Acta Scientiarum Naturalium Universitatis Pekinensis ›› 2020, Vol. 56 ›› Issue (5): 867-874.DOI: 10.13209/j.0479-8023.2020.058

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Relocation and Focus Mechanism Estimation of the Strong Earthquake Ms≥7.0 from 1918 to 1970 around Asia and Analysis of Their Uncertainties

HAN Jiayuan, ZHANG Xianbing, ZHOU Shiyong   

  1. Institute of Theoretical and Applied Geophysics, School of Earth and Space Sciences, Peking University, Beijing 100871
  • Received:2019-12-06 Revised:2020-03-26 Online:2020-09-20 Published:2020-09-20
  • Contact: ZHANG Xianbing, E-mail: xbzhang(at)pku.edu.cn; ZHOU Shiyong, E-mail: zsy(at)pku.edu.cn

亚洲地区1918—1970年7级以上强震重新定位与震源机制测量及结果的不确定性分析

韩甲源, 张献兵, 周仕勇   

  1. 北京大学理论与应用地球物理研究所, 北京大学地球与空间科学学院, 北京100871
  • 通讯作者: 张献兵, E-mail: xbzhang(at)pku.edu.cn; 周仕勇, E-mail: zsy(at)pku.edu.cn
  • 基金资助:
    宁夏回族自治区重点研发计划东西部合作项目(2018BFG02011)和国家自然科学基金(41674047)资助

Abstract:

Through the software of optical character recognition (OCR), this study sorts out seismic phase report of seismic stations worldwide from 1918 to 1970, earthquake location and focal mechanisms (fault plane solution) of part of the earthquakes are measured in Asia and nearby areas at that time. Specific work is carried out in two aspects. 1) Using arrival time and arrival-time difference in 1918?1970 from International Seismological Summery (ISS) and EHB Bulletin, the relocation of 338 earthquakes are calculated, and 316 among them are reliable. 2) Utilizing P wave initial motion in 1933?1970 from ISS and EHB Bulletin, the focal mechanisms of 244 earthquakes are calculated, and 209 among them are reliable. Based on global seismic network observation, the focal mechanisms of modern strong earthquakes in Asia from 1918 to 1970 have been enriched. Another important significance of this study is to provide a set of feasible methods for the study of modern earthquakes, which can be instructive in other regions or in other magnitudes.

Key words: optical character recognition (OCR), modern earthquakes, relocation, character recognition, focal mechanism

摘要:

通过光学字符识别(OCR)软件, 整理世界地震台网1918—1970年的世界台站震相报告, 对该时期发生在亚洲及周边地区7级以上强震的震源位置及部分强震的震源机制(断层面解)进行测量。使用1918—1970年《国际地震资料汇编》(ISS)和EHB Bulletin的震相到时和到时差, 对该时段338个7级以上地震事件进行重新定位, 得到其中316个地震事件的可靠定位。使用1933—1970年ISS和EHB Bulletin的P波初动数据, 对该时段244个地震事件求解震源机制解, 得到其中209个地震事件的震源机制解。研究结果丰富了亚洲地区基于全球地震台网观测的1918—1970年仪器记录早期近现代强震目录震源机制资料, 并提供一种研究近现代地震的可行方法, 对开展其他地区或其他震级范围的仪器记录早期近现代地震研究具有启发作用。

关键词: 光学字符识别(OCR), 近现代地震, 重定位, 文字识别, 震源机制解