Seismological investigations at The Geysers geothermal field
E. L. Majer,Thomas V. McEvilly +1 more
Reads0
Chats0
TLDR
The geysers geothermal field is characterized by regionally anomalous high P-and S-wave velocities and low attenuation, but the anomaly seems to decrease, possibly reversing, with depth as mentioned in this paper.Abstract:
Two short (4 and 6 day) recording periods at The Geysers geothermal field provided useful data on two large refraction explosions and numerous microearthquakes. The vapor-dominated reservoir appears to be characterized by regionally anomalous high P- and S-wave velocities and low attenuation, but the anomaly seems to decrease, possibly reversing, with depth. Microearthquakes occur in a diffuse pattern, with no indication of dominant throughgoing faults and an absence of activity in the main production zone. Mechanisms are generally consistent with northeast-southwest compression. Occurrence rates indicate a slightly high incidence of smaller magnitude shocks. It is possible that the microearthquake activity is related to an expanding steam zone. While the present anomalies appear to delineate the reservoir, it is not certain that they would have been detectable during exploration prior to large-scale exploitation of the field.read more
Figures
Citations
More filters
Journal ArticleDOI
Fault zone models, heat flow, and the depth distribution of earthquakes in the continental crust of the United States
TL;DR: In this article, the authors show that the maximum depth of microseismic activity in various heat flow provinces of the conterminous United States generally correlates well with the frictional to quasi-plastic transition modeled for the different geotherms.
Journal ArticleDOI
Induced seismicity associated with Enhanced Geothermal Systems
Ernest L. Majer,Roy Baria,Mitch Stark,Stephen J. Oates,Julian J. Bommer,Bill Smith,Hiroshi Asanuma +6 more
TL;DR: In this paper, the authors present an up-to-date review of the state of knowledge about induced seismicity during the creation and operation of enhanced geothermal systems, and point out the gaps in knowledge that if addressed will allow an improved understanding of the mechanisms generating the events as well as serve as a basis to develop successful protocols for monitoring and addressing community issues associated with such induced earthquakes.
Journal ArticleDOI
Continental fault structure and the shallow earthquake source
TL;DR: A simple 2-level model for these important structures accounts for the depth distribution of most continental earthquakes, and for the observed range of faulting styles and associated rock deformation textures as mentioned in this paper.
Journal ArticleDOI
Petroleum reservoir characterization using downhole microseismic monitoring
TL;DR: A few key projects were instrumental in the development of downhole microseismic imaging, such as the Cotton Valley imaging project and earlier experiments at the M-Site in the Piceance basin this article.
Journal ArticleDOI
A note on induced stress changes in hydrocarbon and geothermal reservoirs
Paul Segall,Shaun D. Fitzgerald +1 more
TL;DR: In this paper, the authors show that the least horizontal stress decreases with decreasing reservoir pressure, as predicted by poroelasticity, and that dilatant fracturing and normal faulting are always promoted, in extensional environments, near the edge of the reservoir or in regions of high pore-pressure gradient.
References
More filters
Journal ArticleDOI
Tectonic stress and the spectra of seismic shear waves from earthquakes
TL;DR: In this paper, an earthquake model is derived by considering the effective stress available to accelerate the sides of the fault, and the model describes near and far-field displacement-time functions and spectra and includes the effect of fractional stress drop.
Journal ArticleDOI
Role of fluid pressure in mechanics of overthrust faulting: I. Mechanics of fluid-filled porous solids and its application to overthrust faulting
M. King Hubbert,William W. Rubey +1 more
TL;DR: In this article, it was shown that the critical value of the shearing stress can be made arbitrarily small simply by increasing the fluid pressure p. This can be further simplified by expressing p in terms of S by means of the equation which, when introduced into equation (4), gives
Journal ArticleDOI
The frequency-magnitude relation of microfracturing in rock and its relation to earthquakes
TL;DR: In this paper, the frequency-magnitude relation of microfracture deformation was studied and the dependence of the parameter b on rock type, stress, and confining pressure was found to depend primarily on stress.
Journal ArticleDOI
Properties of some common igneous rocks and their melts at high temperatures
TL;DR: The properties of four igneous rocks (a tholeiitic and an alkali-olivine basalt, an andesite, and a rhyolite) and a synthetic lunar sample have been determined at atmospheric pressure over a range of temperatures including their melting interval as discussed by the authors.
Journal ArticleDOI
Stick-slip as a mechanism for earthquakes.
W. F. Brace,James D. Byerlee +1 more
TL;DR: Stick-slip often accompanies frictional sliding in laboratory experi ments with geologic materials and may represent stick slip during sliding along old or newly formed faults in the earth.