Unique strainmeter observations of Vulcanian explosions, Soufrière hills volcano, Montserrat, July 2003
Clarke, A. B.
Sparks, R. S. J.
Young, S. R.
Date of Issue2010
Five Vulcanian explosions were triggered by collapse of the Soufrière Hills Volcano lava dome in 2003. We report strainmeter data for three explosions, characterized by four stages: a short transition between the onset of disturbance and a pronounced change in strain; a quasi-linear ramp accounting for the majority of strain change; a more gradual continued decline of strain to a minimum value; and a strain recovery phase lasting hours. Remarkable ∼800 s barometric gravity waves propagated at ∼30 m s−1. Eruption volumes estimated from plume height and strain data are 0.32–0.42 × 10^6, 0.26–0.49 × 10^6, and 0.81–0.84 × 10^6 m3, for Explosions 3–5 respectively, consistent with quasi-cylindrical conduit drawdown <2 km. The duration of vigorous explosion is given by the strain signature, indicating mass fluxes of order 10^7 kg s−1. Conduit pressures released reflect static weight of porous gas-charged magma, and exsolution-generated overpressures of order 10 MPa.
DRNTU::Science::Geology::Volcanoes and earthquakes
Geophysical research letters
© 2010 American Geophysical Union. This paper was published in Geophysical Research Letters and is made available as an electronic reprint (preprint) with permission of American Geophysical Union. The paper can be found at: [DOI: http://dx.doi.org/10.1029/2010GL042551]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.