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)提供资金的。在任何一天，全世界大约有15-30座火山正在喷发或显示出强烈的动荡迹象(例如，地震活动率、地面变形或气体排放异常高)。火山活动，包括高海拔的火山灰喷发或大量气体排放，对美国和世界各地的人民和财产构成重大危险。虽然许多火山有明显不同的动荡和平静阶段，但众所周知，越来越多的“平静活动”火山表现出高水平的地球物理动荡背景，这表明在非喷发期持续的浅层岩浆活动。对驱动静止活动和高本底率火山地震活动(HBS)的过程的了解，对于检测这些系统中预示火山行为即将发生变化的变化至关重要。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。这项研究包括：1)对地震数据的长期目录进行回顾分析，以确定喷发前地震活动变化的准确性质；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，以研究Telica岩浆室和大楼内发生的背景长期地震活动、形变和其他物理过程(如重力变化)的震源机制；3)整合Telica收集的地震和大地测量数据，以测试和完善静止火山活动的模型。拟议的研究具有变革性，因为它将大大提高对具有代表性的HBS火山静止活动和相关地球物理动荡的机制的了解，这将延伸到世界各地类似的鲜为人知的火山。这项研究还代表了两名从事火山地震学和火山大地测量工作的早期研究人员之间的新合作，并扩大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。这项提议的一个关键影响是为博士生提供部署、维护和分析宽带地震和大地测量网络数据的培训，以及国际研究经验。最后，预计拟议研究的结果将适用于背景活动类似升高的其他火山，包括阿拉斯加的几座火山。由此产生的在背景比率高的情况下确定地震活动性质重大变化的背景将极大地提高世界各地监测机构在这些情况下自信地预测未来爆发活动的可能性的能力。

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.