Viscous flow of magmas from Unzen volcano, Japan - Implications for magma ascent and emplacement

日本云仙火山的岩浆粘性流 - 对岩浆上升和侵位的影响

• 批准号: 5447048
• 负责人: Dr. Kai-Uwe Hess
• 金额: --
• 依托单位: Sektion Mineralogie, Petrologie und Geochemie
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2005
• 资助国家: 德国
• 起止时间: 2004-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5447048?language=en
• 关键词: Viscous; flow; magmas; Unzen; volcano

The lack in understanding the flow behaviour of ascending highly viscous conduit magmas is a major drawback in forecasting explosive volcanic eruptions. Due to the very recent development of a unique high-load, high-temperature deformation apparatus it is now, for the first time, possible to determine the effective non-Newtonian viscosity of rhyolitic multi-phase magmas at strain rates actually occurring prior to and during volcanic eruptions. This opportunity comes when cores from a section of Unzen’s conduit were recently acquired. Taken together, the new technique and the new sample availability provide a unique opportunity to advance the rheological understanding of Unzen. The new data will enable the elaboration of complete volcanic eruption models at Unzen. Such models have important implications for the interpretation of (a) shallow volcanic earthquakes (e.g. low frequency events) and their potential use as indicators for near-future volcanic eruptions, (b) self-sealing mechanisms of the Unzen conduit, and (c) the poorly understood displacement mechanism of Unzen lava lobes, potentially indicative of non-Newtonian flow behaviour.

对上升的高粘性导管岩浆的流动行为缺乏了解是预测爆炸性火山爆发的一个主要缺点。由于最近开发的一个独特的高负荷，高温变形装置，它现在是第一次，可以确定流纹质多相岩浆的有效非牛顿粘度在应变率实际发生之前和期间的火山爆发。这个机会来自于最近获得的一段云仙管道的核心。总之，新技术和新样品的可用性提供了一个独特的机会，以推进对Unzen流变学的理解。新的数据将使详细说明完整的火山喷发模型在云仙。这些模型对以下方面的解释具有重要意义：（a）浅层火山地震（例如低频事件）及其作为近期火山爆发指标的潜在用途;（B）云仙管道的自我封闭机制;（c）云仙熔岩瓣的位移机制，这种机制可能表明非牛顿流动行为，但人们对这种机制知之甚少。