预滑活动可能是地震前兆异常远程关联的物理机理

Pre-slip activity may be the physical mechanism of remote correlation of earthquake precursory anomaly

关注地震前兆异常的远程关联现象,有助于准确预测未来震中位置。2008年汶川M_(W)7.9地震发生前,大约在2008年3月20日前后,华北地块区及次级地块准同步发生了预滑活动。临震前1天,在冀鲁和鲁东黄海地块上,有10个地震台的水位仪、形变仪、地面和井下气压计记录到低频震颤震相Tp,且在地域和时间上与华北地块的预滑活动及此次汶川M_(W)7.9地震的发生相关性较好。推测认为,可能是华北地块区及次级地块在地幔热物质对流力的驱动下发生的震前预滑活动,地下气体逸出激发低频震颤,形成此次汶川M_(W)7.9地震前兆异常的远程关联现象。在数千千米尺度上的预滑活动,可能是地震前兆远程关联的物理机理,厘清异常位置(震中附近或远程关联),对作好未来震中预测具有重要作用。

Paying attention to the phenomenon of remote correlation of the earthquake precursor is helpful in accurately predicting the epicenter position in the future.Before the Wenchuan M_(W) 7.9 earthquake on May 12th,2008,pre-slip activities occurred in the North China tectonic-block region and its sub-tectonic-blocks in a quasi-synchronous manner on March 20,2008.More than 1 day before the impending earthquake,the low-frequency tremor phase Tp was recorded by water level meter,deformation meter,and ground and underground barometers at 10 seismic stations in the Hebei-Shandong and Yellow Sea-East Shandong sub-tectonic-blocks.They are closely related to the pre-slip activity of the North China tectonic blocks and the occurrence of the Wenchuan M_(W) 7.9 earthquake.We speculate that the North China tectonic block and its sub-tectonic block may have experienced a low-frequency tremor after pre-slip activities driven by the convective force of mantle thermal material before the Wenchuan M_(W) 7.9 earthquake.It is the remote-correlation phenomenon of the precursory anomaly of the M_(W) 7.9 earthquake.The pre-slip activity on the scale of thousands of km may be the physical mechanism of the remote correlation of earthquake precursory anomaly.To clarify whether it is the precursory anomaly near the epicenter or the precursory anomaly of remote correlation is undoubtedly crucial to predicting the future epicenter.