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Localized surface disruptions observed by InSAR during strong earthquakes in Java and Hawai'i

Bulletin of the Seismological Society of America

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DOI: 10.1785/0120090175

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Abstract

Interferometric Synthetic Aperture Radar data spanning strong earthquakes on the islands of Java and Hawai‘i in 2006 reveal patches of subsidence and incoherence indicative of localized ground failure. Interferograms spanning the 26 May 2006 Java earthquake suggest an area of about 7.5 km2 of subsidence (~2 cm) and incoherence south of the city of Yogyakarta that correlates with significant damage to housing, high modeled peak ground accelerations, and poorly consolidated geologic deposits. The subsidence and incoherence is inferred to be a result of intense shaking and/or damage. At least five subsidence patches on the west side of the Island of Hawai‘i, ranging 0.3–2.2 km2 in area and 3–8 cm in magnitude, occurred as a result of a pair of strong earthquakes on 15 October 2006. Although no felt reports or seismic data are available from the areas in Hawai‘i, the Java example suggests that the subsidence patches indicate areas of amplified earthquake shaking. Surprisingly, all subsidence areas in Hawai‘i were limited to recent, and supposedly stable, lava flows and may reflect geological conditions not detectable at the surface. In addition, two ‘a‘ā lava flows in Hawai‘i were partially incoherent in interferograms spanning the earthquakes, indicating surface disruption as a result of the earthquake shaking. Coearthquake incoherence of rubbly deposits, like ‘a‘ā flows, should be explored as a potential indicator of earthquake intensity and past strong seismic activity.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Localized surface disruptions observed by InSAR during strong earthquakes in Java and Hawai'i
Series title:
Bulletin of the Seismological Society of America
DOI:
10.1785/0120090175
Volume
100
Issue:
2
Year Published:
2010
Language:
English
Publisher:
Seismological Society of America
Contributing office(s):
Hawaiian Volcano Observatory
Description:
9 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
532
Last page:
540