Multi-Phased Flow Modeling of Vulcanian Explosions with Fountain Collapse on Montserrat

蒙特塞拉特火山喷泉塌陷的 Vulcanian 爆炸的多相流模拟

• 批准号: 0073761
• 负责人: Barry Voight
• 金额: $ 15.02万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-15 至 2004-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0073761&HistoricalAwards=false
• 关键词: Multi; Phased; Flow; Modeling; Vulcanian

VoightEAR-0073761Numerous short-duration explosions occurred during August, September and October 1997, at the Soufriere Hills Volcano, Montserrat, West Indies. These eruptions were accompanied by gravity collapse of heavy parts of the eruption column, that produced pumice and ash flows (pyroclastic flows) and "ash hurricanes" that moved sideways, into adjacent farmlands and formerly populated areas. Many of these eruptions were predicted, and we and other staff of Montserrat Volcano Observatory closely documented the eruptions by continuous seismic monitoring, measured surveys of the eruption clouds,photography, and video. Such data are rare, and in this project, we aim to quantify these eruptions, including the speed and trajectory of the explosion clouds, and then to compare these field-based data to sophisticated models of the eruptions. In our modeling, we will attempt to identify the magma and gas ratios in the eruption conduit before the explosion, and the pressure distribution. Then we will use this information as the starting condition for a "multi-phase" explosion model, in which separated solid and gas phases are allowed to expand dynamically upon release from the conduit tube. We can track the speeds and trajectories of the particles emitted from the conduit, and the particle densities of theerupting particle-and-gas cloud. We hope from this study to establish the main conditions in the conduit that control whether the clouds will continue to rise vertically, or will collapse to form dangerous pyroclastic flows. Pyroclastic flows are the major cause of loss of life in explosive eruptions worldwide, and the improved understanding obtained from this project should help to reduce hazards at a number of locations in this country and abroad.

Voightear-0073761季节短期爆炸发生在1997年8月，9月和10月，在西印度群岛蒙特塞拉特的Soufriere Hills Volcano。这些喷发伴随着喷发柱重量的重力崩溃，产生了浮肿和灰烬流（火山碎屑流）和“烟灰飓风”，这些烟灰是侧向移动到相邻的农田和以前人口稠密的地区。 预测了许多这些喷发，我们和蒙特塞拉特火山天文台的其他工作人员通过连续的地震监测，测量的喷发云，摄影和视频的测量调查来仔细记录喷发。这样的数据很少，在这个项目中，我们旨在量化这些喷发，包括爆炸云的速度和轨迹，然后将这些基于现场的数据与喷发的复杂模型进行比较。在我们的建模中，我们将尝试在爆炸前识别喷发导管中的岩浆和气体比和压力分布。然后，我们将使用此信息作为“多相”爆炸模型的起始条件，在该模型中，从导管管释放时，允许分离的固体和气相动态扩展。我们可以跟踪从导管发出的颗粒的速度和轨迹，以及粒子和气体云的粒子密度。我们希望从这项研究中确定管道中的主要条件，以控制云是否会继续垂直上升，或者会崩溃以形成危险的火山碎屑流。火山碎屑流是全球爆炸性爆发中生命损失的主要原因，从该项目获得的改善理解力应有助于减少该国和国外许多地方的危害。