Beyond elastic rebound: extracting permanent strain from interseismic deformation

超越弹性回弹：从震间变形中提取永久应变

• 批准号: 1520266
• 负责人: Kaj Johnson
• 金额: $ 12万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-15 至 2017-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1520266&HistoricalAwards=false
• 关键词: Beyond; elastic; rebound; extracting; permanent

One of the main uses of GPS data in studying the boundaries of tectonic plates is to understand current rates for fault movements and understand how faults interact. This kind of understanding can all feed into a better assessment of earthquake hazards because it helps us better understand the longer term behavior of fault systems. The researchers in the project will try to reconcile two kinds of models, those that characterize single faults with those that look at long-term evolution of a full plate boundary. The results of this work have important implications for how fast plate boundaries are moving and how the ground around faults deforms over time. The work will use two examples, on in Taiwan, and the other in Southern California. Comparing and contrasting the two areas will improve overall understanding of earthquakes processes.The purpose of the proposed research is to develop dynamic models of geodetic data that extend traditional elastic models to include permanent deformation. The approach is to develop viscoelastic-plastic boundary element models in which the deforming crust is loaded by far-field stresses and faults slip and the surrounding crust deforms in response to the loads. They will employ geodetic data, stress state inferred from focal mechanism data, and geologic and thermochronologic data to constrain the deformation models. In Taiwan they will use the GPS-derived horizontal and vertical velocity fields, an island-wide leveling network, and stress orientations throughout the crust to address several key outstanding issues about the fault architecture responsible for mountain building processes in Taiwan. They will test several models of deep fault geometry and a proposed deep-seated underplating processfor uplifting the core of the mountain range. Model results will be compared with low-temperature thermochronology. In southern California the research will examine models of long-term deformation across the strike-slip fault system to determine the relative contributions of various pate-driving forces (plate boundary forces, gravitational potential energy, mantle drag) and compare predicted long-term fault slip rates with geologic slip rate estimates. They will focus on the important outstanding problem of the portion of deformation that occurs as off-fault inelastic yielding distribution through the crust versus deformation that is accommodated by slip on faults.

GPS数据在研究构造板的边界中的主要用途之一是了解故障运动的当前速率并了解故障的相互作用。这种理解都可以更好地评估地震危害，因为它可以帮助我们更好地理解故障系统的长期行为。项目中的研究人员将尝试调和两种模型，这些模型将单个故障表征的模型与查看完整板边界的长期演变的模型。 这项工作的结果对板界边界的移动方式以及故障周围的地面随时间变化有重要意义。这项工作将在台湾使用两个例子，另一个在南加州。比较和对比这两个领域将改善对地震过程的整体理解。拟议的研究的目的是开发地球数据的动态模型，该模型将传统的弹性模型扩展到包括永久变形。该方法是开发粘弹性塑性边界元素模型，其中变形外壳由远场应力和断层滑动和周围的地壳变形响应载荷响应。他们将采用测量数据，从焦点机理数据推断出的应力状态以及地质和热量方学数据来限制变形模型。在台湾，他们将使用由GPS衍生的水平和垂直速度场，一个整个岛屿的平稳网络以及整个地壳的压力取向，以解决有关负责台湾山区建筑过程的多个关键问题。他们将测试几种深层故障几何形状的模型，并提出了一个深层底层的底层过程，以提高山脉的核心。模型结果将与低温热量学进行比较。在南加州，研究将检查整个走滑断层系统的长期变形模型，以确定各种PATE驾驶力（板界力量，重力势能，地幔阻力）的相对贡献，并将预测的长期断层滑移速率与地质滑动速率估计进行比较。他们将重点关注变形部分的重要杰出问题，而变形部分是通过弹性的分布而屈服与变形的分布，而变形与变形的分布，这是由于断层的滑倒所容纳的。