Research

InSAR in Hawaii

The Hawaiian volcanoes Kilauea and Mauna Loa are among the most active volcanoes in the world.  Kilauea is in continuous eruption since 1983 and Mauna Loa had 38 eruptions since 1850.  The last eruption of Mauna Loa occurred in 1984. Mauna Loa is currently of high interest because GPS measurements conducted by the Hawaii Volcano Observatory (HVO) indicate a swelling of the summit area that began in May 2002 and may be the precursor for increased activity of the volcano. The swelling has been interpreted as due to the influx of new magma into Mauna Loa’s shallow summit magma reservoir. For more information about Mauna Loa please visit the HVO website (http://hvo.wr.usgs.gov/maunaloa/current/main.html).

We use SAR data acquired by the Radarsat 1 satellite of the Canadian Space Agency (CSA) to image the deformation. The SAR data are provided by the Alaska Satellite facility (http://www.asf.alaska.edu). The figures show ground velocity maps obtained by averaging 5-8 independent interferograms, i.e. each map has been constructed from10-16 SAR images. The ground velocity pattern for ascending beam 3 and descending beam 1 is different because of the different imaging geometries. The maps clearly show that the maximum ground deformation occurs east of the rim of the summit caldera. We interpret the observed deformation as caused by the inflation of a shallow magma reservoir and by the slow inflation of a dike-like magma body in the rift zone south of the caldera at 4-6 km depth. Contact: Falk Amelung (famelung@rsmas.miami.edu) and Thomas Walter (twalter@rsmas.miami.edu)