1668年鲁南巨震研究工作座谈会在青岛召开

<正> 公元1668年鲁南8.5级巨震是我国东部地区乞今发生的一次最高震级的历史地震。该巨震在历史上曾一度对鲁南一苏北造成过毁灭性破坏。因此,它对整个鲁苏地区的烈度区划和地震危险区划研究工作带来重要影响。最近由于围绕着鲁南一苏北高烈度地震危险区的重新审定工作的开展,对鲁南巨震的认

Journal of Seismology THE FOCAL PROCESS AND THE PRECURSOR PHENOMENA OF HEZE EARTHQUAKE(M_s=5.9)

In this paper, the faultparameters related to the Heze earthquake (Ms=5.9) occurred in 1983 was deduced from the inversion of the levelling data. The results indicate that the event in question is caused by the motion of left-lateral shearing nomal fault with NW(137.5°)-striking SW-dipping and a dip angle of 45.8°. The length of the earthquake fault is 19km and its width is 29.6 km, the strike-slip is 41.4cm and dipslip is 11.8cm, the stress-drop and the strain-drop are 13.5 bar and 2.0×10~(-5) respectively. Before the occurrence of the earthquake, the megistoseismal region was still in a closing state, but the shearing action was firstly reflected on Daxiaomancheng fault. When the tectonic stress became intensive a mutational pre-dispiacement thus took place. This sort of precursor phenomena appeared on the NE-striking secondary fault with different movement form.