Topographic Controls on the Generation of Elutriated Ash Clouds

9316656 Bursik待验证的主要假设是，淋洗灰云（“coignimbrite”灰云是其中的一个子集）的产生方式强烈地依赖于火山碎屑流和涌流与火山周围地形的相互作用。因此，我们的目标是了解火山灰云的产生机制以及流动和浪涌机制，特别是当它们受到地形的影响时。拟议的研究将包括详细的沉积学测量、实验室实验和理论建模。实地工作将包括一种新的取样策略，适用于1982年墨西哥埃尔奇洪火山的沉积物，这些沉积物位于沿平行流动方向的横断面的紧密间隔的地点。采样策略将产生可用于测试流动行为理论模型的定量数据。实验室实验将在分析实地数据和发展理论模型的同时进行，以便对实地数据的解释和验证理论提供限制。拟议的活动将增加对火山灰云从火山碎屑流和涌流中被洗脱的机制的理解。

9316656 Bursik The primary hypothesis to be tested is that the manner in which elutriated ash clouds (of which 'coignimbrite' ash clouds are a subset) are generated is strongly dependent upon the interaction of pyroclastic flows and surges with the topography surrounding a volcano. Our objectives are therefore to understand ash cloud generating mechanisms and flow and surge mechanisms especially as they are affected by topography. The proposed research will consist of detailed sedimentological measurements, laboratory experiments and theoretical modeling. Field work will consist of a novel sampling strategy applied to the 1982 deposits of El Chichon volcano, Mexico, at closely spaced sites lying along traverse that traverse that parrallel flow directions. The sampling strategy will yield quantitative data that can be used to test theoretical models of flow behavior. Laboratory experiments will be conducted in conjunction with the analysis of the field data and the development of theoretical models to provide constraints on interpretations of field data and validation theory. The proposed activity will yield increased understanding of the mechanisms through which ash clouds are elutriated from pyroclastic flows and surges.