Collaborative Research: RAPID: Submarine record of disastrous earthquakes at a strain partitioned transpressional boundary: Haiti 2010 and 2021

2010年和2021年，海地南部半岛的转换断层沿着发生了两次7.0级和7.2级地震。在该项目期间，将在最近发生地震的牙买加近海沃茨进行海洋调查，以调查这些地震和同一地区以前的地震对构造和沉积的影响。沉积物岩心和高分辨率海底测绘将对活动断层进行成像，并对地震触发的沉积物进行取样。该项目的总体目标是将新图像和样本与法国在2012年收集的现有数据和牙买加合作者收集的现有数据进行比较。该项目的结果将有助于提高对断层运动和地震产生的沉积物沉积特征的认识，并深入了解该板块边界的复杂性和相关危害。一些关键证据，如深海水中悬浮的沉积物和确定再活动沉积物年代的同位素，寿命很短。 其他的记录也会因侵蚀而消失。 因此，该项目具有时间敏感性。 研究生和本科生将在项目期间接受培训。大陆转换边界跨越人口稠密地区，就像2010年海地7.0级和2021年海地7.2级地震一样，沿着这些边界的破裂可能造成灾难性的破坏和生命损失。变换边界只能适应相对运动的适度变化，即使是轻微的倾斜运动也会使它们发生扭压或扭张。这些边界可以演变成复杂的，往往是约束不良的断层系统。Enriquillo-Plantain Garden断层（EPGF）是沿Gonave微板块南部边界沿着向东-西转换的主干。东EPGF跟踪一个突出的山脊，形成了250公里长的海地南部半岛，并植根于逆冲断层带。2010年M7.0和2021年M7.2序列分别使该脊的东部和西部断裂。这两个序列的特征是主震几乎是横向的，而余震主要是向北和向西的。在沿着同一边界的两个地震序列中重复出现的不同断层之间的这种耦合强烈地表明，这些断层形成了一个单一的应变分区的压扭断层系统。研究结果将限制该系统是否延伸到牙买加海峡，是否在最近海地地震所加载的边界海底部分产生类似的大地震，该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查进行评估，被认为值得支持的搜索.

Two earthquakes, M7.0 and M7.2, ruptured sections of the transform fault along Haiti’s southern peninsula in 2010 and 2021. During this project a marine survey in Jamaican waters offshore the recent earthquakes will be conducted to investigate the tectonic and sedimentary effects of these and previous earthquakes in the same region. Sediment cores and high-resolution sub-bottom mapping will image active faults and sample earthquake-triggered sediment deposits. The overarching goal of the project is to compare the new images and samples with pre-existing data collected by the French in 2012 and by collaborators from Jamaica. Results of the project will help improve understanding of fault movement and the character of earthquake-generated sediment deposits and provide insight into the complexities of this plate boundary and the associated hazards. Some key evidence, such as sediment suspended in abyssal water and isotopes that date the remobilized sediments, are short-lived. Other records can be obliterated by erosion. Because of this, the project is time sensitive. Graduate and undergraduate students will be trained during the project.Continental transform boundaries cross heavily populated regions, and as in the M7.0 2010 and M7.2 2021 Haiti earthquakes, ruptures along these boundaries can cause catastrophic damage and loss of life. Transform boundaries can accommodate only modest changes in relative motion, even slightly oblique motion can make them transpressional or transtensional. These boundaries can evolve into complex, often poorly constrained, systems of faults. The Enriquillo-Plantain Garden Fault (EPGF) is the main strand of a sinistral E-W transform along the southern boundary of the Gonave microplate. The eastern EPGF traces a prominent ridge that forms the 250 km long southern peninsula of Haiti and is rooted on a belt of thrust faulting. The 2010 M7.0 & 2021 M7.2 sequences ruptured the eastern and western segments of this ridge, respectively. Both sequences feature mainshocks that were nearly transcurrent, and thrust after-shocks primarily to the north and west. Such coupling between distinct faults repeated in two earthquake sequences along the same boundary strongly suggests that these faults form a single strain-partitioned, transpressional fault system. The results of the study will constrain whether this system extends to the Jamaica Passage, whether it generates similar large earthquakes in the submarine part of the boundary now loaded by recent earthquakes in Haiti, and the fidelity of the sedimentary record for EPGF earthquakes.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.