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

合作研究：2011 年 8 月 23 日，Mw 5.8，弗吉尼亚地震余震序列的密集阵列余震成像 (AIDA)

• 批准号: 1160666
• 负责人: John Hole
• 金额: $ 2.33万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-10-01 至 2012-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1160666&HistoricalAwards=false
• 关键词: Collaborative; Research; Aftershock; Imaging; Dense

This RAPID supports post-seismic deployment of novel high density seismic arrays usinginstruments from the Earthscope Flexible Array provided by IRIS/PASSCAL to investigate theMw 5.8 Virginia earthquake of August 23, 2011. This event had a NE-striking reverse faulting focalmechanism, a hypocentral depth of 6 km (USGS), and occurred in a previously recognized seismicregion known as the ?Central Virginia Seismic Zone?. This event passes with ca. 15 km of a NW-SEoriented deep seismic reflection profile contracted in 1981 by the USGS, providing a rare opportunityto link seismicity to deep structure in the eastern U.S. The preliminary hypocentral estimate suggeststhat the earthquake occurred within a complex zone of east-dipping reflections that define animbricated Paleozoic thrust sheet of the central Appalachian Piedmont that is underlain by Grenvillebasement 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.

该RAPID支持使用IRIS/PASSCAL提供的Earthscope Flexible Array中的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focalmechanism，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被称为？弗吉尼亚中部地震带？此事件随CA一起通过。1981年美国地质勘探局（USGS）对15 km的西北-东南向深地震反射剖面进行了收缩，提供了一个将地震活动与美国东部深部结构联系起来的难得机会。初步震源估计表明，地震发生在一个复杂的东倾反射带内，该反射带确定了阿巴拉契亚山脉中部皮埃蒙特的活动古生代逆冲岩席，该逆冲岩席下面是格伦维尔基底，深度约为1000 m。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。