Dynamic Triggering Seen Clearly: Utilizing Continuous Waveforms and High-Resolution Catalogs to Measure the Importance and Mechanisms of Dynamic Triggering

每当地震发生时，地震波就会从地震中发出，震动地面。30年前，人们发现这些波可以引发距离第一次地震100公里甚至1000公里的其他地震。这种现象被称为动态触发，它是少数几种已知的、可测量的自然应力可以被确定为地震直接原因的情况之一。动态触发似乎是大地震的常见和预期后果，但目前仍不清楚世界上有多少地震是由动态触发引起的。 动力触发是决定地震发生时间和地点的重要因素，还是仅仅是好奇心？这个项目的主要目标是解决这个问题，使用大型数据集，由于最近的进步，计算和仪器。这一提议的更广泛影响包括与日本京都大学的科学家合作，支持一名研究生，以及量化研究中预计地震后的危险增加。研究动态触发的能力受到精确捕获触发应力的能力和记录由此产生的地震的能力的限制。最近在这两个领域都取得了重大进展。利用密集网络的全波形可以改善触发应力的测量。 最近的进展，在目录生成的模板匹配导致目录增加了一个数量级，反过来，增加了检测率的变化。总之，这些数据可以提供动态触发重要性的定量评估。相同的数据也可以用于评估所提出的动态触发机制的预测的次要目标。 该项目将（1）使用波形和现代目录在广泛的频率和方向范围内测量触发，（2）测量地震率变化的时间依赖性，（3）测量作为累积能量的函数的速率变化，并评估地震波的非地震源，以及（4）在大地测量和水文测量的背景下解释触发的地震活动率。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的学术价值和更广泛的影响审查标准。

Every time an earthquake occurs, seismic waves emanate from it and shake the ground. Thirty years ago it was discovered that these waves can trigger other earthquakes 100’s or even 1000’s of kilometers away from the first. This phenomenon is known as dynamic triggering and it is one of the few situations where a known, measurable, natural stress can be identified as the immediate cause of an earthquake. Dynamic triggering appears to be a common and expected consequence of large earthquakes, but it remains unclear what fraction of the world’s earthquakes are caused by dynamic triggering. Is dynamic triggering an important factor in determining when and where earthquakes happen or is it a mere curiosity? The primary goal of this project is to address this question using the large datasets now available due to recent advances in computation and instrumentation. The broader impacts of this proposal include collaboration with scientists at Kyoto University in Japan, support for a graduate student and a quantification of the hazard increase expected after earthquakes in the study. The capacity to study dynamic triggering has been limited by both the ability to accurately capture the triggering stresses and the ability to record the resultant earthquakes. Significant progress has been made in both areas recently. Measuring the triggering stresses can be improved by using the full waveforms of dense networks. Recent progress in catalog generation by template matching has resulted in catalogs that have increased by an order of magnitude and, in turn, increased the detectability of rate changes. Together, these data can provide a quantitative assessment of the importance of dynamic triggering. The same data can also be used for a secondary goal of assessing the predictions of proposed mechanisms of dynamic triggering. This project will (1) measuring triggering using waveforms and a modern catalog over a wide range of frequency and orientations, (2) measuring the time-dependence of the earthquake rate change, (3) measuring rate changes as a function of cumulative energy and evaluating non-earthquake sources of seismic waves and (4) interpreting triggered seismicity rates within the context of geodetic and hydrological measurements.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.