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Earthquake Science 2024年第2期37卷 158-173页

作者： Bonan Cao zengxi ge Department of geophysics School of Earth and Space SciencesPeking UniversityBeijing 100871China Hebei Hongshan National geophysical Observatory for Thick Sediments and Seismic Hazards Peking UniversityBeijing 100871China

In this study,the vertical components of broadband teleseismic P wave data recorded by China Earthquake Network are used to image the rupture processes of the February 6th,2023 Turkish earthquake doublet via back projection *** in two frequency bands(0.5-2 Hz and 1-3 Hz)are used in the imaging *** results show that the rupture of the first event extends about 200 km to the northeast and about 150 km to the southwest,lasting~90 s in *** southwestern rupture is triggered by the northeastern rupture,demonstrating a sequential bidirectional unilateral rupture *** rupture of the second event extends approximately 80 km in both northeast and west directions,lasting~35 s in total and demonstrates a typical bilateral rupture *** cascading ruptures on both sides also reflect the occurrence of selective rupture behaviors on bifurcated *** addition,we observe super-shear ruptures on certain fault sections with relatively straight fault structures and sparse aftershocks.

关键词： 2023 Turkish earthquake doublet back projection method cascading segmented rupture process coseismic triggering super-shear ruptures

新疆TASTE台阵拾震器方位角标定及其对SKS波分裂测量的影响

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北京大学学报（自然科学版） 2024年第5期60卷 822-838页

作者：毛鹏宇叶勃陈永顺盖增喜北京大学地球与空间科学学院北京100871 南方科技大学海洋科学与工程系深圳518055

在对塔里木岩石圈地震台阵(TASTE)的66个宽频带流动台站数据进行严格约束基础上,利用3种国际上常用的方法——P波主成分分析法、P波切向最小能量法和Rayleigh波相关系数法,实现地震仪的拾震器方位角标定。3种方法得出的结果具有较高的... 详细信息

在对塔里木岩石圈地震台阵(TASTE)的66个宽频带流动台站数据进行严格约束基础上,利用3种国际上常用的方法——P波主成分分析法、P波切向最小能量法和Rayleigh波相关系数法,实现地震仪的拾震器方位角标定。3种方法得出的结果具有较高的一致性(相关系数介于0.64~0.91之间),通过综合分析确定最终的地震仪拾震器方位角。其中62个台站地震仪的拾震器方向较稳定,且所有台站均没有出现南北反向、拾震器方位角随时间推移而发生系统性变化的情况。通过与磁偏角对比,发现有40个台站地震仪的拾震器方位角位于磁偏角的±3°范围内,说明TASTE台阵受到的外部干扰较小,台站部署质量较高。通过两个SKS波分裂实例,评估拾震器方位角对SKS波分裂测量产生的影响,论证了在地震学中进行拾震器方位角标定的必要性。

关键词：塔里木盆地拾震器方位角 P波主成分分析法 P波切向最小能量法 Rayleigh波相关系数法磁偏角 SKS波分裂

Long-term seismic network in South China Sea by floating MERMAIDs

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Science China Earth Sciences 2023年第9期66卷 1979-1993页

作者： Yong YU Yongshun John CHEN Zhen GUO zengxi ge Department of Ocean Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China School of Earth and Space Science Peking UniversityBeijing 100871China

Seismic data coverage in ocean regions is sparse,and it is highly challenging to build long-term continuous seismic networks in the oceans due to the restrictions related to the shortage of instruments and great *** lack of data coverage limits effective seismic imaging of deep mantle structures beneath the oceans,which cover 70%of the Earth’s *** newly developed Mobile Earthquake Recorder in Marine Areas by Independent Drivers(MERMAID)can drift with ocean currents at a specified depth while recording seismic *** Southern University of Science and Technology(SUSTech)launched 10 MERMAIDs in the South China Sea(SCS)in May 2021 that formed the South China Sea Floating Seismic Network(SCS-FSN).We analyzed the one-year-long records of the SCS-FSN,identifying 372 cataloged earthquakes and acquiring 1,015 high-quality travel time *** analyzing the records of earthquakes with magnitudes above 7.0 and conducting synthetic waveform calculation,we found that,in addition to the epicentral distance and earthquake magnitude,the earthquake identification ability of the network is also affected by the focal mechanism,sea condition,seafloor relief,and MERMAID working *** the recognition rate of the SCS-FSN is only 16%for earthquakes with magnitudes above 5.5 and epicentral distances less than 90°,this network is expected to collect more than 5,000 high-quality travel time data during its five-year battery *** new data will significantly improve the seismic data coverage,compensating for the lack of long-term continuous seismic network observations in the *** importantly,with this experiment,we are confident that setting up well-designed floating seismic networks in the world’s three oceans could solve the world-class problem of the lack of effective seismic data coverage beneath ocean regions.

关键词： South China Sea MERMAID Floating seismic network Earthquake identification Seismic data coverage

Simulation of the seismic response of sedimentary basins with constant-gradient velocity along arbitrary direction using boundary element method:SH case

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Earthquake Science 2010年第2期23卷 149-155页

作者： zengxi ge Department of geophysics School of Earth and Space Sciences Peking University Beijing 100871 China

We presented a boundary element method using the approximate analytical Green＇s function given by Sanchez-Sesma et al. Coordinate transform is introduced to extend the method to deal with the model with constant-gradient velocity along oblique direction. The method is validated by comparing the numerical results with other independent methods. This method provides a useful tool for analyzing local site effects. We computed seismic response for two series of models. The results in both frequency and time domains are analyzed and show complex amplification patterns. The fundamental mode of resonance is dependent not only on the velocity at the free surface but also on the velocity distribution of the whole basin. For the higher modes of vibration the heterogeneous basin also has its own characteristic.

关键词： boundary element SH wave seismic response constant-gradient velocity

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全球大地震破裂空间复杂度特征研究

北京大学学报（自然科学版） 2022年第4期58卷 635-643页

作者：王静盖增喜北京大学地球与空间科学学院北京100871 河北红山地球物理国家野外科学观测研究站邢台054000

基于有限断层反演得到的滑移数据,用独立滑移单元的数量表征地震破裂复杂度,据此对大地震破裂进行分组,并研究破裂复杂度与主要震源参数之间的关系,探讨破裂复杂度的全球及区域空间分布特征。结果表明,矩震级很大(Mw≥8.5)的事件,地震... 详细信息

基于有限断层反演得到的滑移数据,用独立滑移单元的数量表征地震破裂复杂度,据此对大地震破裂进行分组,并研究破裂复杂度与主要震源参数之间的关系,探讨破裂复杂度的全球及区域空间分布特征。结果表明,矩震级很大(Mw≥8.5)的事件,地震破裂复杂度更大;破裂复杂度较高的地震分布在浅层地壳(≤30km)内的概率最大,随着震源深度增加,破裂复杂度对震源深度的敏感性逐渐消失;走滑断层机制占比较大的事件,破裂复杂度较高;破裂复杂度与地震能矩比没有明确的关系;破裂复杂度的空间分布特征与区域地质构造环境相关。破裂复杂度的空间分布特征可以分为3类,第一类是板块之间简单碰撞产生的俯冲带,板块交界处的滑动速率和方向较为一致,这种情形下以比较简单的事件类型为主;第二类是多板块交界处,或者板块交界处的滑动速率和方向在整个区域内存在差异;第三类是大陆内部的强烈挤压地带。与第一类空间分布特征相比,第二类和第三类情形下破裂复杂度相对更高。地震破裂复杂度可以在一定程度上反映区域应力场的复杂性。

关键词：破裂复杂度震源参数空间分布断层构造背景

Azimuthal Anisotropy Analysis of the Upper Mantle beneath the Tarim Basin, Xinjiang, China Revealed by Shear Wave Splitting

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Azimuthal Anisotropy Analysis of the Upper Mantle beneath th...

Resolving rupture processes of great earthquakes: Reviews and perspective from fast response to joint inversion

2022年中国地球科学联合学术年会

作者： Bo Ye zengxi ge Peking University

Surrounded by Tian Shan orogenic belt, the West Kunlun orogenic and Altyn-Tagh orogen, the Tarim Basin has strong interaction with surrounding orogen belts since Neoproterozoic. In early Permian a mantle plume heated up the Tarim block and formed the Tarim large igneous province. Seismic imaging plays a key role in revealing the deep structure and related physical properties of the crust and upper mantle.

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Science China Earth Sciences 2020年第4期63卷 492-511页

作者： Han YUE Yong ZHANG zengxi ge Teng WANG Li ZHAO School of Earth and Space Sciences Peking UniversityBeijing 200871China

Resolving rupture processes of great earthquakes has fundamental importance to the study of earthquake physics,rupture dynamics, fault zone structure, and evolving processes. It also plays an essential role in earthquake hazard estimation,emergency response and seismic hazard mitigation. This paper reviews the major progress of the earthquake rupture process studies in the last decades, with an emphasize on the research directions of the department geophysics of Peking University including real-time response, back-projection techniques, geodetic data analysis, joint inversion and inversion in complex earth medium. We discussed the advantages and limitations of tradition methods;proposed a systematic and integrated approach from fast-response to detailed study. We also raised perspectives of using source models for ground motion prediction and the possibility of full-dynamic inversion.

关键词： Finite fault model Backprojection Joint inversion Strong motion Simulation

2.5D boundary element simulation of wave propagation in a vertical fluid-filled borehole with irregular shape

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Applied geophysics 2007年第3期4卷 155-163页

作者： ge zengxi Wang Canyun Lei Ting Chen Xiaofei Departrnent of geophysics School-of Space and Sciences Peking University Beijing 100871 Schlumberger-Doll Research Schlumberger Beijing geoScience Center Schlumberger Beijing 100871 China

In this paper, a boundary element formulation in the wave-number space domain for solving the wave equation for a borehole with arbitrary shape in acoustic logging problems is presented. The problem is treated as a two-dimensional medium with the discrete wave- number method in the vertical direction. The method is validated by comparing the results obtained by this method with those obtained by the finite-difference method. The method is used to study the effect on wave propagation in a vertical borehole of a vertical fracture. For a monopole source, the dispersion curves for Stoneley waves yield three branches. For dipole and quadrupole sources, different orientations of the source yield different results. When the dipole source is orthogonal to the fracture, the dispersion curve is similar to that of the open hole, while the curves are quite different when the source is parallel to the fracture. These characteristics enable us to determine the orientation of the vertical fracture.

关键词： Boundary element borehole logging dispersion curves vertical fracture.

High-resolution seismicity imaging and early aftershock migration of the 2023 Kahramanmara?(SE Türkiye)M_W7.9&7.8 earthquake doublet

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Earthquake Science 2023年第6期36卷 417-432页

作者： Hongyang Ding Yijian Zhou zengxi ge Tuncay Taymaz Abhijit Ghosh Haoyu Xu Tahir Serkan Irmak Xiaodong Song Institute of Theoretical and Applied geophysics Peking UniversityBeijing 100871China Department of Earth and Planetary Sciences University of CaliforniaRiverside CA 92521USA Hebei Hongshan National Observatory on Thick Sediments and Seismic Hazards Hebei 054000China Department of geophysical Engineering The Faculty of Minesİstanbul Technical UniversityMaslak 34467SarıyerİstanbulTürkiye Department of geophysical Engineering Kocaeli UniversityUmuttepe 41380KocaeliTürkiye

We build a high-resolution early aftershock catalog for the 2023 SE Türkiye seismic sequence with PALM,a seamless workflow that sequentially performs phase picking,association,location,and matched filter for continuous *** catalog contains 29,519 well-located events in the two mainshocks rupture region during 2023-02-01–2023-02-28,which significantly improves the detection completeness and relocation precision compared to the public routine *** the new PALM catalog,we analyze the structure of the seismogenic fault *** find that the Eastern Anatolian Fault(EAF)that generated the first M_(W)7.9 mainshock is overall near-vertical,whereas complexities are revealed in a small-scale,such as subparallel subfaults,unmapped branches,and *** seismicity on EAF is shallow(ge of depth,extending down to~35 *** also analyze the temporal behavior of seismicity,discovering no immediate foreshocks within~5 days preceding the first mainshock,and no seismic activity on the SF before the second mainshock.

关键词： 2023 Türkiye Earthquake Doublet aftershock catalog PALM fault imaging aftershock migration

台阵网格自动定位方法在鄂尔多斯地块南部和秦岭-大别造山带的应用

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北京大学学报（自然科学版） 2022年第4期58卷 626-634页

作者：杨延昭盖增喜北京大学地球与空间科学学院北京100871 河北红山地球物理国家野外科学观测研究站邢台054000

利用新近发展起来的台阵网格自动事件定位方法,对鄂尔多斯地块及秦岭-大别造山带区域136个宽频带流动台站记录的连续波形进行扫描和定位。通过与地震目录的对比发现,不仅在常规地震带上分布着大量的事件,而且在地震目录中极少发生地震... 详细信息

利用新近发展起来的台阵网格自动事件定位方法,对鄂尔多斯地块及秦岭-大别造山带区域136个宽频带流动台站记录的连续波形进行扫描和定位。通过与地震目录的对比发现,不仅在常规地震带上分布着大量的事件,而且在地震目录中极少发生地震的区域出现大量地震事件集中分布的现象。这些事件主要分布于鄂尔多斯地块南部以及秦岭-大别造山带附近的断层带。经过对定位台站的抽样分析和对定位事件地震波形的仔细人工确认,验证了这些被扫描并定位的事件的真实性。通过慢度分析,获得所定位事件的面波传播视速度,绝大部分事件对应的视速度在2.5~5.2km/s之间,与地震面波群速度相符。所定位的地震事件可用于补充秦岭-大别造山带的地震目录,同时可以通过进一步的波形拟合来分析其震源机制。

关键词：识别和定位面波地震目录事件分布视速度