Geersen Jacob, Ranero César R, Barckhausen Udo, Reichert Christian
GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany.
Barcelona Center for Subsurface Imaging, Instituto de Ciencias del Mar, ICREA at CSIC, Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain.
Nat Commun. 2015 Sep 30;6:8267. doi: 10.1038/ncomms9267.
To date, the parameters that determine the rupture area of great subduction zone earthquakes remain contentious. On 1 April 2014, the Mw 8.1 Iquique earthquake ruptured a portion of the well-recognized northern Chile seismic gap but left large highly coupled areas un-ruptured. Marine seismic reflection and swath bathymetric data indicate that structural variations in the subducting Nazca Plate control regional-scale plate-coupling variations, and the limited extent of the 2014 earthquake. Several under-thrusting seamounts correlate to the southward and up-dip arrest of seismic rupture during the 2014 Iquique earthquake, thus supporting a causal link. By fracturing of the overriding plate, the subducting seamounts are likely further responsible for reduced plate-coupling in the shallow subduction zone and in a lowly coupled region around 20.5°S. Our data support that structural variations in the lower plate influence coupling and seismic rupture offshore Northern Chile, whereas the structure of the upper plate plays a minor role.
迄今为止，决定大型俯冲带地震破裂区域的参数仍存在争议。2014年4月1日，矩震级8.1级的伊基克地震使久负盛名的智利北部地震空区的一部分发生破裂，但仍有大片高耦合区域未破裂。海洋地震反射和多波束测深数据表明，俯冲的纳斯卡板块的构造变化控制着区域尺度的板块耦合变化以及2014年地震的有限范围。在2014年伊基克地震期间，几个逆冲海山与地震破裂的向南和向上倾的终止相关，从而支持了因果联系。通过上覆板块的破裂，俯冲海山可能进一步导致浅俯冲带以及南纬20.5°左右的低耦合区域的板块耦合降低。我们的数据支持下板块的构造变化影响智利北部近海的耦合和地震破裂，而上板块的构造作用较小。
