1997年玛尼7.5级地震前后区域地震活动特征及远场前兆

REGIONAL SEISMICITY CHARACTERS BEFORE AND AFTER THE MANI M_S7.5 EARTHQUAKE AND ITS FAR-FIELD PRECURSORS

分析研究了 1 997年 1 1月 8日玛尼 7.5级地震前区域地震活动特征及远场前兆 .结果表明 :该次地震前 ,在震中南侧形成了一个MS ≥ 5地震空区 ;整个藏北地震带ML ≥ 4.0地震活动减弱 ;在震中东侧 940km处的青海德令哈地应力和距震中 60 0km处的格尔木水温出现了短临异常 .还对该次地震发生的背景和震后调整等问题作了初步探讨 .

Regional seismicity characters before and after the Main M S7.5 earthquake on Nov.8,1997 and its far field precursors are analyzed and studied.The results show that before the earthquake,a gap of M S≥5.0 earthquakes has been formed in the south of the epicenter and frequency of M L≥4.0 earthquake along Zangbei seismic zone decreased;Ground stress of Delingha station which is to the east of the epicenter and 940 km distant from it and groundwater temperature of Geermu station which is about 600 km distant from the epicenter have shows of short and impending anomalies.The background of the earthquake and stress field adjustment after the event are approached.