Collaborative Research: Constraining Volcanic Jet Dynamics with Infrasound Using Numerical and Empirical Models

合作研究：使用数值和经验模型用次声约束火山喷流动力学

• 批准号: 1546139
• 负责人: Robin Matoza
• 金额: $ 6.35万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-11 至 2016-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1546139&HistoricalAwards=false
• 关键词: Collaborative; Research; Constraining; Volcanic; Jet

Explosive volcanic jets produce eruption columns that often form buoyant ash clouds and may fully or partially collapse to form pyroclastic density currents, dangerous fast-moving lateral flows of hot ash and gas. These natural hazards directly threaten surrounding communities and global air traffic. Our ability to mitigate these risks is restricted by our inability to safely measure volcanic jets or monitor them co-eruptively. Infrasound (acoustic signals with frequencies below that of human hearing) provides a means to detect the atmospheric oscillations from volcanoes at distances of meters to thousands of kilometers from the source. This project aims to use these signals to constrain the physics of volcanic jets and measurethem in real-time. These measurements may be used as input parameters for aviation safety ash-cloud prediction models and toward assessing the hazard presented to local communities by a given eruption. Additionally, this work will provide constraints on eruptive parameters and physics for numerical and experimental studies.Recent infrasound recordings of volcanic jets have frequency spectra similar to the acoustic signal produced by man-made jets (jet noise). For the past 60 years, aeroacoustics has studied the relationship between the flow properties of man-made jets and the acoustic signal produced. Our long-term objective is to reverse this concept by determining the flow properties of volcanic jets based on the infrasound signal produced by the eruption. This work represents a first step toward this long-term goal. We begin by building a catalog of infrasonic jet noise observations to determine characteristic volcanic jet noise features and determine any correlations between these features and known eruptive parameters. This process includes searching existing infrasound databases using new signal processing tools and empirical and theoretical propagation modeling. We will then use analytical and numerical models of volcanic jets to adapt established empirical models of man-made jet noise to volcanic systems.This project is supported by the Geophysics and Petrology & Geochemistry Programs and the Experimental Program to Stimulate Competitive Research (EPSCoR).

爆炸性的火山喷气式喷发柱通常形成浮动的灰云，并且可能完全或部分崩溃以形成火山碎屑密度电流，从而危险的快速移动热灰和气体的侧向流动。 这些自然危害直接威胁着社区和全球空中交通。 我们减轻这些风险的能力受到我们无法安全测量火山喷气机或共同监测的能力。 插射（频率低于人类听力的声学信号）提供了一种方法，可检测从米的距离到距离来源数千公里的火山的大气振荡。该项目旨在使用这些信号来实时限制火山喷射和测量的物理。 这些测量值可以用作航空安全灰云预测模型的输入参数，并通过给定的喷发评估向当地社区提出的危害。此外，这项工作将为数值和实验研究提供关于喷发参数和物理的限制。火山喷气机的直发记录的频谱与人造喷气机产生的声学信号相似（JET噪声）。在过去的60年中，航空声学研究了人造飞机的流量与产生的声学信号之间的关系。 我们的长期目标是通过基于喷发产生的非传动信号来确定火山喷气机的流动特性来扭转这一概念。 这项工作是朝着这个长期目标迈出的第一步。 我们首先要构建互媒体喷射噪声观测值的目录，以确定特征性的火山喷射噪声特征，并确定这些特征与已知喷发参数之间的任何相关性。 此过程包括使用新的信号处理工具以及经验和理论传播建模搜索现有的插图数据库。 然后，我们将使用火山喷气机的分析和数值模型来适应人造喷气噪声的经验模型对火山系统。该项目得到了地球物理和岩石学与地球化学计划的支持，以及刺激竞争性研究的实验计划（EPSCOR）。