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Using Satellites to Monitor Deformation: Radar Interferometry

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Examples of interferograms showing deformation of volcanoes
The growing use of Satellite Radar Interferometry is enabling scientists to discover an increasing number of volcanoes that have recently deformed. The implication is that many dormant volcanoes around the world inflate episodically between eruptions without much if any earthquake activity. For example, without the timely development of Satellite Radar Interferometry, the uplift and inferred magma intrusion of Westdahl Peak and Mount Peulik volcanoes would probably have gone unnoticed.

Westdahl Peak Volcano, Alaska

Westdahl Peak Volcano, Alaska An interferogram produced by Zhong Lu and others (2000) revealed about 15 cm (6 inches) of uplift centered on the upper part of the volcano from October 1992 to October 1998, starting soon after the most recent eruption. This time period was not marked by any unusual seismicity that would have drawn attention to the volcano, so its reinflation would likely have gone unnoticed without the radar study.

Mount Peulik Volcano, Alaska

Mount Peulik Volcano, Alaska Mount Peulik had been quiet and largely ignored for almost 150 years until a swarm of earthquakes about 30 km away in 1998 attracted the attention of a few scientists. A series of radar interferograms of the area produced by Zhong Lu and others (2001) reveal an exciting result: the long-dormant volcano rose almost 20 cm sometime between October 1996 and September 1998.


Lu, Z., C. Wicks, D. Dzurisin, W. Thatcher, J. Freymueller, S. McNutt, and D. Mann, 2000, Aseismic inflation of Westdahl volcano, Alaska, revealed by satellite radar interferometry, Geophysical Research Letters, v. 27, p. 1567-1570.

Lu, Z., Wicks, C. Jr., Dzurisin, D., Power, J.A., Moran, S., and Thatcher, W., in press, Magmatic inflation at a dormant stratovolcano: 1996-98 activity at Mount Peulik volcano, Alaska, revealed by satellite radar interferometry, Journal of Geophysical Research.