Collaborative Research: Great Earthquakes, Megathrust Phenomenology and Continental Dynamics in the Southern Andes

合作研究：安第斯山脉南部的大地震、巨型逆冲现象学和大陆动力学

• 批准号: 1118239
• 负责人: Mark Simons
• 金额: $ 72万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1118239&HistoricalAwards=false
• 关键词: Collaborative; Research; Great; Earthquakes; Megathrust

The overall goal of the project is to understand the processes that created and now drive evolution of the modern Andes. In order to do that, we must understand the spatial and temporal variability of stresses generated in the upper plate by coupling at the plate interface and by viscous drag of the asthenosphere. Specifically, the project will focus on the 2010 Mw 8.8 Maule earthquake in Chile, the earthquake cycle along the Nazca-South America plate interface, orogenesis of the Andean system, and its relationship to crustal deformation and mantle flow. The project is structured around two main themes:? How does megathrust phenomenology influence or control the architecture, from forearc to backarc, of the Andean orogeny? ? How do geological materials, shallow structure and slab/mantle dynamics influence or control the behavior and evolution of the megathrust? The PI group will use GPS and INSAR to examine post-seismic transients and combine these with co-seismic data. They will combine many sources of GPS data (German - GFZ and US groups) that have been collected from 1993 to present over the entire orogen in an effort to develop a synoptic model. This includes data from 33 cGPS stations installed in Chile with NSF-RAPID funds immediately following the Maule earthquake. The regional extent of new analysis will include the rupture zone from the 1960 Mw 9.5 earthquake, which still shows post-seismic transient deformation. Among the important geodynamic processes that the project will address are (1) time-variable deformation in the aftermath of a great subduction-zone earthquake; (2) improved models of plate interface rheology and their implications for plate boundary earthquake cycles; and (3) interaction between plate boundary and intraplate deformation over time-scales from decadal to geological. In addition to GPS and InSAR observation of surface deformation, the project brings to bear a number of state-of-the-art observational and modeling approaches; earthquake location and source mechanism determination; geological and geochemical constraints on uplift and erosion rates; inversion for geometric and rheological parameters associated with the plate interface; and large-scale geodynamic modeling. The investigator team is highly qualified to take on these activities, and has a strong track record in previous work in the area. They have developed a strong set of collaborations, both in-country and with other international researchers working in the area.

该项目的总体目标是了解创造和现在推动现代安第斯山脉演变的过程。为了做到这一点，我们必须了解由于板块界面的耦合和软流层的粘性阻力而在上板块产生的应力的时空变异性。具体而言，该项目将侧重于2010年智利8.8兆瓦的毛勒地震、沿纳斯卡-南美洲板块界面的地震旋回、安第斯系的造山作用及其与地壳形变和地幔流动的关系。该项目围绕两个主题展开：？巨型逆冲现象学如何影响或控制安第斯造山运动从弧前到弧后的建筑？地质物质、浅层构造和板块/地幔动力学如何影响或控制巨型逆冲的行为和演化？PI小组将使用GPS和InSAR来检查地震后的瞬变，并将这些与同震数据结合起来。他们将结合许多来源的GPS数据(德国-GFZ和美国组)，这些数据从1993年收集到整个造山带，以努力开发一个天气模型。这包括毛勒地震后立即由NSF-RAPID基金在智利安装的33个CGPS站的数据。新分析的区域范围将包括1960年MW9.5级地震的破裂带，该带仍显示地震后的瞬时变形。该项目将讨论的重要地球动力学过程包括：(1)俯冲带大地震后的时变变形；(2)改进的板块界面流变学模型及其对板块边界地震循环的影响；(3)从十年尺度到地质尺度的板块边界和板块内变形之间的相互作用。除了地表形变的GPS和InSAR观测外，该项目还采用了一些最先进的观测和模拟方法；地震位置和震源机制的确定；对抬升和侵蚀速率的地质和地球化学约束；与板块界面有关的几何和流变参数的反演；以及大规模地球动力学模拟。调查组非常有资格承担这些活动，并且在该地区以前的工作中有很好的记录。他们已经建立了一套强有力的合作，无论是在国内还是与该地区工作的其他国际研究人员。