NSF/EAR-BSF:Aftershock Productivity in Context of Rupture Kinematics

NSF/EAR-BSF：破裂运动学背景下的余震生产力

基本信息

批准号：
1761987
负责人：
Emily Brodsky
金额：
$ 31.26万
依托单位：
University of California-Santa Cruz
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-06-01 至 2023-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1761987&HistoricalAwards=false
关键词：
NSF EAR BSF Aftershock Productivity

项目摘要

Aftershock studies have blossomed in the current data-rich era. Substantial progress has been made in empirically predicting how many aftershocks are produced in the aftermath of an earthquake. Although predicting the timing and size of aftershocks have received more attention historically, the expected total number of aftershocks is just as robust an observation. In general, a magnitude 7 earthquake produces 10 times as many aftershocks as a magnitude 6 and the pattern continues for all magnitudes, i.e., the number of aftershocks increases by a factor of 10 for each magnitude unit. The project asks why does aftershock production follow this pattern? What information does it contain about earthquake mechanics? Why do some earthquakes, like the 2017 Chiapas earthquake produce many aftershocks, while others, like the 2017 Mexico City earthquake produce only a few? And most importantly, can this information be used to anticipate the aftershock production in the critical days following a disaster? This project has broader implications for our understanding of earthquake hazards, and adds to the US-Israel scientific partnership. The work will also support graduate students and an undergraduate researcher to conduct research as part of the project. Significant effort has been spent on these questions utilizing tools from statistical seismology. Many studies have focused on regional earthquakes, where statistics are most robust. Separating out the causes of aftershock production can benefit from information of the slip patterns of individual mainshocks that can be derived using global seismic data. Previous studies have strived to attack this problem by combining aftershock data with information about the timing and distribution of slip. The studies have been insightful, but have generally lacked the number of mainshocks required for statistical analysis. This lack has been, in part, because until recently slip maps were sufficiently difficult that they were only available for a small number of cases. Therefore, it was difficult to ask questions about the relation between aftershocks and mainshock rupture since different models are biased in different ways. This situation has changed dramatically with recently published large compilations of rupture sequences done uniformly with a single method. This work exploits a new era of combining information from kinematic ruptures and their ensuing aftershocks. The researchers will capitalize on this capability and attack aftershock productivity by: (1) using the spatial distribution of aftershocks relative to well-resolved coseismic slip maps to clarify physical origins of the magnitude dependence, (2) investigating regional variations in productivity, and (3) examining the interrelationship between aftershock productivity, regional strength, and arrest criteria for mainshock rupturesThis award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

余震研究在当前数据丰富的时代开发。从经验上预测地震后产生了多少余震，已经取得了重大进展。尽管预测余震的时间和大小在历史上已经受到了更多的关注，但预期的余震总数也同样强大。通常，7级地震产生的余震是幅度6的10倍，所有幅度的模式持续，即，对于每个幅度单位，余震的数量增加了10倍。该项目询问为什么余震生产遵循这种模式？它包含有关地震机制的哪些信息？为什么像2017年奇帕斯地震这样的地震会产生许多余震，而另一些地震则像2017年的墨西哥城市地震只会产生少量？最重要的是，这些信息是否可以用来预测灾难后的关键日子的余震？该项目对我们对地震危害的理解具有更广泛的影响，并增加了以色列科学伙伴关系。这项工作还将支持研究生和本科研究人员作为项目的一部分进行研究。利用统计地震学的工具，已经花费了大量的努力。许多研究集中在统计数据最强大的区域地震上。分离出余震产生的原因可以受益于可以使用全球地震数据得出的单个主震的滑动模式的信息。先前的研究一直在努力通过将余震数据与有关滑移时间和分配的信息相结合，以攻击这一问题。这些研究很有见地，但通常缺乏统计分析所需的主震数。这种缺乏部分原因是，直到最近，滑道地图还是很困难的，因此仅适用于少数情况。因此，由于不同模型以不同的方式有偏见，因此很难询问有关余震和主震破裂之间关系的问题。由于最近发表的大量破裂序列均匀地进行了单一方法，这种情况发生了巨大变化。这项工作利用了将运动破裂及其随后的余震中的信息结合在一起的新时代。研究人员将通过以下方式利用这种能力和攻击余震的生产率：（1）使用相对于解决良好的coseissic滑动图的空间分布来阐明幅度依赖性的物理起源，（2）研究生产率的区域变化，以及（ 3）检查余震生产率，区域实力和Mainshock Rupurethis奖的逮捕标准之间的相互关系反映了NSF的法定任务，并被认为是值得通过基金会的知识分子和更广泛影响的评估审查标准来通过评估来支持的。