Collaborative Research: Earthquake triggering by slow slip events beneath Kilauea's south flank

(a)技术说明本项目涉及对部署在夏威夷基拉韦厄火山南侧的一个由美国国家科学基金会资助的临时地震仪的数据进行分析，该地震仪是我们为预测2007年6月发生的“慢滑事件”而设计和部署的。临时地震阵列记录了高水平的背景地震活动以及两组侧面地震：一次是在2007年6月，由预期的SSE引发的，另一次是在2007年4月，可能是由所罗门群岛8.1级地震的动态波引起的基拉韦厄火山侧面拆离断层的孔隙压力变化引起的。我们的工作包括挑选和定位在临时阵列和美国地质调查局夏威夷火山观测站地震网络上记录的微地震，从首次运动极性获得震源机制，并进行双差断层扫描。我们将把我们的高精度研究结果与该地区地震活动和变形的其他观测结果结合起来。我们期望在一些重要问题上取得进展，如基拉韦厄南侧的构造格局和背景地震活动模式，触发地震群与大地测量观测到的SSE的关系，触发Hilina Pali正断层地震的可能存在，以及分离的摩擦行为。我们将利用密集的临时地震阵列收集的数据，研究发生在夏威夷基拉韦厄火山南侧的地震。该阵列于2007年在美国国家科学基金会的支持下部署，以预测最终于2007年6月发生的“慢滑事件”（SSE）。我们的重点将放在由SSE引发的地震的位置和断层几何形状上，以及可能由遥远的大地震的地震波传递引发的第二组地震。这个项目对于了解夏威夷的地震、滑坡和海啸灾害非常重要，那里的断层类型从常规地震到缓慢地震再到长期蠕变。特别是，理解SSE触发小地震的性质可能为触发大地震（如1975年破坏性的7.2级Kalapana地震）提供线索。该项目得到了地球物理和海洋地质与地球物理项目以及刺激竞争性研究实验项目（EPSCoR）的支持。

(a) Technical description This project involves the analysis of data from a temporary NSF-funded seismometer deployment on the south flank of Kilauea volcano, Hawaii, which we designed and deployed in anticipation of a "slow slip event" (SSE) that occurred in June 2007. The temporary seismic array recorded high levels of background seismicity as well as two swarms of flank earthquakes: one in June 2007, triggered by the expected SSE, and another in April 2007, possibly from a pore pressure change on the detachment fault beneath Kilauea's flank induced by the dynamic waves from the Mw 8.1 Solomon Islands earthquake. Our efforts involve picking and locating microearthquakes recorded on the temporary array and the USGS Hawaiian Volcano Observatory seismic network, obtaining focal mechanisms from first motion polarities, and performing double-difference tomography. We will integrate the results of our high precision study with other observations of seismicity and deformation for this region. We expect to make progress on a number of important questions regarding the tectonic framework and background seismicity patterns of Kilauea's south flank, the relation of the triggered seismic swarms to the geodetically observed SSE's, the possible existence of triggered Hilina Pali normal faulting earthquakes, and the frictional behavior of the detachment.(b) Nontechnical explanation We will study earthquakes occurring beneath the south flank of Kilauea volcano, Hawaii, taking advantage of data collected by a dense, temporary seismic array. The array was deployed in 2007 with NSF support in anticipation of a "slow slip event" (SSE) that ultimately occurred in June 2007. Our focus will be on the locations and fault geometries of earthquakes triggered by this SSE, and by a second set of earthquakes that may have been triggered by passing seismic waves from a large distant earthquake. This project is important for understanding earthquake, landslide, and tsunami hazards in Hawaii, where the style of faulting ranges from regular earthquakes to slow earthquakes to long-term creep. In particular, understanding the nature of the triggering of small earthquakes by the SSE may provide clues to the triggering of large flank earthquakes such as the damaging 1975 magnitude 7.2 Kalapana earthquake.This project was supported by the Geophysics and Marine Geology & Geophysics Programs and the Experimental Program to Stimulate Competitive Research (EPSCoR).