Collaborative Research:Aftershock Imaging with Dense Arrays (AIDA) for the August 23, 2011, Mw 5.8, Virginia earthquake aftershock sequence

该RAPID支持使用IRIS/PASSCAL提供的Earthscope Flexible Array仪器进行新型高密度地震阵列的震后部署，以调查2011年8月23日弗吉尼亚州的Mw 5.8地震。这一事件有一个东北走向的逆断层震源机制，震源深度为6公里（美国地质勘探局），并发生在以前公认的地震区称为中央弗吉尼亚地震带。此事件随CA一起通过。1981年美国地质勘探局承包的15公里西北-东南向深地震反射剖面，提供了一个难得的机会，将地震活动与美国东部的深层结构联系起来。初步震源估计表明，地震发生在东部的一个复杂区域内，倾斜反射，确定了阿巴拉契亚皮埃蒙特中部的叠瓦状古生代逆冲岩席，该逆冲岩席位于格伦维尔基底下方，深度为约通过将地震定位技术与高分辨率结构成像技术相结合，这一实验试图展示如何利用被动和主动地震技术来利用余震，以确定在这两种类型的信息要么稀少要么不存在的区域的深层发震结构以及能量传播特征。记录实验构成了利用新一代记录技术以前所未有的分辨率成像地震过程和相关结构的原型。如果数据像预期的那样丰富，这个实验很可能为未来的余震研究建立一个新的协议。

This RAPID supports post-seismic deployment of novel high density seismic arrays using instruments from the Earthscope Flexible Array provided by IRIS/PASSCAL to investigate the Mw 5.8 Virginia earthquake of August 23, 2011. This event had a NE-striking reverse faulting focal mechanism, a hypocentral depth of 6 km (USGS), and occurred in a previously recognized seismic region known as the Central Virginia Seismic Zone. This event passes with ca. 15 km of a NW-SE oriented deep seismic reflection profile contracted in 1981 by the USGS, providing a rare opportunity to link seismicity to deep structure in the eastern U.S. The preliminary hypocentral estimate suggests that the earthquake occurred within a complex zone of east-dipping reflections that define an imbricated Paleozoic thrust sheet of the central Appalachian Piedmont that is underlain by Grenville basement at a depth of ca. 9 km.By merging the technologies of earthquake location with high resolution structural imaging, this experiment seeks to demonstrate how aftershocks can be exploited by both passive and active seismic techniques to identify seismogenic structures at depth as well as energy propagation characteristics for a region where both types of information are either rare or non-existent. The recording experiment constitutes a prototype for imaging earthquake processes and associated structures with unprecedented resolution by exploiting a new generation recording technologies. If the data proves as rich as expected, this experiment may well establish a new protocol for future aftershocks studies.