The spatial extent of thermal anomalies at Lascar Volcano

Láscar volcano (Chile) has undergone at least 4 vulcanian eruptions and other smaller events between May 2000 and April 2009. Multispectral, thermal infrared images taken during this time by ASTER are used to calculate surface temperatures. The spatial extent and intesity of thermal anomalies are interpreted as varying due to fluctuations in the quantity and temperature of gas being emitted from active fumarole sites. The volcano continues to show a different relationship between thermal radiance and eruptive behaviour to that observed before 1993, the year of the volcano´s greatest historical eruption, indicating that a change in degassing style has persisted since that time. Monitoring the size of thermal anomalies is shown to provide a new perspective for observing and interpreting volcanic processes and may be useful in future predictive models.