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

形成火山口的火山爆发会释放出数十到数百立方公里的火山灰和熔岩，这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经历了20多次形成火山口的喷发，目前有几个活跃的火山口火山。虽然一些阿留申火山口喷发了20平方公里，但许多火山口是在大型爆炸事件中形成的，这些爆炸事件中放置了50-100平方公里的物质。这些事件的影响是广泛的。例如，3400年前的阿尼亚克恰克火山爆发与一场区域性海啸和大面积的火山灰散布在北极地区有关。如果今天发生这样的喷发，不仅会对当地社区造成严重危害，还会对每天飞越阿拉斯加上空的5万名航空乘客造成严重危害。了解促进灾难性火山口形成喷发的条件对于评估阿拉斯加和全球火山系统的喷发前兆和评估危害至关重要。与阿拉斯加火山观测站的合作者密切合作，这项研究的目的是开发一种预测方法来监测阿留申群岛的活火山，并调查引发火山喷发的机制。这项职业补助金的更广泛影响包括调查改善地球科学中代表性不足群体的学生招聘和保留的努力。评估火山灾害需要一种多学科方法，将监测数据与动态模型联系起来。这项CAREER资助将支持火山预测方法的发展，以监测阿留申火山口系统当前的动荡，并调查以前的火山爆发，以确定触发机制。将采用顺序数据同化方法提供多数据流模型-数据融合预测框架。具体来说，地面变形和地震活动模式的地球物理观测将与热力学模型相结合，以跟踪阿留申群岛三个活跃火山口系统的应力演化：Okmok， Westdahl和Veniaminof。这些系统的规模和喷发产物相似，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，利用阿留申群岛广泛的监测数据集，进行一系列数值实验，研究岩浆房大小、体积通量和超压之间的关系，以及这些参数如何与喷发规模和频率的预测联系起来。将对前兆信号进行研究，以更好地了解催化火山喷发的机制。将分析模型和数据的局限性，以便为今后的调查和数据收集工作提供信息。由于这三座目标火山过去都有形成破火山口的喷发记录，研究人员将调查未来形成破火山口喷发的可能性，以及影响火山演变的因素，使其从频繁的小喷发转变为大规模的灾难性喷发。为处理在阿留申群岛活火山系统收集的不同数据集而开发的数据综合框架将对社区产生广泛影响，并可转移到监测全球火山动荡。除了调查引发火山爆发的机制之外，这项工作将为建立社区火山预测框架提供必要的第一步。通过“基于证据的改革的扩大实施和示范”项目，首席研究员将长期跟踪学生群体，制定对招收和保留地球科学领域的妇女和少数民族具有长期影响的战略。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.