期刊文献+
共找到19篇文章
< 1 >
每页显示 20 50 100
New Explorations of Laboratory and On-site Testing of Broadband Seismographs in China
1
作者 XIE Jianbo YANG Dake +6 位作者 LI Xiaojun YUAN Songyong TONG Wanglian MA Jiemei XU Weiwei DING Lisha YE Shishan 《Earthquake Research in China》 CSCD 2019年第1期9-23,共15页
According to different testing purposes, methods and available environmental conditions, the seismograph testing can be divided into laboratory and on-site testing, respectively. The testing of the seismograph's k... According to different testing purposes, methods and available environmental conditions, the seismograph testing can be divided into laboratory and on-site testing, respectively. The testing of the seismograph's key parameters and other concerning technical specifications are well described in guide documents(China Earthquake Administration, 2017). This includes seismometer sensitivity, linearity and clip levels based on the shake table test, as well as the seismometer natural period, damping constant based on electrical calibration(Wang Guangfu,1986; Ple?inger A.,1993) and instrumental self-noise collocation estimation(Holcomb L.G., 1989; Sleeman R. et al., 2006). However, with the development of seismic observation technology, many new requirements for the performance evaluation of seismographs have been put forward, and new testing items and methods have emerged. 展开更多
关键词 BROADBAND seismographs LABORATORY TESTING ON-SITE TESTING
下载PDF
CalculationoflongperiodresponsespectratoearthquakegroundmotionfromseismogramsofType513seismographs
2
作者 俞言祥 汪素云 吕红山 《Acta Seismologica Sinica(English Edition)》 CSCD 1997年第3期51-58,共8页
We introduce in this paper a method to calculate response spectra of earthquake ground motion from seismograms of Type 513 seismograph. The seismograms of two horizontal components of the M s 7.1 earthquake, an a... We introduce in this paper a method to calculate response spectra of earthquake ground motion from seismograms of Type 513 seismograph. The seismograms of two horizontal components of the M s 7.1 earthquake, an aftershock of 1976 M S=7.8 Tangshan earthquake, recorded by type 513 seismograph in Taian station are used as an example. After curve digitization, arc shape curve correction, equal distance interpolation and instrument response correction, the absolute acceleration response spectra, relative velocity response spectra and relative displacement response spectra of different damping ratios in the period range of T ≤10 s are calculated in frequency domain. 展开更多
关键词 response spectrum long period Type 513 seismograph
下载PDF
Implementing and evaluating an automatic centroid moment tensor procedure for the Indonesia region and surrounding areas
3
作者 Madlazim Muhammad Nurul Fahmi +2 位作者 Dyah Permata Sari Ella Meilianda Sorja Koesuma 《Earth and Planetary Physics》 EI CAS CSCD 2024年第4期609-620,共12页
The purpose of this research was to suggest an applicable procedure for computing the centroid moment tensor(CMT)automatically and in real time from earthquakes that occur in Indonesia and the surrounding areas.Gisola... The purpose of this research was to suggest an applicable procedure for computing the centroid moment tensor(CMT)automatically and in real time from earthquakes that occur in Indonesia and the surrounding areas.Gisola software was used to estimate the CMT solution by selecting the velocity model that best suited the local and regional geological conditions in Indonesia and the surrounding areas.The data used in this study were earthquakes with magnitudes of 5.4 to 8.0.High-quality,real-time broadband seismographic data were provided by the International Federation of Digital Seismograph Networks Web Services(FDSNWS)and the European Integrated Data Archive(EIDA)Federation in Indonesia and the surrounding areas.Furthermore,the inversion process and filter adjustment were carried out on the seismographic data to obtain good CMT solutions.The CMT solutions from Gisola provided good-quality solutions,in which all earthquake data had A-level quality(high quality,with good variant reduction).The Gisola CMT solution was justified with the Global CMT(GCMT)solution by using the Kagan angle value,with an average of approximately 11.2°.This result suggested that the CMT solution generated from Gisola was trustworthy and reliable.The Gisola CMT solution was typically available within approximately 15 minutes after an earthquake occurred.Once it met the quality requirement,it was automatically published on the internet.The catalog of local and regional earthquake records obtained through this technology holds great promise for improving the current understanding of regional seismic activity and ongoing tectonic processes.The accurate and real-time CMT solution generated by implementing the Gisola algorithm consisted of moment tensors and moment magnitudes,which provided invaluable insights into earthquakes occurring in Indonesia and the surrounding areas. 展开更多
关键词 centroid moment tensor Gisola International Federation of Digital Seismograph Networks Web Services(FDSNWS) real time Indonesia
下载PDF
Measurement of ice flow velocities from GPS positions logged by short-period seismographs in East Antarctica
4
作者 Lei FU Jingxue GUO Xiaofei CHEN 《Science China Earth Sciences》 SCIE EI CSCD 2021年第8期1381-1389,共9页
The ice flow velocity is a basic feature of glaciers and ice sheets. Measuring ice flow velocities is very important for estimating the mass balance of ice sheets in the Arctic and Antarctic. Traditional methods for m... The ice flow velocity is a basic feature of glaciers and ice sheets. Measuring ice flow velocities is very important for estimating the mass balance of ice sheets in the Arctic and Antarctic. Traditional methods for measuring ice flow velocity include the use of stakes, snow pits and on-site geodetic GPS and remote sensing measurement methods. Geodetic GPS measurements have high accuracy, but geodetic GPS monitoring points only sparsely cover the Antarctic ice sheets. Moreover, the resolution and accuracy of ice flow velocities based on remote sensing measurements are low. Although the accuracy of the location data recorded by the navigation-grade GPS receivers embedded in short-period seismographs is not as good as that of geodetic GPS,the ice flow velocity can be accurately measured by these navigation-grade GPS data collected over a sufficiently long period. In this paper, navigation-grade GPS location data obtained by passive seismic observations during the 36 th Chinese National Antarctic Research Expedition were used to accurately track the movement characteristics of the ice sheet in the Larsemann Hills of East Antarctica and the Taishan Station area. The results showed that the ice sheet in the two study areas is basically moving northwestward with an average ice flow velocity of approximately 1 m mon-1. The results in the Taishan Station area are basically consistent with the geodetic GPS results, indicating that it is feasible to use the embedded GPS location data from shortperiod seismographs to track the movement characteristics of ice sheets. The ice flow characteristics in the Larsemann Hills are more complex. The measured ice flow velocities in the Larsemann Hills with a resolution of 200 m help to understand its characteristics. In summary, the ice flow velocities derived from GPS location data are of great significance for studying ice sheet dynamics and glacier mass balance and for evaluating the systematic errors caused by ice sheet movements in seismic imaging. 展开更多
关键词 Short-period seismograph Antarctic ice sheet Ice flow velocity GPS
原文传递
Velocity structure in the South Yellow Sea basin based on first-arrival tomography of wide-angle seismic data and its geological implications 被引量:2
5
作者 Weina Zhao Zhiqiang Wu +6 位作者 Fanghui Hou Xunhua Zhang Tianyao Hao Hanjoon Kim Yanpeng Zheng Shanshan Chen Huigang Wang 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第2期104-119,共16页
The South Yellow Sea basin is filled with Mesozoic-Cenozoic continental sediments overlying pre-Palaeozoic and Mesozoic-Palaeozoic marine sediments.Conventional multi-channel seismic data cannot describe the velocity ... The South Yellow Sea basin is filled with Mesozoic-Cenozoic continental sediments overlying pre-Palaeozoic and Mesozoic-Palaeozoic marine sediments.Conventional multi-channel seismic data cannot describe the velocity structure of the marine residual basin in detail,leading to the lack of a deeper understanding of the distribution and lithology owing to strong energy shielding on the top interface of marine sediments.In this study,we present seismic tomography data from ocean bottom seismographs that describe the NEE-trending velocity distributions of the basin.The results indicate that strong velocity variations occur at shallow crustal levels.Horizontal velocity bodies show good correlation with surface geological features,and multi-layer features exist in the vertical velocity framework(depth:0–10 km).The analyses of the velocity model,gravity data,magnetic data,multichannel seismic profiles,and drilling data showed that high-velocity anomalies(>6.5 km/s)of small(thickness:1–2 km)and large(thickness:>5 km)scales were caused by igneous complexes in the multi-layer structure,which were active during the Palaeogene.Possible locations of good Mesozoic and Palaeozoic marine strata are limited to the Central Uplift and the western part of the Northern Depression along the wide-angle ocean bottom seismograph array.Following the Indosinian movement,a strong compression existed in the Northern Depression during the extensional phase that caused the formation of folds in the middle of the survey line.This study is useful for reconstructing the regional tectonic evolution and delineating the distribution of the marine residual basin in the South Yellow Sea basin. 展开更多
关键词 ocean bottom seismograph South Yellow Sea basin strata velocity structure wide-angle seismic data CSDP-2
下载PDF
OBS海洋环境信号分析与应用
6
作者 童思友 廖仪 +1 位作者 陈亮 吴志强 《海洋科学》 CAS CSCD 北大核心 2016年第2期145-150,共6页
为研究海洋环境信号在OBS(Ocean Bottom Seismograph)原始数据中的规律及应用,根据OBS原始数据的波形及频谱特征,将研究区划分为5个时间段,依次为旧涌浪阶段、风浪渐强阶段、风浪全盛阶段、风浪消退阶段和新涌浪阶段。结合海洋天气预报... 为研究海洋环境信号在OBS(Ocean Bottom Seismograph)原始数据中的规律及应用,根据OBS原始数据的波形及频谱特征,将研究区划分为5个时间段,依次为旧涌浪阶段、风浪渐强阶段、风浪全盛阶段、风浪消退阶段和新涌浪阶段。结合海洋天气预报,认为上述现象是由偏南风风浪对海流的影响造成的。参考野外地震数据采集记录班报,得到各阶段的时长和距离,计算风浪渐强、全盛和消退阶段OBS附近海流的平均速度。结果表明:OBS原始资料中浅海海洋环境噪音增强的主要因素是风浪,且风浪引起的噪音信号的波形变化特征是渐进式的;OBS可用于接收某种特殊阶段(如台风、海啸等)的噪音信号,并根据噪音信号的波形特征、频谱变化规律和持续时间估算该阶段的海流速度变化。 展开更多
关键词 海洋环境信号 OBS(Ocean BOTTOM Seismograph) 海浪实测
下载PDF
Deepest deep-hole integrated geophysical observation system has successfully installed
7
作者 Xiang-zhi Zeng Zhi-nuo Li 《China Geology》 2019年第3期403-404,共2页
On August 26, 2019, the deep-hole integrated geophysical observation system of the long-term observatory of the Chinese Continental Scientific Drilling project (CCSD) was successfully placed into the deep-hole and rec... On August 26, 2019, the deep-hole integrated geophysical observation system of the long-term observatory of the Chinese Continental Scientific Drilling project (CCSD) was successfully placed into the deep-hole and received signals in real time (Fig. 1). The deep-hole geophysical observation system was installed to expected design depth: two sets of seismographs and three sets of geotherms were placed at the main hole of 1498 m, 2367 m, 3006 m and 3499 m respectively. The temperature of the deepest installation position is up to 98 ℃, the pressure is up to 35 MPa, and the minimum inner diameter is only 175 mm. It is the deepest deep-hole geophysical observation system in China (Fig. 2). 展开更多
关键词 CCSD seismographs GEOPHYSICAL
下载PDF
Airblast and Ground Vibration Monitoring at Chimiwungo Pit
8
作者 Eugie Kabwe Yiming Wang 《Geomaterials》 2016年第1期28-38,共11页
Impacts of airblast and vibrations arise from blasting, a dangerous activity if not designed and performed to standard. This paper evaluates airblast and ground vibration levels and its potential impact on the neighbo... Impacts of airblast and vibrations arise from blasting, a dangerous activity if not designed and performed to standard. This paper evaluates airblast and ground vibration levels and its potential impact on the neighbouring communities. Two calibrated seismographs were used to monitor potential airblast and ground vibration generated from the blast at Chimiwungo Pit. The blast complied with the set limits for infrastructures and slopes monitoring. Vibrations recorded from the trial shot PPV were predicted at 2.46 mm/s and Airblast of 10 mm/s with a maximum of 134 dB at the mine boundary, all remained well below accepted industry standards and guidelines. The airblast and ground vibration levels monitored and recorded were considered to be normal for surface blasting operations and had no negative impact on the nearby township of Manyama. 展开更多
关键词 Airblast BLASTING Chimiwungo Pit seismographs VIBRATION
下载PDF
Location Accuracy of the China National Seismograph Network Estimated by Repeating Events 被引量:1
9
作者 Jiang Changsheng Wu Zhongliang 《Earthquake Research in China》 2006年第1期67-74,共8页
Regionalized location accuracy of the China National Seismograph Network was estimated using the results obtained by studying “repeating earthquakes" or “doublets" in and around China by Schaff and Richard... Regionalized location accuracy of the China National Seismograph Network was estimated using the results obtained by studying “repeating earthquakes" or “doublets" in and around China by Schaff and Richards (2004). It is assumed that the “repeating events" or “doublets" are separated by no more than 1km, and the network measured apparent distance X of “doublets" indicates the order of magnitudes of the location error. It is observed that the average location accuracy of the China National Seismograph Network, as represented by average X value, is in the order of magnitudes of 10km, and is larger in the Qinghai-Xizang (Tibet) Plateau, western and northern Xinjiang, and eastern Inner Mongolia. 展开更多
关键词 Repeating earthquakes Earthquake location Seismograph network
下载PDF
A method for calculating the transfer function of digital seismograph system
10
作者 颜其中 何家斌 高杰 《Acta Seismologica Sinica(English Edition)》 CSCD 2003年第6期693-698,共6页
关键词 digital seismograph system pulse calibration transfer function EMULATION
下载PDF
The November 14, 2001 west of Kunlun Mountain Pass earthquake: An earthquake with unsaturated surface wave magnitude
11
作者 刘瑞丰 陈运泰 +2 位作者 任枭 侯建民 邹立晔 《Acta Seismologica Sinica(English Edition)》 EI CSCD 2005年第5期5-15,共11页
This paper presents an overview of the magnitude determination of the November 14, 2001 west of Kunlun Mountain Pass (KMP) earthquake at the juncture of Xinjiang and Qinghai, northwestern China. Comparisons are made a... This paper presents an overview of the magnitude determination of the November 14, 2001 west of Kunlun Mountain Pass (KMP) earthquake at the juncture of Xinjiang and Qinghai, northwestern China. Comparisons are made among surface wave magnitudes determined by China National Digital Seismograph Network (CNDSN), National Earthquake Information Center (NEIC) of US Geological Survey (USGS) and moment magnitudes de- termined by different institutions in China and abroad. The result shows that different institutions yield different surface wave magnitudes, as different data and calculation formulae are used in magnitude determination. The magnitude of the earthquake in China′s Rapid Earthquake Information Release was given as MS=8.1; measurement given in the formally edited and published Observation Report of China Digital Seismograph Network is MS=8.2; and magnitude determined by USGS/NEIC is MS=8.0. Soon after the occurrence of the KMP earthquake, Harvard University (Harvard), USGS/NEIC, Earthquake Research Institute, Tokyo University (ERI), Center for Analysis and Prediction, China Earthquake Administration (APCEA) and Institute of Geophysics, China Earthquake Ad- ministration (IGCEA) gave the moment magnitude MW as 7.8, 7.7, 7.7, 7.6 and 7.5, respectively, based on data from Global Seismograph Network (GSN), CNDSN and China Digital Seismograph Network (CDSN). These measurements, with an average value of MW=7.7, are close to each other. As moment magnitude is a physical quantity measuring the absolute size of an earthquake and has obvious advantages over conventional magnitude scale, and is the preferred magnitude of the international seismological community. It is concluded that the KMP earthquake is an earthquake with unsaturated surface wave magnitude with moment magnitude MW=7.7 and sur- face wave magnitude MS=8.0. 展开更多
关键词 MAGNITUDE focal mechanism seismograph network
下载PDF
Development of China Digital Seismological Observational Systems
12
作者 刘瑞丰 吴忠良 +2 位作者 阴朝民 陈运泰 庄灿涛 《Acta Seismologica Sinica(English Edition)》 CSCD 2003年第5期568-573,共6页
Development of China Digital Seismological Observational Systems during 1996~2000 and the Capital Circle Area Seismograph Network during 1999~2001 are introduced, and the station distributions, instruments used, main ... Development of China Digital Seismological Observational Systems during 1996~2000 and the Capital Circle Area Seismograph Network during 1999~2001 are introduced, and the station distributions, instruments used, main tasks of National Digital Seismograph Network, Regional Digital Seismograph Network and Portable Digital Seismograph Network are introduced chiefly. 展开更多
关键词 digital seismograph network BROAD-BAND seismic monitoring
下载PDF
Spheroidal oscillations of the Earth stimulated by the Sumatra-Andaman earthquake with CDSN data
13
作者 万永革 盛书中 +2 位作者 周公威 郭燕平 尚丹 《Acta Seismologica Sinica(English Edition)》 CSCD 2007年第4期392-404,共13页
The 0S2-0S54 spheroidal modes of Earth's free oscillations, triggered by the great Sumatra-Andaman earthquake of 26 December 2004 are retrieved from VHZ data recorded by seven upgraded stations of China Digital Seism... The 0S2-0S54 spheroidal modes of Earth's free oscillations, triggered by the great Sumatra-Andaman earthquake of 26 December 2004 are retrieved from VHZ data recorded by seven upgraded stations of China Digital Seismograph Network (CDSN). We compare these spheroidal modes with theoretical free oscillation spectra calculated from the Preliminary Reference Earth Model (PREM) and find a coincidence between their periods. Spectral splitting phenomenon is observed obviously in 0S2, 0S3, 0S4, 2S1 and 1S2 free oscillation modes. What is most noticeable is that the oscillation mode 2S1 is reported for the second time (the first time by Rosat et al) without any data stacking. We simulated the split singlet of 0S2 mode on seven CDSN stations based on general focal mechanism and seismic moment of the earthquake. The result shows that seismic moment of the earthquake can reach 10^23 N.m. We also find that the recording of Earth's free oscillations carries abundant information of source mechanism and earthquake location, which is applicable to the detailed study of source rupture parameters. 展开更多
关键词 China Digital Seismograph Network (CDSN) Sumatra-Andaman earthquake Earth's free os-cillation spheroidal oscillation
下载PDF
Structural Interpretation and Petrophysical Analysis for Reservoir Sand of Lower Goru, Miano Area, Central Indus Basin, Pakistan
14
作者 Muhammad Sohail Khan Farhana Masood +2 位作者 Qadeer Ahmed Ishtiaq Ahmed Khan Jadoon Naveed Akram 《International Journal of Geosciences》 2017年第4期379-392,共14页
The main purpose of this research is to estimate the structural analysis and hydrocarbon potential of Miano Block by using seismic and well log techniques. Miano area hosts a number of gas fields with structural and s... The main purpose of this research is to estimate the structural analysis and hydrocarbon potential of Miano Block by using seismic and well log techniques. Miano area hosts a number of gas fields with structural and stratigraphic traps. The area is located in Central Indus Basin which is a part of an extensional regime exhibiting normal faulting due to the split of the Indian Plate firstly from Africa and then from Madagascar and Seychelles. Miano area recognized as a proven petroleum province which has complex tectonic history of Cretaceous extensional and overprints of Tertiary strike-slip tectonics. The area has prospect with accumulation of hydrocarbons in structural and stratigraphic traps including pinchouts. NW-SE oriented Khairpur and Mari Highs are main structural features with impact on the fault system. The sands of Lower Goru of Lower Cretaceous age are acting as a reservoir in the area. The area has great potential of hydrocarbons for which more exploratory wells are required to be drilled with better insight of structural and stratigraphic traps. 展开更多
关键词 SEISMIC INTERPRETATION Time-and-Depth CONTOUR Map 3D View Synthetic SEISMOGRAPH RESERVOIR Estimation
下载PDF
Chaos Control in Electromechanical Seismograph System with Noise Disturbances
15
作者 郑连清 申滔 陆治国 《Journal of Donghua University(English Edition)》 EI CAS 2012年第3期203-208,共6页
In order to eliminate chaotic oscillation of electromechanical characteristics of seismograph system, the complex dynamic the four-dimensional nonlinear equations of seismograph system were analyzed. Sliding mode meth... In order to eliminate chaotic oscillation of electromechanical characteristics of seismograph system, the complex dynamic the four-dimensional nonlinear equations of seismograph system were analyzed. Sliding mode method was applied to stabilize the chaotic orbits of the eleetromechanieal seismograph system to arbitrary chosen fixed points and periodic orbits precisely, and MATLAB simulations were presented to confirm the validity of the controller. The results show that using sliding mode method can make the system track target orbit strictly and smoothly with short transition time, and its insensitivity to noise disturbances is shown. It also provides reference for relevant chaos control in relevant system. 展开更多
关键词 electromechanical seismograph system chaotic attractor slidine mode: uncertain parameter: noise disturbance SIMULATION
下载PDF
Study on the Method for Obtaining Acceleration Waveform Records from Velocity Type Seismograms of the Digital Seismograph Network
16
作者 YaoLanyu NieYongan ZhaoJinghua BianZhenfu 《Earthquake Research in China》 2004年第3期234-241,共8页
The authors proposed a method for obtaining high-quality acceleration seismograms from velocity type seismograms of digital Seismographic network, and took as an example the analysis and processing of the seismograms ... The authors proposed a method for obtaining high-quality acceleration seismograms from velocity type seismograms of digital Seismographic network, and took as an example the analysis and processing of the seismograms of a same earthquake that was simultaneously recorded by velocity seismograph CTS1-EDAS24 and strong motion seismograph EST-Q4128 installed in Jixian Station, Tianjin. The calculation steps and the processing method have been discussed in detail. From the analysis and the comparison of the obtained results, it is concluded that the proposed method is simple and effective, and it broadens the application of digital seismographic network. 展开更多
关键词 Seismographic network Seismograph characteristics Velocity record Acceleration record Acceleration response spectra Fourier spectra
下载PDF
Zhang Heng’s Seismoscope(3):Disappearance & Scientific Value
17
作者 Feng Rui Wu Yuxia 《Earthquake Research in China》 2014年第2期130-141,共12页
The ancient idea of Heavenly Punishment confused natural phenomena with social issues,which resulted in Zhang Heng’s tragedy in his later years and seismoscope. The instrument might have been lost in the end of the E... The ancient idea of Heavenly Punishment confused natural phenomena with social issues,which resulted in Zhang Heng’s tragedy in his later years and seismoscope. The instrument might have been lost in the end of the Eastern Han Dynasty. A series of extremely serious chaotic social events caused by war took place,such as a fire in Luoyang,forging coins by destroying copper wares,relocation of the capital,sharp population decrease,and the destruction of the Ling Observatory. Zhang’s scientific thought and successful practice had played an important role in ideological enlightenments at the primary stage of modern seismology at the end of the nineteenth century. There is a glorious course of"innovation—inheritance—re-innovation"of scientific and technical development from the inception Zhang Heng’s seismoscope to the modern seismograph invented by Milne,et al. 展开更多
关键词 Heaven-human induction Heavenly punishment Disappearance of Zhang Heng's seismoscope Birth of modern seismology MILNE SEISMOGRAPH
下载PDF
Rule by Criminal Law is a Seismograph for the Protection of Human Rights
18
作者 林维 HU Liang 《The Journal of Human Rights》 2018年第1期10-12,共3页
Criminal law involves crucial rights of the public,including property rights,political rights,freedom,and even life.As a result,on the one hand,any change to the rule by criminal law may have a significant impact on p... Criminal law involves crucial rights of the public,including property rights,political rights,freedom,and even life.As a result,on the one hand,any change to the rule by criminal law may have a significant impact on people’s lives;on the other hand,any change to the rule by criminal law is a highly sensitive issue.In view of these points,the rule by criminal law is often referred to as the seismograph for the protection of human rights,indicating the utmost importance of rule by criminal law 展开更多
关键词 Rule by Criminal Law is a Seismograph for the Protection of Human Rights
下载PDF
Constraining the focal mechanism of the Lushan earthquake with observations of the Earth's free oscillations 被引量:9
19
作者 JIANG Ying HU XiaoGang +1 位作者 LIU ChengLi SUN HePing 《Science China Earth Sciences》 SCIE EI CAS 2014年第9期2064-2070,共7页
The amplitudes of the Earth's free oscillations have a close relationship to earthquake focal mechanisms. Focal mechanisms of large earthquakes can be well analyzed and constrained with observations of long period fr... The amplitudes of the Earth's free oscillations have a close relationship to earthquake focal mechanisms. Focal mechanisms of large earthquakes can be well analyzed and constrained with observations of long period free oscillations. Although the 2013 Lushan earthquake was only moderately sized, observable spherical normal modes were excited and clearly observed by a su- perconductive gravimeter and a broadband seismometer. We compare observed free oscillations with synthetic normal modes corresponding to four different focal mechanisms for the Lushan earthquake. The results show that source parameters can be analyzed and constrained by spherical normal modes in a 2.3-5 mHz frequency band. The scalar seismic moment M~ has a major influence on the amplitudes of free oscillations; additionally, the strike, dip, rake and depth of the hypocenter have mi- nor influences. We found that the synthetic modes corresponding to the focal mechanism determined by the Global Centroid Moment Tensor show agreement to the observed modes, suggesting that earthquake magnitudes predicted in this way can readily reflect the total energy released by the earthquake. The scalar seismic moment obtained by far-field body wave inver- sion is significantly underestimated. Focal mechanism solutions can be improved by joint inversion of far- and near-field data. 展开更多
关键词 Lushan earthquake focal mechanism solutions Earth's free oscillations superconductive gravimeter observations broadband seismograph observations
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部