WorldWideScience

Sample records for accelerographs

  1. Fast Moment Tensor Inversion for Large Earthquakes using the Mexican Accelerographic Network

    Science.gov (United States)

    Juarez, A.; Ramirez-Guzman, L.

    2015-12-01

    The moment tensor calculation that is computed immediately after the occurrence of a major earthquake is limited to the number of unsaturated records in stations near the epicenter and the number of stations that transmit their data in real-time. Accelerographic records, however, are not commonly saturated after major earthquakes. Taking advantage of the wide coverage of the Mexican Accelerographic Network, we use accelerograms observed in real time to compute moment tensor solutions after the occurrence of an earthquake. In our study, we compute the double-couple moment tensor inversion as a least squares problem by minimizing the misfit between synthetic waveforms in three components and observed waveforms. Synthetic Receiver Green's Tensors for each station of the network within the model were previously calculated using a three-dimensional model of South-central Mexico. The database has horizontal spatial resolution of 20 km and a depth spatial resolution of 5 km. Our procedure fits windows containing the P and S waves to compute a fast first-solution. A revised solution is then calculated by fitting the full record. A first solution can be obtained seconds after the P-wave recorded in the station closest to the epicenter. Our results show that it is possible to obtain the moment tensor solution quickly and accurately. Furthermore, we show the resolution and range of uncertainty of the moment tensor solutions compared with that reported by specialized agencies for 30 selected strong earthquakes in Mexico from 2010 to 2014.

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    Julius, Musa, Admiral; Sunardi, Bambang

    2015-04-01

    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 and amplification

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

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    Institute of Scientific and Technical Information of China (English)

    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.

  6. 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

    Institute of Scientific and Technical Information of China (English)

    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.

  7. 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...

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

    OpenAIRE

    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

    OpenAIRE

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

    Science.gov (United States)

    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.

  11. Estimation of source parameters of Chamoli Earthquake, India

    Indian Academy of Sciences (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.

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

    Science.gov (United States)

    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. 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

    OpenAIRE

    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...

  14. 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.

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

    Science.gov (United States)

    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.

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

    CERN Document Server

    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...

  17. 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.

  18. Seismic instrumentation of high-rise buildings

    Institute of Scientific and Technical Information of China (English)

    Guoxin Wang; Weizheng Wang; Katayoun B.Aafshar; Dragi Dojcinovski

    2009-01-01

    An optimal assessment method for the design of accelerograph arrays to monitor the seismic response of high-rise buildings is pre-sented. This method uses a finite element model of the structure based on a simplified multi-degree-of-freedom system model defined using the parameter identification method. The off-diagonal element of the Modal Assurance Criterion (MAC) matrix of mode is taken as the target function in order to facilitate the selection of optimum locations. An example for a high-rise building in Dalian indicates that a minimum of 15 locations provide the optimum sites for monitoring the dynamic response of the selected building in view of eco-nomic benefit.

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

    Energy Technology Data Exchange (ETDEWEB)

    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. Study into the origins and reasons of the longitudinal crack in the turbine/generator floor of the Chute du Diable powerhouse

    Energy Technology Data Exchange (ETDEWEB)

    Daly, Abe [AECOM, Montreal, (Canada)

    2010-07-01

    This study investigated the origins and causes of the longitudinal crack in the generator floor of the Chute du Diable hydroelectric project operated by Rio Tinto Alco in Quebec, Canada. Three dimensional solid models were prepared for the downstream portion of the powerhouse in order to study the crack patterns and relationship between the horizontal and vertical cracks. A finite element model was used to evaluate the influence of different load cases on the behaviour of the powerhouse and to find the relative importance of load cases in relation to the formation of cracks at the downstream end of the powerhouse. Vibration tests were also conducted using an accelerograph. The FEM solid model found that the high amplitude of vibration increases the stress level in the floor slab. Several recommendations were provided to restore the shear and increase the flexural capacity of the slab. These results were compared to similar crack patterns at Chute a La Savanne.

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

    Science.gov (United States)

    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

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

    International Nuclear Information System (INIS)

    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)

  3. An attempt to recalibrate instrumental criteria for intensity assessment

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. Time Lapse Storey Building Early Monitoring Based on Rapid Seismic Response Analysis in Indonesia

    Science.gov (United States)

    Julius, A. M.

    2015-12-01

    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 decreases. 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 increasing of shaking and strongly influenced by local site effect. The constant value of building natural frequency shows the building still in good performance. This

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

    Science.gov (United States)

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

    Indian Academy of Sciences (India)

    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.

  9. Intermediate-Depth Intraplate Strike-Slip Earthquake Along the Subducted Nazca Plate: Stress Conditions Related to Flat-Slab Transition Zone?

    Science.gov (United States)

    Carrizo, D.; Peyrat, S.; Comte, D.; Boroschek, R.

    2013-05-01

    On October 11th, 2012 an strike-slip intraplate earthquake Mw=5.6 occurred at about 15 km NE of Santiago-Chile, at 107 km depth. This earthquake had a distribution of intensities of about VI MM, around Santiago region. In the past only few similar seismic events had been occurred, the majority of them without reported intensities. The location, the focal mechanism, and the depth of this earthquake, make it particularly interesting because the processes responsible for this kind of ruptures is still an open question. Moreover, it was also recorded by a local strong motion networks, allowing for the first time the possibility to study this kind of earthquakes using seismic and accelerographic data. We study the nature of this event using the aftershocks recorded by the Chilean Seismological Network and with a joint inversion of local strong-motion and teleseimic data, to understand the kinematic of rupture. Preliminary results suggest a singular stress condition in the subducted plate related to the transition from flat to normal subduction, which could be accommodated by strike-slip faulting. The strong motion analysis reveals high horizontal accelerations in agreement with high angle fault planes. Understand the tectonic setting associated to this type of earthquakes represents a relevant goal for seismic risk evaluation in the most populated Chilean region.

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

    Science.gov (United States)

    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.

  11. Strong Motion Observations In India-synthesis of Results

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  17. Theoretical design and field deployment of a dense strong motion instrument network for the Alpine Fault, South Island, New Zealand.

    Science.gov (United States)

    Francois, C.; Berril, J.; Pettinga, J.

    2003-04-01

    A dense network of strong motion seismometers is being developed in order to investigate the complexities of the upper crustal rupture process and propagation of major seismogenic sources such as the Alpine Fault and strands of the Marlborough Fault System defining the South Island sector of the Australia-Pacific plate boundary zone. The proposed network is designed as a dense array of approximately 20 accelerographs using the University of Canterbury 12-bit CUSP instrument, now nearing development completion. It will be deployed straddling the Alpine Fault in the central West Coast region of the South Island, and coverage will extend across the region at the Alpine-Hope Fault junction also. The array layout is being designed utilizing the frequency-analysis MUSIC method (Multiple Signal Characterization) developed by Goldstein and Archuleta (1991a&b). Synthetic strong-motion records were computed using an empirical Green's function synthetic seismogram program EMPSYN (Hutchings, 1987). The process of finding an optimal network configuration is dependent on the geometry of the array (study of the frequency analysis performance of the modelled earthquake data for various proposed array configurations), and on the instrument site conditions (geology, communications, accessibility, isolation etc). References Goldstein, P. and R. J. Archuleta (1991a). "Deterministic frequency-wavenumber methods and direct measurements of rupture propagation during earthquakes using a dense array; data analysis." Journal of Geophysical Research, B, Solid Earth and Planets 96(4): 6187-6198. Goldstein, P. and R. J. Archuleta (1991b). "Deterministic frequency-wavenumber methods and direct measurements of rupture propagation during earthquakes using a dense array; theory and methods." Journal of Geophysical Research, B, Solid Earth and Planets 96(4): 6173-6185. Hutchings, L. J. (1987). "Modelling strong earthquake ground motion with empirical Green's function", Ph.D. thesis, Department of

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  20. Study of Spectral Attenuation Laws of Seismic Waves for Michoacán state, México

    Science.gov (United States)

    Vazquez Rosas, R.; Aguirre, J.; Mijares Arellano, H.

    2009-12-01

    Several attenuation relationships have been developed for Mexico, mostly after the earthquake of September 19, 1985, an event that gave great impetus to the development of engineering seismology in Mexico. Since 1985, the number of seismic stations in the country has increased significantly, especially between the Coast of Guerrero and Mexico City. This is due to the infamous large amplifications observed in the lake area of Mexico City with respect to hard ground sites. Some studies have analyzed how seismic waves are attenuated or amplified from the Pacific Coast toward the inland. The attenuation relationship used for seismic hazard assessment in Mexico is that of Ordaz (1989), which uses data from the Guerrero acceleration network. Another recent study is that of García et al. (2005), which uses more recent data from intraplate earthquakes recorded at the Guerrero acceleration network. It is important to note that, since these relations were derived for only part of the Mexican subduction zone and for certain types of seismic sources, caution should be exercised when using them for earthquake risk studies in other regions of Mexico. In the present work, we study the state of Michoacán, one of the most important seimogenic zones in Mexico. Three kinds of sources exist in the state, producing tectonic earthquakes, volcanic earthquakes, and events due to local faults in the region. For this reason, it is of vital importance to study the propagation of seismic waves within Michoacán state, and in this paper in particular we study their attenuation. We installed a temporary network consisting of 7 accelerograph stations across the state, at the following locations: Faro de Brucerías, Aguililla, Apatzingán, Taretán, Pátzcuaro, Morelia, and Maravatío. The stations form a line that is perpendicular to the coastline and has a total length of 366 km, while the distance between neighboring stations varies from 60 to 80 km. Among all the seismic events recorded at

  1. Modernization of the Slovenian National Seismic Network

    Science.gov (United States)

    Vidrih, R.; Godec, M.; Gosar, A.; Sincic, P.; Tasic, I.; Zivcic, M.

    2003-04-01

    The Environmental Agency of the Republic of Slovenia, the Seismology Office is responsible for the fast and reliable information about earthquakes, originating in the area of Slovenia and nearby. In the year 2000 the project Modernization of the Slovenian National Seismic Network started. The purpose of a modernized seismic network is to enable fast and accurate automatic location of earthquakes, to determine earthquake parameters and to collect data of local, regional and global earthquakes. The modernized network will be finished in the year 2004 and will consist of 25 Q730 remote broadband data loggers based seismic station subsystems transmitting in real-time data to the Data Center in Ljubljana, where the Seismology Office is located. The remote broadband station subsystems include 16 surface broadband seismometers CMG-40T, 5 broadband seismometers CMG-40T with strong motion accelerographs EpiSensor, 4 borehole broadband seismometers CMG-40T, all with accurate timing provided by GPS receivers. The seismic network will cover the entire Slovenian territory, involving an area of 20,256 km2. The network is planned in this way; more seismic stations will be around bigger urban centres and in regions with greater vulnerability (NW Slovenia, Krsko Brezice region). By the end of the year 2002, three old seismic stations were modernized and ten new seismic stations were built. All seismic stations transmit data to UNIX-based computers running Antelope system software. The data is transmitted in real time using TCP/IP protocols over the Goverment Wide Area Network . Real-time data is also exchanged with seismic networks in the neighbouring countries, where the data are collected from the seismic stations, close to the Slovenian border. A typical seismic station consists of the seismic shaft with the sensor and the data acquisition system and, the service shaft with communication equipment (modem, router) and power supply with a battery box. which provides energy in case

  2. The Variation of Brune Stress Drop with Hypocentral Depth for Moderate (3.4 ≤ M ≤ 5.8) Earthquakes in Northeastern North America

    Science.gov (United States)

    Boatwright, J.; MacDonald, T.

    2011-12-01

    We analyze broadband (0.05 to 30 Hz) Fourier spectra of S+Lg+surface wave groups from 16 moderate (3.4 ≤ M ≤ 5.8) earthquakes, obtained from the horizontal components of Canadian and American seismographs and accelerographs sited on rock at hypocentral distances from 11 to 625 km. Nine of the earthquakes, including the 1988 M5.8 Saguenay and 2005 M4.6 Rivière-du-Loup earthquakes, are located in a broad area around Charlevoix, on the St. Lawrence Seaway. Four of the earthquakes, including the 2010 M5.0 Val-des-Bois earthquake, are located in the Western Quebec Seismic Zone (WQSZ), which extends NNW through Ottawa from the upper St. Lawrence River. Attenuation analysis of 7 small earthquakes in eastern Quebec and New England corroborates the attenuation model Q = 410f^{0.5} obtained by Boatwright and Seekins (2011) for ray paths in the Appalachian and southeastern Grenville Provinces. The Brune stress drops for the Charlevoix earthquakes are more strongly correlated with hypocentral depth (r = 0.93) than with moment magnitude (r = 0.65). The Saguenay earthquake is the largest and deepest (h = 29 km) of these earthquakes and has the largest stress drop (Δσ = 419 bars). For ray paths to the east and south from the WQSZ, we obtain Q = (412±26)f^{0.50±0.03}; for ray paths to the west from the WQSZ, we obtain Q = (580±64)f^{0.46±0.05}. We use both attenuation models to analyze the four WQSZ earthquakes, and group them together with the 2000 M4.6 Kipawa and 2002 M5.0 Ausable Forks earthquakes. The Brune stress drops for these six events are weakly correlated with depth (r = 0.53) and uncorrelated with moment magnitude (r = 0.05). The Charlevoix earthquakes extend to greater depth and have a higher average stress drop (202 bars) than the WQSZ earthquakes (129 bars). Including the depth dependence of the stress drop in a probabilistic seismic hazard analysis for the Charlevoix area significantly reduces the predicted ground motion, by reducing the probability of a

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

    Science.gov (United States)

    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

  4. Source characteristics of moderate size events using empirical Green funclions: an application to some Guerrero (Mexico subduction zone earthquakes

    Directory of Open Access Journals (Sweden)

    S. K. Singh

    1994-06-01

    Full Text Available The records of an aftershock (M ~ 4 of a moderate size event (M = 5.9 which occurred along the subduction zone of Guerrero (Mexico, are used as empirical Green functions (EGF to determine the source characteristics of the mainshock and of its smaller size (M = 5.5 foreshock. The data consist of accelerograms recorded by the Guerrero Accelerograph Array, a high dynamic range strong motion array. The three events appear to be located close to each other at distances much smaller than the source to receiver distances. The fault mechanism of the mainshock is computed by non-linear inversion of P polarity readings and S wave polarizations determined at two near source stations. The foreshock and aftershock fault mechanisms are similar to that of the mainshock as inferred from long period data and shear wave polarization analysis. The maximum likelihood solution is well constrained, indicating a typical shallow dipping thrust fault mechanism, with the P-axis approximately oriented in a SSW direction. The source time functions (STFs of the mainshock and foreshock events are determined using a new method of deconvolution of the EGF records at three strong motion sites. In this method the STF of the large event is approximated by a superposition of pseudo triangular pulses whose parameters are determined by a non-linear inversion in frequency domain. The source time function of the mainshock shows the presence of two separate pulses, which can be related to multiple rupture episodes. The relative location of mainshock sub-events is done by using plots of isochrones computed from measurementes of the time delay between pulses on the STF records at each station. The first sub-event is located no more than 2.5-3 km away from the other along the fault strike. The STF retrieved from foreshock records shows single pulse waveforms. The computed STFs are used to estimate seismic moments, source radii and stress release of the events assuming a circular fault

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

    Science.gov (United States)

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  8. Ground Motion Prediction Trends For Eastern North America Based on the Next Generation Attenuation East Ground Motion Database

    Science.gov (United States)

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

    2010-12-01

    A five-year Next Generation Attenuation (NGA) East project to develop new ground motion prediction equations for stable continental regions (SCRs), including eastern North America (ENA), has begun at the Pacific Earthquake Engineering Research (PEER) Center funded by the Nuclear Regulatory Commission (NRC), the U.S. Geological Survey (USGS), the Electric Power Research Institute (EPRI), and the Department of Energy (DOE). The initial effort focused on database design and collection of appropriate M>4 ENA broadband and accelerograph records to populate the database. Ongoing work has focused on adding records from smaller ENA earthquakes and from other SCRs such as Europe, Australia, and India. Currently, over 6500 horizontal and vertical component records from 60 ENA earthquakes have been collected and prepared (instrument response removed, filtering to acceptable-signal band, determining peak and spectral parameter values, quality assurance, etc.) for the database. Geologic Survey of Canada (GSC) strong motion recordings, previously not available, have also been added to the NGA East database. The additional earthquakes increase the number of ground motion recordings in the 10 - 100 km range, particularly from the 2008 M5.2 Mt. Carmel, IL event, and the 2005 M4.7 Riviere du Loup and 2010 M5.0 Val des Bois earthquakes in Quebec, Canada. The goal is to complete the ENA database and make it available in 2011 followed by a SCR database in 2012. Comparisons of ground motion observations from four recent M5 ENA earthquakes with current ENA ground motion prediction equations (GMPEs) suggest that current GMPEs, as a group, reasonably agree with M5 observations at short periods, particularly at distances less than 200 km. However, at one second, current GMPEs over predict M5 ground motion observations. The 2001 M7.6 Bhuj, India, earthquake provides some constraint at large magnitudes, as geology and regional attenuation is analogous to ENA. Cramer and Kumar, 2003, have

  9. 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

    Science.gov (United States)

    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

  10. 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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  12. Aceleraciones del terremoto de sámara del 05 de setiembre del 2012

    Directory of Open Access Journals (Sweden)

    Schmidt D., Víctor

    2014-06-01

    Full Text Available Presenta un análisis detallado de los registros de aceleración en el terremoto de Sámara, en la provincia de Guanacaste, Costa Rica. Toma en cuenta datos de los acelerógrafos del Laboratorio de Ingeniería Sísmica (LIS de la Universidad de Costa Rica, colocados a nivel nacional. Presenta una relación entre las aceleraciones máximas y su equivalencia en la escala de intensidad Mercalli, siendo la estación de Nosara la que tiene el registro de aceleración más intenso en la historia instrumental del país. Hace una interpretación de al menos cuatro estados de liberación de energía. Muestra una comparación con otros sismos a nivel mundial, con valores de aceleración alta. Analiza los espectros de respuesta en componentes norte-sur y este oeste, la forma en que decae la aceleración pico con la distancia y compara las Intensidades Arias (IA. Expone los daños ocurridos en algunos edificios públicos y hace una comparación de los daños en el Hospital Monseñor Sanabria, de Puntarenas, por el sismo de Cóbano y el de Sámara It presents a detailed analyses of the acceleration records in the Sámara earthquake, in Guanacaste, Costa Rica. It considers data from the accelerographs from the Seismic Engineering Lab (Laboratorio de Ingeniería Sísmica - LIS from the University of Costa Rica, located nationally. It presents a relation between maximum accelerations and their equivalent on the Mercalli intensity scale. The Nosara station is the one that has the most intense acceleration record in the instrumental history of the country. It interprets at least four stages of energy liberation. It shows a comparison with other earthquakes worldwide with high acceleration values. It analyses response spectrum in components North-South and East-West, the way in which the acceleration peak decreases with the distance and compares the Arias Intensities (IA. It presents the damages in some of the public buildings and compares the damages at the Monse

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

    Science.gov (United States)

    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

  14. 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

    Science.gov (United States)

    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

  15. 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

    Directory of Open Access Journals (Sweden)

    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

  16. Observations of large earthquakes in the Mexican subduction zone over 110 years

    Science.gov (United States)

    Hjörleifsdóttir, Vala; Krishna Singh, Shri; Martínez-Peláez, Liliana; Garza-Girón, Ricardo; Lund, Björn; Ji, Chen

    2016-04-01

    Fault slip during an earthquake is observed to be highly heterogeneous, with areas of large slip interspersed with areas of smaller or even no slip. The cause of the heterogeneity is debated. One hypothesis is that the frictional properties on the fault are heterogeneous. The parts of the rupture surface that have large slip during earthquakes are coupled more strongly, whereas the areas in between and around creep continuously or episodically. The continuously or episodically creeping areas can partly release strain energy through aseismic slip during the interseismic period, resulting in relatively lower prestress than on the coupled areas. This would lead to subsequent earthquakes having large slip in the same place, or persistent asperities. A second hypothesis is that in the absence of creeping sections, the prestress is governed mainly by the accumulative stress change associated with previous earthquakes. Assuming homogeneous frictional properties on the fault, a larger prestress results in larger slip, i.e. the next earthquake may have large slip where there was little or no slip in the previous earthquake, which translates to non-persistent asperities. The study of earthquake cycles are hampered by short time period for which high quality, broadband seismological and accelerographic records, needed for detailed studies of slip distributions, are available. The earthquake cycle in the Mexican subduction zone is relatively short, with about 30 years between large events in many places. We are therefore entering a period for which we have good records for two subsequent events occurring in the same segment of the subduction zone. In this study we compare seismograms recorded either at the Wiechert seismograph or on a modern broadband seismometer located in Uppsala, Sweden for subsequent earthquakes in the Mexican subduction zone rupturing the same patch. The Wiechert seismograph is unique in the sense that it recorded continuously for more than 80 years

  17. Comparative study of the amplification of ground motion using seismic noise and recent earthquakes adjacent to the Cerro Prieto volcano, Baja California

    Science.gov (United States)

    Vega, F. D.; Vidal-Villegas, A.

    2009-12-01

    We have chosen an area of approximately 79 km2, centered around the Cerro Prieto volcano, in the Mexicalli valley, Baja California, based on elevated registered acceleration data. The GEO station, located in the Cerro Prieto geothermal field has registered seismic accelerations on the order of 492 gales. The local residents near the study area have reported feeling numerous smaller magnitude earthquakes, compared to those of the nearby populated city of Mexicalli. Does there exist an amplified seismic signal in the area? If so, what is the cause of the amplification? The objective of our study is to answer these questions and determine the subsurface (0-50 m) structure in 4 specific sites. To obtain these answers, we registered seismic noise samples using short period seismometers (1 s), intermediate (5 s) and 16 bit recorders, along a linear profile which crosses the volcano with an 18 degree NE orientation. Furthermore, we analyzed ground-motion data (from 2004-2006), obtained from 24-bit accelerographs. Using both types of data (noise and accelegraphs) we calculated the H/V spectral ratios, and the relative ratios between both sites. To determine the subsurface structure, we used a unidimensional model of the H/V ratios, based on the methodology used by Huerta-Lopez et al., 2005. The H/V spectral ratios from the seismic noise adjacent to the volcano display amplitude of 1 in the frequency range (0.8 - 30 Hz). In contrast, the amplitude in the volcano crater (159 m.a.s.l.) was 6 in the frequency range (0.8 - 3 Hz). The average H/V relative ratio of the crater and the adjacent sites is 4, with frequencies between 0.8 and 1.2 Hz. The S-wave H/V ratios for the VCP acceleration station (110 m.a.s.l.), are near 8, with frequencies between 1 and 2. The H/V spectral ratios from the seismic noise for the geothermal field display amplitude of 4 for frequencies between 0.8 and 1.3 Hz, while the results from the S wave display amplitudes of 5 between 1.5 and 3 Hz. In the

  18. Strong Motion Seismograph Based On MEMS Accelerometer

    Science.gov (United States)

    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.

  19. 顺式阿曲库铵与琥珀胆碱用于支撑喉镜检查手术的比较研究%Comparision of Cisatracurium and Succinylcholine in Brace Laryngoscopy Operation

    Institute of Scientific and Technical Information of China (English)

    王宏梗; 陈汝聘; 王艳辉; 施萍萍

    2011-01-01

    Objective To compare the muscular relaxation effect and side effects of Cisatracurium and Succinylcholine in brace laryngoscopy operation. Methods Sixty adult patients(ASA Ⅰ ~Ⅱ ), agreed to be on electively brace laryngoscopy operation,were divided randomly into three groups(group Cl ,group C2 and group S, n=20 each). All patients in these three groups were injected intravenously with Fen tanil 4 μg/kg and Propofol 2 mg/kg during the induction of general anesthesia,and then be injected intrave nously with muscle relaxant (Cisatracurium 0. 15 mg/kg for group Cl , Cisatracurium 0. 2 mg/kg for group C2 or succinylcholine 1 mg/kg for group S, respectively). After the induction, continuously intravenous injection with Propofol 5~6 mg ? Kg-1 ? H-1 were used until the operation was over. Two minutes before the operations,all patients in group S were injected intravenously with Fentanil 1. 5 jug/kg and succinylcho line 0. 5 mg/kg, Cisatracurium 0. 05 mg/kg just in case depending on the relaxation level. Neuromuscular (N-M) function -was monitored with accelerograph F(TOF-Watch SX, Organon, the netherlands). The degree of muscle relexation was recorded at the time point of the tracheal intubation, brace laryngoscopy, the end of the operation, 15 min after the operation, 30 min after the operation. Brace laryngoscopy con dition was graded according to a criteria set by the surgeons. Heart rate(HR) was especlly recorded be fore and after the second dose of muscle relaxant was injected intravenously. The rates of muscle pain were also recorded 24 h after the operation. Results The degree of muscle relexation at the time point of 15 min after the operation was significantly lower in group S than that in group Cl and group C2 (P 0. 05). HR was stable and none needed the second dose of muscle relaxant in group Cland group C2, however, HR of all of the patients in group S was significantly slower after the second dose of muscle re laxant was injected intravenously than that