NNSFGEO-NERC: Collaboration: The Role OF Asperities and Slow Slip in Subduction Zone Rupture and Aftershock Sequences: Insights from the 16 April 2016 Pedernales Ecuador Earthquake

NNSFGEO-NERC：合作：凹凸带和慢滑移在俯冲带破裂和余震序列中的作用：2016 年 4 月 16 日厄瓜多尔佩德纳莱斯地震的见解

• 批准号: 1723065
• 负责人: Susan Beck
• 金额: $ 18.11万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2022-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1723065&HistoricalAwards=false
• 关键词: NNSFGEO; NERC; Collaboration; Role; Asperities

The large faults that separate oceanic plates from continental plates in subduction zones generate the largest earthquakes and giant tsunami. Examples include earthquakes with magnitude 9.0 and larger in Chile in 1960, Alaska in 1964, Indonesia in 2004, and Japan in 2011. These giant earthquakes have significant economic and social impact causing loss of life and livelihoods, damage to buildings and infrastructure, disruption of business, and changes in communities that can take years for recovery. Modern instrumentation provides scientists the opportunity to study these faults and the earthquakes they generate in new ways. In April 2016, the Pedernales Earthquake ruptured the subduction zone along the coast of Ecuador in a large Mw 7.8 earthquake. An international rapid response effort deployed a seismic array to record aftershocks following this large earthquake that expanded long term observations of the national seismic and geodetic network in Ecuador. Analysis of these data provide an opportunity to link variations in structure and seismic properties along the subduction zone to the distribution of slip behaviors observed before, during, and after the earthquake. The broader impacts of this research have the potential to benefit society through improved hazard assessment and mitigation strategies for subduction zone earthquakes.A spectrum of fault slip behaviors (earthquakes, non-volcanic tremor, slow slip events, low-frequency earthquakes and very low-frequency earthquakes has been observed in a number of subduction zones globally. While a general framework has developed characterizing the variation in slip behaviors in the dip direction along the plate interface, a direct link between seismic properties and slip behavior and the relationship between slow-slip events and megathrust earthquakes has yet to be established. In April 2016, the Pedernales Earthquake ruptured an approximately 130 km long, 100 km wide segment of the subduction zone along the coast of Ecuador in a large Mw 7.8 megathrust event. Immediately after the earthquake a coordinated international rapid response effort deployed a seismic array (on land and offshore using ocean bottom seismometers, OBS) above the rupture zone and adjacent fault segments where large earthquakes occur on decadal time scales and slow slip events have been observed. The dense on land array combined with offshore OBS instruments provides an exceptional dataset to study the earthquake and aftershock sequence. The seismic array is complemented by rapid response geodetic efforts and long term observations from permanent national seismic and geodetic networks in Ecuador. The researchers will use subduction of the Nazca Plate beneath Ecuador and the Pedernales Earthquake and aftershock sequence to link along strike variations in structure and seismic properties to the distribution of slip behaviors observed (pre-, co- and post-seismic) to determine the relationship between slow slip and megathrust rupture. The integrated analyses from a variety of broadband seismic techniques will be used to examine the persistence of asperities for large to great earthquakes over multiple seismic cycles, the role of asperities in promoting or inhibiting rupture propagation, and the relationship between locked and creeping parts of the subduction interface. Broader impacts of this research will contribute to improved risk assessment from subduction zone earthquakes. In addition we are partnering with Build Change, a non-profit NGO, to develop materials to educate local communities on earthquake hazards and construction techniques to improve resiliency. This project supports academic research infrastructure in seismology and computation, and professional development and training for early career scientists. Results from this research will be integrated into STEM education at both the graduate and undergraduate level.This project is cofunded by the Office of International Science and Engineering.

在俯冲带将海洋板块与大陆板块分开的大断层产生了最大的地震和巨大的海啸。例如，1960 年智利、1964 年阿拉斯加、2004 年印度尼西亚和 2011 年日本发生了 9.0 级及以上的地震。这些特大地震具有重大的经济和社会影响，造成人员伤亡和生计损失、建筑物和基础设施受损、商业中断以及社区发生变化（可能需要数年时间才能恢复）。现代仪器为科学家提供了以新方式研究这些断层及其产生的地震的机会。 2016年4月，佩德纳莱斯地震发生了7.8级大地震，导致厄瓜多尔沿海俯冲带破裂。国际快速响应工作部署了地震阵列来记录这次大地震后的余震，扩大了厄瓜多尔国家地震和大地测量网络的长期观测。对这些数据的分析提供了将俯冲带结构和地震特性的变化与地震前、地震中和地震后观察到的滑动行为分布联系起来的机会。这项研究的更广泛影响有可能通过改进俯冲带地震的危害评估和缓解策略来造福社会。在全球许多俯冲带中观察到了一系列断层滑动行为（地震、非火山震颤、缓慢滑动事件、低频地震和极低频地震）。 沿板块界面的倾角方向，地震特性和滑动行为之间的直接联系以及慢滑动事件和巨型逆冲地震之间的关系尚未建立。 2016 年 4 月，佩德纳莱斯地震导致厄瓜多尔海岸约 130 公里长、100 公里宽的俯冲带在一次 Mw 7.8 的大型逆冲事件中破裂。地震发生后，国际社会立即采取协调一致的快速反应行动 在破裂带和邻近断层段上方部署了地震台阵（在陆地和海上使用海底地震仪，OBS），在这些断层段上发生了十年时间尺度的大地震，并观察到了慢滑移事件。密集的陆地阵列与海上 OBS 仪器相结合，为研究地震和余震序列提供了特殊的数据集。地震台阵辅以快速响应大地测量工作和长期 厄瓜多尔永久国家地震和大地测量网络的观测结果。研究人员将利用厄瓜多尔下方纳斯卡板块的俯冲以及佩德纳莱斯地震和余震序列，将结构和地震特性的沿走向变化与观察到的滑动行为（地震前、地震中和地震后）的分布联系起来，以确定慢滑动和巨型逆冲断裂之间的关系。综合分析 来自各种宽带地震技术的研究将用于研究多个地震周期中大地震的凹凸体的持续性、凹凸体在促进或抑制破裂传播中的作用，以及俯冲界面的锁定部分和蠕变部分之间的关系。这项研究的更广泛影响将有助于改进俯冲带地震的风险评估。此外，我们还与 Build Change 合作， 非营利性非政府组织，开发材料来教育当地社区有关地震灾害和建筑技术的知识，以提高抗灾能力。该项目支持地震学和计算方面的学术研究基础设施，以及早期职业科学家的专业发展和培训。 这项研究的结果将被纳入研究生和本科生的 STEM 教育中。该项目由国际科学与工程办公室共同资助。

项目成果

Structural Control on Megathrust Rupture and Slip Behavior: Insights From the 2016 Mw 7.8 Pedernales Ecuador Earthquake

• DOI: 10.1029/2019jb018001
• 发表时间: 2020-02
• 期刊: Journal of Geophysical Research: Solid Earth
• 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

3D Local Earthquake Tomography of the Ecuadorian Margin in the Source Area of the 2016 Mw 7.8 Pedernales Earthquake

2016 年 Mw 7.8 佩德纳莱斯地震震源区厄瓜多尔边缘的 3D 局部地震层析成像

• DOI: 10.1029/2020jb020701
• 发表时间: 2021
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: León‐Ríos, Sergio;Bie, Lidong;Agurto‐Detzel, Hans;Rietbrock, Andreas;Galve, Audrey;Alvarado, Alexandra;Beck, Susan;Charvis, Philippe;Font, Yvonne;Hidalgo, Silvana
• 通讯作者: Hidalgo, Silvana

Structure of the Ecuadorian forearc from the joint inversion of receiver functions and ambient noise surface waves

接收器函数和环境噪声表面波联合反演的厄瓜多尔前弧结构

• DOI: 10.1093/gji/ggaa237
• 发表时间: 2020
• 期刊: Geophysical Journal International
• 影响因子: 2.8
• 作者: Koch, Clinton D;Lynner, Colton;Delph, Jonathan;Beck, Susan L;Meltzer, Anne;Font, Yvonne;Soto-Cordero, Lillian;Hoskins, Mariah;Stachnik, Josh C;Ruiz, Mario
• 通讯作者: Ruiz, Mario

Crustal thickness and magma storage beneath the Ecuadorian arc

厄瓜多尔弧下的地壳厚度和岩浆储存

• DOI: 10.1016/j.jsames.2021.103331
• 发表时间: 2021
• 期刊: Journal of South American Earth Sciences
• 影响因子: 1.8
• 作者: Koch, Clinton D.;Delph, Jonathan;Beck, Susan L.;Lynner, Colton;Ruiz, Mario;Hernandez, Stephen;Samaniego, Pablo;Meltzer, Anne;Mothes, Patricia;Hidalgo, Silvana
• 通讯作者: Hidalgo, Silvana

Triggered crustal earthquake swarm across subduction segment boundary after the 2016 Pedernales, Ecuador megathrust earthquake

2016 年厄瓜多尔佩德纳莱斯巨型逆冲地震后引发的跨越俯冲段边界的地壳地震群

• DOI: 10.1016/j.epsl.2020.116620
• 发表时间: 2021
• 期刊: Earth and Planetary Science Letters
• 影响因子: 5.3
• 作者: Hoskins, Mariah C.;Meltzer, Anne;Font, Yvonne;Agurto-Detzel, Hans;Vaca, Sandro;Rolandone, Frederique;Nocquet, Jean-Mathieu;Soto-Cordero, Lillian;Stachnik, Joshua C.;Beck, Susan
• 通讯作者: Beck, Susan