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海人口最多的岛屿，分为海地和多米尼加共和国两个国家。这里也是北美和加勒比板块相互推挤和滑过的地方，利用了两个主要断层系统：位于该岛南部的恩里基洛车前草花园断层（EPGF）和位于该岛南部的七棱断层（SF）。北方。这两个故障都是活跃且危险的； EPGF 在 2010 年和 2021 年海地的毁灭性地震中破裂，总共造成超过 25 万人死亡和 90 亿美元的损失。 2010 年地震后，预计接下来会破裂的 EPGF 部分并未破裂； 2021 年地震发生在断层的其他地方。每次地震发生后，基于卫星的雷达数据显示，EPGF 的部分区域仍在继续滑动，但根本没有产生任何小地震，这暗示这些部分可能不会产生大地震。通过调查所有 SF 和 EPGF 段来跟进这一发现，对于评估整个伊斯帕尼奥拉岛的地震风险以及了解 2021 年地震发生地点的原因至关重要。该项目将主要使用卫星雷达和 GPS 数据以及当地机构的地震仪数据来确定 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恩里基洛车前草花园断层带 (EPGFZ) 和 Septentrional 断层带(SFZ) 断层系统可容纳北美-加勒比 (NA-CA) 转换板块边界这部分的大部分应变。 NA-CA 走滑速率约为 17 毫米/年，分布在 EPFGZ 和 SFZ 上，而相对运动的缩短分量（约 5 毫米/年）则通过逆冲断层来调节。对导致 EPGFZ 破裂的海地 2010 年 7.0 级地震和 2021 年 7.2 级地震的研究表明，大部分地震矩发生在承受压挤运动的逆冲断层上。此外，在两次大地震之后，基于卫星的雷达显示 EPGFZ 上存在诱发触发滑移，这表明 EPGFZ 的某些部分可能会发生蠕变。此外，2010 年地震后库仑破坏应力最大的断层段在 2021 年地震中并未破裂。两次地震的动力学表明EPGFZ在地震发生上是分段的。 SFZ 历史上曾发生过大地震，并且能够在 7.6 级地震中破裂。该研究项目将通过综合来自 c 波段 Sentinel-1 和 L 波段 ALOS-2 任务的卫星雷达数据、全球导航卫星系统 (GNSS) 观测数据和地震数据，描述沿 EPGFZ 和 SFZ 的应变分配和累积特征来自海地和多米尼加共和国当地相关机构。主要研究活动包括 (1) 检测瞬态地震滑移事件，(2) 计算 EPGFZ 和 SFZ 的震间表面速度场，以及 (3) 约束力学模型，以表征断层断层的锁、蠕变或从锁的过渡深度到蠕动。研究项目产品将极大地帮助该岛的地震灾害评估。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。