RAPID - Afterslip and triggered slip associated with the Ridgecrest earthquake sequence

当它们发生时，加州的大地震会造成数十亿美元的损失。每一次地震后都会有更多的地震风险意识，并伴随着进一步了解地震过程的科学努力。这一快速增长的动机是需要在2019年7月里奇克雷斯特地震附近的活动断层上迅速部署仪器，以确定地震如何对附近的活动断层施加压力。该计划将安装六个延伸仪，并量化附近断层现在和未来滑动的可能性。数据将每分钟采集一次，并存储在联合国志愿人员组织供公众查阅。这项工作的动机是需要在Ridgecrest地震序列的中心附近的活动断层上紧急部署伸缩仪，以确定地震中的应力变化是否以及如何对附近的活动断层施加压力。在触发滑动后，应力变化往往会在附近断层上建立一个对数衰减的蠕变速率，这可以使用灵敏的延伸仪来测量。地震序列本身是一系列共轭破裂，震级逐渐增大，随后是数千次较小的余震，因为附近的共轭断层格子放松了震中应变。地震产生的动态应力达到了极致，导致断层向南滑动，最远可达墨西哥边境。6个新的延伸仪的部署是对现有延伸仪的补充，现有的延伸仪在破裂两天后部署在地表破裂处。伸长计记录滑移的精度为2微米，范围为2-4米，每分钟采样一次，持续一年。延伸仪将记录一年的滑动数据，这将允许计算速率变化并搜索可用于确定断裂带流变条件的幕式滑动。这一裁决反映了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。

When they occur, major California earthquakes result in billions of dollars damage. Greater awareness of earthquake risk follows each event, and also accompanies scientific efforts to further understand seismic processes. This RAPID is motivated by the need to quickly deploy instruments on active faults near the July 2019 Ridgecrest earthquakes to determine how the earthquake have stressed nearby active faults. The plan is to install six extensometers and to quantify the potential for present and future slip on nearby faults. Data will be acquired once per minute and stored for public access at UNAVCO.This works is motivated by the need to urgently deploy extensometers on active faults near the meizzocenter of the Ridgecrest earthquake sequence to determine whether, and how, stress changes in the earthquake have stressed nearby active faults. Stress changes tend to set up a logarithmically decaying creep rate on nearby faults following triggered slip that can be measured using sensitive extensometers. The seismic sequence itself was a cascade of conjugate ruptures with progressively greater magnitude followed by thousands of smaller aftershocks as a nearby lattice of conjugate faults relaxed epicentral strain. The dynamic stresses from the earthquakes had extreme reach, causing slip to be triggered on faults as far south as the Mexican border. The deployment of 6 new extensometers supplement and existing one deployed across the surface rupture two days after rupture. The extensometers record slip with an accuracy of 2 micrometer over a range of 2-4 meters and sample once per minute for a year. The extensometers will record slip data for a year, which will allow for calculating rate changes and to search for episodic slip that can be used to determine rheological conditions in the fault zone.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.