Collaborative Research: Normal-Fault Facets as Recorders of Erosion and Tectonics

地震是代价高昂且危险的自然灾害。管理它们所代表的风险需要估计过去地质上地震的规模和频率。通常，这种依赖于特定断层过去活动信息的知识很难获得，成本也很高。这个项目测试了一种通过详细的现场测量和一个简单的数学模型来估计过去地震活动的新方法。由于这些环境中的山脉地形也是气候的产物，收集的数据将提供过去一到两个冰期期间风化和侵蚀速度变化的信息。这些关于气候和侵蚀之间关系的信息对各种应用都很重要，包括石油和天然气工业用来研究沉积矿床形成的长期沉积模型。该项目还将通过培训博士后研究助理来促进教育，并将通过为来自代表性不足的少数群体的学生提供本科生暑期研究体验来扩大对科学的参与。该项目与挪威卑尔根大学和英国伦敦大学有很强的国际合作。这项研究将有助于理解气候对自然侵蚀速率和过程的控制以及古地震学。该项目测试了一种新的方法，通过详细测量位于断层附近的山脉的形状和陡度来估计过去的地震活动，这些山脉是由这些断层上的运动形成的。该方法依赖于一个简单的山前形态数学模型，该模型预测了断层平均运动速度与邻近地形陡度之间的定量关系。该项目将通过研究两个已经可以独立估计断层运动速率的地点来测试这一模型：犹他州的瓦萨奇山脉和意大利的亚平宁山脉中部。详细测量这两个地点活动断层附近的地貌形态，并检查随着时间的推移改变地形的风化和侵蚀过程，将测试这种方法在重建过去断层活动方面的工作有多好。研究包括实地调查、数字地形分析、宇宙成因核素分析，以及将小平面斜率分析作为古地震学工具的可行性测试。该项目由地貌学和土地利用动力学、构造学和国际科学与工程计划共同支持。

Earthquakes are expensive and dangerous natural hazards. Managing the risk they represent requires estimating the size and frequency of earthquakes in the geologic past. Often, this knowledge, which relies on information about the past activity of particular faults, is difficult and costly to obtain. This project tests a new method for estimating past earthquake activity through detailed field measurements and a simple mathematical model. Because mountain topography in these settings is also a product of climate, the data collected will provide information on variations in rates of weathering and erosion during the past one to two ice ages. Such information about the relationship between climate and erosion is important for a variety of applications, including models of long-term sedimentation that the oil and gas industry uses to study the formation of sedimentary deposits. The project will also foster education by training a post-doctoral research associate, and it will broaden participation in science by providing an undergraduate summer research experience for a student from an under-represented minority group. The project has a strong international collaboration with the University of Bergen in Norway and the University of London in the UK. This research will contribute both to an understanding of climate control on natural rates and processes of erosion as well as paleoseismology. The project tests a new method for estimating past earthquake activity through detailed measurements of the shape and steepness of mountains that lie next to faults, and which were created by motion on those faults. The method relies on a simple mathematical model for mountain-front form that predicts a quantitative relationship between the average rate of fault motion and the steepness of the adjacent terrain. The project will test this model by studying two locations where independent estimates of fault-motion rate are already available: the Wasatch Mountains, Utah, and the central Apennines Mountains, Italy. Measuring in detail the landscape form adjacent to active faults in these two sites, and examining the processes of weathering and erosion that modify topography over time, will provide a test of how well this method works to reconstruct past fault activity. The research includes field surveys, digital topography analysis, cosmogenic nuclide analysis, and feasibility testing of facet-slope analysis as a paleoseismology tool. This project is jointly supported by the Geomorphology and Land Use Dynamics, Tectonics, and International Science and Engineering programs.