TIME-SERIES ANALYSIS OF EFFUSIVE VOLCANIC ACTIVITY USING THE ERS ALONG-TRACK SCANNING RADIOMETER - THE 1995 ERUPTION OF FERNANDINA VOLCANO,GALAPAGOS-ISLANDS

The ERS-1 Along Track Scanning Radiometer (ATSR) provides frequent sho rtwave and longwave infrared radiance data of every terrestrial volcan ic region, at a spatial resolution of 1 km(2). By adopting a simplifie d model that assumes that any observed active lava flow is composed of two distinct thermal components, toe present techniques that allow su bpixel lava flow areas to be estimated from the ATSR spectral radiance data. Such estimates are especially useful in documenting effusive vo lcanic activity occurring in remote regions, where ground observations may be sparse or completely lacking. We use a time-series ATSR datase t to document the 1995 eruption of Fernandina Volcano, an important bu t isolated volcanic island in the Galapagos archipelago. We estimate t hat in 1995 Fernandina produced a 6 km(2) lava flow field with a volum e of around 20 million m(3), a similar magnitude to previously studied Fernandina eruptions. This is the first time-series analysis of art a ctive Galapagos lava flow produced using remotely sensed data. Previou s Fernandina flows have been investigated many months or years after t he activity had ceased. The current and future availability of frequen t, low-spatial resolution infrared radiance data from spaceborne senso rs such as the Advanced Along Track Scanning Radiometer (AATSR) and th e Moderate Resolution Imaging Spectrometer (MODIS) should ensure that adaptations of these techniques can be used to document future volcani c eruptions occurring in similarly isolated regions. (C) Elsevier Scie nce Inc., 1997.