Deformation and stress-change modeling at Sierra Negra volcano, Galápagos, from ENVISAT INSAR and GPS observations

Sigurjón Jónsson*, William W. Chadwick, Michael Poland, Dennis Geist

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We use radar interferograms and GPS observations to constrain models of magma accumulation and faulting at Sierra Negra volcano, Galápagos, during the years before its 2005 eruption. The data have shown ∼5 m of pre-eruption uplift and multiple trapdoor faulting events on an intra-caldera fault system. We find the pattern of uplift to be consistent with an inflating sill at 2.2 km depth under the caldera. Our deformation modeling and stress-change calculations suggest that the inflating sill triggered faulting on an inward-dipping thrust fault and that the faulting in turn relieved the pressure within the sill. This sill-fault interaction tends to thicken the sill and limit its lateral extent within the area bounded by the fault..

Original languageEnglish (US)
JournalEuropean Space Agency, (Special Publication) ESA SP
Issue number649 SP
StatePublished - 2008
Externally publishedYes

ASJC Scopus subject areas

  • Aerospace Engineering

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