Revealing Quaternary evolution of North American tectonics with geologic block models

该项目将重建过去260万年来北美西部的构造运动。这将通过将地质和卫星数据与现代数学建模技术相结合来实现。地壳中构造运动的分布与未来地震的潜在规模和位置直接相关，因此是美国国家地震灾害模型的关键组成部分，保险公司、政府官员和土地使用管理人员以及公众宣传都使用了该模型。该项目将推进构造建模，并帮助确定地质和卫星数据的潜在局限性，最终改善地震灾害，造福社会。该项目将支持妇女和代表不足的少数群体充分参与STEM，并改善大学水平的STEM教育：该项目的结果将被纳入加州州立大学北岭(一个少数群体服务机构)所有地质学和地球物理学专业的新实验室活动，并将公开提供，PI致力于从代表不足的少数群体中招聘学生研究助理。该项目将评估北美西部地质和大地断层滑动速率之间的差异，以询问第四纪构造变形在空间和时间上的基本性质。可以使用构造地质学(地质滑移率)或使用基于卫星的大地测量(如全球导航卫星系统(GNSS)，包括全球定位系统(GPS))的模型(大地滑移率)来估计断层沿线各点的断层滑移率。地质和大地滑动速率之间的差异可能反映真实的空间或时间变化，限制了对当代构造和地震灾害的解释。为了解决滑动速率的差异，研究小组将建立太平洋-北美板块边界的第一个完全地质块体模型。通常，块体模型受GNSS数据的约束；然而，该团队将更新块体建模方法，以仅用地质滑移率来约束模型。这项工作代表了构造块体建模方面的重大进步，包括一种创新的自动块体闭合算法，该算法将从根本上改进块体模型的开发、测试和解释方式。地质滑动速率约束将根据年龄范围细分，以反映地质时期的北美构造。直接比较受地质约束的块体模型和传统的基于GNSS的块体模型将隔离地质和大地测量在推断板块边界尺度构造变形中的作用。该项目的资金由NSF EAR构造计划提供。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project will reconstruct tectonic motion in western North America over the last 2.6 Million years. This will be accomplished by combining geologic and satellite-based data with modern mathematical modeling techniques. The distribution of tectonic motion in the Earth’s crust is directly related to the potential size and location of future earthquakes and is therefore a critical component of the United States National Seismic Hazard Model, which is used by insurance companies, government officials, and land use managers, as well as in public outreach. This project will advance tectonic modeling and also help identify potential limitations of geologic and satellite-based data, ultimately improving seismic hazard for the benefit of society. The project will support the full participation of women and underrepresented minorities in STEM and improve college-level STEM education: results from this project will be incorporated into a new laboratory exercise for all Geology and Geophysics majors at California State University Northridge (a Minority Serving Institution) that will be made publicly available, and the PI is committed to recruiting student research assistants from underrepresented minorities. This project will evaluate discrepancies between geologic and geodetic fault slip rates in western North America to interrogate the fundamental nature of Quaternary tectonic deformation in space and time. Fault slip rate can be estimated at points along a fault using tectonic geology (geologic slip rates), or by using models based on satellite-based geodetic measurements such as Global Navigation Satellite Systems (GNSS) including the Global Positioning System (GPS) (geodetic slip rates). Discrepancies between geologic and geodetic slip rates may reflect true spatial or temporal variations, limiting interpretation in terms of contemporary tectonics and seismic hazard. To address slip rate discrepancies, the research team will create the first fully geologic block model of the Pacific-North America plate boundary. Typically, block models are constrained by GNSS data; however, the team will update the block modeling methodology to constrain the models exclusively with geologic slip rates. This work represents a significant advance in tectonic block modeling, including an innovative automated block closure algorithm that will fundamentally improve how block models are developed, tested, and interpreted. Geologic slip rate constraints will be subdivided based on the age range to reflect North America tectonics over geologic time. Directly comparing geologically-constrained block models with traditional GNSS-based block models will isolate the role of geologic vs. geodetic observations in inferring plate boundary-scale tectonic deformation.Funding for this project is provided by NSF EAR Tectonics Program.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.