Our interest has been in understanding the processes that contribute to the cyclic generation and destruction of lava domes, particularly those related to cyclic gas pressurization, and triggering by rainfall.
Lava dome failures may occur concurrent with intense rainfall, both in periods of volcanic repose, as relatively quiescent small volume failures, or as energetic collapses, where as much as 90% of the dome may be retrogressively removed over periods of hours. For the first time we treated the thermal hydrology and mechanics that may contribute to these failures where effusive gas-pressures, trapped below a saturated dome rind/carapace, may result in the loss of strength and ultimately in failure of the dome. Specifically, we developed mechanistic models that honored observations at Soufrière Hills (Montserrat, BWI), Unzen (Japan), and Merapi (Indonesia) volcanoes, and provided (1) explanation and quantification of threshold rainfall intensities and durations required to trigger failure, (2) and a quantitative linkage with the roles of pre-collapse dome geometry and antecedent vigor of effusion, in both quantifying the style and timing of collapse, and in qualifying the hazard.
Elsworth, D., Voight, B., Thompson, G., and Young, S.R. (2004) A thermal-hydrologic mechanism for rainfall-triggered collapse of lava domes. In press. Geology. 20 pp.
Simmons, J., Elsworth, D., and Voight, B. (2004) Classification and idealized model analyses of dome collapses at Soufriere Hills volcano, Montserrat, during growth of the first lava dome: November 1995 to March 1998. In press. J. Volc. And Geotherm. Res. 36 pp.
Simmons, J., Elsworth, D., and Voight, B. (2003) Stability of exogenous lava domes during intense precipitation. In press. Bull. Volc., 35 pp.
Elsworth, D., Voight, B., Simmons, J., Young, S.R., and Winkler, B. (2003) Vaporization-induced overpressures as a trigger for the hazardous collapse of lava domes. GeoProc 2003. Proc. Int. Conf. on Coupled T-H-M-C Processes in Geosystems. Stockholm, Sweden, October, pp. 707 - 712. [pdf]
Simmons, J. (2003) Limit Equilibrium Models of Andesite Lava Domes: Replication of Rainfall-triggered and Gravitational Collapses. M.S. Thesis, Geo-Environmental Engineering Program. Pennsylvania State University. 80 pp.
Elsworth, D. and Voight, B. (2001) The mechanics of harmonic gas-pressurization and failure of lava domes. Geophys. J. Int., of the R. Astronomical Soc., 145, 187 – 198. [pdf]