GOES satellite and field observations of the 1998 eruption of Volcan Cerro Azul, Galápagos Islands

Abstract

The 1998 eruption of Volcan Cerro Azul, Isla Isabela, Galapagos Islands, was observed in near real-time by the Geostationary Operational Environmental Satellite-8 (GOES-8) weather satellite. Due to the remote location of the eruption site, 3.9-μm radiance values derived from GOES band 2 provide the best timing of the start and termination of the eruption, which occurred on 15 Sept. and 21 Oct., respectively. Throughout the 36-day long eruption, a total of 1335 thermal infrared images were collected, of which 851 were cloud-free and permitted the thermal anomaly to be detected. A detailed chronology including 77 separate events was assembled from the GOES data and field observations. Numerous attributes of the eruption were observed from the GOES data, including the sizes and dispersal of seven eruption plumes and the occurrence and timing of intra-caldera effusive activity. The growth of a lava flow on the SE flank, the formation of smoke and volcanic haze from the flank vent, and burning of vegetation caused by lava flows entering vegetated areas were monitored both on the ground and with the satellite data. In most cases GOES images were processed as they were received every 30 min and were then distributed over the Internet within minutes of reception. These data provided timely high-temporal information to field parties as well as enabled the documentation of the eruption. The GOES observations of Cerro Azul serve as a further example of the way in which the remote sensing community and field volcanologists can collaborate during future eruptions, and permit the temporal and spatial resolution requirements for future satellites systems to be better defined.