干盐池拉分盆地盆内新生断层大地震记录与海原断裂带级联破裂地震事件

发布时间：2018-04-30 09:43

  本文选题：海原断裂带 + 干盐池拉分盆地　； 参考：《地震地质》2016年04期

【摘要】：沿大型走滑断裂带经常发生导致多个断层段同时破裂的级联破裂地震事件。海原断裂带在1920年海原M 8骀骜地震时3个段同时发生破裂,干盐池拉分盆地即为其西段和中段的分段边界。沿该盆地内新生断层的古地震研究揭示了晚更新世末期以来的至少7次古地震事件证据,最新1次事件为1920年海原地震,1920年海原地震之前的1次事件可能与1092年历史地震对应。对比分析表明,这些事件可能均为超过8级的大地震,其复发呈现地震丛集与单个事件相间排列的规律,当前可能处于最近的1个地震丛集期内。该古地震序列与整个海原断裂带的大地震活动历史的对比表明,干盐池拉分盆地内新生断层在级联破裂地震事件发生时并非总是同时破裂,该断层是否参与破裂可能与该次级联破裂事件的震级大小有关。讨论整个走滑断裂带大地震活动历史时应避免仅依据具有一定规模的拉分盆地内部断层的破裂记录。
[Abstract]:Cascaded faults along large strike-slip fault zones often cause simultaneous rupture of multiple fault segments. During the 1920 Haiyuan M 8 Tai ao earthquake, three segments of Haiyuan fault zone were ruptured at the same time. The dry Yanchi pull-apart basin is the segmental boundary of the western and middle segments of the fault zone. Paleoseismological studies along the new faults in the basin reveal evidence of at least 7 paleoearthquakes since the end of the late Pleistocene, the most recent event being the 1920 Haiyuan earthquake, and one event before the 1920 Haiyuan earthquake may correspond to the 1092 historical earthquake. The comparative analysis shows that these events may all be large earthquakes with M 鈮，

本文编号：1824054