EAGER: Lowering the detection threshold of Antarctic seismicity to reveal undiscovered intraplate deformation

与地球上的其他地方不同，南极洲并不以大地震而闻名，其偏远的自然环境和恶劣的条件使得安装和维护地震探测的地震仪变得困难。一些研究人员认为，大地震的缺乏是由于大陆被不活跃的构造边缘所包围。然而，在过去的二十年里，科学家们发现，在大陆内部发生的地震比以前观察到的要多。这表明历史上的地震目录中遗漏了许多地震。本研究旨在利用新的地震探测和定位技术，从过去25年南极临时和永久地震台站收集的地震数据中寻找缺失的地震。定位这些地震将有助于了解地震是否发生在南极洲以及发生在哪里，并有助于规划未来的地震部署。作为该项目更广泛影响的一部分，“岩石上的女孩”项目将进行一次实地考察，向高中年龄的女孩，特别是那些来自代表性不足背景的女孩，传授使用科学数据的数据可视化技术。南极洲地震活动的空间分布和中震级地震的次数没有明确的定义。目前的地震目录可能由于大陆上地震仪分布的不均匀和稀疏而有偏差。我们将从永久和临时部署中挖掘现有的宽带地震数据，以降低整个南极洲内陆的地震探测阈值，重点关注构造地震。假设是南极洲内部有大量以前未被发现的中等震级地震。这些地震可能与横贯南极山脉、疑似沃斯托克碰撞带、南极西部裂谷系、东西南极洲的地壳成分边界以及白垩纪南极东部裂谷等主要构造特征同时发生。以前的地震部署记录了南极内部的地震，这表明目前的目录中遗漏了许多地震。我们建议使用新颖的地震定位技术，利用pascal实验和永久站点在IRIS存档的25年连续数据进行自动检测和定位。该方法将使用STA/LTA探测器在第一次到达90度距离的p波上，反向时间成像来定位事件，并在克拉通上的密集阵列上进行波束成形，以增强探测和定位。这项工作中使用的探测和定位技术的结合还没有用于远震体波，尽管类似的方法在表面波研究中很有效。如果成功，该项目将为未来通过机器学习方法和/或新的目标数据收集来审查新发现的南极地震活动提供一个优秀的训练数据集。我们计划与“岩石上的女孩”（Girls on Rock）合作，这是一个当地和国际组织，致力于在科学、艺术和荒野探索方面建立一个文化多样化的社区，在夏季实地考察中，将计算机编码整合到实地科学项目中。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。

Part 1: Nontechnical Unlike other locations on the globe Antarctica is not known for having large earthquakes and the remote nature and harsh conditions make it difficult to install and maintain seismometers for earthquake detection. Some researchers believe the lack of large earthquakes is due to the continent being surrounded by inactive tectonic margins. However, in the last two decades, scientists have discovered that more earthquakes occur in the interior of the continent than previously observed. This suggests that there are many earthquakes missing from historic earthquake catalogs. This study aims to find the missing earthquakes using novel earthquake detection and location techniques from seismic data collected from temporary and permanent seismic stations in Antarctica over the last 25 years. Locating these earthquakes will help understand if and where earthquakes are located in Antarctica and will help in planning future seismic deployments. As part of the project broader impacts, a field expedition with the Girls on Rock program will be conducted to teach high school age girls, and especially those from underrepresented backgrounds, data visualization techniques using scientific data. Part 2: Technical The spatial distribution of seismicity and the number of moderate magnitude earthquakes in Antarctica is not well-defined. The current catalog of earthquakes may be biased by uneven and sparse seismograph distribution on the continent. We will mine existing broadband seismic data from both permanent and temporary deployments to lower the earthquake detection threshold across Interior Antarctica, with a focus on tectonic earthquakes. The hypothesis is that Interior Antarctica has abundant moderate magnitude earthquakes, previously undetected. These earthquakes are likely collocated with major tectonic features such as the Transantarctic Mountains, the suspected Vostok collision zone, the West Antarctic Rift System, the crustal compositional boundary between East and West Antarctica, and the Cretaceous East Antarctic Rift. Previous seismic deployments have recorded earthquakes in the Antarctic interior, suggesting there are many earthquakes missing from the current catalog. We propose to use novel earthquake location techniques designed for automated detection and location using 25 years of continuous data archived at IRIS from PASSCAL experiments and permanent stations. The approach will use STA/LTA detectors on the first arrival P-wave to 90 degrees distance, Reverse Time Imaging to locate events, and beamforming at dense arrays strategically located on cratons for enhanced detection and location. The combination of detection and location techniques used in this work has not been used on teleseismic body waves, although similar methods have worked well for surface wave studies. If successful the project would provide an excellent training dataset for future scrutiny of newly discovered Antarctic seismicity with machine learning approaches and/or new targeted data collection. We plan to collaborate with Girls on Rock, a local and international organization committed to building a culturally diverse community in science, art, and wilderness exploration, in a summer field expedition and integrating computer coding into post-field scientific projects.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.