RAPID: Collaborative: April 16, 2016 Mw 7.8 Pedernales Earthquake, Ecuador: The Role of Asperities in Rupture Propagation, Aftershock Sequences, and Post Seismic Deformation

RAPID：协作：2016 年 4 月 16 日厄瓜多尔 7.8 级佩德纳莱斯地震：凹凸体在破裂传播、余震序列和震后变形中的作用

• 批准号: 1642499
• 负责人: Anne Meltzer
• 金额: $ 8.71万
• 依托单位: Lehigh University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-15 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1642499&HistoricalAwards=false
• 关键词: RAPID; Collaborative; April; 16; 2016

A Mw 7.8 earthquake occurred along the Ecuadorian subduction zone on April 16, 2016. This earthquake was devastating to the country, causing 660 fatalities 12,000 injuries, and $3B in property damage. This personal and economic toll is amplified because Ecuador is a developing country, with a troubled economy. Preliminary seismic data from international networks indicate that the April 16 earthquake ruptured from north to south along the interface between the South American and Nazca plates. The ridge formed by the trace of the Galapagos hotspot lies just to the south of the end of the rupture and may have limited the extent of the earthquake. This is one of the principal hypotheses driving this proposal, which will also help determine the relationship between the 2016 earthquake and the Mw 7.8 earthquake that occurred nearby in 1942. Twenty broadband seismometers and 5 continuous GPS instruments will be deployed in the region around the April 16th earthquake, in addition to surveying existing GPS monuments. These seismic and GPS deployments are designed to complement the existing national Ecuadorian network, to map the aftershock sequence in great detail, and evaluate stress transfer between segments of the subduction zone. The area to the south of the Galapagos hotspot track has not ruptured in recent times, but geodetic data indicate that this section is locked. Because it is closer to a large population center, Guayaquil, this locked segment poses an increased seismic hazard.On April 16th, 2016 a Mw7.8 earthquake struck along the Colombia-Ecuador trench near Pedernales, Ecuador. This earthquake represents the release of accumulated strain along the Nazca-South American plate margin since its last ruptures in 1942 and 1958. Initial data suggest that the Mw7.8 earthquake ruptured the same part of the plate interface as the Mw7.8 1942 earthquake. The Pedernales earthquake offers an opportunity to use state of the art technologies to measure the history of slip on the plate interface over the phases of the earthquake cycle: interseismic, coseismic, and postseismic and to study the role of asperities in focusing stress, segmenting ruptures, promoting and/or inhibiting rupture propagation, and the role of slow slip events
in the earthquake cycle. This collaboration with the Escuela Politecnica Nacional (Instituto Geofisico, IG) and Instituto Geografico Military (IGM) shall investigate the co- and post-seismic deformation associated with this destructive event through: 1) deployment of a broadband seismic array to record aftershocks; 2) observation of existing eGPS sites; 3) the installation of five new cGPS stations in regions with low site density, but high potential for post-seismic signals. The Nazca plate subducts beneath the South American plate and/or the North Andes block at
~6 cm yr-1, along the Colombia-Ecuador trench, generating M7.5 earthquakes. The 1906 Mw 8.8 earthquake ruptured a large portion of the plate boundary from central Ecuador to central
Colombia. The April 16th, 2016 Mw7.8 earthquake falls within the rupture area of the 1906
event and appears to overlap with the 1942 event. The Pedernales earthquake, offers the opportunity to test the hypothesis that the asperities for large to great earthquakes are persistent over
multiple cycles, and to investigate the role of asperities in arresting slip along strike
and the relationship between locked and creeping parts of the interface. The combined GPS
and seismic data will provide: 1) high precision aftershock locations and focal mechanisms
and their relation to the interplate rupture zone and adjacent segments; 2) detailed structure
of the Pedernales rupture region; 3) characterization of the postseismic deformation field,
including afterslip and viscoelastic relaxation to quantify coseismic and postseismic stress
transfer; 4) identification of low frequency and/or slow slip aftershocks and/or non-volcanic
tremor, and the role of slow slip events in the earthquake cycle; 5) identification of time
varying changes that might reflect rupture zone healing or other time-varying material properties
in the rupture zone; 6) information to characterize site amplification effects and consequent
variable hazard.

2016年4月16日，厄瓜多尔俯冲带发生了MW 7.8地震。这次地震发生了毁灭性的国家，造成660人死亡12,000次伤害，财产损失$ 3B。由于厄瓜多尔是一个发展中国家，经济困扰，因此这种个人和经济的伤害被放大了。来自国际网络的初步地震数据表明，4月16日的地震沿南美和纳斯卡板之间的界面从北向南破裂。加拉帕戈斯热点痕迹形成的山脊位于破裂末端的南部，可能限制了地震范围。这是推动该提案的主要假设之一，这还将有助于确定1942年附近发生的2016年地震与MW 7.8地震之间的关系。除了调查现有GPS遗迹外，还将在4月16日的地震附近部署20个宽带地震仪和5个连续的GPS仪器。这些地震和GPS部署旨在补充现有的国家厄瓜多尔网络，详细介绍余震序列，并评估俯冲带段之间的压力转移。 Galapagos热点轨道南部​​的区域最近没有破裂，但是大地数据表明该部分已锁定。由于它更接近较大的人口中心瓜亚奎尔（Guayaquil），因此该锁定的细分市场构成了增加的地震危险。2016年4月16日，沿厄瓜多尔Pedernales附近的哥伦比亚 - 远离沟槽袭击了MW7.8地震。自1942年和1958年上一次破裂以来，这场地震代表了沿着纳斯卡南美国板块边缘的累积应变的释放。初始数据表明，MW7.8地震与MW7.8 1942 Eartquake的板界面的同一部分破裂。 Pedernales地震提供了一个机会，可以利用艺术技术在地震周期的阶段测量板界面上的滑倒历史：瞬间，coseismic，coseismin和poestsismic，并研究浓缩性在聚焦压力，段落破裂，促进和/或抑制slotecrules ceptip slotece slopece and sopere and osere and of地球上的作用和＃82222222222。与Escuela Politecnica Nacional（IG IG）和Geografico Morivers（IGM）的这项合作应调查与这一破坏性事件相关的同事和后观察变形，通过以下方式：1）部署宽带地震阵列以记录下震动； 2）观察现有的EGP站点； 3）在站点密度较低的地区安装了五个新的CGPS站，但具有很高的视野信号潜力。南美板块下方和/或北安第斯山脉下方的纳斯卡板托架沿着哥伦比亚 - 埃克多尔沟槽盖住了＆＃8232; 〜6 cm yr-1，产生了M7.5地震。 1906年MW 8.8地震破裂了从中央厄瓜多尔到中央＆＃8232;哥伦比亚的大部分板块边界。 2016年4月16日，MW7.8地震属于1906年的破裂区域，似乎与1942年的活动重叠。 Pedernales地震提供了一个机会，可以测试以下假设：大地震的大而大地震持续存在多个循环，并调查了悬挂式沿撞击及锁定零件之间锁定和爬行零件之间的关系在逮捕滑移中的作用。合并的GPS＆＃8232;将提供：1）高精度的余震位置和焦点机理＆＃8232;及其与板间破裂区和相邻段的关系； 2）Pedernales破裂区域的详细结构＆＃8232; 3）表征后的后变形场，包括后滑动和粘弹性放松，以量化coseissic和seist震动应力＆＃8232;转移； 4）鉴定低频和/或慢速滑动余震和/或非volcanic＆＃8232;震颤以及慢速事件在地震周期中的作用； 5）识别时间＆＃8232;在破裂区域中可能反映破裂区愈合或其他随时间变化的材料特性的变化； 6）信息以表征位点放大效果的信息，并导致可变危险。