2015尼泊尔大地震及喜马拉雅造山带未来地震趋势

2015 NEPAL EARTHQUAKE AND THE FUTURE SEISMIC TREND OF HIMALAYA OROGENIC BELT

2015年4月25日尼泊尔Ms8.1级大地震是发生在喜马拉雅造山带中段的低角度逆冲断层运动,特点是震源很浅,震中烈度达Ⅺ度,震害严重。破裂带走向北西西—南东东,穿越尼泊尔首都加德满都,使首都建筑遭受严重破坏。该震是1934年以来尼泊尔最大地震,标志着喜马拉雅带自1950年以来半个世纪的平静期已经结束。自2005年进入新活动期,至2015年尼泊尔大地震发生已达到活动高潮。预计将持续十到几十年。根据历史地震资料分析,今后可能沿喜马拉雅带走向发生纵向迁移,将在喜马拉雅带东段发生更大的地震,从而使地震高潮达到顶峰而结束,可能对我国西藏东南、不丹和印度边界产生破坏。另外还可能沿着与喜马拉雅带走向垂直方向向北迁移(即横向迁移),在几年之内即可在西藏、青海引起破坏性地震,需要相关省市做好监测预报和防灾工作。

This paper briefly introduces the parameters of the M 8. 1 earthquake on April 25,2015,which is a low angle thrust fault movement in the middle of the Himalaya orogenic belt. The characteristics is that the source is very shallow,the intensity of the earthquake reaches to Ⅺ degree and the earthquake damage is severe. The rupture zone have a strike of the North West-South East,crossing the Nepalese capital Kathmandu,where the construction suffered serious damage. The earthquake was the largest earthquake in Nepal since 1934,which marking the end of the period of peace in Himalaya since 1950. Since entering the new active period in 2005,the great earthquake occurred in Nepal has reached the climax of the event in 2015,which is expected to last ten to several decades. According to the analysis of data of historical earthquakes,it may have a migration along the Himalayan zone in the future,and there will be larger earthquake in the eastern part of the Himalayan belt,so as to reach the top of earthquake tide and then have a end. There may be serious damage to the border of India,Bhutan and east-south region of Tibet. It is also possible to move northwardly along with the Himalaya belt in the vertical direction（ i. e. horizontal migration）,causing destructive earthquakes in Tibet,Qinghai in a few years. It needs to do a good job in monitoring,forecasting,and disaster prevention.