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Deformation of the Aniakchak Caldera, Alaska, mapped by InSAR

January 1, 2004

The deformation of Aniakchak volcano is investigated using 19 ERS-1 / 2 interferometric synthetic aperture radar (InSAR) data from 1992 through 2002. InSAR images from the different time intervals reveal that the10-km-wide caldera has been subsiding during the time of investigation. The pattern of subsidence does not following the pyroclastic flows from the last eruption of the caldera in 1931. The maximum subsidence is near the center of the caldera, with a rate of up to 13 mm/yr. Deformation outside the caldera is insignificant. Least squares inversion of the multi-temporal deformation maps indicates that the subsidence rate has been relatively constant. Field observations have identified numerous fumaroles inside the caldera. In 1973, temperatures of 80??C were measured at a depth of 15 cm in loose volcanic rubble adjacent to the small cinder cone (about 1.5 km northeast of the vent of the 1931 eruption), whereas springs near a caldera lake had a temperature of 25??C in July 1993. Therefore, we suggest the observed subsidence at Aniakchak caldera is most likely caused by the reduction of pore fluid pressure of a hydrothermal system located a few kilometers beneath the caldera.

Publication Year 2004
Title Deformation of the Aniakchak Caldera, Alaska, mapped by InSAR
DOI 10.1109/IGARSS.2004.1369109
Authors Oh-Ig Kwoun, Z. Lu
Publication Type Conference Paper
Publication Subtype Conference Paper
Index ID 70026179
Record Source USGS Publications Warehouse
USGS Organization Earth Resources Observation and Science (EROS) Center