青藏高原东缘重力观测及对芦山M7.0地震的反映

Gravity Observation in the Eastern Margin of Qinghai-Tibetan Plateau and Reflect to the Lushan M7.0 Earthquake

摘要:

介绍了青藏高原东缘地区相对重力与绝对重力的观测情况,系统分析了该区域2010以来的区域重力场变化及其与2013年4月20日四川芦山7.0级地震发生的关系。结果表明:(1)芦山7.0级地震前青藏高原东缘重力变化剧烈,芦山地震发生在沿龙门山断裂带南段的重力变化高梯度带的转弯部位;(2)芦山地震距2008年汶川地震不到100km,芦山震中及汶川地震震中均处于重力变化四象限中心,表明汶川地震震后恢复调整变化对芦山地震具有促进作用;(3)基于流动重力异常变化在芦山7.0级地震前做过一定程度的中期预测,尤其是地点预测。

Abstract:

With the introduction of observation on relative gravity and absolute gravity in the eastern Qinghai-Tibet Plateau,gravity field change of the eastern margin of Tibetan Plateau since 2010 and the reflection on the M7.0 earthquake which occurred on April 20,2013 in Lushan,Sichuan were systematically analyzed.The results showed that:(1)Before the Lushan 7.0 earthquake,the gravity of the eastern margin of Tibetan Plateau changed drastically,and the Lushan earthquake occurred in the turning site of the high gradient zone of gravity variation which was along the southern seciont of Longmenshan fault zone.(2)The Lushan earthquake in 2013was less than 100km from the 2008 Wenchuan earthquake in terms of location,moreover,Lushan and Wenchuan were at the four-quadrant center of gravity change,which indicated that the restoration and change after Wenchuan earthquake had a promoting effect on the Lushan earthquake.(3)A certain medium-term prediction based on the anomaly change of mobile gravity was madebefore the Lushan M7.0earthquake,especially the location prediction.