Monitoring:  | Gas | Ground Deformation | Hydrologic | Remote Sensing | Seismicity |

Remote Sensing of Hot Volcanic Features

Satellite sensors can be useful to monitor the extent and magnitude of thermal features on volcanoes. The presence of new significant thermal signatures or "hot spots" may indicate new heating of the ground before an eruption, represent an eruption in progress, or the presence of a very recent volcanic deposit, including lava flows or pyroclastic flows. In areas where volcanoes either remote or difficult to observe directly, identifying new thermal features can help to draw attention to a restless and potentially hazardous volcano. For example, there are more than 40 historically active volcanoes in Alaska and most are located in very remote and uninhabited areas. Currently, only 14 of these volcanoes are monitored with adequate seismic networks and eruptive activity may not be noticed by pilots or ground observers in nearby villages. New thermal features detected by satellite sensors, however, have helped to detect the onset of new activity at some of these remote volcanoes.

Pavlov Volcano, Alaska 23 September 1996
A satellite image of a thermal signature and an aerial photograph of Pavlof Volcano acquired on the same day show new volcanic activity. In the satellite image, the new thermal feature is red, low meteorological clouds are light blue, and water is dark blue. The photograph, courtesy of S. Schulmeister of the US Fish and Wildlife Service, shows a dark area on the snow-covered summit of Pavlof. This dark area is the source of the thermal signature and likely consists of lava spatter, lava flows, and pathways of small lahars. A smaller, steaming vent can be seen lower down on the flank of the volcano.

Other applications of volcano monitoring using satellites

• Detecting Eruption Clouds with Weather Satellites
• Detecting Sulfur Dioxide Gas in Eruption Clouds