Collaborative Research: HIPER - 3D Onshore-Offshore Imaging of Controls on Subduction Zone Megathrust Rupture and Slip Behavior

合作研究：HIPER - 俯冲带巨型逆冲断裂和滑动行为控制的 3D 陆上-海上成像

• 批准号: 1951203
• 负责人: Anne Meltzer
• 金额: $ 35.1万
• 依托单位: Lehigh University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-01-15 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1951203&HistoricalAwards=false
• 关键词: Collaborative; Research; HIPER; 3D; Onshore

The largest earthquakes worldwide occur in subduction zones where the tectonic plates associated with ocean basins descend into Earth’s interior. These earthquakes occur on large faults that separate the descending oceanic plate from the overlying continental plate. Ground shaking from these earthquakes have significant human and economic impacts. Subduction zone earthquakes that rupture the seafloor can generate tsunamis that cause additional destruction. Regions of the world at risk from these earthquakes include the U.S. Pacific Northwest and Alaska, Central and South America, Japan, and Southeast Asia. Here, the researchers deploy a dense array of seismometers to image at high resolution a portion of the subduction zone that ruptured offshore northern Ecuador in a large earthquake in 2016. The project leverages data acquisition from an offshore and onshore deployment supported by European funding agencies. Analysis of the data provides an opportunity to link variations in structure and seismic properties along the subduction zone to the distribution of slip behaviors that culminates in large earthquakes. Results from this research improve seismic hazard assessment near subduction zones. The project also provides support for a graduate student in seismology and training of undergraduate students.High resolution studies of subduction zones reveal their complexity and diversity of structure and physical properties. Heterogeneity downdip and along strike influences plate coupling and slip behavior on the plate interface, as well as in the downgoing plate and in the upper plate, which ultimately culminates in large magnitude earthquakes. The HIPER project (High Resolution Imaging of the Pedernales Earthquake Rupture Zone) is supported by French and German funding agencies. It acquires active and passive offshore-onshore seismic data along the northern Ecuador subduction zone in and adjacent to the 2016 Mw 7.8 Pedernales rupture. The HIPER project includes 60 ocean-bottom seismometers and 150 land stations that record active source shots from a 3D grid, followed by passive recording of earthquakes. Here, the U.S. team complete the project by deploying a dense array of 3-component short period nodes (~300) and 60 broadband sensors. The goal is to significantly densify the onshore portion of HIPER for active source recording. It also widens the aperture of passive recording to improve lateral coverage and imaging at depth. The combined arrays present an exceptional opportunity for multiscale 3D imaging and examine the relationship between structure, fluids, and variations in slip behavior from seismic to aseismic. Ultimately, it allows to reconcile observations from geodesy and seismology with geology, structure, and seismicity. Data analysis employs machine learning generalized phase detection to significantly increase source detection. It also involves a combination of traveltime and ambient noise tomography, and high frequency receiver functions as input to a multi-step series of inversions to constrain earthquake locations and seismic structure along and above the seismogenic zone.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.

世界上最大的地震发生在与海洋盆地相关的构造板块下降到地球内部的俯冲带，这些地震发生在将下降的海洋板块与上覆大陆板块分开的大断层上，这些地震造成的地面震动具有重大的人类和经济影响。导致海底破裂的俯冲带地震可能会引发海啸，从而导致世界上面临这些地震风险的地区包括美国太平洋西北地区和阿拉斯加、中美洲和南美洲。在这里，研究人员部署了密集的地震仪阵列，对 2016 年厄瓜多尔北部近海发生大地震时破裂的俯冲带的一部分进行高分辨率成像。该项目利用了海上和陆上部署的数据采集。数据分析提供了将俯冲带沿线的结构和地震特性的变化与最终导致大地震的滑移行为的分布联系起来的机会，该研究的结果改进了地震灾害评估。该项目还为地震学研究生和本科生培训提供支持。俯冲带的高分辨率研究揭示了其结构和物理特性的复杂性和多样性，下倾和沿走向的不均匀性对板块耦合和滑动行为的影响。 HIPER 项目（佩德纳莱斯地震破裂带高分辨率成像）得到了法国的支持。它获取厄瓜多尔北部俯冲带 2016 年 Mw 7.8 Pedernales 断裂及其附近的主动和被动近海陆上地震数据。HIPER 项目包括 60 个海底地震仪和 150 个记录主动震源的陆地站。在这里，美国团队通过部署密集的阵列来完成该项目。 3 组件短周期节点（~300）和 60 个宽带传感器的目标是显着致密 HIPER 的陆上部分，以进行主动源记录，同时扩大被动记录的孔径，以改善横向覆盖和深度成像。阵列为多尺度 3D 成像和检查结构、流体以及从地震到抗震的滑动行为变化之间的关系提供了绝佳的机会，最终，它可以协调大地测量学和地震学的观测结果。具有地质学、结构和地震活动性的地震学数据分析采用机器学习广义相位检测来显着增加源检测，它还涉及走时和环境噪声层析成像的组合，以及作为多步骤系列反演的输入的高频接收器功能。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。