REMOTE SENSING OF VOLCANICS: CRATERS OF THE MOON LAVA FIELDS

Developing a method to characterize the physical, chemical and temporal aspects of terrestrial volcanics is a necessary step toward studying volcanics on other planetary bodies. Volcanoes and flows close to populated centers have been studied in varying degree, but remote volcanics remain largely unstudied. Remotely sensed data and derived information can be used to select field sites on Earth and on other planets. Scientists studying volcanics in dangerous areas would benefit from as much advance knowledge of the area as possible before beginning fieldwork. By using satellites and other remote sensing methods, information about the eruptive history can be derived and potentially, the hazard these remote volcanic areas may pose to current and future generations can be estimated. Using Landsat TM, ASTER and other remotely sensed data, the areal extent and characteristics of lava flows can be examined, but verification and refinement of these methods requires collection of data on the ground.

Lava flows at Craters of the Moon National Park were selected to test methods for remote mapping of recent volcanics. These late Pleistocene to Holocene basalt flows have been mapped to 1:100,000 scale (Kuntz et al, 1988) and have only minor vegetative cover. We combined a range of remotely sensed spectral images to optimize recovery of the mapped flows. We have found that major flow units can de distinguished from each other using unsupervised classification of Landsat TM Bands 1-7, but differentiation of minor flows within these units presents greater difficulty. Larger-scale features like edge effects attributable to surface roughness were observed; these features allow us to determine the extent of individual flows, and provide a measure of relative flow age as they become less prominent on older flows.