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: 1951202
• 负责人: Susan Beck
• 金额: $ 25.3万
• 依托单位: University of Arizona
• 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 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1951202&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俯冲带，其中与海洋盆地相关的构造板块下降到地球内部。这些地震发生在将下降的海洋板块与上覆的大陆板块分开的大断层上。这些地震引起的地面震动对人类和经济产生重大影响。导致海底破裂的俯冲带地震可能会引发海啸，造成额外的破坏。世界上面临这些地震风险的地区包括美国西北太平洋地区和阿拉斯加、中美洲和南美洲、日本和东南亚。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大地震中破裂的俯冲带的一部分进行高分辨率成像。该项目利用欧洲资助机构支持的海上和陆上部署的数据采集。对数据的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动行为的分布联系起来的机会。这项研究的结果改进了俯冲带附近的地震危险性评估。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性质的复杂性和多样性。下倾和沿走向的非均质性会影响板块界面以及下行板块和上板块的板块耦合和滑动行为，最终导致大地震。 HIPER 项目（佩德纳莱斯地震破裂区高分辨率成像）得到了法国和德国资助机构的支持。它采集厄瓜多尔北部俯冲带沿 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 个陆地站，用于记录来自 3D 网格的主动源炮，然后被动记录地震。在这里，美国团队通过部署密集的 3 组件短周期节点（约 300 个）阵列和 60 个宽带传感器来完成该项目。目标是显着致密 HIPER 的陆上部分以进行主动源记录。 它还扩大了被动记录的孔径，以改善横向覆盖和深度成像。组合阵列为多尺度 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，它可以将大地测量学和地震学的观测结果与地质学、结构和地震活动性相协调。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断层扫描的组合，以及高频接收器的功能，作为多步骤系列反演的输入，以限制地震发生区沿线和上方的地震位置和地震结构。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。