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

Remote Sensing for Monitoring Volcanoes

This composite satellite image shows the movement of an eruption cloud from Mount Spurr Volcano in Alaska (upper left). The cloud of volcanic ash and gas was erupted at about midnight local Alaska time on September 16, 1992, and was carried by strong winds eastward across Canada and the United States. This eruption cloud is noteworthy because it traveled as a coherent mass for 5 days after the eruption and disrupted commercial air traffic in Canada and the United States. Increasingly, satellites are being used by scientists around the world to track eruption clouds in near real time, especially from Alaskan volcanoes. Alaska daylight time equals GMT (Greenwich Mean Time) minus 8 hours.

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 ultra- violet, infrared, and microwave.

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.

Applications of Satellite Monitoring

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

More Information About Remote Sensing of Volcanoes

• Remote Sensing of Volcanic Eruption Clouds Using AVHRR: A tutorial on the use of Advanced Very High Resolution Radiometer (AVHRR) data for the detection and discrimination of volcanic eruption clouds.
   
• NASA's Earth Observing System (EOS) is a series of polar-orbiting remote-sensing satellites planned for launch beginning in 1999. EOS is a major component of NASA's Mission to Planet Earth, and an interdisciplinary volcanology team is planning to utilize the satellites for a global assessment of active volcanism, volcanic hazards, and volcanic inputs to the atmosphere. This site is courtesy of the Interdisciplinary Science Volcanology Team.