Potential for triggering of earthquakes by stimulation of dry rock geothermal fields
No abstract available.
Open-File Report↗
Geology topics
C. Barry Raleigh
Publications and source records attributed to C. Barry Raleigh.
Focal plane solutions of aftershocks to the Oroville earthquake of August 1, 1975
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Open-File Report↗
Earthquakes in the oil field at Rangely, Colorado
Seven years of seismic data recorded at the Uinta Basin Observatory were searched for earthquakes originating near an oil field at Rangely, Colorado, located 65 km ESE of the observatory. Changes in the number of earthquakes recorded per year appear to correlate with changes in the quantity of fluid injected per year. Between November 1962 and January 1970, 976 earthquakes were detected near the oil field by the UBO station; 320 earthquakes were larger than magnitude 1. Richter magnitudes are estimated from both S-wave and P-wave measurements and a method based on the duration of the seismic signal is used to estimate the magnitude of the larger shocks. The two largest shocks had magnitudes of 3.4 and 3.3. The total seismic energy released was l0 l7 ergs. During this same period the energy used for water injection, measured at the wellhead, was 10 21 ergs.
Colorado↗
Principal stress directions from plastic flow in crystals
Methods for determining orientations of principal stress axes in deformed rocks involve dynamic analysis of twin-gliding and of extinction bands produced by inhomogeneous translation gliding in crystals. The methods, beginning with Turner's (1953) technique for dynamic analysis of calcite twins, have been developed using as guides the results from experiments under controlled laboratory conditions. Structures induced by intragranular flow in calcite, dolomite, quartz, micas, orthopyroxenes, clinopyroxenes, olivine, and other common rock-forming materials, may now be used to derive orientations of principal stresses causing the deformation. The various methods, some new, are discussed in detail and examples of their application to tectonites are given. The usefulness of such studies is illustrated by evaluating the observed orientations of principal stresses around folds in light of new data from a theoretical analysis of large amplitude folding of viscous layers in a less viscous matrix. Other areas of research in structural geology in which these methods should prove useful have also been outlined.
Geological Society of America Bulletin↗