CAREER: Characterizing the Physical/Chemical Evidence of Volcanic Lightning

职业：描述火山闪电的物理/化学证据

• 批准号: 1553878
• 负责人: Kimberly Genareau
• 金额: $ 43.39万
• 依托单位: University of Alabama Tuscaloosa
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-03-01 至 2023-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1553878&HistoricalAwards=false
• 关键词: CAREER; Characterizing; Physical; Chemical; Evidence

Volcanic eruptions and lightning strikes are two of the most impressive and destructive natural phenomena, but much is still unknown about the fundamental processes that allow these events to occur. An emerging new line of research is seeking to determine the complex relationship between explosive volcanism and lightning, specifically: The effect of lightning discharge on the textural and chemical properties of volcanic ash and the resulting signature of volcanic lightning occurrence in the geologic record. In addition to the formation of fulgurites as a result of cloud-to-ground lightning strikes, lightning-induced volcanic spherules (LIVS) form in the atmosphere from the physical transformation of volcanic ash particles into spheres of glass due to the high heat generated during lightning discharge. This project will characterize the physiochemical evidence of volcanic lightning by: 1) identifying LIVS in natural ash fall deposits and analyzing their textural/chemical properties using established methods; 2) performing a series of triggered lightning experiments on manufactured ash samples of known composition and grain size to characterize the physical/chemical effects of volcanic lightning on the samples using various analytical methods; 3) establishing a research team of graduate, undergraduate, and high school students to perform the experiments and analyze the samples; and 4) developing grade school curricula for teaching natural hazards in local schools in order to engage students in the Earth sciences. Fundamental questions addressed by this project, and the integral educational component that involves learners of all ages, may result in potentially transformative concepts the geosciences, atmospheric sciences, and hazard assessment. Textural and geochemical data acquired on the samples will provide evidence for volcanic lightning in the geologic record, allowing researchers to identify these events during eruptions that preceded or eluded human documentation. Results will also reveal the role that lightning plays in altering the chemical characteristics of the local environment. Additionally, the triggered lightning experiments, conducted on manufactured ash samples of known composition, will allow video documentation of fulgurite formation. Through scientific and community presentations, this project will build further interest in volcanology, atmospheric dynamics, and the complex interplay between these natural phenomena, not only in the scientific community, but also in schools and amongst the general public.The primary goal of this project is to characterize the physical/chemical evidence of volcanic lightning occurrence in tephra deposits, which will aid in understanding the frequency of volcanic lightning in the geologic record, contributing to advancing scientific knowledge of volcano-atmosphere interactions, which is an emerging new line of scientific research. Ash fall deposits from numerous volcanic eruptions in Alaska will be analyzed, as volcanic lightning was documented during these explosive events and samples were provided by the Alaska Volcano Observatory. Triggered lightning experiments will be conducted at the International Center for Lightning Research and Testing (ICLRT) on manufactured ash samples (pseudo-ash samples) of known composition and grain size. The established analytical methods that will be utilized for this project include: 1) Scanning electron microscope (SEM), transmission electron microscope (TEM), and electron spin resonance (ESR) examination of lightning-induced volcanic spherules (LIVS) present in natural ash samples to determine their textural and chemical characteristics; 2) ESR, Mossbauer, and titration analyses of both natural, unmodified ash and pre-experimental pseudo-ash; and 3) SEM, TEM, ESR, Mossbauer, and titration analyses of LIVS and fulgurites produced in the triggered lightning experiments. A research team of graduate, undergraduate, and high school students will perform the experiments and analyze the samples. The various analyses, when conducted on the pseudo-ash samples prior to and following the triggered lightning experiments, will allow a direct means to determine the effect of lightning discharge on the morphological transformation, general chemistry, and oxidation/Fe valence state of exposed materials. The natural ash samples will allow a chemical comparison between normal (i.e., unmodified) ash and any LIVS present in the deposits. Following publication of results, the videos of triggered lightning experiments will be displayed on the University of Alabama?s Tephra Lab website, on YouTube, and showcased in the Alabama Museum of Natural History, along with samples of both natural fulgurites and fulgurites created in the triggered lightning experiments. Fundamental questions addressed by this project, and the integral educational component that involves learners of all ages, may result in potentially transformative concepts the geosciences, atmospheric sciences, and hazard assessment. Textural and geochemical data acquired on the samples will provide evidence for volcanic lightning in the geologic record, allowing researchers to identify these events during eruptions that preceded or eluded human documentation. Results will also reveal the role that lightning plays in altering the chemical characteristics of the local environment. Additionally, the triggered lightning experiments, conducted on manufactured ash samples of known composition, will allow video documentation of fulgurite formation. Through scientific and community presentations, this project will build further interest in volcanology, atmospheric dynamics, and the complex interplay between these natural phenomena, not only in the scientific community, but also in schools and amongst the general public.

火山喷发和雷击是最令人印象深刻，最具破坏性的自然现象之一，但是对于允许这些事件发生的基本过程，仍然未知。一项新的研究线正在旨在确定爆炸性火山和闪电之间的复杂关系，特别是：雷电排放对火山灰的质地和化学特性的影响以及地质记录中火山闪电的产生标志。除了由于云到地面的雷击而形成富尔古石之外，由于在闪电放电过程中产生的高热量而导致火山灰颗粒向玻璃球的物理转化，在大气中形成了闪电诱导的火山囊泡（LIVS）。 该项目将通过以下方式表征火山闪电的生理学证据：1）识别天然灰秋季沉积物中的LIV并使用既定方法分析其质地/化学性质； 2）对已知成分和晶粒大小的制成的灰烬样品进行一系列触发闪电实验，以使用各种分析方法来表征火山闪电对样品的物理/化学作用； 3）建立一个研究生，本科生和高中生的研究团队，以进行实验并分析样本； 4）开发小学课程，以教授当地学校的自然危害，以吸引学生参与地球科学。该项目解决的基本问题，以及涉及各个年龄段学习者的整体教育部分，可能会导致地球科学，大气科学和危害评估的潜在变革概念。在样品上获取的纹理和地球化学数据将为地质记录中的火山闪电提供证据，使研究人员能够在人类文档之前或避免人类文档之前识别这些事件。 结果还将揭示闪电在改变当地环境的化学特征方面的作用。 此外，在已知成分的制成的灰分样品上进行的触发闪电实验将允许视频文档孔形成。 Through scientific and community presentations, this project will build further interest in volcanology, atmospheric dynamics, and the complex interplay between these natural phenomena, not only in the scientific community, but also in schools and amongst the general public.The primary goal of this project is to characterize the physical/chemical evidence of volcanic lightning occurrence in tephra deposits, which will aid in understanding the frequency of volcanic lightning in the geologic record, contributing to advancing scientific knowledge of火山 - 大气相互作用，这是新兴的科学研究线。将分析来自阿拉斯加大量火山喷发的灰跌落沉积物，因为在这些爆炸性事件中记录了火山闪电，阿拉斯加火山天文台提供了样品。 触发闪电实验将在国际避雷器研究与测试中心（ICLRT）对已知成分和晶粒尺寸的制造灰分样品（伪灰烬样品）进行。将用于该项目的已建立的分析方法包括：1）扫描电子显微镜（SEM），透射电子显微镜（TEM）和电子自旋共振（ESR）检查闪电诱导的火山球（LIVS）（LIVS），以自然灰分样品中存在，以确定其文本和化学特征； 2）ESR，Mossbauer和天然，未修饰的灰分和实验前伪ash的滴定分析； 3）在触发的闪电实验中产生的LIV和Fulgurites的SEM，TEM，ESR，Mossbauer和滴定分析。 研究生，本科和高中生的研究团队将进行实验并分析样本。在触发闪电实验之前和之后，在对伪ASH样品上进行各种分析将允许直接手段确定闪电放电对暴露材料的形态转化，通用化学和氧化/FE价状态的影响。 天然灰分样品将允许在沉积物中存在的正常（即未修饰）灰分和任何LIV之间进行化学比较。结果发布后，触发的闪电实验的视频将在YouTube上的阿拉巴马大学Tephra实验室网站上显示，并在阿拉巴马州自然历史博物馆中展示，以及在触发的闪电实验中创建的天然富尔古利特人和富尔古特的样本。 该项目解决的基本问题，以及涉及各个年龄段学习者的整体教育部分，可能会导致地球科学，大气科学和危害评估的潜在变革概念。在样品上获取的纹理和地球化学数据将为地质记录中的火山闪电提供证据，使研究人员能够在人类文档之前或避免人类文档之前识别这些事件。 结果还将揭示闪电在改变当地环境的化学特征方面的作用。 此外，在已知成分的制成的灰分样品上进行的触发闪电实验将允许视频文档孔形成。 通过科学和社区的演讲，该项目将对火山学，大气动态以及这些自然现象之间复杂的相互作用的兴趣进一步兴趣，不仅在科学界，而且在学校和公众中。