Diverse deformation patterns of Aleutian volcanoes from InSAR

Zhong Lu1, Dan Dzurisin1, Chuck Wicks2, and John Power3

U.S. Geological Survey1 Cascades Volcano Observatory, Vancouver, Washington2 Earthquake Hazards Program, Menlo Park, California3 Alaska Volcano Observatory, Alaska

Acknowledgements:• ESA Projects AO-567, CAT-2765• Funding from USGS and NASA.• Contributions by many colleagues (O. Kwoun, D. Mann, J. Freymuller, W. Thatcher, S. Moran,

T. Masterlark, R. Rykhus, …)• SAR images from ESA, Alaska Satellite Facility, and JAXA

Outline• About Aleutian Volcanoes

• Case Studies with ERS/Envisat/Radarsat-1/JERS-1/ALOS InSAR imagery

• Summary

• Automated Radar Processing System

• Future directions

• Conduct systematic InSAR-based deformation study of volcanoes in the Aleutian volcanic arc;

• Study the eruption cycle at selected volcanoes by monitoring ground deformation before, during, and after eruptions;

• Develop techniques for the analysis, visualization, and modeling of volcano deformation data in near-real time;

• Combining InSAR observations, data modeling and other geophysical/geological data to construct magma plumbing systems at each volcano;

• The ultimate goal is better understanding of the mechanisms of volcanic unrests, which will enable longer-term forecasts and more effective mitigation of volcano hazards.

Objectives

1978 Crater

1991 Lava

Westdahl Peak

1991 Fissure

Pre-1964 Lava

1964 Lava

Westdahl• Glacier-capped shield volcano• Eruptions: 1964, 1978-79, and 1991-92

Tracking Magma Accumulation at Westdahl

06/1992 – 09/1993

09/1992 – 09/1993

09/1993 – 08/1995 10/1997 – 08/1999

10/1995 – 10/1998

10/1993 – 08/1995 08/1999 – 08/2000

10/1992 – 10/1997

09/1993 – 10/1998

post-eruption

11/21/1991 – 11/30/1991

co-eruption

InSAR images can characterize transient deformation of Westdahl volcano before, during and after the 1991 eruption

09/07/1991 – 10/28/1991

pre-eruption

0 2.83 cm

10 km

Def

orm

atio

n hi

stor

y of

Wes

tdah

l vol

cano

Magma plumbing system for Westdahl volcano, inferred from InSAR and modeling

~7 km

Sea level

Shallow Reservoir

• Shield volcano• Caldera formed 2050 years ago• ~10 minor explosive eruptions (ash) in 20th century• 3 large effusive eruptions (basaltic flows ) in 1945, 1958 and 1997• All eruptions from Cone A

Transient Deformation of Okmok volcano – A breathing volcano

1997-1998 1998-1999 1999-2000 2000-2001 2001-2002

Transient Deformation of Okmok volcano, Alaska

2002-2003 2003-2004

10 km

2005-20062004-2005

0 28.3 cm

0 2.83 cm

1992-1993 1993-1995 1995-1996 1996-1997

Subsidence

Subsidence

1997 eruption

2006-2007

Magma supply rate at the shallow reservoir

• A magma reservoir residing at 3.2 km beneath the center of the caldera, is responsible for the observed deformation before, during and after the 1997 eruption.

• By Fall 2007, 60~80% of the magma volume lost from the reservoir in the 1997 eruption hasbeen replenished.

1997 eruption

Deformation of 1997 lava flows from JERS-1 Imagery

L-ba

nd Im

ages

Surface displacement due to lava contraction and consolidation could reach 2 mm/day or more 4 months after the emplacement

Modeled (magma accumulation)

=

Observed Residual

Deformation of lava flows after 1997 eruption

0 2.83 cm

2001-2002 InSAR Image1997 lava flows subsideat 5-10 cm/year after the 1997 eruption

Dynamic deformation of Seguam volcanoSeguam Volcano: Documented eruptions occurred in 1786-1790, 1827, 1891, 1892, 1901, 1927, 1977, and 1992-1993.

62º

54º

58º-1

68º

-176

º

-160

º

Alaska

o

N 5 km

Multi-temporal InSAR Images

cluster 1cluster 2 cluster 3

potential point sources…

Three clusters dominate, each having a distinctive time-dependent behavior

Dominant Source Clusters

mag

ma

small storagechambers

0 km

7 km

E

dept

h

Modified from Singer et al., 1992.

W

to surface

Geologic: (based on field observations and laboratory measurements)

~30 km

directly

water

Magma Plumbing System

Cluster 1(thermoelastic contraction)

Cluster 2(fluid pressure)

Cluster 3(magma storage chambers)

0 km

7 km

W E

Geophysical (this study): (based on InSAR and modeling)

~30 km

C1 C2

erup

tion

C3

Deformation Associated With Seismic Swarm

Peulik• Statovolcanoes• Last eruption >150 years ago

M5.1

M5.2

Littoral cone

Ukinrek Marrs

Mt Peulik

Becharof Lake

Ugashik

M4.8

Mt Peulik Volcano

• Progressive inflation of 24 cm during 1996-1998• Seismic swarms in May 1998

Akutan•The 2nd most active in the Aleutian arc

• 27 separate eruptive episodes since 1790

• Latest seismic crisis: March 1996

Deformation Associated Magma Intrusion at Aktuan

Deformation mapped by ERS (C-band, λ = 5.66 cm) InSAR

0 11.76 cmrange change

5 km

Akutan Volcano

5 km0 11.76 cm

Akutan

1996 Cracks

Deformation mapped by JERS (L-band, λ = 23.53 cm) InSAR

range change

Akutan Volcano

Observed and modeled deformation images

Observed Modeled

Deformation sources:

• b1: a shallow expanding source representing intrusion of magma.• b2, b3, & b4: contracting sources that together account for observed subsidence of the eastern part of the island.

Volcano Subsidence

AniakchakKiska FisherSummit subsidence (several cm/year) associated with hydrothermal activity(source depth: ~1 km)

1-2 cm/year subsidence (source depth: 3-5 km)

1.5 cm/year subsidence (source depth: 3-5 km)

Insignificant Co-eruptive Deformation?

Shishaldin3rd most active volcanoIn Aleutians.

1993-1996 Imagecovering 1995 eruption

1998-1999 Imagecovering 1998 eruption

• Pre-eruption inflation is compensated by post-eruption deflation

• Magma accumulation/transfer occur relatively quickly

• Magma source is very shallow• No deformation• …

10 km

9/1/2000 – 9/21/2001

1-year Envisat interferogramspanning an eruption in 2001

92-day ALOS interferogram spanning an eruption in 2007 (note: lost coherence)

10 km

7/27 – 10/27, 2007

Frequent eruptions at Cleveland

10 km

ALOS: 9/5-10/21, 2007(note: coherence loss)

Loss of ALOS coherence over snow/glacier

Frequent eruptions at Veniaminof

ERS Stacking: 1992-2000

ERS Stacking: 1992-2000

10 km

ALOS: 7/31- 9/15, 2007(note: loss of coherence)

10 km

Frequent eruptions at Pavlof

Deformation of Aleutian Volcanoes from InSAR

Shishaldin

Lu et al. 2003aMoran et al. 2006

Seguam

Lu et al. 2003aMasterlark & Lu, 2004

Lu et al. 2000c, 2005b

Westdahl

Lu et al. 2000b, 2003b, 2004

Makushin

Lu et al. 2002c0 12 cm

AkutanKiska

Lu et al. 2002b

0 28.3 cm

Okmok

Lu et al. 2000a, 2003c, 2005a;Mann et al. 2002;Patrick et al., 2003

Augustine

Lu et al. 2003aMasterlark et al 2006Lee et al., 2007

Peulik

Lu et al. 2002a

Tanaga

Korovin

Kwoun et al. 2006

Aniakchak

Lu et al., 2007

• InSAR’s all-weather, large-area imaging capability makes it particularly useful for studying a variety of volcanic processes by analyzing surface deformation patterns.

• InSAR is an excellent technique for identifying restless volcanoes long before seismic or other precursory signals are detected.

• InSAR can image deformation in two spatial dimensions over a large region, which makes it an attractive tool for studying a complex deformation field.

• Deformation patterns at the Aleutian volcanoes are diverse. Diverse deformation patterns reflect the fact that Aleutian volcanoes span a broad spectrum of eruptive styles, sizes, magma compositions, and local tectonic settings.

• Differing deformation patterns suggest different magma plumbing systems.

Volcano Dancing –Diverse Styles, Different Rhythms

• RPS utilizes state-of-the-art database approach for SAR and InSAR processing, representing a significant departure and advancement from current InSAR processing which is accomplished using a variety of programs and scripts.

• RPS can semi-automatically process large amounts of SAR data for deformation map production.

• RPS provides a SAR data management system - capable of cataloging, archiving and retrieving the processed images and deformation maps.

• A web-based graphic user interface (GUI) that is independent of computer platforms has been developed to interface RPS so that InSAR processing and deformation map generation are accomplished through a few simple steps of shopping-basket procedures.

• RPS lays out the foundation for real-time processing of InSAR images to monitor volcano deformation, and provides a base capability from which to build.

Radar Processing System (RPS)

– Future studies will focus on synthesize the deformation in Aleutian as a “system” and take into account geochemical, geological and geophysical observations.

– Develop techniques to remove atmospheric delay anomalies• Continuous GPS and weather models

– Develop advanced InSAR techniques (PSInSAR and ScanSAR InSAR) for ground deformation imaging

– Develop innovative deformation modeling methods– Refine RPS for volcano deformation monitoring

Future Directions

Thank you