Collaborative Research: The Spectral and Thermal Response of Active Basaltic Surfaces: Constraining Lava Cooling, Petrology and Flow Propagation Models

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项目编号	1524013
	Collaborative Research: The Spectral and Thermal Response of Active Basaltic Surfaces: Constraining Lava Cooling, Petrology and Flow Propagation Models
	Rachel Lee
主持机构	SUNY College at Oswego
项目开始年	2015
	2015-08-01
项目结束日期	2017-07-31
资助机构	US-NSF
项目类别	Standard Grant
项目经费	30000(USD)
国家	美国
语种	英语
英文摘要	Over half of the world?s volcanoes produce basaltic lava, making it the most common form of volcanic activity on Earth. These volcanoes occur at every tectonic setting and on every continent with much larger outpourings of basaltic lava in the past linked to mass extinction events. Recently, new eruptions (or new phases of ongoing eruptions) have occurred at Tolbachik in Russia (2012-2013); Bardarbunga in Iceland (2014); Etna in Italy (2014); and Kilauea in Hawaii (2014) emphasizing the ongoing hazard potential of basaltic eruptions and the lava flows they produce. For example, a recent lava flow from the Pu?u ?Ō?ō vent in Hawaii threatened both property and to potentially isolate many of the residents in the town of Pahoa had it continued to advance. Therefore, monitoring lava flow direction and velocity becomes critical in these situations. Several analytical models have been introduced in recent years that are designed to estimate lava flow advance using temperature measurements in order to ultimately predict where the flow will stop once it has cooled sufficiently. The temperature of the advancing flow is commonly measured with infrared (IR) instruments from the ground, air, and from orbit. However, there are many factors that can affect the accuracy of these measurements. If assumptions of these factors are incorrect, then errors in the measured temperature could adversely impact the predicted hazard potential. One of these assumptions is the emissivity of the surface material, which is determined by the atomic structure of the surface and ultimately controls how efficiently it radiates heat. Prior emissivity measurements have been made on lava samples once they have cooled to a solid. However, emissivity is not constant and should in fact vary in molten lava because the atomic structure has changed to some degree. There are no quantitative emissivity measurements of molten basaltic lava that exist and therefore this research is designed to make these complex measurements using rigorous laboratory and field data collection followed by testing using an existing flow model. The study will also produce a new automated field-based IR instrument that could be of use to any government agency charged with eruption monitoring. The research will build on prior NSF-funding and continue successful international collaborations between the research group at the University of Pittsburgh and the Australian National University (Australia), the Université Blaise Pascal (France) and the Hawaii Volcano Observatory. The project also provides funding for an early career researcher at SUNY Oswego as well as several undergraduate and graduate students. This research represents a step-change in both remote sensing and flow modeling because it supplies, for the first time, the most accurate IR temperature data on eruption products that are needed to forecast hazards and predict lava flow dynamics. Understanding the cooling, formation and dynamics of active basaltic surfaces will not only help to resolve compositional, textural, and silicate structural changes occurring in the flow, but also becomes critical for any measurement or model reliant upon accurate IR temperatures. The IR wavelengths are sensitive to radiant temperature as well as to the surface emissivity due to the presence of strong IR spectral bands, produced by the Si-O and Al-O bonds in the minerals. Therefore, in order to measure the accurate temperature of active flows it is first necessary to understand the spectral effects caused by the glassy cooling crusts and the molten surfaces. That is the overarching goal of this research, which is divided into two primary tasks: (1) a laboratory-focused study with the goal of measuring the IR emissivity of basaltic glasses and melts using a unique micro-furnace that operates in conjunction with the PI?s laboratory spectrometer; and (2) a field-based study with the goal of advancing existing IR instrumentation capable of collecting similar data. The laboratory measurements acquired under task one will be made on high temperature basaltic melts with an accuracy of greater than 2%. These results will clarify a long-standing debate of whether thermal IR emissivity of molten surfaces is lower than that of the corresponding cooled surfaces (and more fundamentally, if so ? why?). Furthermore, it will provide data to resolve atomic bond-scale processes ongoing during cooling and therefore will also allow for the reconstruction of the cooling history of past lava flows. These results will serve as calibration for the ground-based data collected during the second task. Measurements will be made of active basalt flows using a new multi-spectral IR instrument developed for this project. This will be the first time that an IR camera will be used to acquire spectral rather than temperature data, with future development leading to construction of a ruggedized instrument capable of deployment on remote volcanoes for monitoring fundamental physical properties of lava flows in near real time. Finally, the results from both the laboratory and field measurements will serve as input into the FLOWGO thermo-rheologic model in order to determine their final effects on the model estimated flow length, viscosity and velocity. All of these results will be applicable to satellite-based measurements of temperature and thus has the potential to open entirely new areas of petrology, flow modeling and volcanological remote sensing research.
来源学科分类	Geosciences - Earth Sciences
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/68311
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Rachel Lee.Collaborative Research: The Spectral and Thermal Response of Active Basaltic Surfaces: Constraining Lava Cooling, Petrology and Flow Propagation Models.2015.