摘要
2015年7月3日新疆皮山县发生了Mw6.4级地震,震中位于塔里木盆地西南部的西昆仑山造山带北缘,发震断层为隐伏断层.文章基于分层地壳模型,参考反射地震剖面构建铲状断层模型,通过合成孔径干涉测量(InSAR)数据、远场波形资料、全球定位系统(GPS)数据联合反演获得了此次地震的震源破裂过程.表明该地震断层南倾,走向109°,滑动方向近乎北向,断层面破裂分布较集中,最大滑动量为73cm,主要表现为深度9~13km的低倾角(25°~10°)逆冲滑动,传播时间约12s,破裂由初始破裂点往周围扩散,没有明显的方向性,地表0~4km范围软硬沉积层内没有明显滑动.利用InSAR时序分析方法获取了震源区震后两年内的形变速率,雷达视线向(LOS)最大值约17mm a~(-1),仅在地震上盘观测到明显震后形变,形变趋势与同震位移场类似,表明皮山地震没有完全释放区域累积能量,隐伏断层上方的多层褶皱构造震后依然缓慢隆起,其震后调整模式和余震危险性分析需要利用更多独立数据进一步研究.
引文
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