Geologic analyses of Shuttle Imaging Radar (SIR-B) data of Kilauea Volcano, Hawaii

Analyses of imaging radar data of volcanic terranes on Earth and Venus have emphasized the need for a clearer understanding of how these data can be most effectively used to accomplish important volcanological goals, including the interpretation of eruptive styles and the characterization of the geologic history of volcanic centers. The second Shuttle Imaging Radar experiment (SIR-B) obtained two digital images over the summit caldera and the Southwest Rift Zone of Kilauea Volcano in 1984. Our geologic analyses of these images indicate that SIR-B data are particularly useful for delineating the distribution and surface textural variations of a'a lava flows, for mapping large-scale topographic features with radar-facing slopes, and for identifying an areally extensive pyroclastic deposit. Analyses of the SIR-B data of Kilauea, however, do not permit unambiguous identification of landforms such as pahoehoe lava flows, cinder cones, and fissures. Although separation of low-return units such as pahoehoe lava flows and adjacent pyroclastic ash is not greatly improved using standard image-enhancement techniques, the texture-analysis technique applied here did facilitate discrimination of such smooth-surfaced volcanic deposits. Although analyses of the SIR-B data permit a generally accurate interpretation of the eruptive history of Kilauea, the inability to distinguish low-return pahoehoe flows results in misinterpretation of several aspects of Kilauea volcanism, suggesting that caution should be exercised in the interpretation of SAR data of volcanic terranes.