Monitoring the development of active lava domes using data from the ERS-1 Along Track Scanning Radiometer

Growth of a lava dome often precedes explosive activity at certain types of volcano. We demonstrate the use of frequent, low spatial resolution shortwave infrared (1.6 μm) data from the ERS-1 Along Track Scanning Radiometer (ATSR) in identifying and monitoring active volcanic lava domes. In the absence of reflected sunlight (night-time data) any signal detected at a wavelength of 1.6 μm is likely to be due to thermal emittance from magmaticlly heated areas of the lava dome. Bodies at near-magmatic temperatures emit strongly at this wavelength, which allows features significantly smaller than an ATSR pixel (∼1 km 2) to be detected and monitored. Data from orbiting shortwave infrared sensors could be used as a method of monitoring remote volcanoes that exhibit lava dome phenomena. Such data could assist eruption predictions made at these volcanoes. Two case studies are illustrated, Galeras Volcano, Columbia and Lascar Volcano, Chile. In both cases the interpretations of lava dome activity, made using ATSR shortwave infrared radiance data, match the published field reports. In the case of Lascar the recorded radiances highlight gross changes in summit activity that were often unobserved on the ground but appear to have led to major explosive eruptions throughout 1993 and 1994.