Technical Geologic Overview of Long Valley Caldera for the Casa Diablo IV Geothermal Development Project
Report: Technical Geologic Overview of Long Valley Caldera for the Casa Diablo IV Geothermal Development Project
AbstractLong Valley Caldera in eastern California has been explored for geothermal resources since the 1960s. Early exploration wells (<300m) were drilled around Casa Diablo near the most prominent hot springs and fumaroles on the southwest flank of the Resurgent Dome (Figure 1). Deeper exploration wells were drilled to evaluate early federal lease offerings in the central caldera and later a portion of the caldera west of the Resurgent Dome. Well data established that the principal geothermal reservoir in Long Valley was not located directly beneath the Casa Diablo Hot Springs and did not appear to be related to the Resurgent Dome. Instead, the current hydrothermal system is more complex with shallow production at Casa Diablo supplied by upflow and outflow from a geothermal source beneath the western caldera moat. EGS has been retained by Geologica to provide background data for ESA in preparing the environmental documentation required to assess the potential hydrogeologic and environmental consequences for the planned Mammoth Pacific L.P. expansion of geothermal production. This report addresses geologic considerations in preparing an EIS/EIR including:Geology, soils and mineralsGeologic hazardsSeismic hazardsFaulting/surface ruptureGround shakingSlope stabilityLiquifactionVolcanic hazardsSurface water and shallow groundwaterHot springs and fumarolesGeothermal resourcesGeothermal system evolutionGeothermal developmentConceptual basis for numerical modelingThis review is based on relevant background geologic reports and geothermal exploration experience in Long Valley Caldera. Additional drilling and exploration inherently yields new knowledge or unanticipated results. All of the geologic issues that could result in significant impacts related to expanded geothermal production may not have been identified or may require additional analysis in the future.
- EGS Inc.
- Prepared for Geologica Inc., 2012
- Report Number
- Appendix D: Geologic and Geothermal Resources Technical Report
- Not Provided
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EGS Inc.. 2012. Technical Geologic Overview of Long Valley Caldera for the Casa Diablo IV Geothermal Development Project. San Francisco, CA: Prepared for Geologica Inc.. Report No.: Appendix D: Geologic and Geothermal Resources Technical Report.