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

第一部分：与地球仪上的其他地方不同，南极洲并不以发生大地震而闻名，偏远的自然环境和恶劣的条件使其难以安装和维护用于地震探测的地震仪。 一些研究人员认为，缺乏大地震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，大陆内部发生的地震比以前观察到的要多。这表明有许多地震在历史地震目录中缺失。 这项研究的目的是使用新型地震检测和定位技术，根据过去25年来从南极洲临时和永久地震站收集的地震数据来寻找缺失的地震。确定这些地震的位置将有助于了解南极洲是否发生地震以及地震的位置，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，将与岩石上的女孩计划进行实地考察，教授高中年龄的女孩，特别是那些来自代表性不足的背景，使用科学数据的数据可视化技术。 第2部分：技术南极洲地震活动的空间分布和中等地震的数量没有很好的定义。目前的地震目录可能由于地震仪在非洲大陆的分布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，以降低南极内陆的地震检测阈值，重点是构造地震。假设南极洲内部有大量的中等震级地震，以前未被发现。这些地震可能与主要的构造特征，如横贯南极山脉，疑似东方碰撞区，西南极裂谷系统，东南极和西南极之间的地壳成分边界，以及白垩纪东南极裂谷。以前的地震部署记录了南极内陆的地震，这表明目前的目录中遗漏了许多地震。我们建议使用新的地震定位技术，旨在自动检测和定位使用25年的连续数据存档在IRIS从PASSCAL实验和永久站。该方法将使用STA/LTA探测器在第一个到达P波到90度的距离，逆时成像定位事件，并在密集阵列的波束形成战略上位于增强的检测和定位。在这项工作中使用的检测和定位技术的组合还没有被用于对微重力体波，虽然类似的方法已经工作得很好的表面波研究。如果成功，该项目将为未来使用机器学习方法和/或新的有针对性的数据收集来审查新发现的南极地震活动提供出色的训练数据集。我们计划与致力于在科学、艺术和荒野探索方面建立文化多样性社区的地方和国际组织Girls on Rock合作，进行夏季实地考察，并将计算机编码整合到实地考察后的科学项目中。该奖项反映了NSF的法定使命，并通过使用基金会的智力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.