Geologic hazards impact analysis of potential geothermal resource areas : Circular C-107

Abstract

The same volcanic activity which provides the source of geothermal heat may also create a hazard to people and property. Volcanic hazards include lava flows, pyroclastic fallout, ground deformation, cracking, and subsidence. With proper evacuation planning, lava flows should not be a great danger to people because of their usually slow speed and somewhat predictable paths; however, substantial property damage is a possibility. A significant phenomenon is unique to Kilauea: the southern flanks of its rift zones are much more prone to be covered by lava flows than are the north flanks due to topography. Removal of cooled lava would be feasible if the flows were sufficiently thin and friable, and if the eruption was not lengthy. Using Kilauea as an example, since 1800, the average duration of an eruption has been about 60 days, with many lasting only one day and some, such as the Mauna Ulu and the current Pu'u O eruptions, lasting years.