Collaborative Research: RAPID: Response to the 29 July 2021 Chignik M8.2 Earthquake

该RAPID奖是对2021年7月阿拉斯加半岛Chignik地震（8.2级）的响应。这是自1965年（鼠岛地震）以来美国发生的最大地震。它使阿拉斯加半岛近海的一段大型逆冲断层破裂，上一次破裂是在1938年。该项目部署了一项综合的陆地实地观测活动：大地测量学用于快速勘测附近的纪念碑并记录地震相关的变形，地震学用于部署附近的仪器记录余震。了解这次地震将为评估地震行为模型提供关键信息，从而评估地球上最大地震的危险性。虽然只发生了一次小海啸，但更好地了解破裂将有助于更现实的海啸危害评估。这次地震还通过迅速向地震和大地测量研究界提供数据，为扩大科学参与提供了充分的机会。该计划包括与当地学校、社区和政府联系，并重启一个关注阿拉斯加地球物理学的热门博客。在仪器记录中，奇格尼克地震是一个断层段发生两次大地震的非常罕见的例子，是检验地震循环如何工作的理论的关键地点。地震遵循先前记录的沿走向分段模式，这些分段在锁定行为和地震历史上存在很大差异。这种分段的原因（或者更普遍地说，滑移行为变化的原因）仍然不确定，收集新的数据可能会阐明震间和同震破裂分段背后的控制机制。此外，地震提供了一个很好的实验室来测试断层之间的载荷理论和我们对震后变形的理解。几乎就在一年前，一场7.8级的地震使靠近西面的Shumagin部分破裂，这表明有可能引发地震。这种关系是可以探索的，同时也有可能使东部的下一个部分更接近失败。该项目利用了数十年来在舒马金斯、阿拉斯加半岛和附近岛屿上进行的大地测量工作，以及2018-9年由geoprisms - earthscopi支持的大型阿拉斯加两栖社区地震实验。该项目的成果将对解决与地震特征相关的问题有价值，正如美国国家科学院、工程院和医学院在《地球在时代》报告中所阐述的那样。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This RAPID award is a response to The July 2021 Chignik earthquake (M8.2) along the Alaskan Peninsula. This is the biggest earthquake in the US since 1965 (Rat Islands). It ruptured a segment of the megathrust offshore of the Alaska Peninsula, which last ruptured in 1938. The project deploys an integrated on-land observational field campaigns: geodesy to rapidly resurvey nearby monuments and document earthquake-related deformation, and seismology to deploy nearby instruments to record aftershocks. Understanding this earthquake will provide critical information for evaluating models of earthquake behavior and hence hazard among the planet’s largest earthquakes. Although only a small tsunami occurred, understanding better the rupture will allow for more realistic tsunami hazard assessments. The earthquake also provides ample opportunities for broadening participation in science, through rapidly making available data to the seismic and geodetic research communities. The project includes outreach to local schools, communities and governments and restarts a popular blog focused on geophysics in Alaska.The Chignik earthquake is a very rare example of a fault segment with two great earthquakes in the instrumental record, and is a critical locale to test theories of how seismic cycles work. The earthquake follows a pattern of along-strike segmentation previously documented between segments with large differences in locking behaviors and earthquake histories. The cause of this segmentation (or indeed of the variation in slip behavior more generally) remains uncertain, and collecting new data may elucidate the controlling mechanisms behind interseismic and coseismic rupture segmentation. Additionally, the earthquake provides an excellent laboratory to test theories of fault loading between segments and of our understanding of postseismic deformation. Almost precisely a year earlier, a M7.8 ruptured the abutting Shumagin segment to the west, indicating some possibility of triggering. That relationship can be explored, as well as the potential for bringing the next segment to the east closer to failure. The project takes advantage of decades of geodetic work on the Shumagins, Alaska Peninsula, and nearby islands, and the large 2018-9 GeoPRISMS-EarthScope-supported Alaska Amphibious Community Seismic Experiment. The project's outcome will be valuable in addressing questions related to the characteristics of earthquakes as articulated in the Earth in Time report from the National Academies of Science, Engineering and Medicine.This 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.