Transient volcano deformation sources imaged with interferometric synthetic aperture radar: Application to Seguam Island, Alaska

Journal of Geophysical Research B: Solid Earth
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Abstract

Thirty interferometric synthetic aperture radar (InSAR) images, spanning various intervals during 1992–2000, document coeruptive and posteruptive deformation of the 1992–1993 eruption on Seguam Island, Alaska. A procedure that combines standard damped least squares inverse methods and collective surfaces, identifies three dominant amorphous clusters of deformation point sources. Predictions generated from these three point source clusters account for both the spatial and temporal complexity of the deformation patterns of the InSAR data. Regularized time series of source strength attribute a distinctive transient behavior to each of the three source clusters. A model that combines magma influx, thermoelastic relaxation, poroelastic effects, and petrologic data accounts for the transient, interrelated behavior of the source clusters and the observed deformation. Basaltic magma pulses, which flow into a storage chamber residing in the lower crust, drive this deformational system. A portion of a magma pulse is injected into the upper crust and remains in storage during both coeruption and posteruption intervals. This injected magma degasses and the volatile products accumulate in a shallow poroelastic storage chamber. During the eruption, another portion of the magma pulse is transported directly to the surface via a conduit roughly centered beneath Pyre Peak on the west side of the island. A small amount of this magma remains in storage during the eruption, and posteruption thermoelastic contraction ensues. This model, made possible by the excellent spatial and temporal coverage of the InSAR data, reveals a relatively simple system of interrelated predictable processes driven by magma dynamics.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Transient volcano deformation sources imaged with interferometric synthetic aperture radar: Application to Seguam Island, Alaska
Series title Journal of Geophysical Research B: Solid Earth
DOI 10.1029/2003JB002568
Volume 109
Issue B1
Year Published 2004
Language English
Publisher Wiley
Contributing office(s) Earth Resources Observation and Science (EROS) Center, Volcano Hazards Program
Description B10401:16 p.
Online Only (Y/N) N
Additional Online Files (Y/N) N