Instability and Collapse of Pressurized Lava Domes: A Study of Triggering Mechanisms

该项目将研究在SouFriere Hills火山和Merapi火山观察到的熔岩穹顶的爆炸性和危险的崩解，据推测是由于穹顶核心的气体超压造成的。爆炸失效通常从最初的核心加压事件延迟数小时到数天，这表明向外气体压力扩散在触发失效中所起的作用。扩散的气体超压引发穹顶外围的剥落，最终横切到接近穹顶核心的地方，导致岩心压力的爆炸性释放，并有可能发展成火山碎屑流。这项研究将研究穹顶内部气体传输和力学行为之间的相互作用，定义流体和热扩散速率，并最终为稳定性的有效应力模型提供必要的约束，包括那些代表渐进和倒退破坏的模型。这项研究将研究熔岩穹顶的渐进性坍塌，定义压力扩散和热传输在定义强度损失方面的相互作用，定义加压操作的时间尺度，描绘潜在的坍塌前兆，并对坍塌预测的可能性进行评估。

This project will study the explosive and hazardous disintegration of lava domes, observed at Soufriere Hills volcano and at Merapi volcano, that is hypothesized to result from gaseous overpressurization of the dome core. Explosive failure is typically delayed hours to days from the initial core pressurization event, suggesting the role of outward gas pressure-diffusion in triggering failure. Diffusing gas over-pressures inititate spalling of the dome periphery, that ultimately transects close to the dome core, resulting in the explosive release of core pressure, and the potential development of pyroclastic flows. This study will examine the interplay between gas transport and mechanical behavior within the dome interior, defining fluid and thermal diffusion rates, and ultimately providing the necessary constraint to effective-stress models of stability, including those representing progressive and retrogressive failure. This study will examine the progressive collapse of lava domes, define the interplay of pressure-diffusive and thermal transport in defining strength loss, define the time-scales over which the pressurization operates, delineate potential precursors to collapse, and offer an evaluation of the potential for collapse prediction.