CAREER: Investigating the unrest and eruption potential of caldera forming volcanoes in the Aleutians

形成火山口的爆炸性火山喷发造成数十至数百立方公里的火山灰和熔岩，是地球上最具破坏性的自然灾害之一。北美的阿留申岛弧已经发生了20多次形成火山口的喷发，目前有几座活跃的火山口火山。虽然一些阿留申火山口喷发了20千米，但许多是在大爆炸事件中形成的，侵袭了50到100千米的物质。这些事件的影响是广泛的。例如，3400年前阿尼亚恰克火山的喷发与一场地区性海啸和广泛的火山灰在北极地区的扩散有关。如果今天发生这样的喷发，不仅会对当地社区构成重大危险，而且会对每天飞越阿拉斯加的5万名航空乘客构成重大危险。了解促进灾难性的火山口形成喷发的条件，对于评估喷发前兆和评估阿拉斯加和世界各地火山系统的危害至关重要。这项研究的目的是与阿拉斯加火山观测站的合作者密切合作，开发一种预测方法来监测阿留申群岛的活火山，并调查触发它们喷发的机制。这项职业补助金的更广泛影响包括调查改进从地球科学中代表性不足的群体招收和留住学生的努力。评估火山灾害需要多学科方法，将监测数据与动态模型联系起来。这项职业赠款将支持开发火山预报方法，以监测阿留申火山口系统的当前动乱，并调查以前的喷发，以确定触发机制。序列数据同化方法将被采用，以提供一个多数据流模式-数据融合预报框架。具体地说，地面形变和地震活动模式的地球物理观测将与热机械模型相结合，以跟踪阿留申群岛三个活动火山口系统的应力演化：Okmok、Westdahl和Veniminof。这些系统具有相似的规模和喷发产物，但动荡和喷发历史明显不同。研究人员将利用统计数据同化来利用阿留申群岛现有的广泛监测数据集进行一系列数值实验，以调查岩浆室大小、体积流量和超压作用之间的关系，以及这些参数如何与喷发规模和频率的预测相联系。将对前兆信号进行调查，以更好地了解催化火山喷发的机制。将分析模型和数据限制，以便为今后的调查和数据收集工作提供信息。由于三座目标火山过去都有形成火山口的记录，研究人员将调查未来形成火山口的可能性，以及影响火山演变的因素，使其从频繁的小喷发转变为大型灾难性喷发。为处理在阿留申活动火山系统收集的不同数据集而开发的数据综合框架将对监测世界各地的火山动乱产生广泛的社区影响和可转移性。除了调查引发火山喷发的机制外，这项工作还将为建立社区火山预报框架提供必要的第一步。通过更广泛的(扩大循证改革的实施和示范)计划，首席研究员将随着时间的推移跟踪学生队列，以制定对招募和保留地球科学领域的女性和少数群体具有长期影响的战略。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Caldera-forming explosive volcanic eruptions that emplace tens to hundreds of cubic kilometers of ash and lava are among the most devastating natural hazards on Earth. The Aleutian Island Arc of North America has played host to more than 20 caldera-forming eruptions and currently has several active caldera volcanoes. While some Aleutian calderas have erupted 20 km3, many formed in large explosive events that emplaced 50-100 km3 of material. Impacts from these events were wide reaching. For example, the eruption of Aniakchak 3,400 years ago was associated with a regional tsunami and extensive ash dispersal across the arctic region. If such an eruption were to occur today it would pose a significant hazard not only to local communities but also to 50,000 airline passengers that fly over Alaska each day. Understanding the conditions that promote the development of catastrophic caldera forming eruptions is critical for evaluating eruption precursors and assessing hazards at volcanic systems in Alaska and worldwide. Working closely with collaborators at the Alaska Volcano Observatory, the aim of this research is to develop a forecasting method to monitor active volcanoes in the Aleutians and investigate the mechanisms that trigger their eruption. The broader impacts of this CAREER grant include investigation of efforts to improve recruitment and retention of students from underrepresented groups in the Earth sciences.Evaluating volcanic hazards requires a multidisciplinary approach that links monitoring data with dynamic models. This CAREER grant will support the development of volcano forecasting methods to monitor current unrest at Aleutian caldera systems and investigate previous eruptions to determine triggering mechanisms. Sequential data assimilation methods will be adapted to provide a multi-data stream model-data fusion forecasting framework. Specifically, geophysical observations of ground deformation and seismicity patterns will be combined with thermomechanical models to track the stress evolution of three active caldera systems in the Aleutians: Okmok, Westdahl, and Veniaminof. These systems have comparable sizes and eruptive products, but markedly different unrest and eruption histories. The researchers will utilize statistical data assimilation to take advantage of the extensive monitoring data sets available in the Aleutians to conduct a series of numerical experiments to investigate the relationship between magma chamber size, volume flux, and overpressurization, and how these parameters link to predictions of eruption size and frequency. Precursory signals will be investigated to better understand what mechanisms catalyze volcanic eruption. Model and data limitations will be analyzed to inform future investigations and data collection efforts. As the three target volcanoes have past records of caldera-forming eruptions, the researchers will investigate the potential for future caldera forming eruptions and the factors that impact the evolution of a volcano causing it to transition from frequent small eruptions to large catastrophic eruptions. The development of a data synthesis framework for handling the disparate datasets collected at active volcanic systems in the Aleutians will have broad community impact and transferability to monitoring volcanic unrest worldwide. In additional to investigating the mechanics of triggering volcanic eruptions, this work will provide the necessary first steps towards a community volcano-forecasting framework. Through the WIDER (Widening Implementation and Demonstration of Evidence Based Reforms) program the principal investigator will track cohorts of students over time to develop strategies that have a long-term effect on both recruitment and retention of women and minorities in the Earth sciences.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.