Slow rock fracture as eruption precursor at Soufriere Hills Volcano, Montserrat

Abstract

Abstract. Breakout of magmatic activity at Soufflere Hills volcano, Montserrat, was preceded by a tenfold increase in rate of earthquake occurrence. A new model of subcritical rock failure shows that this increase is consistent with the growth, possibly episodic, of the magma conduit at a rate controlled by progressive weakening of the host country rock. The preferred weakening mechanism is stress corrosion, by which circulating juvenile and hydrothermal fluids chemically attack the country rock and promote failure at stresses smaller than the rock's theoretical strength. The results illuminate the potential for slow-cracking models to enhance eruption forecasts using the inverse-rate technique combined with traditional monitoring methods.

Seismic scaling exponents as a tool in detecting stress corrosion crack growth leading to the September–October 1989 flank eruption at Mt. Etna Volcano

“…These results are consistent with [Anderson and Grew, 1977;Kilburn and Voight, 1998] weakening of the country rock by stress corrosion crack growth acting both in the mid (order of months) and the short-term (order of days), prior to eruption [Main and Meredith, 1991] Results are consistent with a model of stress corrosion crack growth acting at both mid (order of months) and short term (order of days), prov/ding support in modelling precursors of flank eruptions at Mr. Etna volcano.…”

Volcano Seismology: Detecting Unrest in Wiggly Lines

“…X can represent a number of different geophysical precursors, for example low frequency seismic event rate (Salvage and Neuberg 2016), event rate of all recorded seismicity (Kilburn and Voight 1998), or the amplitude of seismic events (Ortiz et al 2003). The parameter a is thought to range between 1 and 2 in volcanic environments (Voight 1988), or may even evolve from 1 towards 2 as seismicity proceeds (Kilburn 2003).…”

An accelerating precursor to predict “time-to-failure” in creep and volcanic eruptions

“…This method works well in retrospective prediction for such laboratory experiments, landslides, and volcanic eruptions (Voight, 1988;Voight, 1994, 1995;Kilburn and Voight, 1998;Murray and Ramirez Ruiz, 2002;Budi-Santoso et al, 2013). Hao et al, 2016 However, the exponent α is not always equal to 2 but exhibits variation.…”

“…Rates of ground deformation and of local fracturing of the crust or volcanic edifice (Voight, 1988;Cornelius and Voight, 1995;Kilburn and Voight, 1998;De la Cruz-Reyna and Reyes-Davila, 2001; Kilburn and Petley, 2003;Sparks, 2003;Smith et al, 2007;Lengliné et al, 2008;Bell and Kilburn, 2012;Kilburn, 2012;Boué et al, 2015;Salvage and Neuberg, 2016) commonly accelerate before volcanic eruptions. Accelerating creep deformation has also been suggested as a method to predict landslides (Saito, 1969;Kilburn and Petley, 2003;Petley et al, 2005).…”

“…Thus, by linearly extrapolating the curve of the inverse rate to zero, the failure time t f can be determined as the intersection with the time axis (Voight, 1988(Voight, , 1989Kilburn and Voight, 1998;De la Cruz-Reyna and Reyes-Davila, 2001;Kilburn and Petley, 2003;Sparks, 2003;Smith et al, 2007;Lengliné et al, 2008;Lavallée et al, 2008;Bell and Kilburn, 2012;Kilburn, 2012), representing an infinite deformation rate. This method works well in retrospective prediction for such laboratory experiments, landslides, and volcanic eruptions (Voight, 1988;Voight, 1994, 1995;Kilburn and Voight, 1998;Murray and Ramirez Ruiz, 2002;Budi-Santoso et al, 2013).…”