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

2010年和2021年，海地南部半岛发生了两次里氏7.0级和里氏7.2级地震，导致部分转换断层破裂。在这个项目中，将对最近发生地震的牙买加近海水域进行海洋调查，以调查这些地震和以前在同一地区发生的地震的构造和沉积影响。沉积物岩心和高分辨率海底测绘将对活动断层和地震引发的沉积物进行成像。该项目的首要目标是将新图像和样本与2012年法国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特征的理解，并提供对该板块边界的复杂性和相关危害的见解。一些关键的证据，如悬浮在深海中的沉积物和确定再活化沉积物年代的同位素，都是短暂的。其他记录可能因侵蚀而消失。正因为如此，这个项目是时间敏感的。项目期间将对研究生和本科生进行培训。大陆转换边界跨越人口稠密地区，正如2010年7.0级和2021年7.2级海地地震一样，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变压或变张。这些边界可以演变成复杂的、通常约束不佳的断层系统。enriquillo -芭蕉园断裂（EPGF）是沿戈纳夫微板块南缘的左东西向断裂的主链。东EPGF沿着一条突出的山脊延伸，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序列分别破坏了该脊的东部和西部。这两个序列的特征都是主震几乎是横向的，余震主要向北和西冲。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表明，这些断层形成了一个单一的应变分割的跨断层系统。研究结果将限制该系统是否延伸到牙买加通道，是否在边界的海底部分产生类似的大地震，现在海地最近发生的地震，以及沉积记录的EPGF地震的保真度。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.