REMOTE SENSING AND GIS EVALUATION OF CO2-INDUCED TREE KILLS AT MAMMOTH MOUNTAIN, CALIFORNIA: 1989 TO PRESENT

Mammoth Mountain, a rhyolite to dacite dome complex on the southwestern rim of the Long Valley Caldera in eastern central California, has shown signs of volcanic unrest since the early 1980s. High concentrations of cold magmatic carbon dioxide (CO₂), vent from the flanks of the mountain, and this gas is responsible for over 170 acres of dead trees in that area since 1990. Shallow magmatic intrusions, inferred from seismic activity, ground deformation, and changes in fumarolic gas composition on and around Mammoth Mountain beginning in 1989, have been interpreted as the source of the CO₂ gas.

Airborne and satellite based remote sensing data for the field area, collected using muti- and hyperspectral [NS001 (TMS), MASTER, ASTER and AVIRIS] sensors, are evaluated to map the spatial and temporal variation in the distribution of magmatic CO₂-induced tree kills between 1989 and present. Two seasons (1998 and 2003) of field spectral measurements have been incorporated into the remote sensing evaluation to establish the reflectance characteristics of the field area, allow for error evaluation, and provide ground truth measurements for improving the quality of the remote sensing analyses. The results of the temporal remote sensing assessment, combined using geographic information systems, are highlighting relationships between surface geology and areas of tree mortality and delineating the migration of tree kills since 1989. These evaluations improve our understanding of the structure and volcanic activity beneath Mammoth Mountain and aid in analysis of future volcanic unrest.