探讨与汶川地震有关的焦点科学问题

基于孕震断层多锁固段脆性破裂理论和新划定的3.6版汶川地震区,再次探讨了与2008年汶川地震有关的若干科学问题,包括该震是否为主震?该震、2013年芦山MS7.0地震、2017年九寨沟M_S7.0地震之间关系?该震是否存在复发周期?该震发生前是否存在显著物理前兆?该震与紫坪铺水库之间关系?研究结果表明:汶川地震并非汶川地震区当前地震周期主震,未来将发生MS8.0~8.3标志性地震;2013年芦山地震和2017年九寨沟地震有直接联系且均与汶川地震密切相关,两者同为下一次标志性地震前的两次显著预震;汶川地震区标志性地震及其未来主震是否存在复发周期目前尚不能作出明确判断;在汶川地震前,由于自1995年12月18日后其震源体的物理状态长期保持近似不变,故不可能观测到显著的中长期与短临物理前兆;紫坪铺水库对汶川地震孕育过程的影响很小,可以忽略。

Discussion on Key Scientific Issues Related to the 2008 Wenchuan Earthquake

Based on both the lately-defined Wenchuan seismic zone (version 3.6) and the theory about the brittle failures of multiple locked patches in a seismogenic fault system, we reanalyzed several focus issues related to the 2008 MS8.1 Wenchuan earthquake. The results show that the 2008 Wenchuan earthquake is not the mainshock in the current seismogenic period of the Wenchuan seismic zone and a MS8.0~8.3 characteristic earthquake will strike this seismic zone; both the 2013 MS7.0 Lushan earthquake and 2017 MS7.0 Jiuzhaigou earthquake are closely related to the 2008 Wenchuan earthquake and are two significant preshocks occurred between the 2008 Wenchuan earthquake and the expected MS8.0~8.3 characteristic earthquake; we are not able to judge at present whether there exist recurrence intervals of the characteristic earthquakes and the mainshock in the Wenchuan seismic zone relying on currently available data; because the physical state of the hypocenter body since December 18, 1995 had remained approximately unchanged prior to the 2008 Wenchuan earthquake, it was indeed difficult that obvious medium-long-term, short-term and imminent earthquake precursors could been observed; there is no causality between the 2008 Wenchuan earthquake and the Zipingpu reservoir and the immediate cause leading to the Wenchuan earthquake can be attributed to the 1976 double earthquake swarm events occurred in Songpan-Pingwu.