Dynamic deformation of Seguam Island, Alaska, 1992-2008, from multi-interferogram InSAR processing

Chang Wook Lee, Zhong Lu, Joong-sun Won, Hyung Sup Jung, Daniel Dzurisin

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

We generated a time-series of ERS-1/2 and ENVISAT interferometric synthetic aperture radar (InSAR) images to study ground surface deformation at Seguam Island from 1992 to 2008. We used the small baseline subset (SBAS) technique to reduce artifacts associated with baseline uncertainties and atmospheric delay anomalies, and processed images from two adjacent tracks to validate our results. Seguam Island comprises the remnants of two late Quaternary calderas, one in the western caldera of the island and one in the eastern part of the island. The western caldera subsided at a constant rate of ~. 1.6. cm/yr throughout the study period, while the eastern caldera experienced alternating periods of subsidence and uplift: ~. 5. cm/year uplift during January 1993-October 1993 (stage 1), ~. 1.6. cm/year subsidence during October 1993-November 1998 (stage 2), ~. 2.0. cm/year uplift during November 1998-September 2000 (stage 3), ~. 1.4. cm/year subsidence during September 2000-November 2005 (stage 4), and ~. 0.8. cm/year uplift during November 2005-July 2007 (stage 5). Source modeling indicates a deflationary source less than 2. km below sea level (BSL) beneath the western caldera and two sources beneath the eastern caldera: an inflationary source 2.5-6.0. km BSL and a deflationary source less than 2. km BSL. We suggest that uplift of the eastern caldera is driven by episodic intrusions of basaltic magma into a poroelastic reservoir 2.5-6.0. km BSL beneath the caldera. Cooling and degassing of the reservoir between intrusions result in steady subsidence of the overlying surface. Although we found no evidence of magma intrusion beneath the western caldera during the study period, it is the site (Pyre Peak) of all historical eruptions on the island and therefore cooling and degassing of intrusions presumably contributes to subsidence there as well. Another likely subsidence mechanism in the western caldera is thermoelastic contraction of lava flows emplaced near Pyre Peak during several historical eruptions, most recently in 1977 and 1992-93.

Original languageEnglish
Pages (from-to)43-51
Number of pages9
JournalJournal of Volcanology and Geothermal Research
Volume260
DOIs
Publication statusPublished - 2013 Jun 15

Fingerprint

calderas
Subsidence
synthetic aperture radar
Synthetic aperture radar
caldera
interferometry
Sea level
subsidence
Processing
sea level
intrusion
uplift
Degassing
degassing
Cooling
volcanic eruptions
magma
volcanic eruption
Time series
cooling

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology

Cite this

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title = "Dynamic deformation of Seguam Island, Alaska, 1992-2008, from multi-interferogram InSAR processing",
abstract = "We generated a time-series of ERS-1/2 and ENVISAT interferometric synthetic aperture radar (InSAR) images to study ground surface deformation at Seguam Island from 1992 to 2008. We used the small baseline subset (SBAS) technique to reduce artifacts associated with baseline uncertainties and atmospheric delay anomalies, and processed images from two adjacent tracks to validate our results. Seguam Island comprises the remnants of two late Quaternary calderas, one in the western caldera of the island and one in the eastern part of the island. The western caldera subsided at a constant rate of ~. 1.6. cm/yr throughout the study period, while the eastern caldera experienced alternating periods of subsidence and uplift: ~. 5. cm/year uplift during January 1993-October 1993 (stage 1), ~. 1.6. cm/year subsidence during October 1993-November 1998 (stage 2), ~. 2.0. cm/year uplift during November 1998-September 2000 (stage 3), ~. 1.4. cm/year subsidence during September 2000-November 2005 (stage 4), and ~. 0.8. cm/year uplift during November 2005-July 2007 (stage 5). Source modeling indicates a deflationary source less than 2. km below sea level (BSL) beneath the western caldera and two sources beneath the eastern caldera: an inflationary source 2.5-6.0. km BSL and a deflationary source less than 2. km BSL. We suggest that uplift of the eastern caldera is driven by episodic intrusions of basaltic magma into a poroelastic reservoir 2.5-6.0. km BSL beneath the caldera. Cooling and degassing of the reservoir between intrusions result in steady subsidence of the overlying surface. Although we found no evidence of magma intrusion beneath the western caldera during the study period, it is the site (Pyre Peak) of all historical eruptions on the island and therefore cooling and degassing of intrusions presumably contributes to subsidence there as well. Another likely subsidence mechanism in the western caldera is thermoelastic contraction of lava flows emplaced near Pyre Peak during several historical eruptions, most recently in 1977 and 1992-93.",
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Dynamic deformation of Seguam Island, Alaska, 1992-2008, from multi-interferogram InSAR processing. / Lee, Chang Wook; Lu, Zhong; Won, Joong-sun; Jung, Hyung Sup; Dzurisin, Daniel.

In: Journal of Volcanology and Geothermal Research, Vol. 260, 15.06.2013, p. 43-51.

Research output: Contribution to journalArticle

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T1 - Dynamic deformation of Seguam Island, Alaska, 1992-2008, from multi-interferogram InSAR processing

AU - Lee, Chang Wook

AU - Lu, Zhong

AU - Won, Joong-sun

AU - Jung, Hyung Sup

AU - Dzurisin, Daniel

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N2 - We generated a time-series of ERS-1/2 and ENVISAT interferometric synthetic aperture radar (InSAR) images to study ground surface deformation at Seguam Island from 1992 to 2008. We used the small baseline subset (SBAS) technique to reduce artifacts associated with baseline uncertainties and atmospheric delay anomalies, and processed images from two adjacent tracks to validate our results. Seguam Island comprises the remnants of two late Quaternary calderas, one in the western caldera of the island and one in the eastern part of the island. The western caldera subsided at a constant rate of ~. 1.6. cm/yr throughout the study period, while the eastern caldera experienced alternating periods of subsidence and uplift: ~. 5. cm/year uplift during January 1993-October 1993 (stage 1), ~. 1.6. cm/year subsidence during October 1993-November 1998 (stage 2), ~. 2.0. cm/year uplift during November 1998-September 2000 (stage 3), ~. 1.4. cm/year subsidence during September 2000-November 2005 (stage 4), and ~. 0.8. cm/year uplift during November 2005-July 2007 (stage 5). Source modeling indicates a deflationary source less than 2. km below sea level (BSL) beneath the western caldera and two sources beneath the eastern caldera: an inflationary source 2.5-6.0. km BSL and a deflationary source less than 2. km BSL. We suggest that uplift of the eastern caldera is driven by episodic intrusions of basaltic magma into a poroelastic reservoir 2.5-6.0. km BSL beneath the caldera. Cooling and degassing of the reservoir between intrusions result in steady subsidence of the overlying surface. Although we found no evidence of magma intrusion beneath the western caldera during the study period, it is the site (Pyre Peak) of all historical eruptions on the island and therefore cooling and degassing of intrusions presumably contributes to subsidence there as well. Another likely subsidence mechanism in the western caldera is thermoelastic contraction of lava flows emplaced near Pyre Peak during several historical eruptions, most recently in 1977 and 1992-93.

AB - We generated a time-series of ERS-1/2 and ENVISAT interferometric synthetic aperture radar (InSAR) images to study ground surface deformation at Seguam Island from 1992 to 2008. We used the small baseline subset (SBAS) technique to reduce artifacts associated with baseline uncertainties and atmospheric delay anomalies, and processed images from two adjacent tracks to validate our results. Seguam Island comprises the remnants of two late Quaternary calderas, one in the western caldera of the island and one in the eastern part of the island. The western caldera subsided at a constant rate of ~. 1.6. cm/yr throughout the study period, while the eastern caldera experienced alternating periods of subsidence and uplift: ~. 5. cm/year uplift during January 1993-October 1993 (stage 1), ~. 1.6. cm/year subsidence during October 1993-November 1998 (stage 2), ~. 2.0. cm/year uplift during November 1998-September 2000 (stage 3), ~. 1.4. cm/year subsidence during September 2000-November 2005 (stage 4), and ~. 0.8. cm/year uplift during November 2005-July 2007 (stage 5). Source modeling indicates a deflationary source less than 2. km below sea level (BSL) beneath the western caldera and two sources beneath the eastern caldera: an inflationary source 2.5-6.0. km BSL and a deflationary source less than 2. km BSL. We suggest that uplift of the eastern caldera is driven by episodic intrusions of basaltic magma into a poroelastic reservoir 2.5-6.0. km BSL beneath the caldera. Cooling and degassing of the reservoir between intrusions result in steady subsidence of the overlying surface. Although we found no evidence of magma intrusion beneath the western caldera during the study period, it is the site (Pyre Peak) of all historical eruptions on the island and therefore cooling and degassing of intrusions presumably contributes to subsidence there as well. Another likely subsidence mechanism in the western caldera is thermoelastic contraction of lava flows emplaced near Pyre Peak during several historical eruptions, most recently in 1977 and 1992-93.

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