Remote Sensing for Monitoring Volcanoes

Satellites Complement Ground-Based Monitoring Methods

The launch of new satellites each year and new developments in remote-sensing techniques have expanded the capability of scientists worldwide to monitor volcanoes using satellites. For the purpose of studying volcanoes, remote sensing is the detection by a satellite's sensors of electromagnetic energy that is absorbed, reflected, radiated, or scattered from the surface of a volcano or from its erupted material in an eruption cloud. A variety of sensors are used to measure wavelengths of energy that are beyond the range of human vision; for example ultraviolet, infrared, and microwave.

Pictured above: This composite satellite image shows the movement of an eruption cloud from Mount Spurr Volcano in Alaska (pictured upper left). The cloud of volcanic ash and gas erupted at about midnight local Alaska time, on September 16, 1992, and was carried by strong winds eastward, across Canada and the United States.

Applications of Satellite Monitoring

• Tracking Eruption Clouds
• Measuring Sulfur Dioxide Gas in Eruption Clouds
• Detecting Hot Features on Volcanoes

The application of remote-sensing techniques for volcano monitoring is far from routine at volcano observatories and the techniques are not likely to replace conventional ground-based monitoring methods. For well-monitored volcanoes, satellite observations are complementary in nature and they can be extremely important for tracking eruption clouds. For many of the world's volcanoes that are either extremely remote or not monitored well, satellite observations of volcanic activity may be all that is available because of the extensive coverage they provide.