CAREER: Response of Fault Systems to Shifts in Tectonic Regime: Implications for the Evolution of and Present-Day Activity of Fault Systems in Southern California

地壳中的断层是如何演化的？ 自从1906年旧金山弗朗西斯科地震以来的100年里，地质学家已经了解了断层如何积累应力和相互作用。 然而，故障行为仍然无法预测。了解活动断层的下一次革命将不仅考虑单个断层，而且考虑整个三维断层系统。本项目正在开发创新的计算机工具，以提高我们对故障系统演化的理解，并将聋人高中生纳入研究计划。本研究通过假设故障演化以最小化系统中的能量来调查故障的系统演化;换句话说，故障系统沿着沿着最小的路径生长。通过评估与活动断层有关的工作，断层系统的演化在三维计算机模型中进行了模拟。 特别是，断层系统如何适应其构造环境的变化？ 例如，在伸展构造环境中发育的断层在后期收缩作用下可能变形无效。 计算机模型显示，在这样的构造移动，一些断层复活，一些连接和一些新的，更有效的断层面的发展。 世界许多地区都经历了结构性变化。 特别令人感兴趣的是，南加州现今的断层系统在过去600万年里是如何演变的。 人口密集和活动断层的结合使得理解南加州的断层演化对于估计未来地震的潜在损害非常重要。该项目的一个重要组成部分是用桌面实验验证断层演化的模型预测。 断层被放入一层厚厚的粘土中，然后拉伸以模拟地球的变形。 这些实验是由研究人员以及全国三所高中的聋人教师和学生进行的。 让聋人学生参与该项目可以：1）激发对地球科学的终身兴趣，2）激励聋人学生在大学里追求科学，3）提高学生的技术沟通技能，4）通过利用他们的空间可视化技能赋予学生权力，5）消除地球科学作为一个健全的职业的观点。聋人学生使用美国手语，一种固有的空间语言。 空间语言的使用，预计将培养空间认知技能的分析相互作用，三维断层表面的关键。事实上，地球科学家可以从聋人社区学习3D数据呈现的创新方法。

How do faults in the Earth's crust evolve? In the 100 years since the 1906 San Francisco earthquake, which instigated the study of earthquake science, geologists have learned much about how faults accumulate stress and interact with one another. However, fault behavior still cannot be predicted. The next revolution in understanding active faulting will consider not just individual faults but entire systems of three-dimensional faults. This project is developing innovative computer tools that will enhance our understanding of fault system evolution and is also incorporating deaf high school students into the research program.This study investigates the systemic evolution of faults by assuming that faults evolve to minimize the energy in the system; in other words, fault systems grow along paths of least resistance. By assessing the work associated with active faulting, the evolution of fault systems is simulated in three-dimensional computer models. In particular, how do fault systems adapt when their tectonic setting changes? For example, faults that developed in an extensional tectonic setting might deform inefficiently under later contraction. The computer models show that upon such tectonic shifts, some faults reactivate, some link up and some new, more efficient fault surfaces develop. Many parts of the world have undergone tectonic shifts. Of particular interest is how the present-day fault systems in Southern California, evolved over the last 6 million years. The combination of dense population and active faulting makes understanding fault evolution in Southern California quite important for estimating potential damage from future earthquakes.An important component of this project is the validation of model predictions of fault evolution with table-top experiments. Faults are put into a thick layer of clay that is then stretched to simulate deformation of the Earth. The experiments are being performed by the researchers as well as deaf teachers and students at three high schools around the country. Incorporating deaf students into the project may: 1) motivate life-long interest in geoscience, 2) inspire deaf students to pursue science in college, 3) improve the technical communication skills of the students 4) empower students by utilizing their spatial visualization skills and 5) dispel views of geoscience as an able-bodied occupation. Deaf students use American Sign Language, an inherently spatial language. The use of spatial language is expected to foster spatial cognitive skills critical for analyzing interacting, three-dimensional fault surfaces. In fact, geoscientists may learn from the deaf community innovative approaches for presentation of 3D data.