RAPID: GPS and InSAR Observations in Bolivia and Chile of the Co-seismic and Post-seismic Deformation Associated with the 1 Apr, 2014 Mw 8.2 Pisagua, Chile, Earthquake

RAPID：玻利维亚和智利与 2014 年 4 月 1 日 Mw 8.2 智利皮萨瓜地震相关的同震和震后变形的 GPS 和 InSAR 观测

• 批准号: 1443317
• 负责人: James Foster
• 金额: $ 10.55万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-05-01 至 2018-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1443317&HistoricalAwards=false
• 关键词: RAPID; GPS; InSAR; Observations; Bolivia

An unusual sequence of earthquakes began in the northern Chile subduction zone on March 16, 2014 with a 10-day long swarm of earthquakes that migrated to the north ? a pattern similar to the swarm of earthquakes that presaged the 2011 magnitude 9.0 Tohoku Japan earthquake, which provoked concern in Chile because this megathrust zone last failed in a magnitude 8.8 earthquake in 1877 and is thought capable of producing a magnitude 9 earthquake again. So far, the largest event in the sequence is the April 1, 2014 magnitude 8.2 Pisagua, Chile earthquake. The ground deformation caused by this large earthquake will persist long after the earthquake and decay over a period of years. Measurements of the surface deformation during and after the event can provide important information about the properties of the earth in the region, improve understanding of deformation processes, and aid in determining regions with a high likelihood of producing large aftershocks. Large dense GPS networks installed by U.S., German, French, Peruvian, and Chilean groups in Chile will record this deformation close to the earthquake epicenter but significant deformation is expected farther away in Bolivia, a very poorly instrumented region. This rapid response project will install new GPS networks in Bolivia, collect data from existing GPS sites in Chile and Bolivia, and analyze satellite synthetic aperture radar data in order to fully capture the ground motion associated with this event. These data will contribute to understanding the physics and hazard potential of large megathrust earthquakes in Chile and elsewhere, such as Cascadia, Alaska, and Japan.The April 1, 2014 Mw 8.2 Pisagua, Chile earthquake was the largest event in an unusual sequence of earthquakes, which began in the northern Chile subduction zone on March 16, 2014. Based on the USGS preliminary teleseismic and surface wave inversion, slip occurred along a 250 km along-strike and about 150 km down-dip section of the Chile megathrust that last failed in an M 8.8 earthquake in 1877. U.S., Chilean, Peruvian, German, and the French groups have built relatively dense continuously operating GPS (CGPS) and survey mode GPS (SGPS) station networks in this region, thus the near-field inter-, co- and post-seismic transient signals will be well observed in northern Chile. However, there will be significant co-seismic and post-seismic transient motion up to 700 km from the main event, incorporating nearly all of the Altiplano and at least much of eastern Cordillera in Bolivia, and the Puna of northwestern Argentina. Measuring the mid- and far-field co- and post-seismic signals in the Altiplano and beyond will be critical to any geodynamic modeling effort. The Bolivian Altiplano, nevertheless, is very poorly instrumented and so cannot, at present, provide the observations required for accurate inversions of afterslip and lithospheric relaxation. In rapid response to the April 1, 2014 Mw 8.2 Pisagua, Chile earthquake, the research team will: (1) install 10 new CGPS stations in Bolivia; (2) reoccupy SGPS sites in Bolivia and Chile; (3) retrieve data from 5 CGPS stations within the PLUTONS network in Bolivia and Chile; and (4) acquire and analyze about 100 SAR scenes from Radarsat-2 and TerraSAR-X. Data will be made immediately available to the international earth science community through the UNAVCO Facility Archive. SAR data will be tasked and made available to the community with the password-protected restrictions required by the foreign space agencies through the WinSAR archive hosted by the UNAVCO Facility. Low latency geodetic data processing could be critical in determining regions with a high likelihood of producing large aftershocks and for hazard mitigation efforts because the largest aftershock (M 7.7 on April 3) was larger than expected, potentially indicating continued unusual activity with the neighboring segments thought to retain a large slip deficit.

2014年3月16日的北部智利俯冲带开始了一系列不寻常的地震序列，其中10天的地震群迁移到北部？一种类似于预示2011年9.0 Tohoku日本地震的地震类似的模式，该地震引起了智利的关注，因为这个大型区域最后一次在1877年发生的8.8地震中失败了，并且被认为能够再次产生9级地震。到目前为止，该序列中最大的事件是智利地震2014年4月1日Pisagua级8.2级。大地震引起的地面变形将在地震和腐烂的时间内持续很长时间。事件期间和之后的表面变形的测量可以提供有关地球在该地区特性，提高对变形过程的理解的重要信息，并有助于确定产生大量余震的可能性高的区域。美国，德国，法国，秘鲁人和智利群体安装的大型密集的GPS网络将记录这种变形接近地震震中，但预计在玻利维亚较远的玻利维亚，这是一个非常不良的乐器地区。这个快速响应项目将在玻利维亚安装新的GPS网络，从智利和玻利维亚的现有GPS站点收集数据，并分析卫星合成孔径雷达数据，以便完全捕获与此事件相关的地面运动。这些数据将有助于了解智利和其他地方大型大型地震的物理和危害潜力，例如卡斯卡迪亚，阿拉斯加和日本。2014年4月1日，MW 8.2 Pisagua Pisagua，智利地震是地震序列中最大的事件，是在北部奇数台上的不寻常地震序列，该地震开始于3月16日，2014年3月16日。波浪反转，沿250 km的沿撞击和约150 km的下垂部分发生滑动，最后一次在1877年的M 8.8地震中失败。在智利北部，可以很好地观察到后的瞬态信号。但是，距离主要事件最高700公里的同志瞬态运动将有明显的同志，几乎纳入了玻利维亚的几乎所有阿尔蒂普拉诺和至少的东部科迪利拉，以及阿根廷西北部的普纳。测量Altiplano及以后的中场和远场共同和后震源信号对于任何地球动力学建模工作至关重要。然而，玻利维亚的阿尔特普拉诺的仪器非常差，因此目前无法提供准确反转后滑动后和岩石圈松弛所需的观察结果。在对2014年4月1日MW 8.2 Pisagua，智利地震的快速响应中，研究小组将：（1）在玻利维亚安装10个新的CGPS车站； （2）玻利维亚和智利的重新占领SGPS地点； （3）从玻利维亚和智利的Plutons网络内的5个CGPS站检索数据； （4）从Radarsat-2和Terrasar-X中获取和分析大约100个SAR场景。数据将通过UNAVCO设施档案立即向国际地球科学界提供。 SAR数据将受到任务，并通过UNAVCO设施托管的Winsar档案馆所需的密码保护限制，并提供给社区。低潜伏期的大地数据处理对于确定产生大余震和危险工作的可能性很大的区域可能至关重要，因为最大的余震（4月3日的M 7.7）比预期的要大，这可能表明持续的非同寻常的活动与邻近的段落被认为保留了大型滑动赤字。