新疆及周边和川、 滇、 青地区大震前椭圆形空区的回顾性研究及讨论

以MAPSIS为平台, 用统一目录对新疆及周边和川、 滇、 青地区17次大地震前的地震分布进行大范围、 长时间扫描, 勾画椭圆形围空区。 除1970年代初期的3次地震外, 大多有较好的围空区。 包括2008年5月汶川8.0级地震和2010年4月玉树7.1级地震。 结果表明, 大震震级与空区长度有一定正相关关系, 但与空区起始时长及空区成形时长没有关系。 讨论认为, 椭圆围空区的确定条件较松, 在复杂情况下用来勾画空区容易出现多维性, 使围空区的可信性下降, 导致地震虚报增加。

Retrospective Research and Discussion on Elliptic Gaps before Large Earthquakes in Xinjiang and its Surrounding, Sichuan-Yunnan and Qinghai Regions

We study seismic distribution before the 17 large earthquakes in Xinijang and its surrounding, Sichuan-Yunnan and Qinghai regions, by scanning in a large range and long-time scale with the uniform seismic catalogue and Mapsis software, and draw elliptic gaps. The results show that except three earthquakes in the early 1970s, most large earthquakes exit good seismic gaps, including the Wenchuan M_S8.0 earthquake on May, 2008 and Yushu M_S7.1 earthquake on April, 2010. The magnitude of large earthquakes and gap length have positive correlations, but the magnitude of large earthquakes and the gap starting and forming time scale have no obvious correlation. The definite condition of ellipse is not strict, so it is easy to be multi-dimensional in drawing gaps in complicated situation, and gap confidence may decrease and false forecast may increase.