Eos, Vol. 70, No. 52, December 26, 1989 Remote Sensing of Volcanos and Volcanic Terrains PAGES 1567, 1571, 1575 Peter J. Mouginis-Mark 1 , David C. Pieri 2 , Peter W. Francis 1 , Lionel Wilson 1 , Stephen Self, William I. Rose 4 , and Charles A. Wood 5 In recent years, much progress has been made in the use of both satellite and air- craft remote sensing techniques to collect data on the dynamics of volcanic erup- tions and on the interactions between volcanos and the atmosphere and eco- sphere. Measurements made in the ultraviolet provide estimates of the mass of S0 2 released, while the hemispheric dispersal of eruption plumes can be tracked via weather satellites. Infrared images can be processed to produce temperature maps of lava flows and volcanic craters, and volumes of volcanic flows and cones can be measured via radar interferometry. Because the study of volcanos crosses many interdisciplinary boundaries, from geology and geophysics to atmospheric chemistry, climatology and ecology, the global perspective provided by satellite remote sensing techniques will become another valuable tool in the analysis of volcanos and their deposits. Many of the most devastating eruptions of recent times, such as that of El Chichon, Mexico, in 1982, and Nevado del Ruiz, Co- lombia, in 1985, have taken place on poorly studied volcanos. Some of these volcanos were thought to be either inactive ui not to present major hazards. Before its lethal erup- tion in 1951, Mount Lamington, New Guinea, was not even known to be a volcano. Indeed, the National Academy of Science Committee for the International Decade for Natural Di- 1 Hawaii Institute of Geophysics, University of Hawaii, Honolulu 2 Jet Propulsion Laboratory, Pasadena, Cal- if. department of Geology, University of Texas at Arlington 4 Department of Geological Engineering, Michigan Technological University, Houghton 5 Johnson Space Center, Houston, Tex. Cover. Landsat image of Mount Etna, Sicily. New technologies enable many vol- canos and volcanic eruptions to be moni- tored via the use of satellite sensors. This color composite (Bands 4, 5, and 7) of Landsat Thematic Mapper scene of Mount Etna in eruption was taken on June 20, 1984. The strong response of the hot active lava flow, in orange, is readily apparent. Note also the large amount of fume (gray plume streaming toward bot- tom of image) that is being given off from the summit. A discussion of the use of sat- ellite remote sensing techniques in volca- nology is in the article "Remote Sensing of Volcanos and Volcanic Terrains" by Peter j. Mouginis-Mark et al. in this issue. saster Reduction (IDNDR) has determined that the "identification and global mapping of all active and potentially active volcanos" is an important science objective for the Decade [National Academy of Sciences, 1987]. However, volcanic eruptions are difficult to study. Apart from the obvious dangers inher- ent in the observation of violent activity at close hand, most of the world's volcanos are located in remote areas where there are no suitably trained and equipped observers. Even under favorable conditions, the scale of both lava-producing and explosive eruptions can be so great as to make useful ground ob- servations hard to achieve. It is rare that suf- ficient manpower is available to make the necessary field measurements of the develop- ment of an entire lava flow field, or to sample the entire spatial and temporal dispersal of an ash plume. Satellite and aircraft remote sensing tech- niques can be used to monitor these poten- tially dangerous volcanos. Remote sensing of- fers a number of advantages over ground- based studies, including that all the world's volcanos can be studied by the same tech- niques, thus providing a globally consistent data set that can be used to monitor temporal variations in volcanic activity; data can be col- lected in areas which are difficult to reach be- cause of physical or political constraints; and a broad range of sensors can be used at wave- lengths ranging from the ultraviolet to the microwave to study a wide range of phenom- ena. These advantages make permanently or- biting sensors, such as those due to fly in the late 1990s on the Earth Observing System (EOS) [Ormsby and Soffen, 1989], particularly attractive as tools to study volcanism. Satellite observations of plume dispersal, changes in atmospheric chemistry, and related perturba- tions in the atmosphere and ecosphere also permit the interdisciplinary effects of volcanic eruptions to be assessed. Fig. 1. Thermal profile for the June 1984 lava flow erupted from Mount Etna, Sici- ly, as derived from Landsat Thematic Mapper data. The flow direction is from top to bottom of the diagram. Vertical axis shows the decrease in temperature calculated for different parts of the flow (note the formation of pronounced "cool" edges of the flow). This page may be freely copied.