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

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.