Remote monitoring of Mount Erebus Volcano, Antarctica, using Polar orbiters: progress and prospects

Abstract. Mount Erebus (Antarctica) is a remote and inhospitable volcano, where ® eld campaigns are possible only during the austral summer. In addition to continuously monitoring seismic instruments and video cameras, data from scanners ¯ own aboard polar orbiting space-craft, such as the Thematic Mapper (TM) andAdvanced VeryHigh ResolutionRadiometer (AVHRR), can contribute to continuous, year-round monitoring of this volcano. Together these data allow measurement of the temperature of, thermal and gas ¯ ux from, and mass ¯ ux to a persistently active lava lake at Erebus ’ summit. The monitoring potential of such polar-orbiting instruments is enhanced by the poleward convergence of sub-spacecraft ground-tracks at the Erebus latitudes, permitting more frequent return periods than at the equator. Ground-based observations show that the Erebus lava lake was active with an area of ~2800m2 and sulphur dioxide (SO2) ¯ ux of (230 Ô 90) tdÕ 1 prior to September 1984. AVHRR-based lake area and SO2 ¯ ux estimates are in good agreement with these measurements, giving (2320 Ô 1200) m2 and (190 Ô 100) tdÕ 1, respectively, during 1980. However during late-1984 the lava lake became buried, with TM data showing re-establishment of the lake, with a TM-derived surface temperature of 578 ± 903ß C, by January 1985. Following these events, ground-based lake area and SO2 ¯ ux measurements show that the lake area and SO2 ¯ ux was lower (180 ± 630m2 and 9 ± 91tdÕ 1, respectively). This is matched by a decline in the AVHRR- and TM-derived rate of magma supply to the lake from 330 Ô 167kgsÕ 1 prior to 1984 to 30 ± 76kgsÕ 1 thereafter. Clearly, a reduction in magma supply to, and activity at, the lava lake occurred during 1984. We look forward to using data from such future polar-orbiting sensors as th