上海徐家汇观象台记录的1933年四川叠溪地震参数计算

Seismic Parameter Calculation of the Diexi Earthquake in Sichuan,Obtained from Drawings Recorded in 1933 at the Xujiahui Observatory,Shanghai

地震学者对1933年叠溪大地震进行了大量研究,由于资料匮乏,学术界至今对该地震的震源位置、震级、发震时间3要素有不同看法。本文利用上海徐家汇观象台1933年四川叠溪大地震三分向记录,通过对叠溪地震事件图纸的重新分析校核,利用IASP91全球走时模型对发震时间、震中距和震级3要素重新行计算和反演,得出的定位结果为:发震时刻为1933年8月25日7时50分15秒、震中距为16.25°、震级为M_(S)7.49。该结果和其他研究学者在发震时刻和震中距上偏差较大,发震时刻相差17 s,震中距相差1°左右,两者偏差较大,究其原因是采用的方法不同,前人是基于宏观资料、现场调查以及后续小震反演得到的结果。

Seismologists have done a lot of research on the 1933 Diexi earthquake in Sichuan.Due to the lack of data,the academic community has different views about the three elements of the event such as hypocentral location,magnitude and occurrence time.In this paper,using the three-way records of the 1933 Sichuan Diexi M7/12 earthquake at the Xujiahui Observatory,the event map has been reanalyzed and checked.Using the IASP91 reference model,the three elements of the time,site and magnitude of the event have been recalculated and inverted.The earthquake occurred at 7∶50∶15 on August 25,1933.The epicenter distance is 16.25°.The magnitude is M_(S)7.49.The comparison between the results studied by other researchers and the results of this paper shows that there is a significant deviation in the parameters of earthquake occurrence time and epicenter distance.The difference on the time of earthquake occurrence is 17 seconds,and the difference in epicenter distance is about 1°.The reason for the difference is that the methods used are different.Previous studies have obtained results based on macroscopic data,onsite investigations,and subsequent small earthquake inversion.