Kinematic rupture process of the 2007 Tocopilla earthquake and its main aftershocks from teleseismic and strong-motion data
Kinematic rupture process of the 2007 Tocopilla earthquake and its main aftershocks from teleseismic and strong-motion data
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DOI：
10.1111/j.1365-246x.2010.04685.x
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发表时间：
2010-09
影响因子：
2.8
通讯作者：
S. Peyrat;R. Madariaga;E. Buforn;J. Campos;G. Asch;J. Vilotte
中科院分区：
文献类型：
--
作者：
S. Peyrat;R. Madariaga;E. Buforn;J. Campos;G. Asch;J. Vilotte
摘要我们研究了2007年11月14日在智利北部托科皮拉市附近的地震空区发生的一次里氏7.6级大地震。利用各种地震资料，我们发现这次地震只破裂了板间地震带的下部，并产生了一系列的板块界面余震。2007年11月15日发生的两次大余震使安托法加斯塔地区的一个主要地理特征--梅吉洛内斯半岛的板间带向海洋方向破裂。2007年12月16日，在主震断层面南底附近发生的一次Mw=6.8的大余震，被证明是一次位于俯冲的纳斯卡板块内部，由板条挤压触发的板条推进地震。这次地震的余震表明，它发生在一个几乎垂直的断层上。托科皮拉地震发生之前，智利、德国和法国的研究人员刚刚安装了一个新的地震台网。加速度测量数据与远场地震数据相结合，提供了对破裂过程相当完整和一致的看法。地震打破了过渡带上方长(130公里)和窄(约30-50公里)的板块界面。使用非线性运动学反演方法，我们确定了破裂发生在两个定义明确的大致椭圆形的斑块上。我们讨论了这一事件对20世纪70年代在智利提出的填补空白的地震模型的影响。
SUMMARY We study a large M w = 7.6 earthquake that occurred on 2007 November 14 in the Northern Chile seismic gap near the city of Tocopilla. Using a variety of seismic data we show that this earthquake ruptured only the lower part of the interplate seismic zone and generated a series of plate interface aftershocks. Two large aftershocks on 2007 November 15 ruptured the interplate zone oceanwards of the Mejillones Peninsula, a major geographical feature in the Antofagasta region. On 2007 December 16, a large M w = 6.8 aftershock, that occurred near the southern bottom of the fault plane of the main event, is shown to be a slab-push earthquake located inside the subducted Nazca Plate and triggered by along slab compression. Aftershocks of this event demonstrate that it occurred on an almost vertical fault. The Tocopilla earthquake took place just after the installation of a new seismological network by Chilean, German and French researchers. The accelerometric data combined with far field seismic data provide a quite complete and consistent view of the rupture process. The earthquake broke a long (130 km) and narrow (about 30–50 km) zone of the plate interface just above the transition zone. Using a non-linear kinematic inversion method, we determined that rupture occurred on two well-defined patches of roughly elliptical shape. We discuss the consequences of this event for models of gap filling earthquakes in Chile proposed in the 1970s.