We show that existing models of TTC and TTP estimation make systematic errors in predicting subject performance, and suggest that a model which weights motion cues by their relative time-to-arrival provides a better account of performance. PMID:22056519

  14. Onboard sea state estimation based on measured ship motions

    DEFF Research Database (Denmark)

    Nielsen, Ulrik Dam; Stredulinsky, David C.

    2011-01-01

    It is possible to obtain estimates of the sea state at the specific position of an advancing vessel by processing measurements of the vessel’s wave-induced responses. The analogy to a wave rider buoy is clear, although the situation of an advancing ship is more complex due to forward speed. The p...

  15. Understanding earthquake hazards in urban areas - Evansville Area Earthquake Hazards Mapping Project

    Science.gov (United States)

    Boyd, Oliver S.

    2012-01-01

    The region surrounding Evansville, Indiana, has experienced minor damage from earthquakes several times in the past 200 years. Because of this history and the proximity of Evansville to the Wabash Valley and New Madrid seismic zones, there is concern among nearby communities about hazards from earthquakes. Earthquakes currently cannot be predicted, but scientists can estimate how strongly the ground is likely to shake as a result of an earthquake and are able to design structures to withstand this estimated ground shaking. Earthquake-hazard maps provide one way of conveying such information and can help the region of Evansville prepare for future earthquakes and reduce earthquake-caused loss of life and financial and structural loss. The Evansville Area Earthquake Hazards Mapping Project (EAEHMP) has produced three types of hazard maps for the Evansville area: (1) probabilistic seismic-hazard maps show the ground motion that is expected to be exceeded with a given probability within a given period of time; (2) scenario ground-shaking maps show the expected shaking from two specific scenario earthquakes; (3) liquefaction-potential maps show how likely the strong ground shaking from the scenario earthquakes is to produce liquefaction. These maps complement the U.S. Geological Survey's National Seismic Hazard Maps but are more detailed regionally and take into account surficial geology, soil thickness, and soil stiffness; these elements greatly affect ground shaking.

  16. Bias reduction for stereo based motion estimation with applications to large scale visual odometry

    NARCIS (Netherlands)

    Dubbelman, G.; Groen, F.C.A.

    2009-01-01

    This contribution addresses the problem of bias in stereo based motion estimation. Using a biased estimator within a visual-odometry system will cause significant drift on large trajectories. This drift is often minimized by exploiting auxiliary sensors, (semi-)global optimization or loop-closing.

  17. Estimation of earthquake source parameters in the Kachchh seismic zone, Gujarat, India, using three component S-wave spectra

    Science.gov (United States)

    Nagamani, Durgada; Mandal, Prantik

    2017-07-01

    Earthquake source parameters and crustal Q0 values for the 138 selected local events of (Mw{:}2.5{-}4.4) the 2001 Bhuj earthquake sequence have been computed through inversion modelling of S-waves from three-component broadband seismometer data. SEISAN software has been used to locate the identified local earthquakes, which were recorded at least three or more stations of the Kachchh seismological network. Three component spectra of S-wave are being inverted by using the Levenberg-Marquardt non-linear inversion technique, wherein the inversion scheme is formulated based on ω 2 source model. SAC Software (seismic analysis code) is being utilized for calculating three-component displacement and velocity spectra of S-wave. The displacement spectra are used for estimating corner frequency (in Hz) and long period spectral level (in nm-s). These two parameters play a key role in estimating earthquake source parameters. The crustal {Q}0 values have been computed simultaneously for each component of three-component broadband seismograph. The estimated seismic moment (M0) and source radius ( r) using S-wave spectra range from 7.03E+12 to 5.36E+15 N-m and 178.56 to 565.21 m, respectively. The corner frequencies for S-wave vary from 3.025 to 7.425 Hz. We also estimated the radiated energy (ES) using velocity spectra, which is varying from 2.76E+06 to 4.07E+11 Joules. The estimated apparent stress drop and static stress drop values range from 0.01 to 2.56 and 0.53 to 36.79 MPa, respectively. Our study also reveals that estimated Q0 values vary from 119.0 to 7229.5, with an average Q0 value of 701. Another important parameter, by which the earthquake rupture process can be recognized, is Zuniga parameter. It suggests that most of the Kachchh events follow the frictional overshoot model. Our estimated static stress drop values are higher than the apparent stress drop values. And the stress drop values are quite larger for intraplate earthquakes than the interplate earthquakes.

  18. Using structures of the August 24, 2016 Amatrice earthquake affected area as seismoscopes for assessing ground motion characteristics and parameters of the main shock and its largest aftershocks

    Science.gov (United States)

    Carydis, Panayotis; Lekkas, Efthymios; Mavroulis, Spyridon

    2017-04-01

    On August 24, 2016 an Mw 6.0 earthquake struck Central Apennines (Italy) resulting in 299 fatalities, 388 injuries and about 3000 homeless in Amatrice wider area. Normal faulting surface ruptures along the western slope of Mt Vettore along with provided focal mechanisms demonstrated a NW-SE striking and SE dipping causative normal fault. The dominant building types in the affected area are unreinforced masonry (URM) and reinforced concrete (RC) buildings. Based on our macroseismic survey in the affected area immediately after the earthquake, RC buildings suffered non-structural damage including horizontal cracking of infill and internal partition walls, detachment of infill walls from the surrounding RC frame and detachment of large plaster pieces from infill walls as well as structural damage comprising soft story failure, symmetrical buckling of rods, compression damage at midheight of columns and bursting of over-stressed columns resulting in partial or total collapse. Damage in RC buildings was due to poor quality of concrete, inadequacy of reinforcement, inappropriate foundation close to the edge of slopes leading to differential settlements, poor workmanship and the destructive effect of vertical ground motions. Damage in URM buildings ranged from cracks and detachment of large plaster pieces from load-bearing walls to destruction due to poor workmanship with randomly placed materials bound by low-strength mortars, the effect of the vertical ground motion, inadequate repair and/or strengthening after previous earthquakes as well as inadequate interventions, additions and extensions to older URM buildings. During field surveying, the authors had the opportunity to observe damage induced not only by the main shock but also by its largest aftershocks (Mw 4.5-5.3) during the first three days of the aftershock sequence (August 24-26). Bearing in mind that: (a) soil conditions in foundations of the affected villages were more or less similar, (b) building damage

  19. Motion

    CERN Document Server

    Graybill, George

    2007-01-01

    Take the mystery out of motion. Our resource gives you everything you need to teach young scientists about motion. Students will learn about linear, accelerating, rotating and oscillating motion, and how these relate to everyday life - and even the solar system. Measuring and graphing motion is easy, and the concepts of speed, velocity and acceleration are clearly explained. Reading passages, comprehension questions, color mini posters and lots of hands-on activities all help teach and reinforce key concepts. Vocabulary and language are simplified in our resource to make them accessible to str

  20. A Particle Filter Approach to Respiratory Motion Estimation in Nuclear Medicine Imaging

    Science.gov (United States)

    Rahni, A. A. Abd.; Lewis, E.; Guy, M. J.; Goswami, B.; Wells, K.

    2011-10-01

    With the continual improvement in spatial resolution of Nuclear Medicine (NM) scanners, it has become increasingly important to accurately compensate for patient motion during image acquisition. Respiratory motion produced by normal lung ventilation is a major source of artefacts in NM emission imaging that can affect large parts of the abdominal thoracic cavity. As such, a particle filter (PF) is proposed as a powerful method for motion correction in emission imaging which can successfully account for previously unseen motion. This paper explores a basic PF approach and demonstrates that it is possible to estimate temporally non-stationary motion using training data consisting of only a single respiratory cycle. Evaluation using the XCAT phantom suggests that the PF is a highly promising approach, and can appropriately handle the complex data that arises in clinical situations.

  1. 4D modeling and estimation of respiratory motion for radiation therapy

    CERN Document Server

    Lorenz, Cristian

    2013-01-01

    Respiratory motion causes an important uncertainty in radiotherapy planning of the thorax and upper abdomen. The main objective of radiation therapy is to eradicate or shrink tumor cells without damaging the surrounding tissue by delivering a high radiation dose to the tumor region and a dose as low as possible to healthy organ tissues. Meeting this demand remains a challenge especially in case of lung tumors due to breathing-induced tumor and organ motion where motion amplitudes can measure up to several centimeters. Therefore, modeling of respiratory motion has become increasingly important in radiation therapy. With 4D imaging techniques spatiotemporal image sequences can be acquired to investigate dynamic processes in the patient’s body. Furthermore, image registration enables the estimation of the breathing-induced motion and the description of the temporal change in position and shape of the structures of interest by establishing the correspondence between images acquired at different phases of the br...

  2. Building damage concentrated in Longtoushan town during the 2014 Ms. 6.5 Ludian earthquake, Yunnan, China: examination of cause and implications based on ground motion and vulnerability analyses

    Science.gov (United States)

    Wang, Xin; Kurahashi, Susumu; Wu, Hao; Si, Hongjun; Ma, Qiang; Dang, Ji; Tao, Dongwang; Feng, Jiwei; Irikura, Kojiro

    2017-09-01

    Though the 2014 Ludian Earthquake had only a moderate magnitude (Ms 6.5), high-level ground motions of almost 1 g occurred at Longtoushan Town (seismic station 53LLT), which located near the intersection of a conjugate-shaped seismogenic fault. The building damages on the pluvial fan and the river terrace at Longtoushan was clearly different. In order to examine the generation of the large acceleration at 53LLT, the focal mechanisms and the rupture processes of the conjugate-shaped seismogenic fault were determined. We found that there were two continuous impulsive waves in the records of 53LLT that were generated from two different faults, the Baogunao fault and the Xiaohe fault, respectively. Site effects on the pluvial fan and the river terrace at Longtoushan Town and their relations to different building damages were examined. We found that the predominant period at the pluvial fan was about 0.25 s, close to the fundamental natural period of multi-story confined masonry buildings. Ground motions on the pluvial fan and the river terrace were simulated through convolving synthesized bedrock motions with the transfer functions, which were analyzed using the one-dimensional underground velocity structures identified from H/V spectral ratios of ambient noise. Building collapse ratios (CRs) are estimated based on the vulnerability function of the 2008 Wenchuan Earthquake and are compared with the observed values. We found that the observed building CRs on the pluvial fan are much higher than the estimated values. High-level ground shaking that is far beyond the design level was a reason for serious building damage.

  3. Influence of Lithostatic Stress on Earthquake Stress Drops in North America

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Earthquake stress drop is a critical parameter for estimating seismic hazard. This parameter can have a strong effect on ground motion amplitudes above ~1Hz and is...

  4. The energy radiated by the 26 December 2004 Sumatra-Andaman earthquake estimated from 10-minute P-wave windows

    Science.gov (United States)

    Choy, G.L.; Boatwright, J.

    2007-01-01

    The rupture process of the Mw 9.1 Sumatra-Andaman earthquake lasted for approximately 500 sec, nearly twice as long as the teleseismic time windows between the P and PP arrival times generally used to compute radiated energy. In order to measure the P waves radiated by the entire earthquake, we analyze records that extend from the P-wave to the S-wave arrival times from stations at distances ?? >60??. These 8- to 10-min windows contain the PP, PPP, and ScP arrivals, along with other multiply reflected phases. To gauge the effect of including these additional phases, we form the spectral ratio of the source spectrum estimated from extended windows (between TP and TS) to the source spectrum estimated from normal windows (between TP and TPP). The extended windows are analyzed as though they contained only the P-pP-sP wave group. We analyze four smaller earthquakes that occurred in the vicinity of the Mw 9.1 mainshock, with similar depths and focal mechanisms. These smaller events range in magnitude from an Mw 6.0 aftershock of 9 January 2005 to the Mw 8.6 Nias earthquake that occurred to the south of the Sumatra-Andaman earthquake on 28 March 2005. We average the spectral ratios for these four events to obtain a frequency-dependent operator for the extended windows. We then correct the source spectrum estimated from the extended records of the 26 December 2004 mainshock to obtain a complete or corrected source spectrum for the entire rupture process (???600 sec) of the great Sumatra-Andaman earthquake. Our estimate of the total seismic energy radiated by this earthquake is 1.4 ?? 1017 J. When we compare the corrected source spectrum for the entire earthquake to the source spectrum from the first ???250 sec of the rupture process (obtained from normal teleseismic windows), we find that the mainshock radiated much more seismic energy in the first half of the rupture process than in the second half, especially over the period range from 3 sec to 40 sec.

  5. Robust Parallel Motion Estimation and Mapping with Stereo Cameras in Underground Infrastructure

    Science.gov (United States)

    Liu, Chun; Li, Zhengning; Zhou, Yuan

    2016-06-01

    Presently, we developed a novel robust motion estimation method for localization and mapping in underground infrastructure using a pre-calibrated rigid stereo camera rig. Localization and mapping in underground infrastructure is important to safety. Yet it's also nontrivial since most underground infrastructures have poor lighting condition and featureless structure. Overcoming these difficulties, we discovered that parallel system is more efficient than the EKF-based SLAM approach since parallel system divides motion estimation and 3D mapping tasks into separate threads, eliminating data-association problem which is quite an issue in SLAM. Moreover, the motion estimation thread takes the advantage of state-of-art robust visual odometry algorithm which is highly functional under low illumination and provides accurate pose information. We designed and built an unmanned vehicle and used the vehicle to collect a dataset in an underground garage. The parallel system was evaluated by the actual dataset. Motion estimation results indicated a relative position error of 0.3%, and 3D mapping results showed a mean position error of 13cm. Off-line process reduced position error to 2cm. Performance evaluation by actual dataset showed that our system is capable of robust motion estimation and accurate 3D mapping in poor illumination and featureless underground environment.

  6. ROBUST PARALLEL MOTION ESTIMATION AND MAPPING WITH STEREO CAMERAS IN UNDERGROUND INFRASTRUCTURE

    Directory of Open Access Journals (Sweden)

    C. Liu

    2016-06-01

    Full Text Available Presently, we developed a novel robust motion estimation method for localization and mapping in underground infrastructure using a pre-calibrated rigid stereo camera rig. Localization and mapping in underground infrastructure is important to safety. Yet it’s also nontrivial since most underground infrastructures have poor lighting condition and featureless structure. Overcoming these difficulties, we discovered that parallel system is more efficient than the EKF-based SLAM approach since parallel system divides motion estimation and 3D mapping tasks into separate threads, eliminating data-association problem which is quite an issue in SLAM. Moreover, the motion estimation thread takes the advantage of state-of-art robust visual odometry algorithm which is highly functional under low illumination and provides accurate pose information. We designed and built an unmanned vehicle and used the vehicle to collect a dataset in an underground garage. The parallel system was evaluated by the actual dataset. Motion estimation results indicated a relative position error of 0.3%, and 3D mapping results showed a mean position error of 13cm. Off-line process reduced position error to 2cm. Performance evaluation by actual dataset showed that our system is capable of robust motion estimation and accurate 3D mapping in poor illumination and featureless underground environment.

  7. EFFICIENT BLOCK MATCHING ALGORITHMS FOR MOTION ESTIMATION IN H.264/AVC

    Directory of Open Access Journals (Sweden)

    P. Muralidhar

    2015-02-01

    Full Text Available In Scalable Video Coding (SVC, motion estimation and inter-layer prediction play an important role in elimination of temporal and spatial redundancies between consecutive layers. This paper evaluates the performance of widely accepted block matching algorithms used in various video compression standards, with emphasis on the performance of the algorithms for a didactic scalable video codec. Many different implementations of Fast Motion Estimation Algorithms have been proposed to reduce motion estimation complexity. The block matching algorithms have been analyzed with emphasis on Peak Signal to Noise Ratio (PSNR and computations using MATLAB. In addition to the above comparisons, a survey has been done on Spiral Search Motion Estimation Algorithms for Video Coding. A New Modified Spiral Search (NMSS motion estimation algorithm has been proposed with lower computational complexity. The proposed algorithm achieves 72% reduction in computation with a minimal (<1dB reduction in PSNR. A brief introduction to the entire flow of video compression H.264/SVC is also presented in this paper.

  8. Is acceleration used for ocular pursuit and spatial estimation during prediction motion?

    Directory of Open Access Journals (Sweden)

    Simon J Bennett

    Full Text Available Here we examined ocular pursuit and spatial estimation in a linear prediction motion task that emphasized extrapolation of occluded accelerative object motion. Results from the ocular response up to occlusion showed that there was evidence in the eye position, velocity and acceleration data that participants were attempting to pursue the moving object in accord with the veridical motion properties. They then attempted to maintain ocular pursuit of the randomly-ordered accelerative object motion during occlusion but this was not ideal, and resulted in undershoot of eye position and velocity at the moment of object reappearance. In spatial estimation there was a general bias, with participants less likely to report object reappearance being behind than ahead of the expected position. In addition, participants' spatial estimation did not take into account the effects of object acceleration. Logistic regression indicated that spatial estimation was best predicted for the majority of participants by the difference between actual object reappearance position and an extrapolation based on pre-occlusion velocity. In combination, and in light of previous work, we interpret these findings as showing that eye movements are scaled in accord with the effects of object acceleration but do not directly specify information for accurate spatial estimation in prediction motion.

  9. Is acceleration used for ocular pursuit and spatial estimation during prediction motion?

    Science.gov (United States)

    Bennett, Simon J; Benguigui, Nicolas

    2013-01-01

    Here we examined ocular pursuit and spatial estimation in a linear prediction motion task that emphasized extrapolation of occluded accelerative object motion. Results from the ocular response up to occlusion showed that there was evidence in the eye position, velocity and acceleration data that participants were attempting to pursue the moving object in accord with the veridical motion properties. They then attempted to maintain ocular pursuit of the randomly-ordered accelerative object motion during occlusion but this was not ideal, and resulted in undershoot of eye position and velocity at the moment of object reappearance. In spatial estimation there was a general bias, with participants less likely to report object reappearance being behind than ahead of the expected position. In addition, participants' spatial estimation did not take into account the effects of object acceleration. Logistic regression indicated that spatial estimation was best predicted for the majority of participants by the difference between actual object reappearance position and an extrapolation based on pre-occlusion velocity. In combination, and in light of previous work, we interpret these findings as showing that eye movements are scaled in accord with the effects of object acceleration but do not directly specify information for accurate spatial estimation in prediction motion.

  10. Cardiac motion and deformation estimation in tagged magnetic resonance imaging

    OpenAIRE

    Morais, Pedro André Gonçalves

    2013-01-01

    Dissertação de mestrado integrado em Engenharia Biomédica (área de especialização em Electrónica Médica) Cardiovascular diseases are the main cause of death in Europe, with an estimate of 4.3 million deaths each year. The assessment of the regional wall deformation is a relevant clinical indicator, and can be used to detect several cardiac lesions. Nowadays, this study can be performed using several image modalities. In the current thesis, we focus on tagged Magnetic Resonance ...

  11. Precise Image-Based Motion Estimation for Autonomous Small Body Exploration

    Science.gov (United States)

    Johnson, Andrew Edie; Matthies, Larry H.

    2000-01-01

    We have developed and tested a software algorithm that enables onboard autonomous motion estimation near small bodies using descent camera imagery and laser altimetry. Through simulation and testing, we have shown that visual feature tracking can decrease uncertainty in spacecraft motion to a level that makes landing on small, irregularly shaped, bodies feasible. Possible future work will include qualification of the algorithm as a flight experiment for the Deep Space 4/Champollion comet lander mission currently under study at the Jet Propulsion Laboratory.

  12. Estimating Internal Respiratory Motion from Respiratory Surrogate Signals Using Correspondence Models

    Science.gov (United States)

    McClelland, Jamie

    It is often difficult or impossible to directly monitor the respiratory motion of the tumour and other internal anatomy during RT treatment. Implanted markers can be used, but this involves an invasive procedure and has a number of other associated risks and problems. An alternative option is to use a correspondence model. This models the relationship between a respiratory surrogate signal(s), such as spirometry or the displacement of the skin surface, and the motion of the internal anatomy. Such a model allows the internal motion to be estimated from the surrogate signal(s), which can be easily monitored during RT treatment. The correspondence model is constructed prior to RT treatment. Imaging data is simultaneously acquired with the surrogate signal(s), and the internal motion is measured from the imaging data, e.g. using deformable image registration. A correspondence model is then fit relating the internal motion to the surrogate signal(s). This can then be used during treatment to estimate the internal motion from the surrogate signal(s). This chapter reviews the most popular correspondence models that have been used in the literature, as well as the different surrogate signals, types of imaging data used to measure the internal motion, and fitting methods used to fit the correspondence model to the data.

  13. Fault Slip Distribution of the 2016 Fukushima Earthquake Estimated from Tsunami Waveforms

    Science.gov (United States)

    Gusman, Aditya Riadi; Satake, Kenji; Shinohara, Masanao; Sakai, Shin'ichi; Tanioka, Yuichiro

    2017-08-01

    The 2016 Fukushima normal-faulting earthquake (Mjma 7.4) occurred 40 km off the coast of Fukushima within the upper crust. The earthquake generated a moderate tsunami which was recorded by coastal tide gauges and offshore pressure gauges. First, the sensitivity of tsunami waveforms to fault dimensions and depths was examined and the best size and depth were determined. Tsunami waveforms computed based on four available focal mechanisms showed that a simple fault striking northeast-southwest and dipping southeast (strike = 45°, dip = 41°, rake = -95°) yielded the best fit to the observed waveforms. This fault geometry was then used in a tsunami waveform inversion to estimate the fault slip distribution. A large slip of 3.5 m was located near the surface and the major slip region covered an area of 20 km × 20 km. The seismic moment, calculated assuming a rigidity of 2.7 × 1010 N/m2 was 3.70 × 1019 Nm, equivalent to Mw = 7.0. This is slightly larger than the moments from the moment tensor solutions (Mw 6.9). Large secondary tsunami peaks arrived approximately an hour after clear initial peaks were recorded by the offshore pressure gauges and the Sendai and Ofunato tide gauges. Our tsunami propagation model suggests that the large secondary tsunami signals were from tsunami waves reflected off the Fukushima coast. A rather large tsunami amplitude of 75 cm at Kuji, about 300 km north of the source, was comparable to those recorded at stations located much closer to the epicenter, such as Soma and Onahama. Tsunami simulations and ray tracing for both real and artificial bathymetry indicate that a significant portion of the tsunami wave was refracted to the coast located around Kuji and Miyako due to bathymetry effects.

  14. Interevent times estimation of major and continuous earthquakes in Hormozgan region based on radial basis function neural network

    Directory of Open Access Journals (Sweden)

    M.R. Mosavi

    2016-01-01

    Full Text Available This paper presents a new method to estimate the time of important earthquakes in Hormozgan region with magnitude greater than 5.5 based on the Radial Basis Function (RBF Neural Network (NN models. Input vector to the network is composed of different seismicity rates between main events that are calculated in convenient and reliable way to create optimized training methods. It helps network with a limited number of training data to estimation. It is common for earthquakes modeling by data-driven methods in this case. In addition, the proposed method is combined with Rosenberg cluster method to remove aftershocks events from the history of catalog for NN to better process the data. The results show that created RBF model successfully estimates the interevent times between large and sequence earthquakes that can be used as a tool to predict earthquake, so that comparison with other NN structure, for example Multi-Layer Perceptron (MLP NN, reveals the superiority of the proposed method. Because of superiority proposed method has higher accuracy, lower costs and simpler network structure.

  15. Reciprocal Estimation of Pedestrian Location and Motion State toward a Smartphone Geo-Context Computing Solution

    Directory of Open Access Journals (Sweden)

    Jingbin Liu

    2015-06-01

    Full Text Available The rapid advance in mobile communications has made information and services ubiquitously accessible. Location and context information have become essential for the effectiveness of services in the era of mobility. This paper proposes the concept of geo-context that is defined as an integral synthesis of geographical location, human motion state and mobility context. A geo-context computing solution consists of a positioning engine, a motion state recognition engine, and a context inference component. In the geo-context concept, the human motion states and mobility context are associated with the geographical location where they occur. A hybrid geo-context computing solution is implemented that runs on a smartphone, and it utilizes measurements of multiple sensors and signals of opportunity that are available within a smartphone. Pedestrian location and motion states are estimated jointly under the framework of hidden Markov models, and they are used in a reciprocal manner to improve their estimation performance of one another. It is demonstrated that pedestrian location estimation has better accuracy when its motion state is known, and in turn, the performance of motion state recognition can be improved with increasing reliability when the location is given. The geo-context inference is implemented simply with the expert system principle, and more sophisticated approaches will be developed.

  16. Theory and validation of magnetic resonance fluid motion estimation using intensity flow data.

    Directory of Open Access Journals (Sweden)

    Kelvin Kian Loong Wong

    Full Text Available BACKGROUND: Motion tracking based on spatial-temporal radio-frequency signals from the pixel representation of magnetic resonance (MR imaging of a non-stationary fluid is able to provide two dimensional vector field maps. This supports the underlying fundamentals of magnetic resonance fluid motion estimation and generates a new methodology for flow measurement that is based on registration of nuclear signals from moving hydrogen nuclei in fluid. However, there is a need to validate the computational aspect of the approach by using velocity flow field data that we will assume as the true reference information or ground truth. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we create flow vectors based on an ideal analytical vortex, and generate artificial signal-motion image data to verify our computational approach. The analytical and computed flow fields are compared to provide an error estimate of our methodology. The comparison shows that the fluid motion estimation approach using simulated MR data is accurate and robust enough for flow field mapping. To verify our methodology, we have tested the computational configuration on magnetic resonance images of cardiac blood and proved that the theory of magnetic resonance fluid motion estimation can be applicable practically. CONCLUSIONS/SIGNIFICANCE: The results of this work will allow us to progress further in the investigation of fluid motion prediction based on imaging modalities that do not require velocity encoding. This article describes a novel theory of motion estimation based on magnetic resonating blood, which may be directly applied to cardiac flow imaging.

  17. Theoretical estimates of magnitudes of earthquakes induced by pore-pressure perturbations with large aspect ratios

    Science.gov (United States)

    Galis, Martin; Ampuero, Jean-Paul; Mai, P. Martin; Cappa, Frédéric

    2017-04-01

    Being able to reliably and accurately estimate the possible maximum magnitude of fluid-injection-induced earthquakes is of critical importance to quantify the associated seismic hazard and to define operational constraints for geo-reservoirs. In previous studies, we developed theoretical estimates of the magnitude of fluid-injection-induced earthquakes based fracture mechanics, assuming circular pressure perturbations. However, natural reservoirs are typically much wider than thicker. Therefore, here we discuss the application of our model to horizontally elongated pressurized regions with realistic aspect ratios. Assuming circular pressure perturbations, we derived a physical model estimating how large a rupture will grow on a given fault and for a given pore-pressure perturbation. We used two approaches. The first, semi-analytical approach is based on pore pressure evolution obtained by solving the diffusion equation for a cylindrical reservoir with no-flow boundaries. The second approach is an approximation to the first one, based on a point-load approximation of the pres-sure perturbation on the fault, allowing derivation of a complete analytical formula relating the magnitude of the largest arrested rupture, Mmax-arr, to injection and slip-weakening friction parameters. We found that the Mmax-arr scales with cumulative injected fluid volume as a power law with exponent of 3/2. In contrast, the Mmax relation by McGarr (2014) is a linear scaling (exponent of 1). While for the dataset used by McGarr (2014) the difference between our and McGarr's models is relatively small, inclusion of datasets with broad range of injected fluid volumes (from 10-10m3 to 1010m3) suggests better agreement with our model. However, inclusion of extended pressure perturbations into our two models, while maintaining the (semi-)analytical character, is not viable. Therefore, we perform numerical dynamic-rupture simulations to investigate rupture nucleation and arrest for pressure

  18. Fuzzy entropy based motion artifact detection and pulse rate estimation for fingertip photoplethysmography.

    Science.gov (United States)

    Paradkar, Neeraj; Chowdhury, Shubhajit Roy

    2014-01-01

    The paper presents a fingertip photoplethysmography (PPG) based technique to estimate the pulse rate of the subject. The PPG signal obtained from a pulse oximeter is used for the analysis. The input samples are corrupted with motion artifacts due to minor motion of the subjects. Entropy measure of the input samples is used to detect the motion artifacts and estimate the pulse rate. A three step methodology is adapted to identify and classify signal peaks as true systolic peaks or artifact. CapnoBase database and CSL Benchmark database are used to analyze the technique and pulse rate estimation was performed with positive predictive value and sensitivity figures of 99.84% and 99.32% respectively for CapnoBase and 98.83% and 98.84% for CSL database respectively.

  19. Implementation and optimization of sub-pixel motion estimation on BWDSP platform

    Science.gov (United States)

    Jia, Shangzhu; Lang, Wenhui; Zeng, Feiyang; Liu, Yufu

    2017-08-01

    Sub-pixel Motion estimation algorithm is a key technology in video coding inter-frame prediction algorithm, which has important influence on video coding performance. In the latest video coding standard H.265/HEVC, interpolation filters based on DCT are used to Sub-pixel motion estimation, but it has very high computation complexity. In order to ensure the real-time performance of hardware coding, we combine the characteristics of BWDSP architecture, using code level optimization techniques to realize the sub-pixel motion estimation algorithm. Experimental results demonstrate that In the BWDSP simulation environment, the proposed method significantly decreases the running clock cycle and thus improves the performance of the encoder.

  20. Estimating the near-surface site response to mitigate earthquake disasters at the October 6th city, Egypt, using HVSR and seismic techniques

    Directory of Open Access Journals (Sweden)

    Adel M.E. Mohamed

    2013-06-01

    Full Text Available The damage caused by earthquake occurrences in different localities necessitates the evaluation of the subsurface structure. A priori estimation of the site effects became a major challenge for an efficient mitigation of the seismic risk. In the case of moderate to large earthquakes, at some distances from large events, severe damage often occurred at zones of unfavorable geotechnical conditions that give rise to significant site effects. The damage distribution in the near-source area is also significantly affected by fault geometry and rupture history. The microtremor (background noises and shallow seismic surveys (through both the seismic refraction and Multi-channel Analysis of Surface Waves (MASW were carried out in a specific area (The club of October 6 city and its adjacent space area. The natural periods derived from the HVSR (Horizontal to Vertical Spectral Ratio analysis vary from 0.37 to 0.56 s. The shallow seismic refraction data, which were conducted at the area, are used to determine the attenuation of P-waves (Qp in different layers, using the pulse-width technique. The evaluation of the site response at the studied area yields amplification factor of the ground motion, ranging between 2.4 and 4.4.

  1. Procedure to estimate maximum ground acceleration from macroseismic intensity rating: application to the Lima, Perú data from the October-3-1974-8.1-Mw earthquake

    Directory of Open Access Journals (Sweden)

    L. Ocola

    2008-01-01

    Full Text Available Post-disaster reconstruction management of urban areas requires timely information on the ground response microzonation to strong levels of ground shaking to minimize the rebuilt-environment vulnerability to future earthquakes. In this paper, a procedure is proposed to quantitatively estimate the severity of ground response in terms of peak ground acceleration, that is computed from macroseismic rating data, soil properties (acoustic impedance and predominant frequency of shear waves at a site. The basic mathematical relationships are derived from properties of wave propagation in a homogeneous and isotropic media. We define a Macroseismic Intensity Scale IMS as the logarithm of the quantity of seismic energy that flows through a unit area normal to the direction of wave propagation in unit time. The derived constants that relate the IMS scale and peak acceleration agree well with coefficients derived from a linear regression between MSK macroseismic rating and peak ground acceleration for historical earthquakes recorded at a strong motion station, at IGP's former headquarters, since 1954. The procedure was applied to 3-October-1974 Lima macroseismic intensity data at places where there was geotechnical data and predominant ground frequency information. The observed and computed peak acceleration values, at nearby sites, agree well.

  2. Procedure to estimate maximum ground acceleration from macroseismic intensity rating: application to the Lima, Perú data from the October-3-1974-8.1-Mw earthquake

    Science.gov (United States)

    Ocola, L.

    2008-01-01

    Post-disaster reconstruction management of urban areas requires timely information on the ground response microzonation to strong levels of ground shaking to minimize the rebuilt-environment vulnerability to future earthquakes. In this paper, a procedure is proposed to quantitatively estimate the severity of ground response in terms of peak ground acceleration, that is computed from macroseismic rating data, soil properties (acoustic impedance) and predominant frequency of shear waves at a site. The basic mathematical relationships are derived from properties of wave propagation in a homogeneous and isotropic media. We define a Macroseismic Intensity Scale IMS as the logarithm of the quantity of seismic energy that flows through a unit area normal to the direction of wave propagation in unit time. The derived constants that relate the IMS scale and peak acceleration agree well with coefficients derived from a linear regression between MSK macroseismic rating and peak ground acceleration for historical earthquakes recorded at a strong motion station, at IGP's former headquarters, since 1954. The procedure was applied to 3-October-1974 Lima macroseismic intensity data at places where there was geotechnical data and predominant ground frequency information. The observed and computed peak acceleration values, at nearby sites, agree well.

  3. Estimating the near-surface site response to mitigate earthquake disasters at the October 6th city, Egypt, using HVSR and seismic techniques

    Science.gov (United States)

    Mohamed, Adel M. E.; Abdel Hafiez, H. E.; Taha, M. A.

    2013-06-01

    The damage caused by earthquake occurrences in different localities necessitates the evaluation of the subsurface structure. A priori estimation of the site effects became a major challenge for an efficient mitigation of the seismic risk. In the case of moderate to large earthquakes, at some distances from large events, severe damage often occurred at zones of unfavorable geotechnical conditions that give rise to significant site effects. The damage distribution in the near-source area is also significantly affected by fault geometry and rupture history. The microtremor (background noises) and shallow seismic surveys (through both the seismic refraction and Multi-channel Analysis of Surface Waves (MASW)) were carried out in a specific area (The club of October 6 city and its adjacent space area). The natural periods derived from the HVSR (Horizontal to Vertical Spectral Ratio) analysis vary from 0.37 to 0.56 s. The shallow seismic refraction data, which were conducted at the area, are used to determine the attenuation of P-waves (Qp) in different layers, using the pulse-width technique. The evaluation of the site response at the studied area yields amplification factor of the ground motion, ranging between 2.4 and 4.4.

  4. Hybrid stochastic ground motion modeling of the Mw 7.8 Gorkha, Nepal earthquake of 2015 based on InSAR inversion

    Science.gov (United States)

    Shen, Wenhao; Li, Yongsheng; Zhang, Jingfa

    2017-06-01

    We derive the coseismic slip distribution on a fault for the 2015, Mw 7.8 Gorkha earthquake based on ALOS-2 wide scan data and the inversion code, SDM (Steepest Descend Method). The results show that the maximum slip is 4.7 m, and the total released seismic moment is 6.02 × 1020 N m, equivalent to an earthquake of Mw ∼7.82. Static stress and slip heterogeneity analyses show that both the average stress drop and corner wavenumber are at a low level. Additionally, we model the observed impulsive behavior at the near-source KATNP station using a hybrid stochastic approach, which combines an analytical approach at low frequencies with a stochastic approach at high frequencies. The good agreement between the hybrid modeling and observed records reveals that the input parameters, such as stress drop or slip distribution, are suitable for the Gorkha earthquake. The success of the modeling indicates that, in addition to the smooth onset of STF (slip-rate time function), the low stress drop and low degree of slip heterogeneity are also responsible for the low level of high-frequency ground motion during the Gorkha earthquake.

  5. Mode extraction on wind turbine blades via phase-based video motion estimation

    Science.gov (United States)

    Sarrafi, Aral; Poozesh, Peyman; Niezrecki, Christopher; Mao, Zhu

    2017-04-01

    In recent years, image processing techniques are being applied more often for structural dynamics identification, characterization, and structural health monitoring. Although as a non-contact and full-field measurement method, image processing still has a long way to go to outperform other conventional sensing instruments (i.e. accelerometers, strain gauges, laser vibrometers, etc.,). However, the technologies associated with image processing are developing rapidly and gaining more attention in a variety of engineering applications including structural dynamics identification and modal analysis. Among numerous motion estimation and image-processing methods, phase-based video motion estimation is considered as one of the most efficient methods regarding computation consumption and noise robustness. In this paper, phase-based video motion estimation is adopted for structural dynamics characterization on a 2.3-meter long Skystream wind turbine blade, and the modal parameters (natural frequencies, operating deflection shapes) are extracted. Phase-based video processing adopted in this paper provides reliable full-field 2-D motion information, which is beneficial for manufacturing certification and model updating at the design stage. The phase-based video motion estimation approach is demonstrated through processing data on a full-scale commercial structure (i.e. a wind turbine blade) with complex geometry and properties, and the results obtained have a good correlation with the modal parameters extracted from accelerometer measurements, especially for the first four bending modes, which have significant importance in blade characterization.

  6. Interaction force and motion estimators facilitating impedance control of the upper limb rehabilitation robot.

    Science.gov (United States)

    Mancisidor, Aitziber; Zubizarreta, Asier; Cabanes, Itziar; Bengoa, Pablo; Jung, Je Hyung

    2017-07-01

    In order to enhance the performance of rehabilitation robots, it is imperative to know both force and motion caused by the interaction between user and robot. However, common direct measurement of both signals through force and motion sensors not only increases the complexity of the system but also impedes affordability of the system. As an alternative of the direct measurement, in this work, we present new force and motion estimators for the proper control of the upper-limb rehabilitation Universal Haptic Pantograph (UHP) robot. The estimators are based on the kinematic and dynamic model of the UHP and the use of signals measured by means of common low-cost sensors. In order to demonstrate the effectiveness of the estimators, several experimental tests were carried out. The force and impedance control of the UHP was implemented first by directly measuring the interaction force using accurate extra sensors and the robot performance was compared to the case where the proposed estimators replace the direct measured values. The experimental results reveal that the controller based on the estimators has similar performance to that using direct measurement (less than 1 N difference in root mean square error between two cases), indicating that the proposed force and motion estimators can facilitate implementation of interactive controller for the UHP in robotmediated rehabilitation trainings.

  7. A Robust Subpixel Motion Estimation Algorithm Using HOS in the Parametric Domain

    Directory of Open Access Journals (Sweden)

    E. M. Ismaili Aalaoui

    2009-02-01

    Full Text Available Motion estimation techniques are widely used in todays video processing systems. The most frequently used techniques are the optical flow method and phase correlation method. The vast majority of these algorithms consider noise-free data. Thus, in the case of the image sequences are severely corrupted by additive Gaussian (perhaps non-Gaussian noises of unknown covariance, the classical techniques will fail to work because they will also estimate the noise spatial correlation. In this paper, we have studied this topic from a viewpoint different from the above to explore the fundamental limits in image motion estimation. Our scheme is based on subpixel motion estimation algorithm using bispectrum in the parametric domain. The motion vector of a moving object is estimated by solving linear equations involving third-order hologram and the matrix containing Dirac delta function. Simulation results are presented and compared to the optical flow and phase correlation algorithms; this approach provides more reliable displacement estimates particularly for complex noisy image sequences. In our simulation, we used the database freely available on the web.

  8. A Robust Subpixel Motion Estimation Algorithm Using HOS in the Parametric Domain

    Directory of Open Access Journals (Sweden)

    Ibn-Elhaj E

    2009-01-01

    Full Text Available Motion estimation techniques are widely used in todays video processing systems. The most frequently used techniques are the optical flow method and phase correlation method. The vast majority of these algorithms consider noise-free data. Thus, in the case of the image sequences are severely corrupted by additive Gaussian (perhaps non-Gaussian noises of unknown covariance, the classical techniques will fail to work because they will also estimate the noise spatial correlation. In this paper, we have studied this topic from a viewpoint different from the above to explore the fundamental limits in image motion estimation. Our scheme is based on subpixel motion estimation algorithm using bispectrum in the parametric domain. The motion vector of a moving object is estimated by solving linear equations involving third-order hologram and the matrix containing Dirac delta function. Simulation results are presented and compared to the optical flow and phase correlation algorithms; this approach provides more reliable displacement estimates particularly for complex noisy image sequences. In our simulation, we used the database freely available on the web.

  9. Some Key Features of the Strong-Motion Data from the M 6.0 Parkfield, California, Earthquake of 28 September 2004

    Science.gov (United States)

    Shakal, A.; Haddadi, H.; Graizer, V.; Lin, K.; Huang, M.

    2006-01-01

    The 2004 Parkfield, California, earthquake was recorded by an extensive set of strong-motion instruments well positioned to record details of the motion in the near-fault region, where there has previously been very little recorded data. The strong-motion measurements obtained are highly varied, with significant variations occurring over only a few kilometers. The peak accelerations in the near fault region range from 0.13g to over 1.8g (one of the highest acceleration recorded to date, exceeding the capacity of the recording instrument The largest accelerations occurred near the northwest end of the inferred rupture zone. These motions are consistent with directivity for a fault rupturing from the hypocenter near Gold Hill toward the northwest. However, accelerations up to 0.8g were also observed in the opposite direction, at the south end of the Cholame Valley near Highway 41, consistent with bilateral rupture, with rupture southeast of the hypocenter. Several stations near and over the rupturing fault recorded relatively weak motions, consistent with seemingly paradoxical observations of low shaking damage near strike-slip faults. This event had more ground-motion observations within 10 km of the fault than many other earthquakes combined. At moderate distances peak horizontal ground acceleration (PGA) values dropped off more rapidly with distance than standard relationships. At close-in distance the wide variation of PGA suggests a distance-dependent sigma may be important to consider. The near-fault ground-motion variation is greater than that assumed in ShakeMap interpolations, based on the existing set of observed data. Higher density of stations near faults may be the only means in the near future to reduce uncertainty in the interpolations. Outside of the near-fault zone the variance is closer to that assumed. This set of data provides the first case where near-fault radiation has been observed at an adequate number of stations around the fault to allow

  10. EEG-based learning system for online motion sickness level estimation in a dynamic vehicle environment.

    Science.gov (United States)

    Lin, Chin-Teng; Tsai, Shu-Fang; Ko, Li-Wei

    2013-10-01

    Motion sickness is a common experience for many people. Several previous researches indicated that motion sickness has a negative effect on driving performance and sometimes leads to serious traffic accidents because of a decline in a person's ability to maintain self-control. This safety issue has motivated us to find a way to prevent vehicle accidents. Our target was to determine a set of valid motion sickness indicators that would predict the occurrence of a person's motion sickness as soon as possible. A successful method for the early detection of motion sickness will help us to construct a cognitive monitoring system. Such a monitoring system can alert people before they become sick and prevent them from being distracted by various motion sickness symptoms while driving or riding in a car. In our past researches, we investigated the physiological changes that occur during the transition of a passenger's cognitive state using electroencephalography (EEG) power spectrum analysis, and we found that the EEG power responses in the left and right motors, parietal, lateral occipital, and occipital midline brain areas were more highly correlated to subjective sickness levels than other brain areas. In this paper, we propose the use of a self-organizing neural fuzzy inference network (SONFIN) to estimate a driver's/passenger's sickness level based on EEG features that have been extracted online from five motion sickness-related brain areas, while either in real or virtual vehicle environments. The results show that our proposed learning system is capable of extracting a set of valid motion sickness indicators that originated from EEG dynamics, and through SONFIN, a neuro-fuzzy prediction model, we successfully translated the set of motion sickness indicators into motion sickness levels. The overall performance of this proposed EEG-based learning system can achieve an average prediction accuracy of ~82%.

  11. Seismic Safety Margins Research Program, Phase I. Project II: seismic input. Compilation, assessment and expansion of the strong earthquake ground motion data base

    Energy Technology Data Exchange (ETDEWEB)

    Crouse, C B; Hileman, J A; Turner, B E; Martin, G R

    1980-04-01

    A catalog has been prepared which contains information for: (1) world-wide, ground-motion accelerograms, (2) the accelerograph sites where these records were obtained, and (3) the seismological parameters of the causative earthquakes. The catalog is limited to data for those accelerograms which have been digitized and published. In addition, the quality and completeness of these data are assessed. This catalog is unique because it is the only publication which contains comprehensive information on the recording conditions of all known digitized accelerograms. However, information for many accelerograms is missing. Although some literature may have been overlooked, most of the missing data has not been published. Nevertheless, the catalog provides a convenient reference and useful tool for earthquake engineering research and applications.

  12. Robust cardiac motion estimation using ultrafast ultrasound data: a low-rank topology-preserving approach

    Science.gov (United States)

    Aviles, Angelica I.; Widlak, Thomas; Casals, Alicia; Nillesen, Maartje M.; Ammari, Habib

    2017-06-01

    Cardiac motion estimation is an important diagnostic tool for detecting heart diseases and it has been explored with modalities such as MRI and conventional ultrasound (US) sequences. US cardiac motion estimation still presents challenges because of complex motion patterns and the presence of noise. In this work, we propose a novel approach to estimate cardiac motion using ultrafast ultrasound data. Our solution is based on a variational formulation characterized by the L 2-regularized class. Displacement is represented by a lattice of b-splines and we ensure robustness, in the sense of eliminating outliers, by applying a maximum likelihood type estimator. While this is an important part of our solution, the main object of this work is to combine low-rank data representation with topology preservation. Low-rank data representation (achieved by finding the k-dominant singular values of a Casorati matrix arranged from the data sequence) speeds up the global solution and achieves noise reduction. On the other hand, topology preservation (achieved by monitoring the Jacobian determinant) allows one to radically rule out distortions while carefully controlling the size of allowed expansions and contractions. Our variational approach is carried out on a realistic dataset as well as on a simulated one. We demonstrate how our proposed variational solution deals with complex deformations through careful numerical experiments. The low-rank constraint speeds up the convergence of the optimization problem while topology preservation ensures a more accurate displacement. Beyond cardiac motion estimation, our approach is promising for the analysis of other organs that exhibit motion.

  13. Sensitivity of broad-band ground-motion simulations to earthquake source and Earth structure variations: an application to the Messina Straits (Italy)

    KAUST Repository

    Imperatori, W.

    2012-03-01

    In this paper, we investigate ground-motion variability due to different faulting approximations and crustal-model parametrizations in the Messina Straits area (Southern Italy). Considering three 1-D velocity models proposed for this region and a total of 72 different source realizations, we compute broad-band (0-10 Hz) synthetics for Mw 7.0 events using a fault plane geometry recently proposed. We explore source complexity in terms of classic kinematic (constant rise-time and rupture speed) and pseudo-dynamic models (variable rise-time and rupture speed). Heterogeneous slip distributions are generated using a Von Karman autocorrelation function. Rise-time variability is related to slip, whereas rupture speed variations are connected to static stress drop. Boxcar, triangle and modified Yoffe are the adopted source time functions. We find that ground-motion variability associated to differences in crustal models is constant and becomes important at intermediate and long periods. On the other hand, source-induced ground-motion variability is negligible at long periods and strong at intermediate-short periods. Using our source-modelling approach and the three different 1-D structural models, we investigate shaking levels for the 1908 Mw 7.1 Messina earthquake adopting a recently proposed model for fault geometry and final slip. Our simulations suggest that peak levels in Messina and Reggio Calabria must have reached 0.6-0.7 g during this earthquake.

  14. Environmental effects and building damage induced by the vertical component of ground motion during the August 24, 2016 Amatrice (Central Italy) earthquake

    Science.gov (United States)

    Carydis, Panayotis; Lekkas, Efthymios; Mavroulis, Spyridon

    2017-04-01

    On August 24, 2016 an Mw 6.0 earthquake struck central Italy resulting in 299 fatalities, 388 injuries and about 3000 homeless. The provided focal mechanisms demonstrated a NW-SE striking seismic normal fault which is consistent with the spatial distribution of the coseismic surface ruptures observed along the western slope of Mt Vettore. Based on our field reconnaissance in the affected area immediately after the earthquake, extensive secondary environmental effects including landslides, rockfalls and ground cracks were also observed. Most landslides were generated within the Amatrice intermontane basin, which, instead of a flat surface, comprises isolated flat hills and ridges with relatively high and steep slopes extending several meters above the low-lying part of the basin consisting of Quaternary deposits and with several villages founded at their top. Landslides generated along the steep slopes of Amatrice, Accumoli and Pescara del Tronto flat hills were due to topographical amplification of the earthquake motion derived from accelerometric recordings analysis along with the action of the vertical component of the ground motion and the already established instability conditions resulting from river incision and erosion at the base of the hills. Strong evidences of the effect of the vertical ground motion in reinforced concrete (RC) buildings are the symmetrical buckling of reinforcement, compression damage and crushing at midheight and in other parts of columns, undamaged windows and unbroken glass panels as well as partial collapse of the buildings that usually occur along the vertical axis within the plan of the building. On the contrary, high flexible structures such as castle and bell towers in Arcuata del Tronto and Amatrice respectively were not affected by the vertical ground motion. During the action of the vertical component of the ground motion in Amatrice affected area, stationary waves were formed vertically in the observed structures resulting

  15. Estimation of the Demand for Hospital Care After a Possible High-Magnitude Earthquake in the City of Lima, Peru.

    Science.gov (United States)

    Bambarén, Celso; Uyen, Angela; Rodriguez, Miguel

    2017-02-01

    Introduction A model prepared by National Civil Defense (INDECI; Lima, Peru) estimated that an earthquake with an intensity of 8.0 Mw in front of the central coast of Peru would result in 51,019 deaths and 686,105 injured in districts of Metropolitan Lima and Callao. Using this information as a base, a study was designed to determine the characteristics of the demand for treatment in public hospitals and to estimate gaps in care in the hours immediately after such an event. A probabilistic model was designed that included the following variables: demand for hospital care; time of arrival at the hospitals; type of medical treatment; reason for hospital admission; and the need for specialized care like hemodialysis, blood transfusions, and surgical procedures. The values for these variables were obtained through a literature search of the databases of the MEDLINE medical bibliography, the Cochrane and SciELO libraries, and Google Scholar for information on earthquakes over the last 30 years of over magnitude 6.0 on the moment magnitude scale. If a high-magnitude earthquake were to occur in Lima, it was estimated that between 23,328 and 178,387 injured would go to hospitals, of which between 4,666 and 121,303 would require inpatient care, while between 18,662 and 57,084 could be treated as outpatients. It was estimated that there would be an average of 8,768 cases of crush syndrome and 54,217 cases of other health problems. Enough blood would be required for 8,761 wounded in the first 24 hours. Furthermore, it was expected that there would be a deficit of hospital beds and operating theaters due to the high demand. Sudden and violent disasters, such as earthquakes, represent significant challenges for health systems and services. This study shows the deficit of preparation and capacity to respond to a possible high-magnitude earthquake. The study also showed there are not enough resources to face mega-disasters, especially in large cities. Bambarén C , Uyen A

  16. Vision System for Coarsely Estimating Motion Parameters for Unknown Fast Moving Objects in Space

    Directory of Open Access Journals (Sweden)

    Min Chen

    2017-12-01

    Full Text Available Motivated by biological interests in analyzing navigation behaviors of flying animals, we attempt to build a system measuring their motion states. To do this, in this paper, we build a vision system to detect unknown fast moving objects within a given space, calculating their motion parameters represented by positions and poses. We proposed a novel method to detect reliable interest points from images of moving objects, which can be hardly detected by general purpose interest point detectors. 3D points reconstructed using these interest points are then grouped and maintained for detected objects, according to a careful schedule, considering appearance and perspective changes. In the estimation step, a method is introduced to adapt the robust estimation procedure used for dense point set to the case for sparse set, reducing the potential risk of greatly biased estimation. Experiments are conducted against real scenes, showing the capability of the system of detecting multiple unknown moving objects and estimating their positions and poses.

  17. Early Site Permit Demonstration Program: Guidelines for determining design basis ground motions. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    1993-03-18

    This report develops and applies a methodology for estimating strong earthquake ground motion. The motivation was to develop a much needed tool for use in developing the seismic requirements for structural designs. An earthquake`s ground motion is a function of the earthquake`s magnitude, and the physical properties of the earth through which the seismic waves travel from the earthquake fault to the site of interest. The emphasis of this study is on ground motion estimation in Eastern North America (east of the Rocky Mountains), with particular emphasis on the Eastern United States and southeastern Canada. Eastern North America is a stable continental region, having sparse earthquake activity with rare occurrences of large earthquakes. While large earthquakes are of interest for assessing seismic hazard, little data exists from the region to empirically quantify their effects. Therefore, empirically based approaches that are used for other regions, such as Western North America, are not appropriate for Eastern North America. Moreover, recent advances in science and technology have now made it possible to combine theoretical and empirical methods to develop new procedures and models for estimating ground motion. The focus of the report is on the attributes of ground motion in Eastern North America that are of interest for the design of facilities such as nuclear power plants. Specifically considered are magnitudes M from 5 to 8, distances from 0 to 500 km, and frequencies from 1 to 35 Hz.

  18. Comparison of Point and Line Features and Their Combination for Rigid Body Motion Estimation

    DEFF Research Database (Denmark)

    Pilz, Florian; Pugeault, Nicolas; Krüger, Norbert

    2009-01-01

    This paper discusses the usage of dierent image features and their combination in the context of estimating the motion of rigid bodies (RBM estimation). From stereo image sequences, we extract line features at local edges (coded in so called multi-modal primitives) as well as point features (by...... means of SIFT descriptors). All features are then matched across stereo and time, and we use these correspondences to estimate the RBM by solving the 3D-2D pose estimation problem. We test dierent feature sets on various stereo image sequences, recorded in realistic outdoor and indoor scenes. We...

  19. Modeling the effects of source and path heterogeneity on ground motions of great earthquakes on the Cascadia Subduction Zone Using 3D simulations

    Science.gov (United States)

    Delorey, Andrew; Frankel, Arthur; Liu, Pengcheng; Stephenson, William J.

    2014-01-01

    We ran finite‐difference earthquake simulations for great subduction zone earthquakes in Cascadia to model the effects of source and path heterogeneity for the purpose of improving strong‐motion predictions. We developed a rupture model for large subduction zone earthquakes based on a k−2 slip spectrum and scale‐dependent rise times by representing the slip distribution as the sum of normal modes of a vibrating membrane.Finite source and path effects were important in determining the distribution of strong motions through the locations of the hypocenter, subevents, and crustal structures like sedimentary basins. Some regions in Cascadia appear to be at greater risk than others during an event due to the geometry of the Cascadia fault zone relative to the coast and populated regions. The southern Oregon coast appears to have increased risk because it is closer to the locked zone of the Cascadia fault than other coastal areas and is also in the path of directivity amplification from any rupture propagating north to south in that part of the subduction zone, and the basins in the Puget Sound area are efficiently amplified by both north and south propagating ruptures off the coast of western Washington. We find that the median spectral accelerations at 5 s period from the simulations are similar to that of the Zhao et al. (2006) ground‐motion prediction equation, although our simulations predict higher amplitudes near the region of greatest slip and in the sedimentary basins, such as the Seattle basin.

  20. Imaging source slip distribution by the back-projection of P-wave amplitudes from strong-motion records: a case study for the 2010 Jiasian, Taiwan, earthquake

    Science.gov (United States)

    Chao, Wei-An; Zhao, Li; Wu, Yih-Min; Lee, Shiann-Jong

    2013-06-01

    We propose an approach to imaging earthquake source rupture process by direct back-projection of local high-frequency (0.1-2.5 Hz) P-wave displacements from strong-motion records. A series of synthetic experiments are performed which demonstrate that our approach is capable of recovering the spatial-temporal distribution of the source slip with a good station coverage and a high average coherence value between the target and template waveforms. We demonstrate the effectiveness of our approach by applying it to image the slip distribution of an earthquake occurred on 2010 March 4, in Jiasian (Mw = 6.0 and ML = 6.4) in southern Taiwan. The resulting moment-rate amplitude images show that the source rupture initiated at the vicinity of the hypocentre, followed by a moderate moment-rate release to the southeast of the hypocentre and a subsequent upward propagation, and finally propagated in the northwest direction, in agreement with the distribution of aftershocks. The majority of the slip at 17-20 km depth occurred to the west of the hypocentre, in a general agreement with the slip distributions obtained from dislocation model and finite-fault inversions. Our modified back-projection approach relies on seismic waveforms with the considerations of a recent 3-D structure model, high average coherence value, station correction factor and simplified amplitude correction. It is computationally efficient and allows for near real-time determinations of source slip distributions after earthquakes using strong-motion records. A quick result for the rupture model can be used in the calculation of strong ground-motion, providing important, useful and timely information for seismic hazard mitigation.

  1. Simulation of earthquake ground motions in the eastern United States using deterministic physics‐based and site‐based stochastic approaches

    Science.gov (United States)

    Rezaeian, Sanaz; Hartzell, Stephen; Sun, Xiaodan; Mendoza, Carlos

    2017-01-01

    Earthquake ground‐motion recordings are scarce in the central and eastern United States (CEUS) for large‐magnitude events and at close distances. We use two different simulation approaches, a deterministic physics‐based method and a site‐based stochastic method, to simulate ground motions over a wide range of magnitudes. Drawing on previous results for the modeling of recordings from the 2011 Mw 5.8 Mineral, Virginia, earthquake and using the 2001 Mw 7.6 Bhuj, India, earthquake as a tectonic analog for a large magnitude CEUS event, we are able to calibrate the two simulation methods over this magnitude range. Both models show a good fit to the Mineral and Bhuj observations from 0.1 to 10 Hz. Model parameters are then adjusted to obtain simulations for Mw 6.5, 7.0, and 7.6 events in the CEUS. Our simulations are compared with the 2014 U.S. Geological Survey weighted combination of existing ground‐motion prediction equations in the CEUS. The physics‐based simulations show comparable response spectral amplitudes and a fairly similar attenuation with distance. The site‐based stochastic simulations suggest a slightly faster attenuation of the response spectral amplitudes with distance for larger magnitude events and, as a result, slightly lower amplitudes at distances greater than 200 km. Both models are plausible alternatives and, given the few available data points in the CEUS, can be used to represent the epistemic uncertainty in modeling of postulated CEUS large‐magnitude events.

  2. Tracking of electroencephalography signals across brain lobes using motion estimation and cross-correlation

    Science.gov (United States)

    Lim, Seng Hooi; Nisar, Humaira; Yap, Vooi Voon; Shim, Seong-O.

    2015-11-01

    Electroencephalography (EEG) is the signal generated by electrical activity in the human brain. EEG topographic maps (topo-maps) give an idea of brain activation. Functional connectivity helps to find functionally integrated relationship between spatially separated brain regions. Brain connectivity can be measured by several methods. The classical methods calculate the coherence and correlation of the signal. We have developed an algorithm to map functional neural connectivity in the brain by using a full search block matching motion estimation algorithm. We have used oddball paradigm to examine the flow of activation across brain lobes for a specific activity. In the first step, the EEG signal is converted into topo-maps. The flow of activation between consecutive frames is tracked using full search block motion estimation, which appears in the form of motion vectors. In the second step, vector median filtering is used to obtain a smooth motion field by removing the unwanted noise. For each topo-map, several activation paths are tracked across various brain lobes. We have also developed correlation activity maps by following the correlation coefficient paths between electrodes. These paths are selected when the correlation coefficient between electrodes is >70%. We have compared the motion estimation path with the correlation coefficient activation maps. The tracked paths obtained by using motion estimation and correlation give very similar results. The inter-subject comparison shows that four out of five subjects tracked path involves all four (occipital, temporal, parietal, frontal) brain lobes for the same stimuli. The intra-subject analysis shows that three out of five subjects show different tracked lobes for different stimuli.

  3. Automatic motion estimation using flow parameters for dynamic contrast-enhanced ultrasound

    Science.gov (United States)

    Barrois, Guillaume; Coron, Alain; Lucidarme, Olivier; Bridal, S. Lori

    2015-03-01

    Dynamic contrast-enhanced ultrasound (DCE-US) sequences are subject to motion which can disturb functional flow quantification. This can make estimated parameters more variable or unreliable. Methods that compensate for motion are therefore desirable. The most commonly used motion correction techniques in DCE-US register the images in the sequence with respect to a user-selected reference image. However, this image may not include all features that are representative of the whole sequence. Moreover, image-based registration neglects pertinent, functional-flow information contained in the DCE-US sequence. An operator-free method is proposed that combines the motion estimation and flow-parameter quantification (M/Q method) in a single mathematical framework. This method is based on a realistic multiplicative model of the DCE-US noise. By computing likelihood in this model, motion and flow parameters are both estimated iteratively. First, the maximization is accomplished by estimating functional and motion parameters. Then, a final registration based on a non-parametric temporal smoothing of the sequence is performed. This method is compared to a conventional (mutual information) registration method where all the images of the sequence are registered with respect to a reference image chosen by an expert. The two methods are evaluated on simulated sequences and DCE-US sequences acquired in patients (N = 15). The M/Q method demonstrates significantly (p < 0.05) lower Dice coefficients and Hausdorff distance than the conventional method on the simulated data sets. On the in vivo sequences analysed, the M/Q methods outperformed the conventional method in terms of mean Dice and Hausdorff distance on 80% of the sequences, and in terms of standard deviation of Dice and Hausdorff distance on 87% of the sequences.

  4. Motion correction for improved estimation of heart rate using a visual spectrum camera

    Science.gov (United States)

    Tarbox, Elizabeth A.; Rios, Christian; Kaur, Balvinder; Meyer, Shaun; Hirt, Lauren; Tran, Vy; Scott, Kaitlyn; Ikonomidou, Vasiliki

    2017-05-01

    Heart rate measurement using a visual spectrum recording of the face has drawn interest over the last few years as a technology that can have various health and security applications. In our previous work, we have shown that it is possible to estimate the heart beat timing accurately enough to perform heart rate variability analysis for contactless stress detection. However, a major confounding factor in this approach is the presence of movement, which can interfere with the measurements. To mitigate the effects of movement, in this work we propose the use of face detection and tracking based on the Karhunen-Loewe algorithm in order to counteract measurement errors introduced by normal subject motion, as expected during a common seated conversation setting. We analyze the requirements on image acquisition for the algorithm to work, and its performance under different ranges of motion, changes of distance to the camera, as well and the effect of illumination changes due to different positioning with respect to light sources on the acquired signal. Our results suggest that the effect of face tracking on visual-spectrum based cardiac signal estimation depends on the amplitude of the motion. While for larger-scale conversation-induced motion it can significantly improve estimation accuracy, with smaller-scale movements, such as the ones caused by breathing or talking without major movement errors in facial tracking may interfere with signal estimation. Overall, employing facial tracking is a crucial step in adapting this technology to real-life situations with satisfactory results.

  5. Frequency-Domain Joint Motion and Disparity Estimation Using Steerable Filters

    Directory of Open Access Journals (Sweden)

    Dimitrios Alexiadis

    2018-02-01

    Full Text Available In this paper, the problem of joint disparity and motion estimation from stereo image sequences is formulated in the spatiotemporal frequency domain, and a novel steerable filter-based approach is proposed. Our rationale behind coupling the two problems is that according to experimental evidence in the literature, the biological visual mechanisms for depth and motion are not independent of each other. Furthermore, our motivation to study the problem in the frequency domain and search for a filter-based solution is based on the fact that, according to early experimental studies, the biological visual mechanisms can be modelled based on frequency-domain or filter-based considerations, for both the perception of depth and the perception of motion. The proposed framework constitutes the first attempt to solve the joint estimation problem through a filter-based solution, based on frequency-domain considerations. Thus, the presented ideas provide a new direction of work and could be the basis for further developments. From an algorithmic point of view, we additionally extend state-of-the-art ideas from the disparity estimation literature to handle the joint disparity-motion estimation problem and formulate an algorithm that is evaluated through a number of experimental results. Comparisons with state-of-the-art-methods demonstrate the accuracy of the proposed approach.

  6. A phase field method for joint denoising, edge detection, and motion estimation in image sequence processing

    NARCIS (Netherlands)

    Preusser, T.; Droske, M.; Garbe, C. S.; Telea, A.; Rumpf, M.

    2007-01-01

    The estimation of optical flow fields from image sequences is incorporated in a Mumford-Shah approach for image denoising and edge detection. Possibly noisy image sequences are considered as input and a piecewise smooth image intensity, a piecewise smooth motion field, and a joint discontinuity set

  7. A Variational Approach to Joint Denoising, Edge Detection and Motion Estimation

    NARCIS (Netherlands)

    Telea, Alexandru; Preusser, Tobias; Garbe, Christoph; Droske, Marc; Rumpf, Martin

    2006-01-01

    The estimation of optical flow fields from image sequences is incorporated in a Mumford–Shah approach for image denoising and edge detection. Possibly noisy image sequences are considered as input and a piecewise smooth image intensity, a piecewise smooth motion field, and a joint discontinuity set

  8. Navigation Aiding by a Hybrid Laser-Camera Motion Estimator for Micro Aerial Vehicles.

    Science.gov (United States)

    Atman, Jamal; Popp, Manuel; Ruppelt, Jan; Trommer, Gert F

    2016-09-16

    Micro Air Vehicles (MAVs) equipped with various sensors are able to carry out autonomous flights. However, the self-localization of autonomous agents is mostly dependent on Global Navigation Satellite Systems (GNSS). In order to provide an accurate navigation solution in absence of GNSS signals, this article presents a hybrid sensor. The hybrid sensor is a deep integration of a monocular camera and a 2D laser rangefinder so that the motion of the MAV is estimated. This realization is expected to be more flexible in terms of environments compared to laser-scan-matching approaches. The estimated ego-motion is then integrated in the MAV's navigation system. However, first, the knowledge about the pose between both sensors is obtained by proposing an improved calibration method. For both calibration and ego-motion estimation, 3D-to-2D correspondences are used and the Perspective-3-Point (P3P) problem is solved. Moreover, the covariance estimation of the relative motion is presented. The experiments show very accurate calibration and navigation results.

  9. Navigation Aiding by a Hybrid Laser-Camera Motion Estimator for Micro Aerial Vehicles

    Directory of Open Access Journals (Sweden)

    Jamal Atman

    2016-09-01

    Full Text Available Micro Air Vehicles (MAVs equipped with various sensors are able to carry out autonomous flights. However, the self-localization of autonomous agents is mostly dependent on Global Navigation Satellite Systems (GNSS. In order to provide an accurate navigation solution in absence of GNSS signals, this article presents a hybrid sensor. The hybrid sensor is a deep integration of a monocular camera and a 2D laser rangefinder so that the motion of the MAV is estimated. This realization is expected to be more flexible in terms of environments compared to laser-scan-matching approaches. The estimated ego-motion is then integrated in the MAV’s navigation system. However, first, the knowledge about the pose between both sensors is obtained by proposing an improved calibration method. For both calibration and ego-motion estimation, 3D-to-2D correspondences are used and the Perspective-3-Point (P3P problem is solved. Moreover, the covariance estimation of the relative motion is presented. The experiments show very accurate calibration and navigation results.

  10. Earthquake Hazards Program: Earthquake Scenarios

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A scenario represents one realization of a potential future earthquake by assuming a particular magnitude, location, and fault-rupture geometry and estimating...

  11. Constraining ground motion parameters and determining the historic earthquake that damaged the vaults underneath the Old City of Jerusalem

    Science.gov (United States)

    Yagoda-Biran, G.; Hatzor, Y. H.

    2013-12-01

    Evidence for seismically induced damage are preserved in historic masonry structures below the Old City of Jerusalem at a site known locally as the 'Western Wall Tunnels' complex, possibly one of the most important tourist attractions in the world. In the tunnels, structures dated to 500 BC and up until modern times have been uncovered by recent archeological excavation. One of the interesting findings is a 100 m long bridge, composed of two rows of barrel vaults, believed to have been constructed during the 3rd century AD to allow easy access to the Temple Mount. In one of the vaults a single masonry block is displaced 7 cm downward with respect to its neighbors (see figure below). Since the damage seems seismically driven, back analysis of the damage with the numerical Discontinuous Deformation Analysis (DDA) method was performed, in order to constrain the peak ground acceleration (PGA) that had caused the damage. First the numerical method used for back analysis was verified with an analytical solution for the case of a rocking monolithic column, then validated with experimental results for site response analysis. The verification and validation prove the DDA is capable of handling dynamic and wave propagation problems. Next, the back analysis was performed. Results of the dynamic numerical simulations suggest that the damage observed at the vault was induced by seismic vibrations that must have taken place before the bridge was buried underground, namely when it was still in service. We find that the PGA required for causing the observed damage was high - between 1.5 and 2 g. The PGA calculated for Jerusalem on the basis of established attenuation relationships for historic earthquakes that struck the region during the relevant time period is about one order of magnitude lower: 0.14 and 0.48 g, for the events that took place at 362 and 746 AD, respectively. This discrepancy is explained by local site effects that must have amplified bedrock ground motions by a

  12. Temporal regularization of ultrasound-based liver motion estimation for image-guided radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    O’Shea, Tuathan P., E-mail: tuathan.oshea@icr.ac.uk; Bamber, Jeffrey C.; Harris, Emma J. [Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS foundation Trust, Sutton, London SM2 5PT (United Kingdom)

    2016-01-15

    Purpose: Ultrasound-based motion estimation is an expanding subfield of image-guided radiation therapy. Although ultrasound can detect tissue motion that is a fraction of a millimeter, its accuracy is variable. For controlling linear accelerator tracking and gating, ultrasound motion estimates must remain highly accurate throughout the imaging sequence. This study presents a temporal regularization method for correlation-based template matching which aims to improve the accuracy of motion estimates. Methods: Liver ultrasound sequences (15–23 Hz imaging rate, 2.5–5.5 min length) from ten healthy volunteers under free breathing were used. Anatomical features (blood vessels) in each sequence were manually annotated for comparison with normalized cross-correlation based template matching. Five sequences from a Siemens Acuson™ scanner were used for algorithm development (training set). Results from incremental tracking (IT) were compared with a temporal regularization method, which included a highly specific similarity metric and state observer, known as the α–β filter/similarity threshold (ABST). A further five sequences from an Elekta Clarity™ system were used for validation, without alteration of the tracking algorithm (validation set). Results: Overall, the ABST method produced marked improvements in vessel tracking accuracy. For the training set, the mean and 95th percentile (95%) errors (defined as the difference from manual annotations) were 1.6 and 1.4 mm, respectively (compared to 6.2 and 9.1 mm, respectively, for IT). For each sequence, the use of the state observer leads to improvement in the 95% error. For the validation set, the mean and 95% errors for the ABST method were 0.8 and 1.5 mm, respectively. Conclusions: Ultrasound-based motion estimation has potential to monitor liver translation over long time periods with high accuracy. Nonrigid motion (strain) and the quality of the ultrasound data are likely to have an impact on tracking

  13. Estimation of recurrence interval of large earthquakes on the central Longmen Shan fault zone based on seismic moment accumulation/release model.

    Science.gov (United States)

    Ren, Junjie; Zhang, Shimin

    2013-01-01

    Recurrence interval of large earthquake on an active fault zone is an important parameter in assessing seismic hazard. The 2008 Wenchuan earthquake (Mw 7.9) occurred on the central Longmen Shan fault zone and ruptured the Yingxiu-Beichuan fault (YBF) and the Guanxian-Jiangyou fault (GJF). However, there is a considerable discrepancy among recurrence intervals of large earthquake in preseismic and postseismic estimates based on slip rate and paleoseismologic results. Post-seismic trenches showed that the central Longmen Shan fault zone probably undertakes an event similar to the 2008 quake, suggesting a characteristic earthquake model. In this paper, we use the published seismogenic model of the 2008 earthquake based on Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) data and construct a characteristic seismic moment accumulation/release model to estimate recurrence interval of large earthquakes on the central Longmen Shan fault zone. Our results show that the seismogenic zone accommodates a moment rate of (2.7 ± 0.3) × 10¹⁷ N m/yr, and a recurrence interval of 3900 ± 400 yrs is necessary for accumulation of strain energy equivalent to the 2008 earthquake. This study provides a preferred interval estimation of large earthquakes for seismic hazard analysis in the Longmen Shan region.

  14. Motion estimation for H.264/AVC on multiple GPUs using NVIDIA CUDA

    Science.gov (United States)

    Pieters, Bart; Hollemeersch, Charles F.; Lambert, Peter; Van de Walle, Rik

    2009-08-01

    To achieve the high coding efficiency the H.264/AVC standard offers, the encoding process quickly becomes computationally demanding. One of the most intensive encoding phases is motion estimation. Even modern CPUs struggle to process high-definition video sequences in real-time. While personal computers are typically equipped with powerful Graphics Processing Units (GPUs) to accelerate graphics operations, these GPUs lie dormant when encoding a video sequence. Furthermore, recent developments show more and more computer configurations come with multiple GPUs. However, no existing GPU-enabled motion estimation architectures target multiple GPUs. In addition, these architectures provide no early-out behavior nor can they enforce a specific processing order. We developed a motion search architecture, capable of executing motion estimation and partitioning for an H.264/AVC sequence entirely on the GPU using the NVIDIA CUDA (Compute Unified Device Architecture) platform. This paper describes our architecture and presents a novel job scheduling system we designed, making it possible to control the GPU in a flexible way. This job scheduling system can enforce real-time demands of the video encoder by prioritizing calculations and providing an early-out mode. Furthermore, the job scheduling system allows the use of multiple GPUs in one computer system and efficient load balancing of the motion search over these GPUs. This paper focuses on the execution speed of the novel job scheduling system on both single and multi-GPU systems. Initial results show that real-time full motion search of 720p high-definition content is possible with a 32 by 32 search window running on a system with four GPUs.

  15. A Review on Block Matching Motion Estimation and Automata Theory based Approaches for Fractal Coding

    Directory of Open Access Journals (Sweden)

    Shailesh Kamble

    2016-12-01

    Full Text Available Fractal compression is the lossy compression technique in the field of gray/color image and video compression. It gives high compression ratio, better image quality with fast decoding time but improvement in encoding time is a challenge. This review paper/article presents the analysis of most significant existing approaches in the field of fractal based gray/color images and video compression, different block matching motion estimation approaches for finding out the motion vectors in a frame based on inter-frame coding and intra-frame coding i.e. individual frame coding and automata theory based coding approaches to represent an image/sequence of images. Though different review papers exist related to fractal coding, this paper is different in many sense. One can develop the new shape pattern for motion estimation and modify the existing block matching motion estimation with automata coding to explore the fractal compression technique with specific focus on reducing the encoding time and achieving better image/video reconstruction quality. This paper is useful for the beginners in the domain of video compression.

  16. Quaternionic Spatiotemporal Filtering for Dense Motion Field Estimation in Ultrasound Imaging

    Directory of Open Access Journals (Sweden)

    Marion Adrien

    2010-01-01

    Full Text Available Abstract Blood motion estimation provides fundamental clinical information to prevent and detect pathologies such as cancer. Ultrasound imaging associated with Doppler methods is often used for blood flow evaluation. However, Doppler methods suffer from shortcomings such as limited spatial resolution and the inability to estimate lateral motion. Numerous methods such as block matching and decorrelation-based techniques have been proposed to overcome these limitations. In this paper, we propose an original method to estimate dense fields of vector velocity from ultrasound image sequences. Our proposal is based on a spatiotemporal approach and considers 2D+t data as a 3D volume. Orientation of the texture within this volume is related to velocity. Thus, we designed a bank of 3D quaternionic filters to estimate local orientation and then calculate local velocities. The method was applied to a large set of experimental and simulated flow sequences with low motion ( 1 mm/s within small vessels ( 1 mm. Evaluation was conducted with several quantitative criteria such as the normalized mean error or the estimated mean velocity. The results obtained show the good behaviour of our method, characterizing the flows studied.

  17. VIDEO DENOISING USING SWITCHING ADAPTIVE DECISION BASED ALGORITHM WITH ROBUST MOTION ESTIMATION TECHNIQUE

    Directory of Open Access Journals (Sweden)

    V. Jayaraj

    2010-08-01

    Full Text Available A Non-linear adaptive decision based algorithm with robust motion estimation technique is proposed for removal of impulse noise, Gaussian noise and mixed noise (impulse and Gaussian with edge and fine detail preservation in images and videos. The algorithm includes detection of corrupted pixels and the estimation of values for replacing the corrupted pixels. The main advantage of the proposed algorithm is that an appropriate filter is used for replacing the corrupted pixel based on the estimation of the noise variance present in the filtering window. This leads to reduced blurring and better fine detail preservation even at the high mixed noise density. It performs both spatial and temporal filtering for removal of the noises in the filter window of the videos. The Improved Cross Diamond Search Motion Estimation technique uses Least Median Square as a cost function, which shows improved performance than other motion estimation techniques with existing cost functions. The results show that the proposed algorithm outperforms the other algorithms in the visual point of view and in Peak Signal to Noise Ratio, Mean Square Error and Image Enhancement Factor.

  18. State-of-the-Art for Assessing Earthquake Hazards in the United States. Report 25. Parameters for Specifying Intensity-Related Earthquake Ground Motions.

    Science.gov (United States)

    1987-09-01

    and Sponheuer, W. 1969. Scale of Seismic Intensity: Proc. Fourth World Conf. on Earthquake Engineering, Santiago, Chile . Murphy, J. R., and O’Brien, L...Predom V/H el, V/I Vel V/H Displ V/H sec VIH Period Period Predom Accel cm/sec Vel cm Disp .05 Dur sec sec Period S11 2 0.48 MODIFIED MERCALLI INTENSITY...0.1 0. 0.16 142.20 Long. Vert Hor Vert Ratio Ratio Vert Ratio Vert r io Du r atio Predom Predom VIH Acce V/H Vel V /H Dspi V H sec 1, H Period Period

  19. Motion-robust parameter estimation in abdominal diffusion-weighted MRI by simultaneous image registration and model estimation.

    Science.gov (United States)

    Kurugol, Sila; Freiman, Moti; Afacan, Onur; Domachevsky, Liran; Perez-Rossello, Jeannette M; Callahan, Michael J; Warfield, Simon K

    2017-07-01

    Quantitative body DW-MRI can detect abdominal abnormalities as well as monitor response-to-therapy for applications including cancer and inflammatory bowel disease with increased accuracy. Parameter estimates are obtained by fitting a forward model of DW-MRI signal decay to the observed data acquired with several b-values. The DW-MRI signal decay models typically used do not account for respiratory, cardiac and peristaltic motion, however, which may deteriorate the accuracy and robustness of parameter estimates. In this work, we introduce a new model of DW-MRI signal decay that explicitly accounts for motion. Specifically, we estimated motion-compensated model parameters by simultaneously solving image registration and model estimation (SIR-ME) problems utilizing the interdependence of acquired volumes along the diffusion-weighting dimension. To accomplish this, we applied the SIR-ME model to the in-vivo DW-MRI data sets of 26 Crohn's disease (CD) patients and achieved improved precision of the estimated parameters by reducing the coefficient of variation by 8%, 24% and 8% for slow diffusion (D), fast diffusion (D*) and fast diffusion fraction (f) parameters respectively, compared to parameters estimated with independent registration in normal-appearing bowel regions. Moreover, the parameters estimated with the SIR-ME model reduced the error rate in classifying normal and abnormal bowel loops to 12% for D and 10% for f parameter with a reduction in error rate by 13% and 11% for D and f parameters, respectively, compared to the error rate in classifying parameter estimates obtained with independent registration. The experiments in DW-MRI of liver in 20 subjects also showed that the SIR-ME model improved the precision of parameter estimation by reducing the coefficient of variation to 7% for D, 23% for D*, and 8% for the f parameter. Using the SIR-ME model, the coefficient of variation was reduced by 4%, 14% and 6% for D, D* and f parameters, respectively, compared

  20. On Drift Parameter Estimation in Models with Fractional Brownian Motion by Discrete Observations

    Directory of Open Access Journals (Sweden)

    Yuliya Mishura

    2014-06-01

    Full Text Available We study a problem of an unknown drift parameter estimation in a stochastic differen- tial equation driven by fractional Brownian motion. We represent the likelihood ratio as a function of the observable process. The form of this representation is in general rather complicated. However, in the simplest case it can be simplified and we can discretize it to establish the a. s. convergence of the discretized version of maximum likelihood estimator to the true value of parameter. We also investigate a non-standard estimator of the drift parameter showing further its strong consistency. 

  1. Simulation of broad-band strong ground motion for a hypothetical Mw 7.1 earthquake on the Enriquillo Fault in Haiti

    Science.gov (United States)

    Douilly, Roby; Mavroeidis, George P.; Calais, Eric

    2017-10-01

    The devastating 2010 Mw 7.0 Haiti earthquake demonstrated the need to improve mitigation and preparedness for future seismic events in the region. Previous studies have shown that the earthquake did not occur on the Enriquillo Fault, the main plate boundary fault running through the heavily populated Port-au-Prince region, but on the nearby and previously unknown transpressional Léogâne Fault. Slip on that fault has increased stresses on the segment of Enriquillo Fault to the east of Léogâne, which terminates in the ˜3-million-inhabitant capital city of Port-au-Prince. In this study, we investigate ground shaking in the vicinity of Port-au-Prince, if a hypothetical rupture similar to the 2010 Haiti earthquake occurred on that segment of the Enriquillo Fault. We use a finite element method and assumptions on regional tectonic stress to simulate the low-frequency ground motion components using dynamic rupture propagation for a 52-km-long segment. We consider eight scenarios by varying parameters such as hypocentre location, initial shear stress and fault dip. The high-frequency ground motion components are simulated using the specific barrier model in the context of the stochastic modeling approach. The broad-band ground motion synthetics are subsequently obtained by combining the low-frequency components from the dynamic rupture simulation with the high-frequency components from the stochastic simulation using matched filtering at a crossover frequency of 1 Hz. Results show that rupture on a vertical Enriquillo Fault generates larger horizontal permanent displacements in Léogâne and Port-au-Prince than rupture on a south-dipping Enriquillo Fault. The mean horizontal peak ground acceleration (PGA), computed at several sites of interest throughout Port-au-Prince, has a value of ˜0.45 g, whereas the maximum horizontal PGA in Port-au-Prince is ˜0.60 g. Even though we only consider a limited number of rupture scenarios, our results suggest more intense ground

  2. Volcano-tectonic earthquakes: A new tool for estimating intrusive volumes and forecasting eruptions

    Science.gov (United States)

    White, Randall A.; McCausland, Wendy

    2016-01-01

    We present data on 136 high-frequency earthquakes and swarms, termed volcano-tectonic (VT) seismicity, which preceded 111 eruptions at 83 volcanoes, plus data on VT swarms that preceded intrusions at 21 other volcanoes. We find that VT seismicity is usually the earliest reported seismic precursor for eruptions at volcanoes that have been dormant for decades or more, and precedes eruptions of all magma types from basaltic to rhyolitic and all explosivities from VEI 0 to ultraplinian VEI 6 at such previously long-dormant volcanoes. Because large eruptions occur most commonly during resumption of activity at long-dormant volcanoes, VT seismicity is an important precursor for the Earth's most dangerous eruptions. VT seismicity precedes all explosive eruptions of VEI ≥ 5 and most if not all VEI 4 eruptions in our data set. Surprisingly we find that the VT seismicity originates at distal locations on tectonic fault structures at distances of one or two to tens of kilometers laterally from the site of the eventual eruption, and rarely if ever starts beneath the eruption site itself. The distal VT swarms generally occur at depths almost equal to the horizontal distance of the swarm from the summit out to about 15 km distance, beyond which hypocenter depths level out. We summarize several important characteristics of this distal VT seismicity including: swarm-like nature, onset days to years prior to the beginning of magmatic eruptions, peaking of activity at the time of the initial eruption whether phreatic or magmatic, and large non-double couple component to focal mechanisms. Most importantly we show that the intruded magma volume can be simply estimated from the cumulative seismic moment of the VT seismicity from:

  3. Evaluation of a direct motion estimation/correction method in respiratory-gated PET/MRI with motion-adjusted attenuation.

    Science.gov (United States)

    Bousse, Alexandre; Manber, Richard; Holman, Beverley F; Atkinson, David; Arridge, Simon; Ourselin, Sébastien; Hutton, Brian F; Thielemans, Kris

    2017-06-01

    Respiratory motion compensation in PET/CT and PET/MRI is essential as motion is a source of image degradation (motion blur, attenuation artifacts). In previous work, we developed a direct method for joint image reconstruction/motion estimation (JRM) for attenuation-corrected (AC) respiratory-gated PET, which uses a single attenuation-map (μ-map). This approach was successfully implemented for respiratory-gated PET/CT, but since it relied on an accurate μ-map for motion estimation, the question of its applicability in PET/MRI is open. The purpose of this work is to investigate the feasibility of JRM in PET/MRI and to assess the robustness of the motion estimation when a degraded μ-map is used. We performed a series of JRM reconstructions from simulated PET data using a range of simulated Dixon MRI sequence derived μ-maps with wrong attenuation values in the lungs, from -100% (no attenuation) to +100% (double attenuation), as well as truncated arms. We compared the estimated motions with the one obtained from JRM in ideal conditions (no noise, true μ-map as an input). We also applied JRM on 4 patient datasets of the chest, 3 of them containing hot lesions. Patient list-mode data were gated using a principal component analysis method. We compared SUVmax values of the JRM reconstructed activity images and non motion-corrected images. We also assessed the estimated motion fields by comparing the deformed JRM-reconstructed activity with individually non-AC reconstructed gates. Experiments on simulated data showed that JRM-motion estimation is robust to μ-map degradation in the sense that it produces motion fields similar to the ones obtained when using the true μ-map, regardless of the attenuation errors in the lungs (PET/MRI clinical datasets. It provides a potential alternative to existing methods where the motion fields are pre-estimated from separate MRI measurements. © 2017 University College London (UCL). Medical Physics published by Wiley Periodicals, Inc

  4. Earthquake Warning Performance in Vallejo for the South Napa Earthquake

    Science.gov (United States)

    Wurman, G.; Price, M.

    2014-12-01

    In 2002 and 2003, Seismic Warning Systems, Inc. installed first-generation QuakeGuardTM earthquake warning devices at all eight fire stations in Vallejo, CA. These devices are designed to detect the P-wave of an earthquake and initiate predetermined protective actions if the impending shaking is estimated at approximately Modifed Mercalli Intensity V or greater. At the Vallejo fire stations the devices were set up to sound an audio alert over the public address system and to command the equipment bay doors to open. In August 2014, after more than 11 years of operating in the fire stations with no false alarms, the five units that were still in use triggered correctly on the MW 6.0 South Napa earthquake, less than 16 km away. The audio alert sounded in all five stations, providing fire fighters with 1.5 to 2.5 seconds of warning before the arrival of the S-wave, and the equipment bay doors opened in three of the stations. In one station the doors were disconnected from the QuakeGuard device, and another station lost power before the doors opened completely. These problems highlight just a small portion of the complexity associated with realizing actionable earthquake warnings. The issues experienced in this earthquake have already been addressed in subsequent QuakeGuard product generations, with downstream connection monitoring and backup power for critical systems. The fact that the fire fighters in Vallejo were afforded even two seconds of warning at these epicentral distances results from the design of the QuakeGuard devices, which focuses on rapid false positive rejection and ground motion estimates. We discuss the performance of the ground motion estimation algorithms, with an emphasis on the accuracy and timeliness of the estimates at close epicentral distances.

  5. Estimate of Seismological Parameters for the 1908 Messina Earthquake Through a new Data set Within the SISMOS Project.

    Science.gov (United States)

    Palombo, B.; Ferrari, G.; Bernardi, F.; Hunstad, I.; Perniola, B.

    2008-12-01

    The 1908 earthquake is one of the most catastrophic events in Italian history, recorded by most of the historical seismic stations existing at that time. Some of the seismograms recorded by these stations have already been used by many authors for the purpose of studying source characteristics, although only copies of the original recordings were available. Thanks to the Euroseismos project (2002-2007) and to the Sismos project, most of the original data (seismogram recordings and instrument parameter calibrations) for these events are now available in digital formats. Sismos technical facilities now allow us to apply the modern methods of digital-data analysis for the earthquakes recorded by mechanical and electromagnetic seismographs. The Sismos database has recently acquired many original seismograms and related instrumental parameters for the 1908 Messina earthquake, recorded by 14 stations distributed worldwide and never before used in previous works. We have estimated the main event parameters (i.e. location, Ms, Mw and focal mechanism) with the new data set. The aim of our work is to provide the scientific community with a reliable size and source estimation for accurate and consistent seismic hazard evaluation in Sicily, a region characterized by high long-term seismicity.

  6. Angular Motion Estimation Using Dynamic Models in a Gyro-Free Inertial Measurement Unit

    Directory of Open Access Journals (Sweden)

    Otmar Loffeld

    2012-04-01

    Full Text Available In this paper, we summarize the results of using dynamic models borrowed from tracking theory in describing the time evolution of the state vector to have an estimate of the angular motion in a gyro-free inertial measurement unit (GF-IMU. The GF-IMU is a special type inertial measurement unit (IMU that uses only a set of accelerometers in inferring the angular motion. Using distributed accelerometers, we get an angular information vector (AIV composed of angular acceleration and quadratic angular velocity terms. We use a Kalman filter approach to estimate the angular velocity vector since it is not expressed explicitly within the AIV. The bias parameters inherent in the accelerometers measurements’ produce a biased AIV and hence the AIV bias parameters are estimated within an augmented state vector. Using dynamic models, the appended bias parameters of the AIV become observable and hence we can have unbiased angular motion estimate. Moreover, a good model is required to extract the maximum amount of information from the observation. Observability analysis is done to determine the conditions for having an observable state space model. For higher grades of accelerometers and under relatively higher sampling frequency, the error of accelerometer measurements is dominated by the noise error. Consequently, simulations are conducted on two models, one has bias parameters appended in the state space model and the other is a reduced model without bias parameters.

  7. Angular motion estimation using dynamic models in a gyro-free inertial measurement unit.

    Science.gov (United States)

    Edwan, Ezzaldeen; Knedlik, Stefan; Loffeld, Otmar

    2012-01-01

    In this paper, we summarize the results of using dynamic models borrowed from tracking theory in describing the time evolution of the state vector to have an estimate of the angular motion in a gyro-free inertial measurement unit (GF-IMU). The GF-IMU is a special type inertial measurement unit (IMU) that uses only a set of accelerometers in inferring the angular motion. Using distributed accelerometers, we get an angular information vector (AIV) composed of angular acceleration and quadratic angular velocity terms. We use a Kalman filter approach to estimate the angular velocity vector since it is not expressed explicitly within the AIV. The bias parameters inherent in the accelerometers measurements' produce a biased AIV and hence the AIV bias parameters are estimated within an augmented state vector. Using dynamic models, the appended bias parameters of the AIV become observable and hence we can have unbiased angular motion estimate. Moreover, a good model is required to extract the maximum amount of information from the observation. Observability analysis is done to determine the conditions for having an observable state space model. For higher grades of accelerometers and under relatively higher sampling frequency, the error of accelerometer measurements is dominated by the noise error. Consequently, simulations are conducted on two models, one has bias parameters appended in the state space model and the other is a reduced model without bias parameters.

  8. Motion parameter estimation by tracking stationary three-dimensional straight lines in image sequences

    Science.gov (United States)

    Habib, Ayman

    The purpose of this work is to utilize extracted linear features from imagery collected by a Mobile Mapping System (MMS) for the purpose of motion parameter estimation. The MMS is assumed to be equipped with two or more cameras. The relative relationship between these cameras is rigid, i.e. it does not change from one epoch to the other and can be determined by a calibration procedure. An optimal (minimal) representation of 3-D straight lines that requires only four parameters is discussed. The perspective transformation of the extracted linear features back and forth between image and object space is derived. By tracking stationary linear features in successive image sequences, the motion parameters, rotation and displacement, between the system's position at the corresponding epochs can be estimated. The suggested algorithm works as follows. First, straight-line features are extracted from the imagery. Then, a model space coordinate system is defined for each system position at which an image set is collected. The origin of this system can be chosen as the perspective center of one of the cameras onboard. Then, the linear features in successive image sets are projected into the corresponding model space. It has to be noted that the projection procedure is performed separately for the image sets under consideration. The mathematical model that relates the parameters of the resulting conjugate lines to the motion parameters of the system is derived. The relationship is obtained by imposing four constraints on the four degrees of freedom of any conjugate lines. The suggested algorithm is used to estimate the motion parameters using conjugate linear features in successive stereo-pairs collected by the GPS van of the Ohio State University. This algorithm will be helpful in deriving the motion parameters of the vehicle during periods of failure of the positioning component onboard, e.g. GPS loss of lock for a long time interval.

  9. The July 17, 2011, ML 4.7, Po Plain (northern Italy earthquake: strong-motion observations from the RAIS network

    Directory of Open Access Journals (Sweden)

    Marco Massa

    2012-06-01

    Full Text Available On July 17, 2011, at 18:30:23 UTC, a ML 4.7 earthquake occurred on the east side of the Po Plain (northern Italy, between the towns of Ferrara and Rovigo. The epicentral coordinates provided by the National Earthquake Center of the Istituto Nazionale di Geofisica e Vulcanologia (National Institute of Geophysics and Volcanology, INGV were 45.01˚N and 11.41˚E (http://iside.rm.ingv.it/iside. The depth of the hypocenter was constrained at 8.1 km, corresponding to a buried active source that existed in the area. The source of the event was characterized by a predominant left-transverse focal mechanism, even if there was also an important reverse component. Although it did not produce relevant damage, the earthquake was clearly felt in an area of about 50 km radius around the epicenter. The maximum observed intensity was V on the Mercalli-Cancani-Sieberg (MCS scale, with a predominant distribution of damage towards the north-west. This study provides an overview of the strong-motion waveforms of the mainshock as recorded by the RAIS (Rete Accelerometrica Italia Settentrionale strong-motion network, in particular focusing on the recordings provided by the stations located in the central part of the basin, which were installed in correspondence with hundreds of soft sediments. The preliminary results show the relevant influence of the basin on the seismic wavefield, highlighting in particular a possible site-amplification phenomena, and also affecting the ground motion at long periods (T >1 s. The systematic underestimations provided by the empirical ground-motion predictive models calibrated for Italy in terms of acceleration response spectra up to 2.0 s support this hypothesis. The sharing of the 24 waveforms (in raw sac and ascii formats recorded by RAIS is assured by the availability of the data at the ftp site: ftp://ftp.mi.ingv.it/download/RAIS-FR_rel01/.

  10. Visual Tilt Estimation for Planar-Motion Methods in Indoor Mobile Robots

    Directory of Open Access Journals (Sweden)

    David Fleer

    2017-10-01

    Full Text Available Visual methods have many applications in mobile robotics problems, such as localization, navigation, and mapping. Some methods require that the robot moves in a plane without tilting. This planar-motion assumption simplifies the problem, and can lead to improved results. However, tilting the robot violates this assumption, and may cause planar-motion methods to fail. Such a tilt should therefore be corrected. In this work, we estimate a robot’s tilt relative to a ground plane from individual panoramic images. This estimate is based on the vanishing point of vertical elements, which commonly occur in indoor environments. We test the quality of two methods on images from several environments: An image-space method exploits several approximations to detect the vanishing point in a panoramic fisheye image. The vector-consensus method uses a calibrated camera model to solve the tilt-estimation problem in 3D space. In addition, we measure the time required on desktop and embedded systems. We previously studied visual pose-estimation for a domestic robot, including the effect of tilts. We use these earlier results to establish meaningful standards for the estimation error and time. Overall, we find the methods to be accurate and fast enough for real-time use on embedded systems. However, the tilt-estimation error increases markedly in environments containing relatively few vertical edges.

  11. Joint disparity and motion estimation using optical flow for multiview Distributed Video Coding

    DEFF Research Database (Denmark)

    Salmistraro, Matteo; Raket, Lars Lau; Brites, Catarina

    2014-01-01

    Distributed Video Coding (DVC) is a video coding paradigm where the source statistics are exploited at the decoder based on the availability of Side Information (SI). In a monoview video codec, the SI is generated by exploiting the temporal redundancy of the video, through motion estimation and c...... flow. The proposed SI generation algorithm allows for RD improvements up to 10% (Bjøntegaard) in bit-rate savings, when compared with block-based SI generation algorithms leveraging temporal and inter-view redundancies....... and compensation techniques. In a multiview scenario, the correlation between views can also be exploited to further enhance the overall Rate-Distortion (RD) performance. Thus, to generate SI in a multiview distributed coding scenario, a joint disparity and motion estimation technique is proposed, based on optical...

  12. Kernel Density Estimation based Self learning Sampling Strategy for Motion Planning of Repetitive Tasks

    Science.gov (United States)

    2016-10-09

    Kernel Density Estimation based Self -learning Sampling Strategy for Motion Planning of Repetitive Tasks Thomas Fridolin Iversen and Lars-Peter...optimized. The system is thereby self -learning and improves performance over time. The sampler is tested on a variety of planners and against other... manages to sample fewer new configurations within the given time. The WS sampler is roughly as good as the uniform sampler, while the OB sampler is

  13. Motion estimation for H.264/AVC on multiple GPUs using NVIDIA CUDA

    OpenAIRE

    Pieters, Bart; Hollemeersch, Charles; Lambert, Peter; Van de Walle, Rik

    2009-01-01

    To achieve the high coding efficiency the H.264/AVC standard offers, the encoding process quickly becomes computationally demanding. One of the most intensive encoding phases is motion estimation. Even modern CPUs struggle to process high-definition video sequences in real-time. While personal computers are typically equipped with powerful Graphics Processing Units (GPUs) to accelerate graphics operations, these GPUs lie dormant when encoding a video sequence. Furthermore, recent developments...

  14. ROBUST PARALLEL MOTION ESTIMATION AND MAPPING WITH STEREO CAMERAS IN UNDERGROUND INFRASTRUCTURE

    OpenAIRE

    Liu, Chun; Li, Zhengning; Zhou, Yuan

    2016-01-01

    Presently, we developed a novel robust motion estimation method for localization and mapping in underground infrastructure using a pre-calibrated rigid stereo camera rig. Localization and mapping in underground infrastructure is important to safety. Yet it’s also nontrivial since most underground infrastructures have poor lighting condition and featureless structure. Overcoming these difficulties, we discovered that parallel system is more efficient than the EKF-based SLAM approach since para...

  15. Comparing C- and L-band SAR images for sea ice motion estimation

    OpenAIRE

    J. Lehtiranta; S. Siiriä; Karvonen, J

    2015-01-01

    Pairs of consecutive C-band synthetic-aperture radar (SAR) images are routinely used for sea ice motion estimation. The L-band radar has a fundamentally different character, as its longer wavelength penetrates deeper into sea ice. L-band SAR provides information on the seasonal sea ice inner structure in addition to the surface roughness that dominates C-band images. This is especially useful in the Baltic Sea, which lacks multiyear ice and icebergs, known to be confusing ta...

  16. Image artefact propagation in motion estimation and reconstruction in interventional cardiac C-arm CT

    Science.gov (United States)

    Müller, K.; Maier, A. K.; Schwemmer, C.; Lauritsch, G.; De Buck, S.; Wielandts, J.-Y.; Hornegger, J.; Fahrig, R.

    2014-06-01

    The acquisition of data for cardiac imaging using a C-arm computed tomography system requires several seconds and multiple heartbeats. Hence, incorporation of motion correction in the reconstruction step may improve the resulting image quality. Cardiac motion can be estimated by deformable three-dimensional (3D)/3D registration performed on initial 3D images of different heart phases. This motion information can be used for a motion-compensated reconstruction allowing the use of all acquired data for image reconstruction. However, the result of the registration procedure and hence the estimated deformations are influenced by the quality of the initial 3D images. In this paper, the sensitivity of the 3D/3D registration step to the image quality of the initial images is studied. Different reconstruction algorithms are evaluated for a recently proposed cardiac C-arm CT acquisition protocol. The initial 3D images are all based on retrospective electrocardiogram (ECG)-gated data. ECG-gating of data from a single C-arm rotation provides only a few projections per heart phase for image reconstruction. This view sparsity leads to prominent streak artefacts and a poor signal to noise ratio. Five different initial image reconstructions are evaluated: (1) cone beam filtered-backprojection (FDK), (2) cone beam filtered-backprojection and an additional bilateral filter (FFDK), (3) removal of the shadow of dense objects (catheter, pacing electrode, etc) before reconstruction with a cone beam filtered-backprojection (cathFDK), (4) removal of the shadow of dense objects before reconstruction with a cone beam filtered-backprojection and a bilateral filter (cathFFDK). The last method (5) is an iterative few-view reconstruction (FV), the prior image constrained compressed sensing combined with the improved total variation algorithm. All reconstructions are investigated with respect to the final motion-compensated reconstruction quality. The algorithms were tested on a mathematical

  17. How do "ghost transients" from past earthquakes affect GPS slip rate estimates on southern California faults?

    Science.gov (United States)

    Hearn, E. H.; Pollitz, F. F.; Thatcher, W. R.; Onishi, C. T.

    2013-04-01

    In this study, we investigate the extent to which viscoelastic velocity perturbations (or "ghost transients") from individual fault segments can affect elastic block model-based inferences of fault slip rates from GPS velocity fields. We focus on the southern California GPS velocity field, exploring the effects of known, large earthquakes for two end-member rheological structures. Our approach is to compute, at each GPS site, the velocity perturbation relative to a cycle average for earthquake cycles on particular fault segments. We then correct the SCEC CMM4.0 velocity field for this perturbation and invert the corrected field for fault slip rates. We find that if asthenosphere viscosities are low (3 × 1018 Pa s), the current GPS velocity field is significantly perturbed by viscoelastic earthquake cycle effects associated with the San Andreas Fault segment that last ruptured in 1857 (Mw = 7.9). Correcting the GPS velocity field for this perturbation (or "ghost transient") adds about 5 mm/a to the SAF slip rate along the Mojave and San Bernardino segments. The GPS velocity perturbations due to large earthquakes on the Garlock Fault (most recently, events in the early 1600s) and the White Wolf Fault (most recently, the Mw = 7.3 1952 Kern County earthquake) are smaller and do not influence block-model inverted fault slip rates. This suggests that either the large discrepancy between geodetic and geologic slip rates for the Garlock Fault is not due to a ghost transient or that un-modeled transients from recent Mojave earthquakes may influence the GPS velocity field.

  18. Tohoku earthquake: a surprise?

    CERN Document Server

    Kagan, Yan Y

    2011-01-01

    We consider three issues related to the 2011 Tohoku mega-earthquake: (1) how to evaluate the earthquake maximum size in subduction zones, (2) what is the repeat time for the largest earthquakes in Tohoku area, and (3) what are the possibilities of short-term forecasts during the 2011 sequence. There are two quantitative methods which can be applied to estimate the maximum earthquake size: a statistical analysis of the available earthquake record and the moment conservation principle. The latter technique studies how much of the tectonic deformation rate is released by earthquakes. For the subduction zones, the seismic or historical record is not sufficient to provide a reliable statistical measure of the maximum earthquake. The moment conservation principle yields consistent estimates of maximum earthquake size: for all the subduction zones the magnitude is of the order 9.0--9.7, and for major subduction zones the maximum earthquake size is statistically indistinguishable. Starting in 1999 we have carried out...

  19. A Highly Parallel and Scalable Motion Estimation Algorithm with GPU for HEVC

    Directory of Open Access Journals (Sweden)

    Yun-gang Xue

    2017-01-01

    Full Text Available We propose a highly parallel and scalable motion estimation algorithm, named multilevel resolution motion estimation (MLRME for short, by combining the advantages of local full search and downsampling. By subsampling a video frame, a large amount of computation is saved. While using the local full-search method, it can exploit massive parallelism and make full use of the powerful modern many-core accelerators, such as GPU and Intel Xeon Phi. We implanted the proposed MLRME into HM12.0, and the experimental results showed that the encoding quality of the MLRME method is close to that of the fast motion estimation in HEVC, which declines by less than 1.5%. We also implemented the MLRME with CUDA, which obtained 30–60x speed-up compared to the serial algorithm on single CPU. Specifically, the parallel implementation of MLRME on a GTX 460 GPU can meet the real-time coding requirement with about 25 fps for the 2560×1600 video format, while, for 832×480, the performance is more than 100 fps.

  20. The USGS Earthquake Scenario Project

    Science.gov (United States)

    Wald, D. J.; Petersen, M. D.; Wald, L. A.; Frankel, A. D.; Quitoriano, V. R.; Lin, K.; Luco, N.; Mathias, S.; Bausch, D.

    2009-12-01

    The U.S. Geological Survey’s (USGS) Earthquake Hazards Program (EHP) is producing a comprehensive suite of earthquake scenarios for planning, mitigation, loss estimation, and scientific investigations. The Earthquake Scenario Project (ESP), though lacking clairvoyance, is a forward-looking project, estimating earthquake hazard and loss outcomes as they may occur one day. For each scenario event, fundamental input includes i) the magnitude and specified fault mechanism and dimensions, ii) regional Vs30 shear velocity values for site amplification, and iii) event metadata. A grid of standard ShakeMap ground motion parameters (PGA, PGV, and three spectral response periods) is then produced using the well-defined, regionally-specific approach developed by the USGS National Seismic Hazard Mapping Project (NHSMP), including recent advances in empirical ground motion predictions (e.g., the NGA relations). The framework also allows for numerical (3D) ground motion computations for specific, detailed scenario analyses. Unlike NSHMP ground motions, for ESP scenarios, local rock and soil site conditions and commensurate shaking amplifications are applied based on detailed Vs30 maps where available or based on topographic slope as a proxy. The scenario event set is comprised primarily by selection from the NSHMP events, though custom events are also allowed based on coordination of the ESP team with regional coordinators, seismic hazard experts, seismic network operators, and response coordinators. The event set will be harmonized with existing and future scenario earthquake events produced regionally or by other researchers. The event list includes approximate 200 earthquakes in CA, 100 in NV, dozens in each of NM, UT, WY, and a smaller number in other regions. Systematic output will include all standard ShakeMap products, including HAZUS input, GIS, KML, and XML files used for visualization, loss estimation, ShakeCast, PAGER, and for other systems. All products will be

  1. Ground motion attenuation during M 7.1 Darfield and M 6.2 Christchurch, New Zealand, earthquakes and performance of global Ppedictive models

    Science.gov (United States)

    Segou, Margaret; Kalkan, Erol

    2011-01-01

    The M 7.1 Darfield earthquake occurred 40 km west of Christchurch (New Zealand) on 4 September 2010. Six months after, the city was struck again with an M 6.2 event on 22 February local time (21 February UTC). These events resulted in significant damage to infrastructure in the city and its suburbs. The purpose of this study is to evaluate the performance of global predictive models (GMPEs) using the strong motion data obtained from these two events to improve future seismic hazard assessment and building code provisions for the Canterbury region.The Canterbury region is located on the boundary between the Pacific and Australian plates; its surface expression is the active right lateral Alpine fault (Berryman et al. 1993). Beneath the North Island and the north South Island, the Pacific plate subducts obliquely under the Australian plate, while at the southwestern part of the South Island, a reverse process takes place. Although New Zealand has experienced several major earthquakes in the past as a result of its complex seismotectonic environment (e.g., M 7.1 1888 North Canterbury, M 7.0 1929 Arthur's Pass, and M 6.2 1995 Cass), there was no evidence of prior seismic activity in Christchurch and its surroundings before the September event. The Darfield and Christchurch earthquakes occurred along the previously unmapped Greendale fault in the Canterbury basin, which is covered by Quaternary alluvial deposits (Forsyth et al. 2008). In Figure 1, site conditions of the Canterbury epicentral area are depicted on a VS30 map. This map was determined on the basis of topographic slope calculated from a 1-km grid using the method of Allen and Wald (2007). Also shown are the locations of strong motion stations.The Darfield event was generated as a result of a complex rupture mechanism; the recordings and geodetic data reveal that earthquake consists of three sub-events (Barnhart et al. 2011, page 815 of this issue). The first event was due to rupturing of a blind reverse

  2. Implications of some early Jewish sources for estimates of earthquake hazardin the Holy Land

    Directory of Open Access Journals (Sweden)

    I. Karcz

    2004-06-01

    Full Text Available For the past two millennia the Holy Land was under the yoke of successive invaders and oppressors, not a fertile ground for growth of historiographic traditions. Consequently, earthquake cataloguers had to rely largely on chronicles and texts written at distant administrative and cultural centers of the day, where earthquake destruction suffered by a culturally and economically depressed province may have been overshadowed by damage in more important parts of the empire. On this assumption, and aided by an implicit notion that the lands bounded by the Dead Sea Rift and Anatolian Fault systems are seismically contiguous, early cataloguers often extended the impact of earthquakes documented in nearby East Mediterranean countries to the Holy Land. Once published, such reports of supposed destructive intensities in Israel were used by Judaic scholars and archaeologists to date poorly defined, often metaphoric, literary seismic echoes, and to justify assigning seismic origin to equivocal signs of damage, asymmetry, or abandonment at archaeological sites of corresponding age. The spread of damage and intensity portraits are therefore enhanced and distorted, and so is their application in palaeoseismic analysis. Four test cases are presented, illustrating the use and misuse of local Judaic sources in identifying destructive intensities supposedly generated in the Holy Land by earthquakes of 92 B.C., 64 B.C. and 31 B.C., and in postulating a regional seismic catastrophe in 749 A.D..

  3. Estimates of source parameters of 4.9 Kharsali earthquake using ...

    Indian Academy of Sciences (India)

    ... the computation of time series of the 22 July 2007 4.9 Kharsali earthquake. It occurred close to the Main Central Thrust (MCT)where seismic gap exists.The main shock and 17 aftershocks were located by closely spaced eleven seismograph stations in a network that involved VSAT based real-time seismic monitoring.

  4. Perspectives on earthquake hazards in the New Madrid seismic zone, Missouri

    Science.gov (United States)

    Thenhaus, P.C.

    1990-01-01

    A sequence of three great earthquakes struck the Central United States during the winter of 1811-1812 in the area of New Madrid, Missouri. they are considered to be the greatest earthquakes in the conterminous U.S because they were felt and caused damage at far greater distances than any other earthquakes in U.S history. The large population currently living within the damage area of these earthquakes means that widespread destruction and loss of life is likely if the sequence were repeated. In contrast to California, where the earthquakes are felt frequently, the damaging earthquakes that have occurred in the Easter U.S-in 155 (Cape Ann, Mass.), 1811-12 (New Madrid, Mo.), 1886 (Charleston S.C) ,and 1897 (Giles County, Va.- are generally regarded as only historical phenomena (fig. 1). The social memory of these earthquakes no longer exists. A fundamental problem in the Eastern U.S, therefore, is that the earthquake hazard is not generally considered today in land-use and civic planning. This article offers perspectives on the earthquake hazard of the New Madrid seismic zone through discussions of the geology of the Mississippi Embayment, the historical earthquakes that have occurred there, the earthquake risk, and the "tools" that geoscientists have to study the region. The so-called earthquake hazard is defined  by the characterization of the physical attributes of the geological structures that cause earthquakes, the estimation of the recurrence times of the earthquakes, the estimation of the recurrence times of the earthquakes, their potential size, and the expected ground motions. the term "earthquake risk," on the other hand, refers to aspects of the expected damage to manmade strctures and to lifelines as a result of the earthquake hazard.  

  5. Estimation of Ground Reaction Forces and Moments During Gait Using Only Inertial Motion Capture

    Directory of Open Access Journals (Sweden)

    Angelos Karatsidis

    2016-12-01

    Full Text Available Ground reaction forces and moments (GRF&M are important measures used as input in biomechanical analysis to estimate joint kinetics, which often are used to infer information for many musculoskeletal diseases. Their assessment is conventionally achieved using laboratory-based equipment that cannot be applied in daily life monitoring. In this study, we propose a method to predict GRF&M during walking, using exclusively kinematic information from fully-ambulatory inertial motion capture (IMC. From the equations of motion, we derive the total external forces and moments. Then, we solve the indeterminacy problem during double stance using a distribution algorithm based on a smooth transition assumption. The agreement between the IMC-predicted and reference GRF&M was categorized over normal walking speed as excellent for the vertical (ρ = 0.992, rRMSE = 5.3%, anterior (ρ = 0.965, rRMSE = 9.4% and sagittal (ρ = 0.933, rRMSE = 12.4% GRF&M components and as strong for the lateral (ρ = 0.862, rRMSE = 13.1%, frontal (ρ = 0.710, rRMSE = 29.6%, and transverse GRF&M (ρ = 0.826, rRMSE = 18.2%. Sensitivity analysis was performed on the effect of the cut-off frequency used in the filtering of the input kinematics, as well as the threshold velocities for the gait event detection algorithm. This study was the first to use only inertial motion capture to estimate 3D GRF&M during gait, providing comparable accuracy with optical motion capture prediction. This approach enables applications that require estimation of the kinetics during walking outside the gait laboratory.

  6. Estimation of Ground Reaction Forces and Moments During Gait Using Only Inertial Motion Capture.

    Science.gov (United States)

    Karatsidis, Angelos; Bellusci, Giovanni; Schepers, H Martin; de Zee, Mark; Andersen, Michael S; Veltink, Peter H

    2016-12-31

    Ground reaction forces and moments (GRF&M) are important measures used as input in biomechanical analysis to estimate joint kinetics, which often are used to infer information for many musculoskeletal diseases. Their assessment is conventionally achieved using laboratory-based equipment that cannot be applied in daily life monitoring. In this study, we propose a method to predict GRF&M during walking, using exclusively kinematic information from fully-ambulatory inertial motion capture (IMC). From the equations of motion, we derive the total external forces and moments. Then, we solve the indeterminacy problem during double stance using a distribution algorithm based on a smooth transition assumption. The agreement between the IMC-predicted and reference GRF&M was categorized over normal walking speed as excellent for the vertical ( ρ = 0.992, rRMSE = 5.3%), anterior ( ρ = 0.965, rRMSE = 9.4%) and sagittal ( ρ = 0.933, rRMSE = 12.4%) GRF&M components and as strong for the lateral ( ρ = 0.862, rRMSE = 13.1%), frontal ( ρ = 0.710, rRMSE = 29.6%), and transverse GRF&M ( ρ = 0.826, rRMSE = 18.2%). Sensitivity analysis was performed on the effect of the cut-off frequency used in the filtering of the input kinematics, as well as the threshold velocities for the gait event detection algorithm. This study was the first to use only inertial motion capture to estimate 3D GRF&M during gait, providing comparable accuracy with optical motion capture prediction. This approach enables applications that require estimation of the kinetics during walking outside the gait laboratory.

  7. Play estimation with motions and textures with automatic generation of template space-time map

    Science.gov (United States)

    Aoki, Kyota; Aita, Ryo; Fukiba, Takuro

    2015-07-01

    It is easy to retrieve the small size parts from small videos. It is also easy to retrieve the middle size part from large videos. However, we have difficulties to retrieve the small size parts from large videos. We have large needs for estimating plays in sport videos. Plays in sports are described as the motions of pla