Merging lab and field data: seismic indicators of earthquake nucleation

地震开始在地球深处的一个鲜为人知的过程称为地震成核。我们对地震成核的理解大多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。该项目汇集了俄克拉荷马州的地震现场记录和大规模实验室实验，目的是将两组数据联系起来，以确定可以用地震观测进行测试的地震成核物理模型。比大多数实验室实验更大，米大小的样本装有实验室版本的地震网络，因此可以与现场的地震记录进行更直接的比较。更好地理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提出，地震不是开始瞬间发生的，而是在缓慢滑动之前发生的。然而，该模型的地震影响尚不清楚，其适用于地壳条件的辩论。建议的实验室实验允许在受控条件下直接观察负三级地震的成核。米大小的样本装有传感器阵列，可以记录缓慢滑动和成核过程的任何地震特征，包括震级为负7的前震和初始P波地震图。然后，该项目将在实验室开发的地震引发和地震/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.