Collaborative Research: Toward an Understanding of Magmatic and Seismogenic Processes Beneath Quiescently Active Volcanoes

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。在任何一天，全世界大约有15-30座火山要么在喷发，要么表现出强烈的动荡迹象（例如，异常高的地震活动率、地面变形或气体排放）。火山活动，包括高海拔火山灰喷发或大量气体的排放，对美国和世界各地的人民和财产构成重大威胁。虽然许多火山有明显不同的不动和静止阶段，但已知越来越多的“静止活跃”火山表现出高水平的地球物理不动背景，这表明在非喷发时期持续的浅层岩浆活动。了解驱动静态活动和高背景率火山地震活动（HBS）的过程对于探测这些系统的变化至关重要，这些变化预示着火山行为即将发生变化。拟议的项目是对尼加拉瓜Telica火山的背景岩浆和地震活动进行深入研究。该研究包括：1)对地震数据的长期目录进行回顾性分析，以确定爆发前地震活动变化的精确性质；2)在Telica上共同部署宽带地震和高速率连续全球定位系统网络，为期三年，以研究背景长周期地震活动、变形和其他物理过程的源机制(例如：泰利卡岩浆房和岩浆大厦内发生的重力变化；泰利卡收集的地震和大地测量数据的整合，以测试和完善静止火山作用的模型。这项提议的研究具有变动性，因为它将大大提高人们对哈佛商学院一座代表性火山的静止活动和相关地球物理动荡机制的理解，并将扩展到世界各地类似的、人们知之甚少的火山。这项研究也代表了两位从事火山地震学和火山大地测量学工作的早期研究人员之间的新合作，并扩展了他们的机构与尼加拉瓜火山和地震监测机构INETER之间的现有合作关系。该提案的一个关键影响是为博士生提供宽带地震和大地测量网络数据的部署、维护和分析方面的培训，以及国际研究经验。最后，预计拟议的研究结果将适用于其他显示出类似背景活动升高的火山，包括阿拉斯加的几座火山。在存在高背景率的情况下，确定地震活动特征的重大变化的结果将大大提高世界各地监测机构的能力，使其能够自信地预测在这些情况下未来爆发活动的可能性。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). On any given day, approximately 15-30 volcanoes worldwide are either in eruption or show strong signs of unrest (e.g., anomalously high rates of seismic activity, ground deformation, or gas emissions). Volcanic activity, including high-altitude eruptions of ash or emission of large volumes of gas, poses a significant hazard to people and property in the United States and worldwide. Although many volcanoes have clearly distinct phases of unrest and quiescence, a growing number of 'quiescently active' volcanoes are known to exhibit high background levels of geophysical unrest suggestive of persistent shallow magmatic activity during non-eruptive periods. An understanding of the processes that drive quiescent activity and high-background-rate volcanic seismicity (HBS) is critical for the detection of changes in these systems that signal impending changes in the volcano's behavior. The proposed project is for an in-depth study of background magmatic and seismic activity at Telica Volcano, Nicaragua. The study consists of 1) a retrospective analysis of a long-term catalog of seismic data to determine the precise nature of changes in seismicity preceding eruptive episodes, 2) a three-year co-deployment of broadband seismic and high-rate continuous Global Positioning System networks on Telica to study the source mechanisms of background long period seismicity, deformation, and other physical processes (e.g., gravity changes) occurring within Telica's magma chamber and edifice and 3) integration of seismic and geodetic data collected from Telica to test and refine models of quiescent volcanism. The proposed study is transformative as it will result in a greatly improved understanding of the mechanism of quiescent activity and associated geophysical unrest at a representative HBS volcano, which will extend to similar poorly-understood volcanoes worldwide. This study also represents a new collaboration between two early-career researchers working in volcano seismology and volcano geodesy, and extends existing collaborative relationships between their institutions and INETER, the Nicaraguan volcano and earthquake monitoring agency. A key impact of this proposal is the provision for Ph.D. student training in the deployment, maintenance, and analysis of data from broadband seismic and geodetic networks, along with international research experience. Finally, it is anticipated that the results of the proposed study will be applicable to other volcanoes showing similar elevated background activity, including several in Alaska. The resulting context for identification of significant changes in the character of seismicity in the presence of a high background rate will greatly improve the ability of monitoring agencies worldwide to confidently forecast the likelihood of future eruptive activity in these situations.