Structural Control on Megathrust Rupture and Slip Behavior: Insights From the 2016 Mw 7.8 Pedernales Ecuador Earthquake
Structural Control on Megathrust Rupture and Slip Behavior: Insights From the 2016 Mw 7.8 Pedernales Ecuador Earthquake
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DOI：
10.1029/2019jb018001
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发表时间：
2020-02
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通讯作者：
L. Soto‐Cordero;A. Meltzer;E. Bergman;M. Hoskins;J. Stachnik;H. Agurto‐Detzel;A. Alvarado;S. Beck;P. Charvis;Y. Font;G. Hayes;S. Hernández;C. Lynner;S. León‐Ríos;J. Nocquet;M. Régnier;A. Rietbrock;F. Rolandone;M. Ruiz
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作者：
L. Soto‐Cordero;A. Meltzer;E. Bergman;M. Hoskins;J. Stachnik;H. Agurto‐Detzel;A. Alvarado;S. Beck;P. Charvis;Y. Font;G. Hayes;S. Hernández;C. Lynner;S. León‐Ríos;J. Nocquet;M. Régnier;A. Rietbrock;F. Rolandone;M. Ruiz
纳斯卡板块进入厄瓜多尔俯冲带时的海底地形不均匀，这为记录海底粗糙度对滑动行为和巨型逆冲断层破裂的影响提供了机会。2016年厄瓜多尔足目7.8级地震之后，出现了丰富而活跃的震后序列。一项国际协调的快速反应工作安装了一个临时地震网络，以加强厄瓜多尔永久性国家地震网络的沿海台站。82个陆上短、中周期和宽频带地震台站和6个海底地震仪记录了主震后一年多的Pedernales震后足目序列。一个强大的地震目录结合校准的重新定位的一个子集的震级≥4地震显示出明显的空间和时间聚类。一系列的滑动行为适应震后变形，包括地震，慢滑动事件，地震群。通过多个地震周期的板块耦合和地震集群和滑动行为的一致性模型揭示了一个分段的俯冲带，主要由俯冲海底地形，增生的岩石和继承的结构控制。2016年的足目主震引发了中强地震（5 ≤ M ≤ 7），主震破裂以北的地震群靠近1906年8.8级地震的震中，并位于1958年7.7级地震中破裂的俯冲带部分。
The heterogeneous seafloor topography of the Nazca Plate as it enters the Ecuador subduction zone provides an opportunity to document the influence of seafloor roughness on slip behavior and megathrust rupture. The 2016 Mw 7.8 Pedernales Ecuador earthquake was followed by a rich and active postseismic sequence. An internationally coordinated rapid response effort installed a temporary seismic network to densify coastal stations of the permanent Ecuadorian national seismic network. A combination of 82 onshore short and intermediate period and broadband seismic stations and six ocean bottom seismometers recorded the postseismic Pedernales sequence for over a year after the mainshock. A robust earthquake catalog combined with calibrated relocations for a subset of magnitude ≥4 earthquakes shows pronounced spatial and temporal clustering. A range of slip behavior accommodates postseismic deformation including earthquakes, slow slip events, and earthquake swarms. Models of plate coupling and the consistency of earthquake clustering and slip behavior through multiple seismic cycles reveal a segmented subduction zone primarily controlled by subducted seafloor topography, accreted terranes, and inherited structure. The 2016 Pedernales mainshock triggered moderate to strong earthquakes (5 ≤ M ≤ 7) and earthquake swarms north of the mainshock rupture close to the epicenter of the 1906 Mw 8.8 earthquake and in the segment of the subduction zone that ruptured in 1958 in a Mw 7.7 earthquake.