Surface Deformation of Seguam Volcano, Alaska by magma supply dynamics using SAR interferometry

摘要

Seguam Volcano is located in the central Aleutian arc, in Alaska, where three representative caldera margins have been placed. Those caldera margins have district own mechanism due to dynamics interrelation caused by deflation of the shallow magma source or inflation of the deep magma one that span the time period from 1992 to 2007. Especially, SBAS (small baseline subset) technique applied by multiple interferograms generates the temporal deformation map by reducing atmospheric artifacts, DEM errors and etc. While the subsidence around the eastern caldera had been caused by deflation of shallow source, the uplift might have been influenced by a deep source. These results of precise surface deformation mapping with an improved SBAS InSAR technique provide better understandings of the dynamic magma plumbing systems in the Seguam volcano. Seguam Island has unique characteristics of holding three different mechanisms associated with caldera margins, among which only eastern caldera margin has reiterated the subsidence and uplift of crustal surface by extrusion or intrusion of lava flow in the reservoir. For this reason, the eastern caldera margin might be more dangerous than others because of its possibility of eruption due to its unstable magma source.