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Elsworth, D.
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- PublicationOpen AccessHealing of simulated fault gouges aided by pressure solution: results from rock analogue experiments(2007-09-25)
; ; ; ;Niemeijer, A.; Penn State, USA ;Marone, C.; Penn State, USA ;Elsworth, D.; Penn State, USA; ; ; ; ; ;Vinciguerra, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Bernabé, Y.; MIT, USA; see Abstract Volume109 141 - PublicationRestrictedThe 1980 pressure response and flank failure of Mount St. Helens (USA) inferred from seismic scaling exponents(2005)
; ; ; ;Vinciguerra, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Elsworth, D.; University Park, Department of Energy and Geo-Environmental Engineering ;Malone, S.; University of Washington, Earth and Space Science; ; The cataclysmic 18 May 1980 eruption at Mount St. Helens was preceded by intense seismic activity marking the mechanical response of the volcanic edifice to interior pressurisation. This seismicity is analysed to yield the temporal change in the seismic scaling exponent, D, inferred from the seismic b-value, that in-turn is related to the seismic moment of an earthquake. Time evolution of D preceding the eruption onset reveals: (1) a major decrease in D occurring over only a few days at the end of March; (2) a steady but stepped decrease in D (steps ~5–10 days) occurring from the end of March to early May; (3) a sharp decrease in D in early May; and (4) steady low values of D occurring 2–3 days before the eruption onset. This response is interpreted as major ruptures, formed at the end of March, arresting and participating in, but not triggering the ultimate failure of the flank. Rather, the rate of interior fracturing slowed in the 2 months preceding the 18 May 1980 major blast, and the triggering of failure is consistent with interior gas overpressurisation. The occurrence of two swarms of low frequency seismic events and the high values of the harmonic tremor indicate the action of interior pressurisation on a cycle of 20–25 days. Solutions are applied to represent the harmonic interior pressurisation of the edifice by gas exsolving from the volcano core. The transient radial migration of overpressured gas may reduce the apparent strength of the edifice, and ultimately trigger failure of the flank. Importantly, this mechanism is capable of triggering flank failure both after multiple core pressurisation cycles have been sustained, and as core pressures are low and diminishing—and may be a minimum. These twin attributes are both apparent in the seismic record for Mount St. Helens, used as a proxy for the unrecorded timing and magnitude of gas pressurisation at the volcano core.162 69 - PublicationOpen AccessThe effect of dilatancy and compaction on the stability of fluid infiltrated fault gouge(2007-09-25)
; ; ; ;Samuelson, J.; Penn State, USA ;Marone, C.; Penn State, USA ;Elsworth, D.; Penn State, USA; ; ; ; ; ;Vinciguerra, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Bernabé, Y.; MIT, USA; see Abstract Volume115 204 - PublicationOpen AccessA pressure vessel for true-triaxial deformation and fluid flow during frictional shear(2007-09-25)
; ; ; ; ; ; ; ; ; ;Marone, C.; Penn. State Univ., USA ;Carperter, B.; Penn. State Univ., USA ;Elsworth, D.; Penn. State Univ., USA ;Faoro, I.; Penn. State Univ., USA ;Ikari, M.; Penn. State Univ., USA ;Knuth, M.; Penn. State Univ., USA ;Niemeijer, A.; Penn. State Univ., USA ;Saffer, D.; Penn. State Univ., USA ;Samuelson, J.; Penn. State Univ., USA; ; ; ; ; ; ; ; ; ; ;Vinciguerra, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italiasee Abstract Volume168 493 - PublicationOpen AccessThe influence of the shear stress on the evolution of the permeability in fractured novaculite and diorite(2007-09-25)
; ; ; ; ;Faoro, I.; Penn State, USA ;Niemeijer, A.; Penn State, USA ;Marone, C.; Penn State, USA ;Elsworth, D.; Penn State, USA; ; ; ; ; ; ;Vinciguerra, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Bernabé, Y.; MIT, USA; see Abstract Volume119 222 - PublicationOpen AccessDistinct element modeling of coupled chemo-mechanical compaction of rock salt(2007-09-25)
; ; ; ; ;Min, Ki-Bok; Penn State, USA ;Niemeijer, A.; Penn State, USA ;Elsworth, D.; Penn State, USA ;Marone, C.; Penn State, USA; ; ; ; ; ; ;Vinciguerra, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Bernabé, Y.; MIT, USA; see Abstract Volume110 141