Thermal and Rheological Controls on the Emplacement of Basaltic Lava Flows

9902851 Cashman玄武岩熔岩流，虽然在各种条件下侵位，但可根据流动表面形态和流动前进的机制分为三种类型之一- pahoehoe、`a`a或块状。定性而言，不同流动类型的形成可以用熔岩壳强度和流动内部流变学的差异来解释。然而，流动类型之间的过渡的限制条件必须定量地了解准确建模的力学流动，并预测的速度和最终程度的熔岩流在喷出式喷发的进步。 我们认为，这种理解的关键是量化参数之间的反馈控制熔岩地壳的稳定性和随之而来的冷却（和结晶）的熔岩流内部。 为此，我们将进行（a）夏威夷（莫纳罗亚山和基拉韦厄）和意大利（莫纳罗亚山和基拉韦厄山）的熔岩流实地研究。埃特纳），以记录熔岩冷却和结晶的速度，（B）实验室和理论研究，以确定晶体对熔岩流变学的影响，（c）非层流系统的模拟实验，以确定保存稳定结壳的极限流动条件。我们预计，结果将有广泛的应用，建模和预测的熔岩流行为，除了有助于悬浮液流变学的研究和搅拌（中断）流的表面固化的一般研究。

9902851CashmanBasaltic lava flows, although emplaced under a wide range of conditions, can be classified as one of three types - pahoehoe, `a`a, or blocky - on the basis of both flow surface morphology and on the mechanism by which the flows advance. Qualitatively, the formation of distinct flow types can be explained by differences in strengths of lava crusts and in the rheologies of flow interiors. However, limiting conditions for transitions between flow types must be quantitatively understood for accurate modeling of the mechanics of flow, and for predicting the rates and ultimate extent of lava flow advance during effusive eruptions. We suggest that key to this understanding is quantification of feedback between parameters controlling the stability of lava crusts and the consequent cooling (and crystallization) of lava flow interiors. Toward this end, we will perform (a) field-based studies of lava flows in Hawai`i (Mauna Loa and Kilauea) and Italy (Mt. Etna) to document rates of lava cooling and crystallization, (b) laboratory and theoretical studies to determine the effect of crystals on lava rheology, and (c) analog experiments of non-laminar systems to determine limiting flow conditions for preservation of stable crusts. We anticipate that the results will have broad applications to modeling and predictions of lava flow behavior, in addition to contributing to research on suspension rheology and to general studies of surface solidification of stirred (disrupted) flows.