Merging lab and field data: seismic indicators of earthquake nucleation

地震开始于地球深处，在一种鲜为人知的过程中被称为地震成核。我们对地震成核的大部分了解是实验室岩石力学实验的结果，但基于实验室的模型很难应用于天然地震的观测。该项目将俄克拉荷马州地震的现场记录和大规模实验室实验结合在一起，目的是将这两组数据联系起来，以确定可以用地震观测验证的地震成核的物理模型。这些米大小的样品比大多数实验室实验都要大，是用实验室版的地震台网测量的，因此可以更直接地与现场地震记录进行比较。更好地了解地震成核过程将有助于我们理解地震发生的原因，如何避免地震，以及如何更好地解释前震等地震线索。最常被引用的地震成核模型认为，地震不是瞬时开始的，而是在缓慢滑动之前发生的。然而，该模型的地震含义尚不清楚，其对地壳条件的适用性也存在争议。拟议的实验室实验允许在受控条件下直接观察到震级为负三级的地震的成核过程。米级大小的样品配备了传感器阵列，可以记录成核过程的缓慢滑动和任何地震特征，包括震级为负的七次前震和初始P波地震记录。然后，该项目将在实验室开发的地震引发和地震/无地震相互作用的物理模型的背景下，严格解释在俄克拉荷马州中北部收集的地震数据。

Earthquakes begin deep within the earth in a poorly understood process known as earthquake nucleation. Much of our understanding of earthquake nucleation is the result of laboratory rock mechanics experiments, but the laboratory-based models are difficult to apply to observations of natural earthquakes. This project brings together field recordings of earthquakes in Oklahoma and large scale laboratory experiments with the goal of linking both sets of data to identify a physical model of earthquake nucleation that can be tested with seismic observations. Larger than most laboratory experiments, the meter-sized samples are instrumented with a laboratory version of a seismic network, so a more direct comparison can be made to seismic recordings made in the field. A better understanding of the earthquake nucleation process will help us understand why earthquakes occur, how to avoid them, and how to better interpret seismic clues such as foreshocks.The most commonly cited model of earthquake nucleation proposes that earthquakes do not begin instantaneously but are preceded by slow slip. However, the model's seismic implications are unclear, and its applicability to crustal conditions is debated. The proposed laboratory experiments allow the direct observation of the nucleation of magnitude negative three earthquakes under controlled conditions. The meter-sized sample is instrumented with arrays of sensors that can record both slow slip and any seismic signatures of the nucleation process including magnitude negative seven foreshocks and initial P-wave seismograms. This project will then rigorously interpret seismic data collected in north-central Oklahoma within the context of physical models of earthquake initiation and seismic/aseismic interactions developed in the laboratory.