Seismological Determination of Mass Ejection Rates of Explosive Eruptions

该项目的主要目标是通过将流体力学模型与地震学数据相结合，开发直接测量火山喷发中喷出物质随时间变化的方法。第二个目标是利用测量的物质喷射率来研究火山爆发的起始过程。研究的火山喷发包括：(1)1964年堪察加半岛的Shiveluch火山喷发；2)堪察加半岛Karymsky火山喷发，1997年夏季，有高质量的数字数据；3)圣海伦斯火山的小喷发持续了整个1980年；4)日本浅间山的数次喷发；5) 1991年菲律宾皮纳图博火山喷发。从这项研究中获得的信息将对火山爆发的特征提供约束，也将对火山危害的量化具有重要意义。例如，测量的物质喷射率将为火山喷发的动力学模型提供直接约束。在圣海伦火山，与后来的事件相比，这次爆炸的质量通量异常大。这一差异可能阐明了爆炸的不同特征，并有助于解释其不成比例的破坏性影响。

9903085 Kanamori The main objective of this project is to develop methods to directly measure the ejected mass in volcanic eruptions as a function of time by combining a fluid mechanical model with seismological data. A secondary goal is to use the measured mass ejection rate to study the initiation process of volcanic eruptions. The eruptions to be studied include 1) the 1964 Shiveluch eruption in Kamchatka; 2) eruptions at Karymsky, Kamchatka, during the summer of 1997, for which high quality digital data are available; 3) small eruptions of Mount St. Helens which continuied throughout 1980; 4) several erutpions of mount Asama, Japan; and 5) the 1991 eruption of Mount Pinatubo in the Philippines. The information obtained from this study will provide constraints on the characteristics of volcanic eruptions and will also be important for quantifying volcanic hazards. For example, the measured mass ejection rate will provide a direct constraint on dynamical models of an eruption. At Mount St. Helens, the blast had an exceptionally large mass flux compared to later events. This difference may clarify the distinguishing features of blasts and help account for their disproportionally devastating effects.