Collaborative Research: Triggering of Antarctic Icequakes, Slip Events, and other Tectonic Phenomena by Distant Earthquakes

南极洲的表面积与美国大陆大致相同，尽管我们对其潜在的地质和地震活动知之甚少。在过去的几十年里，跨国公司在地球物理基础设施上的投资，特别是宽带地震仪的使用，使我们能够观察到许多有趣的自然现象，包括冰山崩裂、冰流滑动和构造地震。为了特别利用这些过去的投资，我们将分析过去和现在的数据，以更好地了解南极的地震活动。我们最近的研究表明，世界上其他地方发生的某些大地震引发了南极洲各个站点附近的冰运动。我们计划利用尖端的计算技术，对tb级的可用数据进行详尽的搜索，以发现地震期间冰裂缝、冰流滑动和地球运动的额外证据。我们研究的一个具体重点将包括调查这些现象中的一些是否可能由外部影响触发，包括从遥远的地震、海洋潮汐或季节性融化中通过的表面波。我们计划制作一个已确定活动的目录并公开分享，以便公众和研究人员可以轻松访问它。为了吸引更广泛的受众，我们将在德克萨斯州奥斯汀市和佐治亚州亚特兰大市区的高中班级（包括大学先修课程班）进行讲座，重点介绍地震危险、气候变化和南极洲地理的一般方面。该项目将为本科生提供研究机会，为研究生提供培训，并为早期职业科学家提供支持。近年来，新一代大地测量和地震仪器作为永久台站部署在整个南极洲（POLENET），此外还部署了较短持续时间（少于3年）的台站（例如AGAP/TAMSEIS）。这些努力正在为解决有关地壳尺度构造和冰盖及其相互作用的基本问题提供关键的基础设施。我们计划对南极洲的构造和冰震活动进行系统的探测，主要关注背景地震活动、远程触发的地震活动和冰川滑动事件。我们提出的任务包括：(1)确定整个南极大陆的构造和冰源地震活动性。(2)在最近~15年的全球大地震期间，对南极洲其他触发事件的详尽搜索。(3)确定触发源机制，以及这些触发事件是否也在其他时间发生，通过使用匹配过滤器分析多年的数据（其中触发的本地事件用于检测类似事件）。(4)进一步分析惠兰斯冰原5.5年的GPS观测结果，认为最大地震后发生了粘滑事件。对南极冰盖如何响应外部扰动（如遥远的大地震和最近的冰卸荷所产生的动态应力）的进一步了解，可以更好地理解冰的破坏和相关的动力过程。通过利用过去十年在南极洲安装地震仪的巨大后勤投资，我们的项目将建立一个详尽的构造地震、冰震、冰裂事件和任何其他可探测的近地表地震现象的目录。

The continent of Antarctica has approximately the same surface area as the continental United States, though we know significantly less about its underlying geology and seismic activity. Multinational investments in geophysical infrastructure over the last few decades, especially broadband seismometers operating for several years, are allowing us to observe many interesting natural phenomena, including iceberg calving, ice stream slip, and tectonic earthquakes. To specifically leverage those past investments, we will analyze past and current data to gain a better understanding of Antarctic seismicity. Our recent research revealed that certain large earthquakes occurring elsewhere in the world triggered ice movement near various stations throughout Antarctica. We plan to conduct an exhaustive search of the terabytes of available data, using cutting-edge computational techniques, to uncover additional evidence for ice crevassing, ice stream slip, and earth movement during earthquakes. One specific focus of our research will include investigating whether some of these phenomena may be triggered by external influences, including passing surface waves from distant earthquakes, ocean tides, or seasonal melt. We plan to produce a catalog of the identified activity and share it publicly, so the public and researchers can easily access it. To reach a broader audience, we will present talks to high school classes, including Advanced Placement classes, in the Austin, Texas and Atlanta, Georgia metropolitan areas with emphasis on general aspects of seismic hazard, climate variability, and the geographies of Antarctica. This project will provide research opportunities for undergraduates, training for graduate students, and support for an early-career scientist.In recent years, a new generation of geodetic and seismic instrumentation has been deployed as permanent stations throughout Antarctica (POLENET), in addition to stations deployed for shorter duration (less than 3 years) experiments (e.g. AGAP/TAMSEIS). These efforts are providing critical infrastructure needed to address fundamental questions about both crustal-scale tectonic structures and ice sheets, and their interactions. We plan to conduct a systematic detection of tectonic and icequake activities in Antarctica, focusing primarily on background seismicity, remotely-triggered seismicity, and glacier slip events. Our proposed tasks include: (1) Identification of seismicity throughout the Antarctic continent for both tectonic and ice sources. (2) An exhaustive search for additional triggered events in Antarctica during the last ~15 years of global significant earthquakes. (3) Determination of triggered source mechanisms and whether those triggered events also occur at other times, by analyzing years of data using a matched-filter analysis (where the triggered local event is used to detect similar events). (4) Further analysis of GPS measurements over a ~5.5 year period from Whillans Ice Plain, which suggests that triggering of stick-slip events occurred after the largest earthquakes. An improved knowledge of how the Antarctic ice sheet responds to external perturbations such as dynamic stresses from large distant earthquakes and recent ice unloading could lead to a better understanding of ice failure and related dynamic processes. By leveraging the vast logistical investment to install seismometers in Antarctica over the last decade, our project will build an exhaustive catalog of tectonic earthquakes, icequakes, calving events, and any other detectable near-surface seismic phenomena.