Publications
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Non-double-couple earthquake mechanisms at the Geysers geothermal area, California
Inverting P- and S-wave polarities and P:SH amplitude ratios using linear programming methods suggests that about 20% of earthquakes at The Geysers geothermal area have significantly non-double-couple focal mechanisms, with explosive volumetric components as large as 33% of the seismic moment. This conclusion contrasts with those of earlier studies, which interpreted data in terms of double couple
Authors
A. Ross, G. R. Foulger, B. R. Julian
Long-term geochemical surveillance of fumaroles at Showa-Shinzan dome, Usu volcano, Japan
This study investigates 31 years of fumarole gas and condensate (trace elements) data from Showa-Shinzan, a dacitic dome-cryptodome complex that formed during the 1943-1945 eruption of Usu volcano. Forty-two gas samples were collected from the highest-temperature fumarole, named A-1, from 1954 (800??C) to 1985 (336??C), and from lower-temperature vents. Condensates were collected contemporaneously
Authors
R.B. Symonds, Y. Mizutani, Paul H. Briggs
Geomagnetic storms, the Dst ring-current myth and lognormal distributions
The definition of geomagnetic storms dates back to the turn of the century when researchers recognized the unique shape of the H-component field change upon averaging storms recorded at low latitude observatories. A generally accepted modeling of the storm field sources as a magnetospheric ring current was settled about 30 years ago at the start of space exploration and the discovery of the Van Al
Authors
W.H. Campbell
Exsolved magmatic fluid and its role in the formation of comb-layered quartz at the Cretaceous Logtung W-Mo deposit, Yukon Territory, Canada
Comb-layered quartz is a type of unidirectional solidification texture found at the roofs of shallow silicic intrusions that are often associated spatially with Mo and W mineralisation. The texture consists of multiple layers of euhedral, prismatic quartz crystals (Type I) that have grown on subplanar aplite substrates. The layers are separated by porphyritic aplite containing equant phenocrysts o
Authors
J. B. Lowenstern, W.D. Sinclair
This dynamic earth: the story of plate tectonics
In the early 1960s, the emergence of the theory of plate tectonics started a revolution in the earth sciences. Since then, scientists have verified and refined this theory, and now have a much better understanding of how our planet has been shaped by plate-tectonic processes. We now know that, directly or indirectly, plate tectonics influences nearly all geologic processes, past and present. Indee
Authors
W. Jacquelyne Kious, Robert I. Tilling
Chemical analyses for the geologic map of the Island of Hawaii
No abstract available.
Authors
E.W. Wolfe
Data base of impact craters on Venus based on analysis of Magellan radar images and altimetry data
No abstract available.
Authors
Gerald G. Schaber, Randolph L. Kirk, Robert G. Strom
Photographs of the 1989-90 eruptions of Redoubt Volcano, Alaska
No abstract available.
Authors
A.L. Roach, Christina A. Neal, R. G. McGimsey
Provisional geologic map of Augustine Volcano, Alaska
No abstract available.
Authors
R. B. Waitt, J. E. Beget, Juergen Kienle
Geothermal resources in the Crater Lake area, Oregon
No abstract available.
Authors
Charles R. Bacon, Manuel Nathenson
Database of potential sources for earthquakes larger than magnitude 6 in Northern California
The Northern California Earthquake Potential (NCEP) working group, composed of many contributors and reviewers in industry, academia and government, has pooled its collective expertise and knowledge of regional tectonics to identify potential sources of large earthquakes in northern California. We have created a map and database of active faults, both surficial and buried, that forms the basis for
Authors