Post-eruptive inflation of Okmok Volcano, Alaska, from InSAR, 2008–2014

Remote Sensing
By: , and 

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Abstract

Okmok, a ~10-km wide caldera that occupies most of the northeastern end of Umnak Island, is one of the most active volcanoes in the Aleutian arc. The most recent eruption at Okmok during July-August 2008 was by far its largest and most explosive since at least the early 19th century. We investigate post-eruptive magma supply and storage at the volcano during 2008–2014 by analyzing all available synthetic aperture radar (SAR) images of Okmok acquired during that time period using the multi-temporal InSAR technique. Data from the C-band Envisat and X-band TerraSAR-X satellites indicate that Okmok started inflating very soon after the end of 2008 eruption at a time-variable rate of 48-130 mm/y, consistent with GPS measurements. The “model-assisted” phase unwrapping method is applied to improve the phase unwrapping operation for long temporal baseline pairs. The InSAR time-series is used as input for deformation source modeling, which suggests magma accumulating at variable rates in a shallow storage zone at ~3.9 km below sea level beneath the summit caldera, consistent with previous studies. The modeled volume accumulation in the 6 years following the 2008 eruption is ~75% of the 1997 eruption volume and ~25% of the 2008 eruption volume.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Post-eruptive inflation of Okmok Volcano, Alaska, from InSAR, 2008–2014
Series title Remote Sensing
DOI 10.3390/rs71215839
Volume 7
Issue 12
Year Published 2016
Language English
Publisher Multidisciplinary Digital Publishing Institute
Contributing office(s) Volcano Science Center
Description 17 p.
First page 16778
Last page 16794
Country United States
State Alaska
Other Geospatial Okmok Volcano
Online Only (Y/N) N
Additional Online Files (Y/N) N