RT Journal Article SR Electronic T1 Spaceborne radar measurements of the eruption of Soufrière Hills Volcano, Montserrat JF Geological Society, London, Memoirs JO Geological Society, London, Memoirs FD Geological Society of London SP 583 OP 594 DO 10.1144/GSL.MEM.2002.021.01.27 VO 21 IS 1 A1 Wadge, G. A1 Scheuchl, B. A1 Stevens, N. F. YR 2002 UL http://mem.lyellcollection.org/content/21/1/583.abstract AB Radar measurements from space are used to help monitor the evolution of a Peléean eruption on Soufrière Hills Volcano, Montserrat, during 1996 to April 1999. Data from four radar systems are used: ERS-1, ERS-2, Radarsat and JERS-1. We demonstrate that ratio images of backscattered radar energy collected at different times provide useful qualitative summary maps of gross topographic change (e.g. infilling of valleys with deposits) and changes in backscattering properties with time. Radar phase data using the interferometry technique can also provide valuable change detection information. Phase coherence images for ERS-1 and ERS-2 pairs with only one day separation on 25 and 26 September 1997 and 8 and 9 April 1999 allow the areal extent of some pyroclastic flows deposits emplaced during those 24-hour periods to be mapped. Generally, the radar phase can only be retrieved from those parts of the volcano where the vegetation is destroyed by pyroclastic flow deposits and local slopes are not too steep. Quantitative information on the topography of the volcano can also be extracted from the phase data, though not routinely from the new lava dome that grew during 1995-1998. By comparing the radar-measured post-eruption topography with the pre-eruption topography the thickness of the pyroclastic flow deposits (up to 85 m in some valleys on the northeastern slopes) are mapped. Radar interferometry also supplies a means of measuring surface deformation between radar images.