Coseismic geodetic and geophysical variations detected for the January 19th, 2021 San Juan earthquake. Tectonic implications

IF 1.7 4区地球科学 Q3 GEOSCIENCES, MULTIDISCIPLINARY

Journal of South American Earth Sciences Pub Date : 2024-11-17 DOI:10.1016/j.jsames.2024.105262

Gemma Acosta , Marcos A. Sánchez , Francisco Ruiz , Federico Carballo , M. Flavia Leiva

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引用次数: 0

Abstract

The coseismic surface variations and crustal deformation in the Central Precordillera region of San Juan (Argentina) as a consequence of the Mw 6.5 earthquake of January 19th, 2021 (2:46 UTC) were characterized by a multidisciplinary team, integrating information from Gravity, Seismology, GNSS and DInSAR (Synthetic Aperture Radar Differential Interferometry) techniques.

Prior to the occurrence of the event, several periodic measures were taken at fixed reference points throughout San Juan province. The results of the data analysis show significant changes in height corresponding to the uplifting of a few centimeters of the hanging wall block in accordance with the estimated deformation obtained by the focal mechanism. In addition, the transcurrent component is evident in the GNSS vectors calculated after the earthquake. These results are consistent with the Gravity variations measured at the control points. This indicates the uplifting of the basement of Central Precordillera while the elastic Andean compressional deformation migrates N-E related to the Tulum lineament. The joint analysis of 4D gravity with GNSS heights shows an accumulation of deformation involving the lower crust prior to the earthquake, and the release of stresses with permanent deformation, which partially complies with the laws of isostasy in the Precordillera, after the earthquake.

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为 2021 年 1 月 19 日圣胡安地震探测到的同震大地测量和地球物理变化。构造影响

2021 年 1 月 19 日（世界协调时 2:46），阿根廷圣胡安省中部前山地带发生了 6.5 级地震，多学科小组综合重力、地震学、全球导航卫星系统和 DInSAR（合成孔径雷达差分干涉测量）技术的信息，对地震造成的共震面变化和地壳变形进行了研究。数据分析结果表明，高度发生了显著变化，与焦点机制估算的变形量相符，悬壁块发生了几厘米的隆起。此外，地震后计算出的全球导航卫星系统矢量中的横流成分也很明显。这些结果与在控制点测量到的重力变化一致。这表明前阿尔卑斯山脉中部的基底发生了隆起，而安第斯山脉的弹性压缩变形则向与图卢姆线相关的 N-E 方向移动。对四维重力和全球导航卫星系统高度的联合分析表明，地震前涉及下地壳的变形累积，地震后永久变形的应力释放，部分符合 Precordillera 的等压线规律。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of South American Earth Sciences 地学-地球科学综合

CiteScore

3.70

自引率

22.20%

发文量

364

审稿时长

6-12 weeks

期刊介绍： Papers must have a regional appeal and should present work of more than local significance. Research papers dealing with the regional geology of South American cratons and mobile belts, within the following research fields: -Economic geology, metallogenesis and hydrocarbon genesis and reservoirs. -Geophysics, geochemistry, volcanology, igneous and metamorphic petrology. -Tectonics, neo- and seismotectonics and geodynamic modeling. -Geomorphology, geological hazards, environmental geology, climate change in America and Antarctica, and soil research. -Stratigraphy, sedimentology, structure and basin evolution. -Paleontology, paleoecology, paleoclimatology and Quaternary geology. New developments in already established regional projects and new initiatives dealing with the geology of the continent will be summarized and presented on a regular basis. Short notes, discussions, book reviews and conference and workshop reports will also be included when relevant.