Study of the structure and seismicity of the February 27, 2010 Chile Mw 8.8 earthquake rupture zone

该小组提案的主要目标在摘要文件中说明。拟议项目的主要目标是利用2010年2月27日马乌莱8.8级地震开始的智利南部边缘沿着地震序列，进一步了解大地震、会聚边缘结构和震后弛豫过程之间的关系。这一序列提供了一个前所未有的机会，可以对余震活动和大地震破裂带的结构进行非常详细的成像，并确定该地区的精确速度模型。主震发生后不久，各国际小组在整个500公里长的破裂带沿着安装了由142个地震仪站组成的密集网络。在该项目的第一阶段，将利用绝对和相对震源定位技术探测和定位余震。余震的时空行为反映了震后弛豫过程及其结构。余震将有助于阐明在大地震的震后阶段应力是如何释放的，并将解析俯冲带浅部的结构。将应用当地地震层析成像来确定速度模型。为了处理正在发生的余震系列的大量地震图数据，将应用、测试和改进以前的（半）自动化技术。Pichilemu市周围一个明显和持续的地壳地震活动集群，包括一个MW 6.9级的正常断层余震，将是重点地区之一。其目的将是回避的原因，这些伸展事件的会聚俯冲带设置。建议与其他俯冲带背景进行比较，以更好地了解2010年马乌莱大地震序列的区域地震构造情况。

The principle aims of the group proposal are described in the summary document. The main objective of the proposed project is to further our understanding of the relationships between great earthquakes, the structure of convergent margins and postseismic relaxation processes using the earthquake sequence along the Southern Chilean margin which started on 27 February 2010 with the Mw 8.8 Maule earthquake. This sequence provides an unprecedented opportunity to image the aftershock activity in great detail and structure of the rupture zone of a great earthquake, and to determine an accurate velocity model for the region. A dense network of 142 seismograph stations was installed by various international teams shortly after the mainshock along the entire 500 km long rupture zone. In the first stage of the project, aftershocks will be detected and located using absolute and relative hypocentre location techniques. The spatial-temporal behaviour of the aftershocks reflects postseismic relaxation processes and the structure therein. The aftershocks will help to clarify how stress is released in the postseismic phase of a great earthquake, and will resolve structures within the shallow part of the subduction zone. Local earthquake tomography will be applied to determine the velocity model. In order to process the large amount of seismogram data of the ongoing aftershock series previous (semi-)automated techniques will be applied, tested and improved. A pronounced and ongoing cluster of crustal seismicity around the city of Pichilemu, including a normal faulting aftershock of magnitude Mw 6.9 will be one of the focus areas. The aim will be to eludicate the reason for these extensional events in the convergent subduction zone setting. A comparison with other subduction zone settings is suggested to better understand the regional seismotectonic situation of the great 2010 Maule earthquake sequence.