The 23 June 2020 La Crucecita earthquake occurred at 10:29 hr on the coast of Oaxaca in an Mw 7 4 megathrust event at 22 6 km depth and triggered a tsunami recorded at tide gauge stations and a Deep-ocean Assessment and Reporting of Tsunamis off the coast of Mexico Immediately after the earthquake, a rapid response effort was coordinated by members of the Tsunami and Paleoseismology Laboratory, Universidad Nacional Autónoma de México Despite the challenges posed by the Coronavirus disease 2019 (COVID-19) pandemic crisis, a postearthquake and post-tsunami field survey went ahead two days after the event We describe here the details of the rapid response survey of the vertical coseismic deformation, tsunami, geologic effects, and lessons from working in the field during the COVID-19 crisis We surveyed 44 km along the coast of Oaxaca Because of the COVID-19 pandemic, some local communities enforced rules of confinement We solved most of the challenges faced during this crisis by rapidly networking with local organizations prior to surveying We assessed coseismic uplift by means of mortality caused by vertical displacement of intertidal organisms and resurveying of benchmarks, and we measured tsunami runup Our results show coastal uplift of 0 53 m near the epicenter and decreasing farther away from it;uplift was up to 0 8 m in areas related to exposure of the coast Of our values of coastal uplift, about 0 53 m fit well with the 0 55 m of uplift reported by tide gauge data at Huatulco Coastal uplift and low tide at the time of the event limited the tsunami inundation and runup on the Oaxaca coast Nevertheless, we found tsunami inundation evidence at four confined coastal sites reaching a maximum runup of 1 5 m The enclosed morphology of these sites determined higher runup and tsunami inundation Local coastal morphology effects are not detected in tsunami models lacking detailed bathymetry and topography This issue needs to be addressed during tsunami hazard assessments © Seismological Society of America

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2020 年 6 月 23 日 Mw 7.4 La Crucecita，瓦哈卡，墨西哥地震和海啸：COVID-19 危机期间的快速响应现场调查

2020 年 6 月 23 日 La Crucecita 地震发生在瓦哈卡海岸的 10:29 时，发生了 Mw 7 4 巨型逆推事件，深度为 22 6 公里，并引发了潮汐监测站记录的海啸和深海海啸评估和报告墨西哥海岸 地震发生后，墨西哥国立自治大学海啸和古地震学实验室的成员立即协调了快速响应工作，尽管面临 2019 年冠状病毒病 (COVID-19) 大流行危机、地震后和- 海啸现场调查在事件发生两天后进行 我们在此详细介绍垂直同震变形、海啸、地质效应的快速响应调查，以及在 COVID-19 危机期间实地工作的经验教训 我们在瓦哈卡海岸沿线 44 公里进行了调查 由于 COVID-19 大流行，一些当地社区实施了禁闭规定 我们通过快速联网解决了这场危机期间面临的大部分挑战在调查前与当地组织合作 我们通过潮间带生物垂直位移和重新测量基准点造成的死亡率评估了同震抬升，并测量了海啸抬升 我们的结果显示，震中附近的海岸抬升为 0 53 m，远离震中处降低；与海岸暴露有关的区域的隆起高达 0 8 m 在我们的沿海隆起值中，约 0 53 m 与 Huatulco 的潮汐计数据报告的 0 55 m 隆起非常吻合 事件发生时的沿海隆起和低潮限制了瓦哈卡海岸的海啸淹没和上升 然而，我们在 4 点发现了海啸淹没的证据受限制的沿海站点达到 1 5 m 的最大爬升 这些站点的封闭形态决定了更高的爬升和海啸淹没 在缺乏详细测深和地形的海啸模型中未检测到当地沿海形态效应 在海啸危害评估期间需要解决这个问题 © Seismological美国社会我们在四个受限制的沿海地点发现了海啸淹没的证据，最大上升高度为 1 5 m 这些地点的封闭形态决定了更高的上升和海啸淹没 在缺乏详细水深测量和地形的海啸模型中未检测到局部海岸形态效应 这个问题需要解决在海啸灾害评估期间得到解决 © 美国地震学会我们在四个受限制的沿海地点发现了海啸淹没的证据，最大上升高度为 1 5 m 这些地点的封闭形态决定了更高的上升和海啸淹没 在缺乏详细水深测量和地形的海啸模型中未检测到局部海岸形态效应 这个问题需要解决在海啸灾害评估期间得到解决 © 美国地震学会