Triggered slip events following the 2010 and 2021 Haiti earthquakes and their implications to seismic hazard in Hispaniola

2010 年和 2021 年海地地震引发的滑动事件及其对伊斯帕尼奥拉岛地震灾害的影响

• 批准号: 2321754
• 负责人: Shimon Wdowinski
• 金额: $ 34.59万
• 依托单位: Florida International University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2321754&HistoricalAwards=false
• 关键词: Triggered; slip; events; following; 2010

Hispaniola is the most populous island in the Caribbean and is split into two countries, Haiti and the Dominican Republic. It is also where the North American and Caribbean plates push toward and slide past past each other, making use of two major fault systems: the Enriquillo Plantain Garden Fault (EPGF) in the south part of the island and the Septentrional Fault (SF) in the north. Both faults are active and hazardous; the EPGF ruptured in the devasting 2010 and 2021 Haiti earthquakes, together causing over 250,000 deaths and US$ 9 billion in damage. After the 2010 earthquake, sections of the EPGF that were expected to rupture next did not; the 2021 earthquake occurred elsewhere on the fault. After each earthquake, satellite-based radar data showed that parts of the EPGF were continuing to slip without producing any small earthquakes at all, hinting that these segments might not generate large earthquakes. Following up on this finding by investigating all SF and EPGF segments is crucial for assessing seismic risks throughout Hispaniola and for understanding why the 2021 earthquake happened where it did. This project will primarily use satellite-based radar and GPS data, along with seismometer data from local agencies, to determine the motion and earthquake potential of the EPGF and the SF. The project will foster collaboration between the Florida International University (FIU) and stakeholders in Haiti and the Dominican Republic, as well as scientists in France and South Korea.The island of Hispaniola hosts the Enriquillo Plantain Garden Fault Zone (EPGFZ) and Septentrional Fault Zone (SFZ) fault systems that accommodate most of the strain at this part of the North America-Caribbean (NA-CA) transform plate boundary. NA-CA strike-slip rate of ~17 mm/yr is partitioned on the EPFGZ and SFZ while a shortening component of the relative motion (~5 mm/yr) is accommodated via thrust faulting. Studies of the Mw 7.0 2010 and Mw 7.2 2021 Haiti earthquakes that ruptured the EPGFZ suggested that most of the seismic moment occurred on thrust faults that take up transpressional motion. Also, following both large earthquakes, satellite-based radar revealed an induced triggered slip on the EPGFZ, suggesting that segments of the EPGFZ may creep. Furthermore, the segments of the fault with the maximum Coulomb Failure Stress following the 2010 earthquake did not rupture during the 2021 earthquake. The dynamics of two earthquakes indicate that the EPGFZ is seismogenically segmented. The SFZ hosted historical large earthquakes and is capable of rupturing in a Mw ~7.6 earthquake. This research project will characterize strain partitioning and accumulation along the EPGFZ and SFZ by synthesizing satellite-based radar data from the c-band Sentinel-1 and L-band ALOS-2 missions, Global Navigation Satellite Systems (GNSS) observations, and earthquake data from the relevant local agencies in Haiti and the Dominican Republic. The main research activities include (1) detecting transient aseismic slip events, (2) calculating interseismic surface velocity fields of the EPGFZ and SFZ, and (3) constraining mechanical models that will characterize fault segment depth of lock, creeping, or transition from lock to creeping. The research project products will greatly aid in the seismic hazard assessment of the island.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.

伊斯帕尼奥拉岛是加勒比地区人口最多的岛屿，分为两个国家，海地和多米尼加共和国。它也是北美和加勒比板块相互推挤和滑动的地方，利用两个主要的断层系统：岛上南部的Enriquillo Plantain Garden Fault（EPGF）和北部的Septentrional Fault（SF）。这两个断层都是活跃和危险的; EPGF在2010年和2021年海地地震中破裂，共造成25万多人死亡和90亿美元的损失。2010年地震后，预计EPGF接下来会破裂的部分没有破裂; 2021年地震发生在断层的其他地方。每次地震后，基于卫星的雷达数据显示，EPGF的部分地区继续滑动，根本没有产生任何小地震，暗示这些部分可能不会产生大地震。通过调查所有SF和EPGF部分来跟进这一发现，对于评估整个伊斯帕尼奥拉岛的地震风险以及了解2021年地震发生的原因至关重要。该项目将主要利用卫星雷达和全球定位系统数据，沿着当地机构的地震仪数据，以确定EPGF和SF的运动和地震潜力。该项目将促进佛罗里达国际大学（FIU）与海地和多米尼加共和国的利益相关者以及法国和韩国的科学家之间的合作。伊斯帕尼奥拉岛拥有Enriquillo Plantain Garden断层带（EPGFZ）和Septentrional断层带（SFZ）断层系统，这些断层系统容纳了北美-加勒比海（NA-CA）转换板块边界这一部分的大部分应变。NA-CA走滑速率约为17 mm/yr，在EPFGZ和SFZ上划分，而相对运动的缩短分量（约5 mm/yr）通过逆冲断层作用调节。对2010年海地发生的Mw 7.0和2021年海地发生的Mw 7.2地震的研究表明，大部分地震力矩发生在逆冲断层上，逆冲断层承担了压扭运动。此外，在这两次大地震之后，基于卫星的雷达显示EPGFZ上的诱发触发滑动，这表明EPGFZ的部分可能会蠕动。此外，2010年地震后库仑破裂应力最大的断层段在2021年地震中没有破裂。两次地震的动力学特征表明，EPGFZ是分段的。SFZ承载了历史上的大地震，并且能够在Mw ~7.6的地震中破裂。这一研究项目将综合来自C波段哨兵-1和L波段ALOS-2飞行任务的星基雷达数据、全球导航卫星系统观测数据以及海地和多米尼加共和国有关地方机构提供的地震数据，从而确定沿EPGFZ和SFZ沿着的应变分布和积累情况。主要的研究活动包括：（1）检测瞬态地震滑动事件，（2）计算EPGFZ和SFZ的震间表面速度场，以及（3）约束力学模型，这些模型将表征锁定、蠕动或从锁定到蠕动的过渡的断层段深度。该研究项目的产品将大大有助于该岛的地震危险评估。该奖项反映了NSF的法定使命，并被认为值得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来支持。