A CHRONOLOGY OF THE 1991 TO 1993 MOUNT-ETNA ERUPTION USING ADVANCED VERY HIGH-RESOLUTION RADIOMETER DATA - IMPLICATIONS FOR REAL-TIME THERMAL VOLCANO MONITORING

Between December 1991 and March 1993 a continuous effusive eruption at Mount Etna built a 7.6 km(2) lava flow field. Flows extended to withi n 1 km of the town of Zafferana before a successful artificial diversi on was carried out higher up the volcano. During this eruption the spa ceborne advanced very high resolution radiometer (AVHRR) acquired 308 images on which the activity could be detected. Since these data can b e freely and directly available, such coverage potentially allows regu lar, real-time monitoring. Ground observations and a flow map that we produced using a SPOT image and electronic distance measurement allowe d us to develop and test data extraction techniques. AVHRR radiance ma ps were consistent with known locations of surface activity. These doc umented the transition from channel to tube fed phases, the changing t hreat to Zafferana, and flow diversion. Quantitative analysis of the A VHRR data enabled estimation of active lava area, thermal flux, effusi on rates, and total flow field volume. Our estimates for eruption rate and total flow field volume, 5.6 to 7.6 m(3)/s and 220 x 10(6) to 300 x 10(6) m(3), respectively, are in agreement with published ground-ba sed estimates of 5.8 m(3)/s and 235 x 10(6) m(3). These correlations d emonstrate the high degree of confidence that can now be placed in int erpretations of AVHRR time series for eruptions where ground-based dat a are scanty.