Tectonic Context and Possible Triggering of the 2019–2020 Puerto Rico Earthquake Sequence
Tectonic Context and Possible Triggering of the 2019–2020 Puerto Rico Earthquake Sequence
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2019-2020 年波多黎各地震序列的构造背景和可能触发
DOI：
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发表时间：
2022
影响因子：
3.3
通讯作者：
R. Govers
中科院分区：
文献类型：
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作者：
Marjolein Blasweiler;M. Herman;Fenna Houtsma;R. Govers
波多黎各西南部附近2019-2020年地震序列的地壳事件释放了一个历史上前所未有的地震时刻。该序列涉及至少两个，也许三个相互作用的断层系统。最大的6.4 Mw事件可能是由北Boquerón Bay-Punta Montalva断裂带东部延伸的左侧走滑事件引发的。主震发生在一个正常的断层带，这个断层带延伸到一个区域，在那里，以前的研究记录了拉伸变形，超出了庞塞断层和巴霍塔斯马尼亚断层。主震引起的库仑应力变化可能引发了进一步的正常断层余震，在这两个断裂带相互作用的地区发生了左旋走滑事件，并可能沿着第三个向南延伸的瓜亚尼拉断裂带发生了右旋走滑余震。地震序列的伸展方向一致为西北偏北—东南偏南，与全球导航卫星系统推断的伊斯帕尼奥拉岛东部相对于波多黎各西部的运动方向一致，与上覆板块边界带的地应力估计一致。
An historically unprecedented seismic moment was released by crustal events of the 2019–2020 earthquake sequence near southwest Puerto Rico. The sequence involved at least two, and perhaps three interacting fault systems. The largest Mw 6.4 event was likely triggered by left lateral strike-slip events along the eastern extension of the North Boquerón Bay-Punta Montalva fault zone. The mainshock occurred in a normal fault zone that extends into a region where previous studies documented extensional deformation, beyond the Ponce fault and the Bajo Tasmanian fault. Coulomb stress changes by the mainshock may have triggered further normal-faulting aftershocks, left lateral strike-slip events in the region where these two fault zones interacted, and possibly right lateral strike-slip aftershocks along a third structure extending southward, the Guayanilla fault zone. Extension directions of the seismic sequence are consistently north-northwest–south-southeast-oriented, in agreement with the Global Navigation Satellite Systems-inferred motion direction of eastern Hispaniola relative to western Puerto Rico, and with crustal stress estimates for the overriding plate boundary zone.