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Sample records for accelerographs

  1. Geotechnical investigations made on the soils under the accelerographic stations of Ancona-Rocca and Ancona-Palombina

    This report presents the results of the geotechnical investigations, made on the soils under the accelerographic stations of Ancona-Rocca and Ancona-Palombina, which, during 1972 seismic crisis, recorded a great number of significant accelerograms. (author)

  2. Earthquake response of storey building in Jakarta using accelerographs data analysis

    Julius, Admiral Musa, E-mail: admiralmusajulius@yahoo.com [Study Program of Geophysics, Indonesia State College of Meteorology Climatology and Geophysics (STMKG), Jl. Perhubungan 1 No. 5, Bintaro 15221 (Indonesia); Jakarta Geophysics Observatory, Indonesia Agency of Meteorology Climatology and Geophysics (BMKG), Jl. Angkasa 1 No. 2, Kemayoran, Jakarta 10720 (Indonesia); Sunardi, Bambang, E-mail: b.sunardi@gmail.com [Research and Development Center, Indonesia Agency of Meteorology Climatology and Geophysics (BMKG), Jl. Angkasa 1 No. 2, Kemayoran, Jakarta 10720 (Indonesia)

    2015-04-24

    As seismotectonic, the Jakarta city will be greatly affected by the earthquake which originated from the subduction zone of the Sunda Strait and south of Java. Some occurrences of earthquakes in these location are often perceived by the occupants in the upper floors of multi-storey buildings in Jakarta but was not perceived by the occupants on the ground floor. The case shows the difference in ground-motion parameters on each floor height. The analysis of the earthquake data recorded by accelerographs on different floors need to be done to know the differences in ground-motion parameters. Data used in this research is accelerograph data installed on several floors in the main building of Meteorology Climatology and Geophysics Agency with a case study of Kebumen earthquake on January 25{sup th} 2014. Parameters analyzed include the Peak Ground Acceleration (PGA), Peak Ground Displacement (PGD), Peak Spectral Acceleration (PSA), Amplification (Ag), and the Effective Duration of earthquake (t{sub e}). Research stages include accelerographs data acquisition in three (3) different floors, conversion and data partition for each component, conversion to units of acceleration, determination of PGA, PGD, PSA, Ag and t{sub e} as well as data analysis. The study shows the value of PGA on the ground floor, 7{sup th} floor and 15{sup th} floors, respectively are 0.016 g, 0.053 g and 0.116 g. PGD on the ground floor, 7{sup th} floor and 15{sup th} floor respectively are 2.15 cm, 2.98 cm and 4.92 cm. PSA on the ground floor, 7{sup th} floor and 15{sup th} floor respectively are 0.067 g, 0.308 g and 0.836 g. Amplification of the peak acceleration value on the ground floor, 7{sup th} floor and 15{sup th} floor to the surface rock are 4.37, 6.07 and 7.30. Effective duration of the earthquake on the ground floor, 7{sup th} floor and 15{sup th} floor respectively are 222.28 s, 202.28 s and 91.58 s. In general, with increasing floor of the building, the value of the

  3. Earthquake response of storey building in Jakarta using accelerographs data analysis

    As seismotectonic, the Jakarta city will be greatly affected by the earthquake which originated from the subduction zone of the Sunda Strait and south of Java. Some occurrences of earthquakes in these location are often perceived by the occupants in the upper floors of multi-storey buildings in Jakarta but was not perceived by the occupants on the ground floor. The case shows the difference in ground-motion parameters on each floor height. The analysis of the earthquake data recorded by accelerographs on different floors need to be done to know the differences in ground-motion parameters. Data used in this research is accelerograph data installed on several floors in the main building of Meteorology Climatology and Geophysics Agency with a case study of Kebumen earthquake on January 25th 2014. Parameters analyzed include the Peak Ground Acceleration (PGA), Peak Ground Displacement (PGD), Peak Spectral Acceleration (PSA), Amplification (Ag), and the Effective Duration of earthquake (te). Research stages include accelerographs data acquisition in three (3) different floors, conversion and data partition for each component, conversion to units of acceleration, determination of PGA, PGD, PSA, Ag and te as well as data analysis. The study shows the value of PGA on the ground floor, 7th floor and 15th floors, respectively are 0.016 g, 0.053 g and 0.116 g. PGD on the ground floor, 7th floor and 15th floor respectively are 2.15 cm, 2.98 cm and 4.92 cm. PSA on the ground floor, 7th floor and 15th floor respectively are 0.067 g, 0.308 g and 0.836 g. Amplification of the peak acceleration value on the ground floor, 7th floor and 15th floor to the surface rock are 4.37, 6.07 and 7.30. Effective duration of the earthquake on the ground floor, 7th floor and 15th floor respectively are 222.28 s, 202.28 s and 91.58 s. In general, with increasing floor of the building, the value of the peak ground acceleration, peak ground displacement, peak spectral acceleration

  4. Real-time simulation of ground displacement by digital accelerograph record

    金星; 马强; 李山有

    2005-01-01

    With the development of accelerograph, strong ground motion data can be widely applied to many fields. Especially, it is an important milestone for strong motion observation to expand application fields into earthquake monitoring that real-time simulation of ground displacement can be obtained by strong motion records for determining three earthquake parameters. For the purpose of application, on the basis of principle of seismic response of single-degree-of-freedom (SDOF) system, this paper presents a suit of formula of simulating ground displacement records by using strong ground motion records with the help of simulator of SDOF system. The research results show that the technique is very efficient and can be widely applied to earthquake monitoring.

  5. 基于马尔科夫过程的机电控制系统可靠性评估%Reliability Evaluation of Accelerograph System Based on Markov Process

    王振全; 王道震

    2013-01-01

      首先将其马尔科夫过程引入到不可修复系统中,建立机电控制系统的马尔科夫模型并导出相应的状态转移矩阵和微分方程组。然后将现代控制理论中的拉普拉斯变换法应用到微分方程的求解中,并解算出相应的可靠性指标。最后,利用 Matlab 对新模型和旁联模型进行可靠性仿真,对比发现该模型的可靠度和 MTBF 比旁联模型有很大改善。%  Markov process to the no-repairable system was introduced and the corresponding Markov model state transition matrices and differential equations of the accelerograph system were derived. Laplace transform method in modern control theory was applied to solve differential equations, and the corresponding reliability index was calculated. The reliability simulation was carried out with MATLAB,the reliability and MTBF of the new model have improved compared to that of the sequentially operating units model.

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

    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...

  7. Strong ground motion data from the 1983 Borah Peak, Idaho earthquake recorded at the Idaho National Engineering Laboratory

    The 1983 Borah Peak, Idaho Earthquake was the largest normal faulting event to occur in the last 20 years. There were no near-field recordings of ground motion during the main shock, however, thirteen accelerographs in a permanent array at the Idaho National Engineering Laboratory (INEL) recorded the event at epicentral distances of 90-110 km. Peak horizontal accelerations (PGA) recorded at accelerographs above ground-floor level range from 0.037 to 0.187 g. Accelerographs at basement and free-field sites recorded as low as 0.022 g and as high as 0.078 g. Peak vertical accelerations range from 0.016 g ground level to 0.059 g above ground floor level. A temporary array of digital seismographs deployed by the US Geological Survey (USGS) in the epicentral area recorded ground motion from six large aftershocks at epicentral distances of 4-45 km; the largest of these aftershocks also triggered four accelerographs in the INEL array. Two separate analyses were used to estimate near-field ground motion. The first analysis uses the attenuation of the aftershock PGA measurements to extrapolate the INEL main shock PGA measurements into the near-field. This estimates an upper limit of 0.8 g for near-field ground motion. In the second analysis, a set of main shock accelerograms were synthesized. Wave propagation effects were determined from aftershock recordings at one of the USGS portable stations and an INEL seismograph station. These effects were removed from one of the INEL main shock acceleration traces. The synthetic accelerograms were derived for a hypothetical station southwest of Mackay, Idaho. The PGA measured from the synthetic accelerograms were 0.08, 0.14, 0.15, 0.23 g. These estimates correlate well with ground motion expected for an area of Intensity VII. 12 references, 8 figures, 1 table

  8. ARQUITECTURA DE UN SISTEMA DISTRIBUIDO PARA GESTIÓN DE EMERGENCIAS SÍSMICAS

    ZAMBRANO VIZUETE, ANA MARÍA

    2015-01-01

    [EN] This thesis project has a different and innovative approach to detect seismic events in real time gaining knowledge of the community through a hierarchical architecture in 3 layers: The first layer, a low-cost distributed network which takes advantage of the current huge trend; the smartphone; a multi-sensor, multi-network, multi-task device embedded into a small processing computer able to be reprogrammed, for example, in an "accelerograph" through an efficient in precision and power c...

  9. Site response and seismic wavefield in Toluca city, Mexico, from strong motion records

    Hugo Ferrer-Toledo; Martín Cárdenas-Soto; Francisco J. Chávez-García

    2006-01-01

    Since 1993 a network of 6 accelerographs has been operating in the city of Toluca. To date, only one seismic event has been recorded by all six stations. We analyse in detail those records with the purpose of measuring site response and analyzing the recorded wavefield. We compute spectral ratios of Fourier amplitude spectra relative to a reference station and of the horizontal components relative to the vertical recorded at each site. We compare the traces in different period bands, analyse ...

  10. Providing a Model for Assessment of Horizontal and Vertical Earthquake

    Taleb Sadeghian

    2013-01-01

    In this study, the effect of place soil and seismic vulnerability has not been considered in determining the earthquake force, although all results have been based on scale accelerographs. Moreover, the importance of structures has not been rated based on small or large spans, decorative or structural structure and the effect of these cases is not considered. In this regard, double-layer barrel vaults have been studied and effect of horizontal and vertical seismic force on it reviewed and equ...

  11. The 2001 Mw7.7 Bhuj, India Earthquake and Eastern North American Ground-Motion Attenuation Relations: Seismic Hazard Implications

    Cramer, C. H.; Bhattacharya, S. N.; Kumar, A.

    2002-12-01

    It has been suggested that the Mw7.7 2001 Bhuj, India earthquake occurred in a stable continental region with ground-motion attenuation properties similar to eastern North America (ENA). No strong motion recordings for M7 or greater earthquakes have been recorded in ENA, so, if the two regions share similar properties, then observations from the Bhuj earthquake provide important information for hazard assessments in ENA as well as India. This thesis can be tested using seismic data for the Bhuj mainshock. The Indian Meteorological Department recorded accelerograph and broadband seismograph data at distances of 500 to 1800 km. Accelerograph and engineering seismoscope data were recorded at distances of 40 to 1100 km by the Department of Earthquake Engineering at the Indian Institute of Technology, Roorkee. We have processed the accelerograph and broadband data for response spectral accelerations and corrected them to a common NEHRP site class using Joyner and Boore (2000) site factors. The geologic conditions at each recording site were determined using the geologic map of India and categorized as Quaternary sediments, Tertiary sediments, or hard rock. Comparisons were then made to available ENA ground-motion attenuation relations. For peak ground acceleration (PGA) and 1.0 s spectral acceleration (Sa), the geologically-corrected Bhuj data generally fall among the ENA ground-motion attenuation relations. The Bhuj mainshock ground-motion data agree with the collective predictions of the ENA relations given the random uncertainty in ground-motion measurements of a factor of two or more plus the ground-motion attenuation relation modeling uncertainty. From an engineering perspective, this comparison supports the thesis that seismic-wave attenuation in stable continental India is similar to eastern North America.

  12. Compilation of strong-motion records from the August 6, 1979 Coyote Lake earthquake

    Porcella, R.L.; Matthiesen, R.B.; McJunkin, R.D.; Ragsdale, J.T.

    1979-01-01

    This report represents a joint effort by the OSMS, CDMG and the U.S. Geological Survey (USGS). The report summarizes all strong-motion accelerograph records recovered from the August 6, 1979 Coyote Lake earthquake. The majority of accelerograms were recorded at stations operated by the OSMS-CDMG and USGS; the latter organization operates a network of instruments that belong to various federal agencies. Documentation of strong-motion data for the Coyote Lake earthquake best serves the scientific community if presented as a single data set.

  13. Estimation of source parameters of Chamoli Earthquake, India

    Y Pandey; R Dharmaraju; P K S Chauhan

    2001-06-01

    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 from the Strong Motion Data are presented. The seismic moment for this event has been found to be of the order of 1025 dyne.cm and the moment mag- nitude has been calculated in the range of 6.53-6.69 at different stations. The stress drop and source radius for the earthquake are also calculated.

  14. Evidence for fault-related directionality and localized site effects from strong motion recordings of the 2003 Boumerdes (Algeria) earthquake : consequences on damage distribution and the Algerian seismic code

    Laouami, N.; Slimani, A.; Bouhadad, Y.; Chatelain, Jean-Luc; Nour, A.

    2006-01-01

    The Algiers-Boumerdes region has been struck by a destructive magnitude 6.8 (M-w) earthquake on May 21, 2003. The study presented in this paper is based on main shock strong motions from 13 stations of the Algerian accelerograph network. A maximum 0.58g peak ground acceleration (PGA) has been recorded at 20 km from the epicenter, only about 150 in away from a PGA of 0.34g, with both a central frequency around 5 Hz, explained by a strong very localized site effect, confirmed by receiver functi...

  15. Detecting cosmic string passage through the Earth by consequent global earthquake

    Motohashi, Hayato

    2013-01-01

    Effects invoked by the passage of the cosmic string through the Earth are investigated. The cosmic string induces global oscillations of the Earth whose amplitude and acceleration both linearly depend on the string line density. For the line density maximally allowed by the cosmic observations, the oscillations are perceivable even to human beings and may cause serious damages to the environment. Use of the sophisticated accelerograph enables us to detect the string of a line density down to ten orders of magnitude smaller than the cosmologically relevant value.

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

    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.

  17. Dynamic deformations of shallow sediments in the Valley of Mexico, Part I: Three-dimensional strains and rotations recorded on a seismic array

    Bodin, P.; Gomberg, J.; Singh, S.K.; Santoyo, M.

    1997-01-01

    We study the spatial variation in earthquake ground motions, or equivalently the dynamic displacement gradient field, using a novel analysis procedure borrowed from geodesy. Seismic data recorded in the Valley of Mexico by a microarray of three three-component surface accelerographs and two three-component accelerographs at depths of 30 m and 102 m constrain our estimates of the dynamic displacement gradient field (from which strains and rotations derive) for four moderate earthquakes at distances of 250 to 300 km. Our study focuses on the effects of low-velocity surface materials on the deformation. At the surface, the gradients corresponding to deformation across vertical planes dominate, and vertical-axis rotations are of similar magnitudes as strains. The greatest peak surface gradient we observed was 206 ??strain for the 14 September 1995 Mw 7.5 earthquake at a distance of ???300 km. However, much larger gradients occur across horizontal planes (???u/???z, where u is a horizontal displacement and z is depth) at some depth between 0 and 30 m. These values are about a factor 10 greater than the corresponding gradient components at the surface, ???u/???z for the 14 September earthquake equaled or exceeded 665 ??strain at depth. The dynamic deformations experienced in Mexico City undoubtedly have occurred before and will occur again in other densely populated areas. However, in many other regions, the sediment response will not remain linear and elastic, resulting instead in liquefaction and ground failure.

  18. Instrumental Intensity as a Tool for Post-Earthquake Damage Assessment: Validation for the Strong Vrancea Earthquakes of August 1986 and May 1990

    Craifaleanu, I G

    2012-01-01

    The frequency-dependent spectrum based seismic intensity, also called instrumental intensity, is calculated basically from the integration of the square values of spectral acceleration ordinates. The values of the instrumental intensity are calibrated to match the values of the EMS-98 intensity scale, providing a promising analytical indicator for estimating the destructive potential of earthquakes. Previous studies have shown that the proposed index could be used as a basis for the development of a new improved seismic intensity scale. The paper presents a set of maps describing the spatial distribution of instrumental intensity ordinates for three seismic events recorded in 1986 and 1990. These events, generated by the Vrancea source, are the strongest earthquakes in Romania for which accelerographic data was recorded at multiple stations. Intensity maps were generated for separate significant frequency bands, in order to reveal the destructiveness of the considered earthquakes for different building catego...

  19. INL Seismic Monitoring Annual Report: January 1, 2004 - December 31, 2004

    S. Payne; A. Holland; J. Hodges; R. Berg

    2005-09-01

    During 2004, INL analyzed more than 2,300 earthquakes. There were 487 earthquakes with magnitudes up to 4.0 located within the 161-km (100-mile) radius of the Idaho National Laboratory (INL). Seventeen small to moderate earthquakes of magnitudes from 3.0 to 5.0 occurred with the region outside the 161-km radius. Earthquakes activity occurred in areas that have experienced seismic activity in the past, the Basin and Range northwest of the INL, southwestern Montana, Yellowstone Park, Wyoming, Jackson, Wyoming, and southeastern Idaho. One earthquake was located northeast of Idaho Falls, Idaho within the eastern Snake River Plain (ESRP). No earthquakes were located within the INL boundaries. Earthquakes were not recorded by strong-motion accelerographs located in INL facilities.

  20. Compilation, assessment and expansion of the strong earthquake ground motion data base. Seismic Safety Margins Research Program (SSMRP)

    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. (author)

  1. An attempt to recalibrate instrumental criteria for intensity assessment

    Horea SANDI

    2014-12-01

    Full Text Available The authors contributed during a quite long period of time to the development of comprehensive and flexible system of estimating seismic intensity on the basis of instrumental (accelerographic data on earthquake ground motion. The system makes it possible to determine for a record, according to needs, global intensities, intensities corresponding to definite frequencies, intensities averaged upon a spectral band, continuous or discrete intensity spectra. Moreover, the intensity measures developed may rely, according to choice, on different outcomes of processing of primary instrumental data. A problem to which the paper is devoted is represented by the calibration of an important parameter, namely the logarithm base adopted in view of conversing instrumental information to intensity measures. After the attempts of the past, new sources are used this time to solve the problem. Alternative solutions are examined and discussed in this view.

  2. INL Seismic Monitoring Annual Report: January 1, 2009 – December 31, 2009

    N. S. Carpenter; S. J. Payne; J. M. Hodges; R. G. Berg

    2010-09-01

    The Idaho National Laboratory (INL) has accumulated 37 years of earthquake data (1972-2009). This report covers the earthquake activity from January 1, 2009 through December 31, 2009 and is a continuation of previous annual reports on earthquake activity surrounding the eastern Snake River Plain (ESRP) and within and near the INL. It discusses the earthquake activity that has occurred around the local region and within a 161-km radius around the INL centered at 43? 39.00' N, 112? 47.00' W). It discusses the seismic station and strong motion accelerograph instrumentation used to record earthquake data and how they were analyzed. It also includes a brief discussion of continuous GPS (Global Positioning System) stations co-located at INL seismic stations.

  3. Cross-correlations of ambient noise recorded by accelerometers.

    Rábade García, S. E.; Ramirez-Guzman, L.

    2014-12-01

    We investigate the ambient noise cross-correlations obtained by using properly corrected accelerometric recordings, and determine velocity structure in central Mexico based on a dispersion analysis. The data used comprise ten months of continuous recordings - from April 2013 to January 2014 - of ambient seismic noise at stations operated by the National Seismological Service of Mexico and the Engineering Strong Ground Motion Network of the National Autonomous University of Mexico (UNAM). The vertical component of ambient noise was base-line corrected, filtered, and properly integrated before extracting Green's functions (GF), which were compared successfully against GF obtained using recordings from broadband velocity sensors. In order to obtain dispersion curves, we estimated group and phase velocities applying the FTAN analysis technique and obtained s-wave velocity profiles at selected regions. We conclude and highlight that the use of widely deployed accelerographs to conduct regional studies using ambient noise tomography is feasible

  4. Proposal of Screening Method of Sleep Disordered Breathing Using Fiber Grating Vision Sensor

    Aoki, Hirooki; Nakamura, Hidetoshi; Nakajima, Masato

    Every conventional respiration monitoring technique requires at least one sensor to be attached to the body of the subject during measurement, thereby imposing a sense of restraint that results in aversion against measurements that would last over consecutive days. To solve this problem, we developed a respiration monitoring system for sleepers, and it uses a fiber-grating vision sensor, which is a type of active image sensor to achieve non-contact respiration monitoring. In this paper, we verified the effectiveness of the system, and proposed screening method of the sleep disordered breathing. It was shown that our system could equivalently measure the respiration with thermistor and accelerograph. And, the respiratory condition of sleepers can be grasped by our screening method in one look, and it seems to be useful for the support of the screening of sleep disordered breathing.

  5. Seismic Safety Margins Research Program, Phase I. Project II: seismic input. Compilation, assessment and expansion of the strong earthquake ground motion data base

    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.

  6. Providing a Model for Assessment of Horizontal and Vertical Earthquake

    Taleb Sadeghian

    2013-01-01

    Full Text Available In this study, the effect of place soil and seismic vulnerability has not been considered in determining the earthquake force, although all results have been based on scale accelerographs. Moreover, the importance of structures has not been rated based on small or large spans, decorative or structural structure and the effect of these cases is not considered. In this regard, double-layer barrel vaults have been studied and effect of horizontal and vertical seismic force on it reviewed and equations are presented in order to evaluate the equivalent static force of horizontal and vertical earthquake. Presented equations facilitate determining the equivalent static force due to earthquake for space structures, but they also have deficiencies which solving them can be useful for researchers who want to continue the way.

  7. Seismic Monitoring with NetQuakes: The First 75 in the Pacific Northwest

    Bodin, P.; Vidale, J. E.; Luetgert, J. H.; Malone, S. D.; Delorey, A. A.; Steele, W. P.; Gibbons, D. A.; Walsh, L. K.

    2011-12-01

    NetQuakes accelerographs are relatively inexpensive Internet-aware appliances that we are using as part of our regional seismic monitoring program in the Pacific Northwest Seismic Network (PNSN). To date we have deployed approximately 65 units. By the end of 2011, we will have at least 75 systems sited and operating. The instruments are made by Swiss manufacturer GeoSig, Ltd., and have been obtained by PNSN through several cooperative programs with the US Geological Survey (USGS). The NetQuakes systems have increased the number of strong-motion stations in the Pacific Northwest by ~50%. NetQuakes instruments connect to the Internet via wired or wireless telemetry, obtain accurate timing vie Network Time Protocol, and are designed to be located in the ground floor of houses or small buildings. At PNSN we have concentrated on finding NetQuakes hosts by having technologically savvy homeowners self-identify as a response to news reports about the NetQuakes project. Potential hosts are prioritized by their proximity to target sites provided by a regional panel of experts who studied the region's strong-ground-motion monitoring needs. Recorded waveforms, triggered by strong motion or retrieved from a buffer of continuous data, are transmitted to Menlo Park, and then on to PNSN in Seattle. Data are available with latency of a few minutes to a little over an hour, and are automatically incorporated with the rest of PNSN network data for analysis and the generation of earthquake products. Triggered data may also be viewed by the public via the USGS website, [http://earthquake.usgs.gov/monitoring/netquakes/map/pacnw]. We present examples of ground motion recordings returned to date. Local earthquakes up to M4 (at a distance of ~60 km) reveal interesting patterns of local site effects. The 11 March M9 Tohoku, Japan earthquake produced ground motions recorded on the PNSN accelerographs, including many NetQuakes systems, that reveal the extent and severity of basin

  8. Strong Motion Observations In India-synthesis of Results

    Bansal, B. K.; Gupta, G. D.; Srivastava, H. N.

    During the last two decades strong motion arrays have been installed in the various parts of Himalaya including N-E India through the Department of Science &Technology. Several moderate earthquakes have been recorded by these networks, which have brought out interesting results about the pattern of attenuation of ground acceleration in these regions. The networks are being strengthened further covering the entire Indian region. Significant improvement in the strong motion data have been made possible with the installation of digital accelerographs with GPS timing systems. The paper presents the strong motion results of Bhuj (2001) and other earthquakes recorded at Delhi, Ahmedabad, Koyna region, besides Himalaya and NE India. The most interesting results pertain to the distinct difference in the attenuation characteristics in the Himalayan region vis-à-vis NE India. The paper also summarizes the methods used to synthesize expected ground motions by random summation of the Empirical Green's Function and the stochastic methods for different site conditions in Delhi due to a possible great earthquake (M=8.0) in the central Himalayas. It is concluded that for reliable assessment of strong ground acceleration, the network of stations needs further improvement.

  9. 1D and 2D site amplification effects at Tarcento (Friuli, NE Italy), 30 years later

    Cauzzi, Carlo; Faccioli, Ezio; Costa, Giovanni

    2011-01-01

    A temporary accelerometer network has been installed in Tarcento (Friuli, NE Italy), a small town heavily hit by the 1976-1977 Friuli earthquake sequence, as a part of an ongoing research project aimed at ground motion simulation and generation of shakemaps in the near-field of an earthquake. The network operated from October 2008 to April 2010 and consisted of three K2 accelerographs with internal Episensor, distributed over a linear array of about 1.5 km length. Tarcento town had been chosen, at the end of the 1970s, as the ideal site for a pilot microzonation study, the first of this kind in Italy, in which a substantial number of field (and laboratory) tests were carried out in order to assess the mechanical properties of local alluvium deposits and their complex (3D) geometrical configuration. The data from the temporary network, illustrated herein, allow for proper verification and review of some of the quantitative predictions formulated in the 1980 study. As argued in the discussion section, we also believe that the data are apt to provide valuable information of more general interest on the complex seismic response of alluvium-filled valleys, and we show therein how the observations can be interpreted in the light of presently available parametric simulation studies and simplified criteria for handling basin amplification effects.

  10. Liquefaction-induced settlement, site effects and damage in the vicinity of Yalova City during the 1999 Izmit earthquake, Turkey

    Ferhat Ozcep; Savas Karabulut; Oguz Özel; Tazegul Ozcep; Nazire İmre; Halil Zarif

    2014-02-01

    Yalova City (Turkey) is in a tectonically active location that is particularly affected by the northern branch of the North Anatolian Fault Zone. Magnitudes 7.4 and 7.2 earthquakes in 1999 caused great destruction in Yalova. The heavy damage to buildings and other civil engineering structures was mainly due to liquefaction-induced settlement and site effects such as resonance and amplification. In the first phase of this study, the soil liquefaction potential index (PL) and the induced soil settlement were estimated. In the second phase, the effects on sites in Yalova soil were investigated using microtremor and earthquake data. The fundamental periods and amplification in soft soil were compared with microtremor data and strong ground motion records obtained by a local array of eight accelerograph stations deployed in Yalova. Thirty-seven ‘single site’ ambient noise measurements were taken in a dense grid of points covering the centre of the city. A comparison between fundamental periods obtained from strong ground motion records and from microtremor measurements showed similarities, in the 0.1–5 Hz range. Finally, soil liquefaction and amplification (or resonance) were divided into regions according to the extent of damage and the geotechnical/geophysical results.

  11. Instrumental Intensity as a Tool for Post-Earthquake Damage Assessment: Validation for the Strong Vrancea Earthquakes of August 1986 and May 1990

    Ioan Sorin BORCIA

    2011-07-01

    Full Text Available The frequency-dependent spectrum based seismic intensity, also called instrumental intensity, is calculated basically from the integration of the square values of spectral acceleration ordinates. The values of the instrumental intensity are calibrated to match the values of the EMS-98 intensity scale, providing a promising analytical indicator for estimating the destructive potential of earthquakes. Previous studies have shown that the proposed index could be used as a basis for the development of a new improved seismic intensity scale. The paper presents a set of maps describing the spatial distribution of instrumental intensity ordinates for three seismic events recorded in 1986 and 1990. These events, generated by the Vrancea source, are the strongest earthquakes in Romania for which accelerographic data was recorded at multiple stations. Intensity maps were generated for separate significant frequency bands, in order to reveal the destructiveness of the considered earthquakes for different building categories. Results were compared and correlated with previous studies on Vrancea earthquakes and with information provided by building damage reports from the considered earthquakes.

  12. Changes in Seismic Response of the Natural Resources Building, Olympia, WA Due to Earthquake Shaking

    Bodin, P.; Vidale, J. E.; Walsh, T.; Cakir, R.; Celebi, M.

    2008-12-01

    The Natural Resources Building (NRB) in Olympia was shaken by three earthquakes (Mw=5.8, 6.8, and 5.0) between 1999 and 2001. Building motions were recorded on digital accelerographs, which comprise one of the best dense digital recordings to date of repeated strong shaking an a building. N-S motions dominate the fundamental mode of vibration of the building. In the 1999 earthquake, the frequency of this fundamental mode was 1.3Hz during motions of 10%g. The frequency dropped to 0.7Hz during the 2001 Nisqually strong motions, in which the strongest shaking included high-frequency transients of up to 0.18 g, several of which are visible on widely spaced stations. The weaker 2001 Satsop earthquake motions showed the frequency remained depressed at less than 1Hz for the eastern side of the structure, although the western side had recovered to 1.3Hz. An ambient noise survey in 2008 showed the fundamental frequency of N/S vibrations remains about 1.0Hz for the eastern side of the building and 1.3Hz for the western side. These results suggest that in the Nisqually earthquake, the east side of the NRB suffered a permanent reduction in fundamental mode frequency of 37% due to loss of stiffness by undetermined mechanism.

  13. Sediment Thicknesses and Qs vs. Qp Relations in the Kachchh Rift Basin, Gujarat, India Using Sp Converted Phases

    Mandal, Prantik

    2007-01-01

    Delineation of the top sedimentary structure and its Qs vs. Qp relationship using the travel-time difference of direct S and converted Sp phase is key to understanding the seismic hazard of any sedimentary basin area. We constructed filtered displacement waveforms from local ETNA Episensor acceleration recordings as well as local velocity recordings of aftershocks of the 2001 Bhuj earthquake recorded by the Kachchh seismological network of the National Geophysical Research Institute (NGRI), Hyderabad, India during 2001 2004. Stations are within 15 70km of epicenters, and the resulting displacement waveforms are generally simple, displaying prominent P, Sp, and S wave pulses. Particle motion of P and S waves suggest near-vertical raypaths consistent with preliminary depth estimates. The direct S wave on the horizontal component is characterized by lower frequency content than the converted Sp phase on the vertical component. This difference in frequency content between S and Sp phases can be explained in terms of different attenuation effects for P and S waves in the unconsolidated sediments. The Sp phase is generated by S-to-P phase conversion at the base of Mesozoic sediments of the Kachchh basin. Travel-time inversion (VELEST) of 2565 P and 2380 S arrivals from 658 well located aftershocks recorded at 8 14 three-component local seismic stations led to 1 D velocity models indicated very slow sediments in the upper 0 2 km depth range (Vp: 2.92 km/s and Vs: 0.90 km/s) and an increasing trend of velocities with depth at 2 40 km depth. The estimated sediment thicknesses beneath 12 accelerograph and 6 seismograph sites from the estimated velocity model and the travel-time difference between S and converted Sp phases reaches a maximum of (1.534 ± 0.117) km beneath Bandri (near the location of 2001 Bhuj mainshock) and attains a minimum sediment thickness of (0.858 ± 0.104) km beneath Ramvav and Burudia. The spectral ratios between Sp and S from 159 three

  14. Crustal heterogeneities beneath the 2011 Talala, Saurashtra earthquake, Gujarat, India source zone: Seismological evidence for neo-tectonics

    Singh, A. P.; Mishra, O. P.; Rastogi, B. K.; Kumar, Santosh

    2013-01-01

    During the 1st decade of the 21st century, the study area of Talala, Saurashtra of western India witnessed three damaging earthquakes of moderate magnitude, year 2007 [Mw 5.0; Mw 4.8] and in the year 2011 [Mw 5.1] that generated public panic in the region. The last damaging moderate earthquake of the 20th October 2011 in Talala region (21.09°N;70.45°E), located at about 200 km south to the devastating 2001 Bhuj (23.412°N, 70.232°E) mainshock (Mw 7.6), jolted the entire Saurashtra region of Gujarat. A long series of aftershocks followed hereafter, recorded at nine seismograph/accelerograph stations. Hypocenters of aftershocks were relocated accurately using absolute and relative travel time (double-difference) method. In this study, we, for the first time, determined 3-D tomographic images of the upper crust beneath the 2011 Talala earthquake source zone by inverting about 1135 P and 1125 S wave arrival time data. Estimates of seismic velocities (Vp, Vs) and Poisson's ratio (σ) structures offer a reliable interpretation of crustal heterogeneities and their bearing on geneses of moderate earthquakes and their aftershock sequences beneath the source zone. It is found that the 2011 Talala mainshock hypocenter depth (6 km) is located near the boundary of the low and high velocity (Vp, Vs) and the source zone is associated with low-σ anomalies guarded by the prominent high-σ anomalies along the active fault zone having strike-slip motion beneath the earthquake source zone. The pattern of distribution of (Vp, Vs, σ) and its association with occurrences of aftershocks provide seismological evidence for the neo-tectonics in the region having left lateral strike-slip motion of the fault.

  15. The Beni Haoua, Algeria, Mw 4.9 earthquake: source parameters, engineering, and seismotectonic implications

    Abbes, Khadidja; Dorbath, Louis; Dorbath, Catherine; Djeddi, Mohamed; Ousadou, Farida; Maouche, Said; Benkaci, Nassima; Slimani, Abdennasser; Larbes, Said; Bouziane, Djillali

    2016-04-01

    A moderate Mw 4.9 earthquake struck the Beni Haoua (Algeria) coastal area on April 25, 2012. The mainshock was largely recorded by the accelerograph network of the Centre National de Recherche Appliquée en Génie Parasismique (CGS). The same day the earthquake occurred, eight mobile short period stations were deployed through the epicentral area. In this study, we use accelerogram and seismogram data recorded by these two networks. We combined the focal mechanism built from the first motion of P waves and from waveform inversion, and the distribution of aftershocks to well constrain the source parameters. The mainshock is located with a shallow focal depth, ˜9 km, and the focal mechanism shows a nearly pure left lateral strike slip motion, with total seismic moment of 2.8 × 1016 N.m (Mw = 4.9). The aftershocks mainly cluster on a narrow NS strip, starting at the coast up to 3-4 km inland. This cluster, almost vertical, is concentrated between 6 and 10 km depth. The second part of this work concerns the damage distribution and estimated intensity in the epicentral area. The damage distribution is discussed in connection with the observed maximum strong motion. The acceleration response spectrum with 5 % damping of the mainshock and aftershocks give the maximum amplitude in high frequency which directly affects the performance of the high-frequency structures. Finally, we tie this earthquake with the seismotectonic of the region, leading to conclude that it occurred on a N-S transform zone between two major compressional fault zones oriented NE-SW.

  16. The Engineering Strong Ground Motion Network of the National Autonomous University of Mexico

    Velasco Miranda, J. M.; Ramirez-Guzman, L.; Aguilar Calderon, L. A.; Almora Mata, D.; Ayala Hernandez, M.; Castro Parra, G.; Molina Avila, I.; Mora, A.; Torres Noguez, M.; Vazquez Larquet, R.

    2014-12-01

    The coverage, design, operation and monitoring capabilities of the strong ground motion program at the Institute of Engineering (IE) of the National Autonomous University of Mexico (UNAM) is presented. Started in 1952, the seismic instrumentation intended initially to bolster earthquake engineering projects in Mexico City has evolved into the largest strong ground motion monitoring system in the region. Today, it provides information not only to engineering projects, but also to the near real-time risk mitigation systems of the country, and enhances the general understanding of the effects and causes of earthquakes in Mexico. The IE network includes more than 100 free-field stations and several buildings, covering the largest urban centers and zones of significant seismicity in Central Mexico. Of those stations, approximately one-fourth send the observed acceleration to a processing center in Mexico City continuously, and the rest require either periodic visits for the manual recovery of the data or remote interrogation, for later processing and cataloging. In this research, we document the procedures and telecommunications systems used systematically to recover information. Additionally, we analyze the spatial distribution of the free-field accelerographs, the quality of the instrumentation, and the recorded ground motions. The evaluation criteria are based on the: 1) uncertainty in the generation of ground motion parameter maps due to the spatial distribution of the stations, 2) potential of the array to provide localization and magnitude estimates for earthquakes with magnitudes greater than Mw 5, and 3) adequacy of the network for the development of Ground Motion Prediction Equations due to intra-plate and intra-slab earthquakes. We conclude that the monitoring system requires a new redistribution, additional stations, and a substantial improvement in the instrumentation and telecommunications. Finally, we present an integral plan to improve the current network

  17. The Mw 7.7 Tocopilla, Chile, Earthquake of 14 November 2007: A Comprehensive Study Using Teleseismic, Local and InSAR data.

    Campos, J.; Peyrat, S.; Bejar, M.; Socquet, A.; Meneses, G.; Perez, A.; Madariaga, R.; Favreau, P.; Bernard, P.; Barrientos, S.; Armijo, R.; Asch, G.; Sobesiak, M.; Vilotte, J.

    2008-05-01

    A large Mw 7.7 earthquake took place in the Northern Chile subduction zone severely affecting the cities of Tocopilla, Maria Elena, Quillagua and Mejillones . The earthquake was very well recorded by many broadband stations at teleseismic distances and by more than 10 three-component accelerographs in the near field, four of them right above the rupture region. These data plus InSAR interferograms spanning the date of the earthquake were independently analysed and inverted to determine the characteristics of this event. Two main patches of energy release, located along the plate interface, close to the Chilean coast were clearly identified from the waveform inversion. These patches, separated by 60 to 65 km, ruptured from north to south with a velocity between 2.8 to 3.0 km/s. This rupture scenario is consistent with the modelling of InSAR interferograms by Bejar et al (2008) and the kinematic inversion of near field data by Peyrat et al (2008). Most of the early aftershocks, which took place during the two weeks following the main event, occurred near the Southern end of the rupture zone, just North of the Mejillones Peninsula. The majority of them were thrust events with focal mechanisms similar to that of the mainshock, except for the largest aftershock that took place on 16 December at the southern end of the rupture zone. The latter is a compressional event at 40 km depth, with compression along the slab ("slab push" mechanism). This complex pattern of seismicity, in addition to the lack of co-seismic displacement along the plate interface beneath the Mejillones Peninsula, indicates that structures under the peninsula play a significant role in the subduction process. Bejar et al (2008), Rupture geometry and slip associated with the 2007 November 14 Mw = 7.7 Tocopilla (Chile) earthquake, as preliminary determined by InSAR and GPS observations, this meeting Peyrat et al. (2008). Detailed source process of the 2007 Tocopilla earthquake, this meeting.

  18. A P-wave based, on-site method for Earthquake Early Warning

    Zollo, Aldo

    2016-04-01

    Can we rapidly predict the potential damage of earthquakes by-passing the estimation of its location and magnitude? One possible approach is to predict the expected peak ground shaking at the site and the earthquake magnitude from the initial P-peak amplitude and characteristic period, respectively. The idea, first developed by Wu and Kanamori (2005), is to combine the two parameters for declaring the alert once the real-time measured quantities have passed pre-defined thresholds. Our proposed on-site early warning method generalized this approach, based on the analysis of strong motion data from modern accelerograph networks in Japan, Taiwan and Italy (Zollo et al., 2010). It is based on the real-time measurement of the period (τc) and peak displacement (Pd) parameters at one or more co-located stations at a given target site to be protected against the earthquake effects. By converting these real-time proxies in predicted values of Peak Ground Velocity (PGV) or instrumental intensity (IMM) and magnitude, an alert level is issued at the recording site based on a decisional table with four entries defined upon threshold values of the parameters Pd and Tc. The latter ones are set according to the error bounds estimated on the derived prediction equations. A near-source network of stations running the onsite method can provide the event location and transmit the information about the alert levels recorded at near-source stations to more distant sites, before the arrival of the most destructive phase. The network-based approach allows for the rapid and robust estimation of the Potential Damage Zone (PDZ), that is the area where most of earthquake damage is expected (Colombelli et al., 2012). A new strategy for a P-wave based, on-site earthquake early warning system has been developed and tested on Japanese strong motion data and under testing on Italian data. The key elements are the real-time, continuous measurement of three peak amplitude parameters and their

  19. Source Fault of the Dec.26, 2003 Bam Earthquake (Mw6.5) in Southeastern Iran Inferred From Aftershock Observation Data by Temporal High-Sensitive-Seismograph Network

    Suzuki, S.; Matsushima, T.; Ito, Y.; Hosseini, S. K.; Nakamura, T.; Arash, J.; Sadeghi, H.; Maleki, M.; Aghda, F.

    2004-05-01

    The Bam earthquake occurred in southeastern Iran at 05:26 A.M.(local time) on December 26, 2003 (epicenter: 29.010N, 58.266E, Mo=6.6x10**18Nm, Mw=6.5; ref.1). The earthquake had strike-slip mechanism (strike=175, dip=85, slip=153; ref.2) and source parameters (focal depth=4km, fault dimension=20kmx15km, Dmax=1.0m, stress drop=3.7MPa; ref.2). The earthquake struck the ancient city of Bam and killed more than 40,000 people. It shows that one third of about 120,000 in population in and around Bam city were killed. The main reason of such a big damage may be caused by weak adobe and brick houses; even so, the damage was too much big. We, therefore, are researching other cause of such a big damage. Taking instruments from Japan for this aim we installed 9 high sensitive seismographs and one accelerograph in and around Bam city on February 6-8, 2004. And we observed aftershocks and continue during one month. Reading P and S arriving times of about 100 aftershocks occurring from February 6 to 10, we determined those preliminary hypocenters and magnitudes. Those epicenters (errors<500m) distribute mainly from northeastern Bam city to south direction with about 20km length. It means that the fault of the main shock passed just under eastern half of Bam city where most of houses and buildings were heavily damaged. This fault is about 4 km away west from Bam fault which is presented in geological map (ref.3). A north-south vertical cross-section of the hypocentral distribution (maybe errors < 1km) shows that most of their depths are shallower than 14km and a seismic gap exists in the laterally middle part of their distribution and shallower than 6 km in depth. The shallow seismic gap may correspond to a main fracture zone as shown in the slip distribution figure proposed by Yamanaka (ref.2). This main fracture occurring shallower than about 6 km in depth must be one of causes of the big damage in Bam. (Reference) ref1:USGS,http://neic.usgs.gov/neis/FM/, ref 2: ERI, U. Tokyo

  20. Source Parameters of the Deadly Mw 7.6 Kashmir Earthquake of 8 October, 2005

    Mandal, Prantik; Chadha, R. K.; Kumar, N.; Raju, I. P.; Satyamurty, C.

    2007-10-01

    During the last six years, National Geophysical Research Institute, Hyderabad has established a semi-permanent seismological network of 5 8 broadband seismographs and 10 20 accelerographs in the Kachchh seismic zone, Gujarat with a prime objective to monitor the continued aftershock activity of the 2001 Mw 7.7 Bhuj mainshock. The reliable and accurate broadband data for the 8 October Mw 7.6 2005 Kashmir earthquake and its aftershocks from this network as well as Hyderabad Geoscope station enabled us to estimate the group velocity dispersion characteristics and one-dimensional regional shear velocity structure of the Peninsular India. Firstly, we measure Rayleigh-and Love-wave group velocity dispersion curves in the period range of 8 to 35 sec and invert these curves to estimate the crustal and upper mantle structure below the western part of Peninsular India. Our best model suggests a two-layered crust: The upper crust is 13.8 km thick with a shear velocity (Vs) of 3.2 km/s; the corresponding values for the lower crust are 24.9 km and 3.7 km/sec. The shear velocity for the upper mantle is found to be 4.65 km/sec. Based on this structure, we perform a moment tensor (MT) inversion of the bandpass (0.05 0.02 Hz) filtered seismograms of the Kashmir earthquake. The best fit is obtained for a source located at a depth of 30 km, with a seismic moment, Mo, of 1.6 × 1027 dyne-cm, and a focal mechanism with strike 19.5°, dip 42°, and rake 167°. The long-period magnitude (MA ~ Mw) of this earthquake is estimated to be 7.31. An analysis of well-developed sPn and sSn regional crustal phases from the bandpassed (0.02 0.25 Hz) seismograms of this earthquake at four stations in Kachchh suggests a focal depth of 30.8 km.

  1. Relocation of Early and Late Aftershocks of the 2001 Bhuj Earthquake Using Joint Hypocentral Determination (JHD) Technique: Implication toward the Continued Aftershock Activity for more than Four Years

    Mandal, Prantik; Narsaiah, R.; Sairam, B.; Satyamurty, C.; Raju, I. P.

    2006-08-01

    We employed layered model joint hypocentral determination (JHD) with station corrections to improve location identification for the 26 January, 2001 Mw 7.7 Bhuj early and late aftershock sequence. We relocated 999 early aftershocks using the data from a close combined network (National Geophysical Research Institute, India and Center for Earthquake Research Institute, USA) of 8 18 digital seismographs during 12 28 February, 2001. Additionally, 350 late aftershocks were also relocated using the data from 4 10 digital seismographs/accelerographs during August 2002 to December 2004. These precisely relocated aftershocks (error in the epicentral locationBhuj earthquake. The aftershock zone is confined to a 60-km long and 40-km wide region lying between the KMF to the south and NWF to the north, extending from 2 to 45 km depth. Estimated focal depths suggest that the aftershock zone became deeper with the passage of time. The P- and S-wave station corrections determined from the JHD technique indicate that the larger values (both +ve and -ve) characterize the central aftershock zone, which is surrounded by the zones of smaller values. The station corrections vary from -0.9 to +1.1 sec for the P waves and from -0.7 to +1.4 sec for the S waves. The b-value and p-value of the whole aftershock (2001 2004) sequences of Mw ≥ 3 are estimated to be 0.77 ± 0.02 and 0.99 ± 0.02, respectively. The p-value indicates a smaller value than the global median of 1.1, suggesting a relatively slow decay of aftershocks, whereas, the relatively lower b-value (less than the average b-value of 1.0 for stable continental region earthquakes of India) suggests a relatively higher probability for larger earthquakes in Kachchh in comparison to other stable continental regions of the Indian Peninsula. Further, based on the b-value, mainshock magnitude and maximum aftershock magnitude, the Bhuj aftershock sequence is categorized as the Mogi's type II sequence, indicating the region to be of

  2. Iterative de-convolution of the local waveforms: Characterization of the seismic sources in Kachchh, India

    Mandal, Prantik; Satyamurty, C.; Raju, I. P.

    2009-12-01

    The deviatoric and double couple (DC) constrained moment tensor inversions of multiple point sources (10-20 s) for regional (or local) earthquakes, developed by Zahradnik et al. (2005), has been applied on the data of nine significant Bhuj aftershocks of Mw4.4- Mw5.6 recorded at three-component 5-15 accelerograph and 5-11 seismograph stations (epicentral distances < 130 km). The deviatoric moment tensor solutions of events on the north Wagad fault (NWF) in the 15-29 km depth range reveal a systematic depth-wise variation in the faulting patterns. At shallow depth (~ 15 km), they suggest a left lateral strike-slip movement with a minor reverse component along a south dipping plane (~ 61°), whereas, at 18-22 km depth range they change to pure reverse movement on a preferred south dipping plane (10-54°) and finally they change to the normal movement with minor strike-slip (S-S) component at deeper (25-29 km) depth range. The deviatoric MT solution of one event on the south Wagad fault (SWF) suggests a reverse movement with a minor S-S component on a 35° southeast dipping plane at 24 km depth. The deviatoric MT solutions for two events on the Gedi fault reveal a reverse movement with a minor left-lateral strike-slip component on an E-W trending and south dipping (40-61°) plane at 3-4 km depth. Whereas, one event on the Island belt fault (IBF) suggests a right lateral strike slip movement with a normal component on an almost vertical (~ 79°) plane at 29 km depth. The deviatoric moment tensor solutions of all the nine events show a larger (94-99%) double-couple (DC) component at shallow (3-15 km) depth range suggesting domination of brittle failure in the upper crust beneath the Kachchh region. However, the deeper events show larger non-DC (i.e. compensated linear vector dipole, CLVD) component suggesting increase in deviation from the double-couple (DC) solution in the lower crust (15-30 km depth range). This increase in non-DC component could be attributed to the

  3. Source Parameters of the 8 October, 2005 Mw7.6 Kashmir Earthquake

    Mandal, Prantik; Chadha, R. K.; Kumar, N.; Raju, I. P.; Satyamurty, C.

    2007-12-01

    During the last six years, the National Geophysical Research Institute, Hyderabad has established a semi-permanent seismological network of 5 broadband seismographs and 10 accelerographs in the Kachchh seismic zone, Gujarat, with the prime objective to monitor the continued aftershock activity of the 2001 Mw7.7 Bhuj mainshock. The reliable and accurate broadband data for the Mw 7.6 (8 Oct., 2005) Kashmir earthquake and its aftershocks from this network, as well as from the Hyderabad Geoscope station, enabled us to estimate the group velocity dispersion characteristics and the one-dimensional regional shear-velocity structure of peninsular India. Firstly, we measure Rayleigh- and Love-wave group velocity dispersion curves in the range of 8 to 35 sec and invert these curves to estimate the crustal and upper mantle structure below the western part of peninsular India. Our best model suggests a two-layered crust: The upper crust is 13.8-km thick with a shear velocity (Vs) of 3.2 km/s; the corresponding values for the lower crust are 24.9 km and 3.7 km/sec. The shear velocity for the upper mantle is found to be 4.65 km/sec. Based on this structure, we perform a moment tensor (MT) inversion of the bandpass (0.05 0.02 Hz) filtered seismograms of the Kashmir earthquake. The best fit is obtained for a source located at a depth of 30 km, with a seismic moment, Mo, of 1.6 × 1027 dyne-cm, and a focal mechanism with strike 19.5°, dip 42°, and rake 167°. The long-period magnitude (MA ~ Mw) of this earthquake is estimated to be 7.31. An analysis of well-developed sPn and sSn regional crustal phases from the bandpassed (0.02 0.25 Hz) seismograms of this earthquake at four stations in Kachchh suggests a focal depth of 30.8 km.

  4. Investigation of the Local Soil Effects at the New Strong-Motion Array (MATNet) in Hatay-K.Maras Region, Turkey

    Polat, O.; Çeken, U.

    2014-12-01

    The national strong-motion network in Turkey (TR-KYH) is owned and operated by the Prime Ministry, Disaster and Emergency Management Presidency Earthquake Department (AFAD). All TR-KYH stations generates real-time continuous data. A new dense strong-motion array (MATNet) has been installed near Hatay-K.Maras areas. It is at the SW corner of the East Anatolia Fault Zone (EAFZ). Primary target of MATNet is to investigate local site effects. Other important goal is to evaluate them as a part of early warning and preliminary damage estimate system. We also aim to develop a new attenuation relationship in the future from records including this new array. Most recorders are deployed as free-field and mounted in the container which is designed and produced for specific purposes. Hatay, Iskenderun and K.Maras cities have residential, industrial and dense populated areas. New stations are installed on different geological units in 1-3 km or 5-15 km intervals in city centers. Distances increase up to 30 km at the outside of settlements. The MATNet contains 55 triaxial force-balance accelerometers and capable to record explosions. A recent earthquake (Mw=4.5) occurred in the Gulf of Iskenderun on 14 February 2014, and triggered the MATNet and other regional accelerographs (80 triaxial strong-motion stations in total). Location of MATNet strong-motion stations in Hatay-K.Maras Region, Turkey, and distribution of triggered accelerometers during the recent earthquake (Mw=4.5), have been shown in the figure as a- and b-. In the present study, we analyzed to estimate the site response in the frequency range 0.5-10.0 Hz using the reference site (SSR) and HVSR techniques. The site response values thus obtained at each strong-motion sites were observed to be associated with the Quaternary formations. The maximum site amplifications at 0.5-1.8 Hz are detected as 10 around Hatay city, 6-8 (for 0.8-2.3 Hz) near K.Maras and Iskenderun areas. It is apparent that in both 0.5-1.8 and 0

  5. Storey building early monitoring based on rapid seismic response analysis

    Julius, Musa, Admiral; Sunardi, Bambang; Rudyanto, Ariska

    2016-05-01

    Within the last decade, advances in the acquisition, processing and transmission of data from seismic monitoring has contributed to the growth in the number structures instrumented with such systems. An equally important factor for such growth can be attributed to the demands by stakeholders to find rapid answers to important questions related to the functionality or state of "health" of structures during and immediately of a seismic events. Consequently, this study aims to monitor the storey building based on seismic response i. e. earthquake and tremor analysis at short time lapse using accelerographs data. This study used one of storey building (X) in Jakarta city that suffered the effects of Kebumen earthquake January 25th 2014, Pandeglang earthquake July 9th 2014, and Lebak earthquake November 8th 2014. Tremors used in this study are tremors after the three following earthquakes. Data processing used to determine peak ground acceleration (PGA), peak ground velocity (PGV), peak ground displacement (PGD), spectral acceleration (SA), spectral velocity (SV), spectral displacement (SD), A/V ratio, acceleration amplification and effective duration (te). Then determine the natural frequency (f0) and peak of H/V ratio using H/V ratio method.The earthquakes data processing result shows the value of peak ground motion, spectrum response, A/V ratio and acceleration amplification increases with height, while the value of the effective duration give a different viewpoint of building dynamic because duration of Kebumen earthquake shows the highest energy in the highest floor but Pandeglang and Lebak earthquake in the lowest floor. Then, tremors data processing result one month after each earthquakes shows the natural frequency of building in constant value. Increasing of peak ground motion, spectrum response, A/V ratio, acceleration amplification, then decrease of effective duration following the increase of building floors shows that the building construction supports the

  6. Rigorous noise test and calibration check of strong-motion instrumentation at the Conrad Observatory in Austria.

    Steiner, R.; Costa, G.; Lenhardt, W.; Horn, N.; Suhadolc, P.

    2012-04-01

    In the framework of the European InterregIV Italy/Austria project: "HAREIA - Historical and Recent Earthquakes in Italy and Austria" the Central Institute for Meteorology and Geodynamics (ZAMG) and Mathematic and Geosciences Department of University of Trieste (DMG) are upgrading the transfrontier seismic network of South-Eastern Alps with new 12 accelerometric stations to enhance the strong motion instrument density near the Austria/Italy border. Various public institutions of the provinces Alto Adige (Bolzano Province), Veneto (ARPAV) and Friuli Venezia Giulia (Regional Civil Defense) in Italy and in the Austrian province of Tyrol are involved in the project. The site selection was carried out to improve the present local network geometry thus meeting the needs of public Institutions in the involved regions. In Tyrol and Alto Adige some strategic buildings (hospitals and public buildings) have been selected, whereas in Veneto and Friuli Venezia Giulia the sites are in the free field, mainly located near villages. The instruments will be installed in an innovative box, designed by ZAMG, that provides electric and water isolation. The common choice regarding the instrument selection has been the new Kinemetrics Basalt ® accelerograph to guarantee homogeneity with the already installed instrumentation and compatibility with the software already in use at the different seismic institutions in the area. Prior to deployment the equipment was tested at the Conrad Observatory and a common set-up has been devised. The Conrad Observatory, seismically particularly quiet, permits to analyze both the sensor and the acquisition system noise. The instruments were connected to the network and the data sent in real-time to the ZAMG data center in Vienna and the DMG data center in Trieste. The data have been collected in the database and analyzed using signal processing modules PQLX and Matlab. The data analysis of the recordings at the ultra-quiet Conrad Observatory pointed out

  7. Damage and Shaking Intensity in the M5.7 Canyondam Earthquake

    Boatwright, J.; Chapman, K.; Gold, M. B.; Hardebeck, J. L.

    2013-12-01

    An M5.7 earthquake occurred southeast of Lake Almanor, CA, at 8:47 PM on May 23, 2013. Double-difference relocations of the main shock and aftershocks indicate that the earthquake nucleated at 11 km depth and ruptured up dip on a fault striking 292° and dipping 70° to the northeast. The earthquake cracked foundations, broke chimneys, and ruptured plumbing around Lake Almanor. We canvassed communities around the lake and to the south and east for earthquake damage, adding reports from our interviews to the geocoded 'Did You Feel It?' reports and to a set of damage reports collected by the Plumas County Office of Emergency Services. Three communities suffered significant damage. In Lake Almanor West, 14 km and 290° from the hypocenter, one wood-frame house was shifted on its foundation, the cripple wall of another house was racked, and water and gas pipes in five houses were ruptured. This damage indicates the shaking approached MMI 8. In Lake Almanor Country Club, 10 km and 310° from the hypocenter, more than 40 chimneys were cracked, broken, or collapsed, a coupling for the municipal water tank was ruptured, and a 200-foot long fissure opened on a slope facing the lake. This damage indicates shaking between MMI 7 and MMI 8, consistent with the accelerograph recording of PGA = 38% g and PGV = 30 cm/s at the Fire Station in Lake Almanor Country Club. This CSMIP station and a PG&E station on the crest of the Butt Valley Dam obtained the only recordings within 50 km of the epicenter. In Hamilton Branch, 10 km and 345° from the hypocenter, a foundation of a wood-frame house was damaged, and 14 chimneys and a water pipe were broken, indicative of MMI 7 shaking. All three communities are underlain by Tertiary and Quaternary basalts. The communities of Chester, Westwood, and Greenville were less damaged, suffering cracked drywall, broken windows, and objects thrown from shelves. The intensities in the three most strongly damaged communities increase as the azimuth

  8. Determination of the Attenuation Equation of Strong Motion in the Michoacán State

    Vazquez Rosas, R.; Aguirre, J.; Ramirez-Guzman, L.

    2014-12-01

    Several attenuation relationships have been developed to Mexico, mostly after the September 19, 1985 earthquake which has meant a watershed in the development of Mexican seismological engineering. Since 1985, the number of seismic stations has increased significantly especially between the Coast of Guerrero and Mexico City because of the large amplifications that have acurrect on lake zone and hard ground sites in Mexico City. Some studies have analyzed how the seismic waves are attenuated or amplified from the Pacific coast towards the continent. The attenuation relationship used for seismic hazard assessment in Mexico is due to Ordaz (1989) this was obtained from data from the Guerrero acceleration network. Another recent study is that conducted by (Garcia et al., 2005) with recent data from the Guerrero acceleration network considering intraplate earthquakes. It is important to note that all these relations cover to only part of the Mexican subduction zone, and for some types of seismic sources it may be not suitable to study the earthquake risk in other regions of Mexico. For this work we consider the state of Michoacán, because it has one of the most important seismogenic zones in Mexico. Within the state there are three different kinds of seismic sources: and volcanic tectonic earthquakes and those caused by local faults in the region. Then it is a vital issue to study the seismic wave propagation within the state. We installed a temporary network with 9 accelerographic stations, located at Faro de Brucerías, Aguililla, Apatzingán, Taretán, Uruapan, Nueva Italia Pátzcuaro, Morelia and Maravatío, Michoacán. The stations formed a perpendicular line to the coast, with a total length of 366 km, the distance between stations varies from 60 to 80 km. Among the total seismic events recorded, we selected 7 seismic events located in the Michoacán coastline, from 4.1 to 5.1 Mw. With those records, Q quality factor (107.215 f 0.74) was calculated for frequencies

  9. The NetQuakes Project - Research-quality Seismic Data Transmitted via the Internet from Citizen-hosted Instruments (Invited)

    Luetgert, J. H.; Oppenheimer, D. H.; Hamilton, J.

    2010-12-01

    The USGS seeks accelerograph spacing of 5-10 km in selected urban areas of the US to obtain spatially un-aliased recordings of strong ground motions during large earthquakes. These dense measurements will improve our ability to make rapid post-earthquake assessments of expected damage and contribute to the continuing development of engineering standards for construction. To achieve this goal the USGS and its university partners are deploying “NetQuakes” seismographs, designed to record moderate to large earthquakes from the near field to about 100 km. The instruments have tri-axial Colibrys 2005SF MEMS sensors, clip at 3g, and have 18-bit resolution. These instruments are uniquely designed for deployment in private homes, businesses, public buildings and schools where there is an existing Broadband connection to the Internet. The NetQuakes instruments connect to a local network using WiFi and then via the Internet to USGS servers to a) upload triggered accelerograms in miniSEED format, P arrival times, and computed peak ground motion parameters immediately after an earthquake; b) download software updates; c) respond to requests for log files, execute UNIX scripts, and upload waveforms from long-term memory for quakes with peak motions below the trigger threshold; d) send state-of-health (SOH) information in XML format every 10 minutes; and e) synchronize instrument clocks to 1ms accuracy using the Network Time Protocol. NetQuakes instruments cost little to operate and save about $600/yr/site compared to instruments that transmit data via leased telemetry. After learning about the project through press releases, thousands of citizens have registered to host an instrument at http://earthquake.usgs.gov/netquakes using a Google Map interface that depicts where we seek instrument sites. The website also provides NetQuakes hosts access to waveform images recorded by instruments installed in their building. Since 3/2009, the NetQuakes project has installed over 100

  10. Local network deployed around the Kozloduy NPP - a useful tool for seismological monitoring

    Solakov, Dimcho; Simeonova, Stela; Dimitrova, Liliya; Slavcheva, Krasimira; Raykova, Plamena; Popova, Maria; Georgiev, Ivan

    2015-04-01

    Processor (SNDP) software package. Strong motion accelerographs and GPS instrumentation are installed permanently within the near region. The equipment is periodically upgraded and calibrated to provide adequate information in line with updated international operational practice. The results of the 17 years of operation of LSN "Kozloduy" are presented in the present study. The multiple studies carried out indicate that LSN jointly with NOTSSI provide reliable registration of weak seismicity in the near (30 km) region of NPP site. Earthquakes recorded within and near the network are carefully analyzed in connection with seismotectonic studies of the near region. The seismological database acquired is homogeneous for the entire region to the extent possible or, at a minimum, is sufficiently complete for characterizing, from a seismotectonic point of view, features relevant to the site.

  11. Use of spectral acceleration data for determination of three-dimensional attenuation structure in the Pithoragarh region of Kumaon Himalaya

    Joshi, A.; Mohanty, M.; Bansal, A. R.; Dimri, V. P.; Chadha, R. K.

    2010-04-01

    Three-dimensional attenuation structures are related to the subsurface heterogeneities present in the earth crust. An algorithm for estimation of three-dimensional attenuation structure in the part of Garhwal Himalaya, India has been presented by Joshi (Curr Sci 90:581-585, 2006b; Nat Hazards 43:129-146, 2007). In continuation of our earlier approach, we have presented a method in which strong motion data have been used to estimate frequency-dependent three-dimensional attenuation structure of the region. The border district of Pithoragarh in the Higher Himalaya, India, lies in the central seismic gap region of Himalaya. This region falls in the seismic zones IV and V of the seismic zoning map of India. A dense network consisting of eight accelerographs has been installed in this region. This network has recorded several local events. An algorithm based on inversion of strong motion digital data is developed in this paper to estimate attenuation structure at different frequencies using the data recorded by this network. Twenty strong motion records observed at five stations have been used to estimate the site amplification factors using inversion algorithm defined in this paper. Site effects obtained from inversion has been compared with that obtained using Nakamura (1988) and Lermo et al. (Bull Seis Soc Am 83:1574-1594, 1993) approach. The obtained site amplification term has been used for correcting spectral acceleration data at different stations. The corrected spectral acceleration data have been used as an input to the developed algorithm to avoid effect of near-site soil amplification term. The attenuation structure is estimated by dividing the entire area in several three-dimensional block of different frequency-dependent shear wave quality factor Q β ( f). The input to this algorithm is the spectral acceleration of S phase of the corrected accelerogram. The outcome of the algorithm is given in terms of attenuation coefficient and source acceleration

  12. Seismicity at the northeast edge of the Mexican Volcanic Belt (MVB) and activation of an undocumented fault: the Peñamiller earthquake sequence of 2010-2011, Querétaro, Mexico

    Clemente-Chavez, A.; Figueroa-Soto, A.; Zúñiga, F. R.; Arroyo, M.; Montiel, M.; Chavez, O.

    2013-10-01

    The town of Peñamiller in the state of Querétaro, Mexico, is located at the northeast border of the seismogenic zone known as the Mexican Volcanic Belt (MVB), which transects the central part of Mexico with an east-west orientation. In the vicinity of this town, a sequence of small earthquakes occurred during the end of 2010 and beginning of 2011. Seismicity in the continental regimen of central Mexico is not too frequent; however, it is known that there are precedents of large earthquakes (Mw magnitude greater than 6.0) occurring in this zone. Three large earthquakes have occurred in the past 100 yr: the 19 November 1912 (MS = 7.0), the 3 January 1920 (MS = 6.4), and the 29 June 1935 (MS = 6.9) earthquakes. Prior to the instrumental period, the earthquake of 11 February 1875, which took place near the city of Guadalajara, caused widespread damage. The purpose of this article is to contribute to the available seismic information of this region. This will help advance our understanding of the tectonic situation of the central Mexico MVB region. Twenty-four shallow earthquakes of the Peñamiller seismic sequence of 2011 were recorded by a temporary accelerograph network installed by the Universidad Autónoma de Querétaro (UAQ). The data were analyzed in order to determine the source locations and to estimate the source parameters. The study was carried out through an inversion process and by spectral analysis. The results show that the largest earthquake occurred on 8 February 2011 at 19:53:48.6 UTC, had a moment magnitude Mw = 3.5, and was located at latitude 21.039° and longitude -99.752°, at a depth of 5.6 km. This location is less than 7 km away in a south-east direction from downtown Peñamiller. The focal mechanisms are mostly normal faults with small lateral components. These focal mechanisms are consistent with the extensional regimen of the southern extension of the Basin and Range (BR) province. The source area of the largest event was estimated to

  13. Seismicity at the northeast edge of the Mexican Volcanic Belt (MVB and activation of an undocumented fault: the Peñamiller earthquake sequence of 2010–2011, Querétaro, Mexico

    A. Clemente-Chavez

    2013-10-01

    Full Text Available The town of Peñamiller in the state of Querétaro, Mexico, is located at the northeast border of the seismogenic zone known as the Mexican Volcanic Belt (MVB, which transects the central part of Mexico with an east–west orientation. In the vicinity of this town, a sequence of small earthquakes occurred during the end of 2010 and beginning of 2011. Seismicity in the continental regimen of central Mexico is not too frequent; however, it is known that there are precedents of large earthquakes (Mw magnitude greater than 6.0 occurring in this zone. Three large earthquakes have occurred in the past 100 yr: the 19 November 1912 (MS = 7.0, the 3 January 1920 (MS = 6.4, and the 29 June 1935 (MS = 6.9 earthquakes. Prior to the instrumental period, the earthquake of 11 February 1875, which took place near the city of Guadalajara, caused widespread damage. The purpose of this article is to contribute to the available seismic information of this region. This will help advance our understanding of the tectonic situation of the central Mexico MVB region. Twenty-four shallow earthquakes of the Peñamiller seismic sequence of 2011 were recorded by a temporary accelerograph network installed by the Universidad Autónoma de Querétaro (UAQ. The data were analyzed in order to determine the source locations and to estimate the source parameters. The study was carried out through an inversion process and by spectral analysis. The results show that the largest earthquake occurred on 8 February 2011 at 19:53:48.6 UTC, had a moment magnitude Mw = 3.5, and was located at latitude 21.039° and longitude −99.752°, at a depth of 5.6 km. This location is less than 7 km away in a south-east direction from downtown Peñamiller. The focal mechanisms are mostly normal faults with small lateral components. These focal mechanisms are consistent with the extensional regimen of the southern extension of the Basin and Range (BR province. The source area of the largest event was

  14. Strong Motion Seismograph Based On MEMS Accelerometer

    Teng, Y.; Hu, X.

    2013-12-01

    application program layer mainly concludes: earthquake parameter module, local database managing module, data transmission module, remote monitoring, FTP service and so on. The application layer adopted multi-thread process. The whole strong motion seismograph was encapsulated in a small aluminum box, which size is 80mm×120mm×55mm. The inner battery can work continuesly more than 24 hours. The MEMS accelerograph uses modular design for its software part and hardware part. It has remote software update function and can meet the following needs: a) Auto picking up the earthquake event; saving the data on wave-event files and hours files; It may be used for monitoring strong earthquake, explosion, bridge and house health. b) Auto calculate the earthquake parameters, and transferring those parameters by 3G wireless broadband network. This kind of seismograph has characteristics of low cost, easy installation. They can be concentrated in the urban region or areas need to specially care. We can set up a ground motion parameters quick report sensor network while large earthquake break out. Then high-resolution-fine shake-map can be easily produced for the need of emergency rescue. c) By loading P-wave detection program modules, it can be used for earthquake early warning for large earthquakes; d) Can easily construct a high-density layout seismic monitoring network owning remote control and modern intelligent earthquake sensor.

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

    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