Investigating the crustal structure and fault geometry of the 2021 Haiti earthquake

海地极易受到大地震的影响。2010年海地7.0级和2021年7.2级地震分别造成20多万人和2,000人死亡。我们越好地了解过去的地震，识别活动断层，并准确定位可能发生强烈地面震动的地点，我们就越能为防止未来的悲剧做得越多。该项目将使加州大学河滨分校的地震学家能够清楚地确定2021年地震期间哪些断层破裂，并找到未来大地震期间最有可能发生强烈地面震动的地区。探测和定位余震将有助于圈定2021年破裂的断层以及其他活动断层。绘制出地壳中地震速度如何在3D中变化的地图，将揭示地震速度异常缓慢的地区，这表明岩石较软，因此在地震期间放大了震动。该项目将促使海地当地科学家对当地地震监测产生持久影响，以进行地震危险性评估。该项目还将吸引年轻的海地学生，希望能激励一些人投身地球科学事业。2021年海地7.2级地震发生在2010年毁灭性地震十年后，发生在海地南部恩里基洛芭蕉园断裂带(EPGFZ)组成的断层网络内。初步的大地测量观测表明，这次地震与2010年的地震相似，当时破裂的西部发生了左旋走滑，东部发生了逆滑。来自区域地震台网的初始余震位置过于分散，无法证实这一假设，也不清楚这次地震是发生在主断层上还是发生在次级断层上。此外，考虑到2010年地震的严重破坏主要发生在地震速度较低的沉积盆地，放大了地震震动，2021年地震破坏程度较高的地区也可能被这种物质覆盖。利用2021年地震后部署的地震台新获得的数据，我们将应用创新技术高精度地探测和定位余震，并调查该地区的三维地壳速度结构。该项目将直接影响研究和教育，为加州大学河滨分校社区中代表性较低的群体中的当地本科生提供研究机会。该项目还将使海地人民受益，方法是聘请当地海地科学家对当地地震监测产生持久影响，进行地震危险性评估，并为海地年轻学生提供机会，使他们能够激励子孙后代从事地球科学事业。该奖项反映了国家科学基金会的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Haiti is extremely vulnerable to large earthquakes. The M7.0 2010 and M7.2 2021 earthquakes in Haiti caused more than 200,000 and 2,000 deaths, respectively. The better we understand past earthquakes, identify active faults, and pinpoint locations with possible strong ground shaking, the more we can do to prevent future tragedy. This project will allow seismologists at the University of California, Riverside to clearly identify which faults ruptured during the 2021 earthquake, and find areas where strong ground shaking is most likely to occur during future large earthquakes. Detecting and locating aftershocks will help delineate the faults that ruptured in 2021, as well as other active faults. Mapping out how seismic velocities in the crust vary in 3D will bring to light regions with unusually slow seismic velocities, which indicate softer rocks and hence amplified shaking during an earthquake. This project will engage local Haitian scientists to have a lasting impact on local earthquake monitoring for seismic hazard assessment. The project will also engage young Haitian students, in the hope that some will be inspired to pursue careers in the geosciences. The 2021 M7.2 Haiti earthquake, which struck a decade after the devastating 2010 earthquake, occurred within the network of faults comprising the Enriquillo Plantain Garden Fault Zone (EPGFZ) in southern Haiti. Preliminary geodetic observations suggest that this earthquake is similar to the 2010 event where left-lateral strike-slip occurred on the western part of the rupture and reverse slip on the eastern part. Initial aftershock locations from the regional seismic network are too diffuse to confirm this hypothesis, and it is not clear whether this event occurred on the main fault or on secondary faults. Furthermore, considering that heavy damage from the 2010 earthquake occurred primarily in a sedimentary basin with low seismic velocities that amplified seismic shaking, it is possible that areas experiencing high levels of damage from the 2021 earthquake are also underlain by such material. Using newly available data from seismic stations that were deployed following the 2021 earthquake, we will apply innovative techniques to detect and locate the aftershocks with high precision, and investigate the 3D crustal velocity structure in that region. This project will directly impact research and education by offering research opportunities for local undergraduate students from underrepresented groups within the U. C. Riverside community. The project will also benefit the people of Haiti by engaging local Haitian scientists to have a lasting impact on local earthquake monitoring for seismic hazard assessment, and providing opportunities to young Haitian students so that they can inspire future generations to pursue careers in geosciences.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.