Structure, Stress, Earthquake Sources, and Dynamic Triggering in Katmai, Alaska

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。研究人员将利用密集的临时地震阵列收集的数据，研究阿拉斯加卡特迈地区的地震，地壳结构和应力。地震阵列于2008年部署，以三叉戟火山为中心，将运行到2010年年中。卡特迈是世纪最大的火山爆发的所在地，也是美国地震最活跃的火山地区之一。根据以前的研究，卡特迈山口地区很可能存在一个岩浆库。研究重点将是该地区的地下结构，正在发生的地震类型及其对岩浆储存和运动的可能影响，以及驱动地震和火山活动的力量。该项目对于了解卡特迈火山造成的危险非常重要。该项目涉及分析2008年7月在阿拉斯加卡特迈山口中心直径15公里区域部署的11个三分量宽带地震仪器临时阵列的数据，并辅之以阿拉斯加火山观测站网络台站的数据。临时阵列将运行到2010年春末或夏初。卡特迈是世纪最大的火山爆发的所在地，也是美国地震最活跃的火山地区之一。研究的主要目标是探索卡特迈地区的地下结构、地震活动性、震源机制、应力状态和地震触发。研究将侧重于速度和衰减层析成像，地震活动性，震源机制和剪切波分裂研究。层析成像工作，包括速度和衰减的P和S模型，将旨在确定卡特迈山口地区下方是否存在岩浆体。速度模型将用于获得准确的地震位置和断层面的解决方案。 重新定位的地震活动性和震源机制将用于检查该地区下方的孕震结构的特征，震源机制和剪切波分裂将使人们深入了解应力状态。他们还将利用阵列数据探索地震的动态触发过程。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The investigators will study earthquakes, crustal structure, and stress in the Katmai area of Alaska, taking advantage of data collected by a dense, temporary seismic array. The seismic array was deployed in 2008, centered on Trident volcano, and will be operated through mid-2010. Katmai was the locus of the largest volcanic eruption in the 20th century and is one of the most seismically active volcanic regions in the United States. Based on previous research, it is likely that a magma reservoir resides under the Katmai Pass area. The research focus will be on the subsurface structure beneath this area, the types of earthquakes that are occurring and their possible implications for storage and movement of magma, and the forces that are driving the seismic and volcanic activity. This project is important for understanding the volcanic hazard posed by Katmai. This project involves the analysis of data from a temporary array of 11 three-component, broadband seismic instruments deployed in July 2008 in a 15 km diameter area centered on Katmai Pass, Alaska, supplemented by data from the surrounding Alaska Volcano Observatory (AVO) network stations. The temporary array will operate until late spring or early summer 2010. Katmai was the locus of the largest volcanic eruption in the 20th century and is one of the most seismically active volcanic regions in the United States. The main goals of the study are to explore the subsurface structure, seismicity, source mechanisms, state of stress, and earthquake triggering in the Katmai area. The research will focus on velocity and attenuation tomography, seismicity, source mechanisms, and shear wave splitting studies. The tomography work, including both P and S models for velocity and attenuation, will be aimed at determining if a magma body is present beneath the Katmai Pass area. The velocity model will be used to obtain accurate earthquake locations and fault plane solutions. The relocated seismicity and source mechanisms will be used to examine the character of the seismogenic structures beneath the area, and the source mechanisms and shear wave splitting will yield insight into the state of stress. They will also explore the process of dynamic triggering of earthquakes using data from their array.