Publications
Filter Total Items: 3103
Lessons in reducing volcano risk Lessons in reducing volcano risk
No abstract available.
Authors
Robert I. Tilling, Peter W. Lipman
Reappraisal of three calcareous nannofossil species: Coccolithus crassus, Toweius magnicrassus, and Toweius callosus Reappraisal of three calcareous nannofossil species: Coccolithus crassus, Toweius magnicrassus, and Toweius callosus
Type material of calcareous nannofossil index species Coccolithus crassus and two geographically widespread species Toweius magnicrassus and T. callosus have been studied by both light and SEM microscopy and morphometric measurements were made. Coccolithus crassus resembles Coccolithus pelagicus but has a raised cycle of elements around the centre of the distal shield. It probably...
Authors
Wuchang Wei, L. Liu, David Bukry
Internal structure of the Sierra Nevada batholith based on specific gravity and gravity measurements Internal structure of the Sierra Nevada batholith based on specific gravity and gravity measurements
About 6,000 specific‐gravity (SG) measurements of samples collected from nearly 200 granitic plutons comprising the central Sierra Nevada batholith yield a SG contour map across the batholith from 36.25° to 38° north latitude. With notable exceptions, SG decreases from values generally greater than 2.7 in the west to less than 2.6 over a few small areas of high‐silica, high‐potassium...
Authors
H.W. Oliver, Bryan Moore, R. F. Sikora
Where lava meets the sea; Kilauea Volcano, Hawaii Where lava meets the sea; Kilauea Volcano, Hawaii
Active volcanoes on the island of Hawai'i provide scientists with exceptional opportunities to observe volcanic phenomena at close range. Such an opportunity occurred on November 24, 1992, when geologists from the Hawaiian Volcano Observatory (HVO) witnessed spectacular explosive interactions between lava and seawater on the southeast coast of the island. As seawater invaded submarine...
Authors
T. N. Mattox
Deformation of the Wineglass Welded Tuff and the timing of caldera collapse at Crater Lake, Oregon Deformation of the Wineglass Welded Tuff and the timing of caldera collapse at Crater Lake, Oregon
Four types of deformation occur in the Wineglass Welded Tuff on the northeast caldera rim of Crater Lake: (a) vertical tension fractures; (b) ooze-outs of fiamme: (c) squeeze-outs of fiamme; and (d) horizontal pull-apart structures. The three types of plastic deformation (b-d) developed in the lower part of the Wineglass Welded Tuff where degree of welding and density are maximum...
Authors
H. Kamata, K. Suzuki-Kamata, C. R. Bacon
Heat flow from four new research drill holes in the Western Cascades, Oregon, U.S.A. Heat flow from four new research drill holes in the Western Cascades, Oregon, U.S.A.
Conceptual models of the thermal structure of the Oregon Cascade Range propose either (1) a narrow zone of magmatic heat sources, flanked by shallow heat-flow anomalies caused by lateral ground-water flow; or (2) a wide zone of magmatic heat sources, with localized, generally negligible ground-water effects. The proposed narrow heat source coincides with the Quaternary volcanic arc...
Authors
S. E. Ingebritsen, M. A. Scholl, D. R. Sherrod
Volcanic activity in Alaska: September 1991-September 1992 Volcanic activity in Alaska: September 1991-September 1992
More than 40 historically active volcanic centers, each consisting of one or more volcanoes, are located on the Alaska Peninsula and Aleutian Islands (see map on next page). On average, at least one of these volcanoes erupts each year.
Authors
Game McGimsey
Scanning electron microscope observations of sublimates from Merapi Volcano, Indonesia Scanning electron microscope observations of sublimates from Merapi Volcano, Indonesia
Sublimates were sampled from high-temperature (up to 800°C) fumaroles at Merapi volcano, Indonesia in January 1984. Sampling is accomplished by inserting silica tubes into high-temperature vents. Volcanic gas flows through the tubes and sublimates precipitate on the inner walls in response to the temperature gradient. With decreasing temperature (800–500°C) in the tubes, there are five...
Authors
Robert B. Symonds
Thermodynamic evaluation and restoration of volcanic gas analyses: An example based on modern collection and analytical methods Thermodynamic evaluation and restoration of volcanic gas analyses: An example based on modern collection and analytical methods
Thermodynamic evaluation and restoration procedures are applied to a set of 10 volcanic gas analyses obtained by modern collection and analytical methods. The samples were collected from a vigorously fuming fissure during episode 1 of the Puu Oo eruption of Kilauea Volcano in 1983. A variety of analytical techniques were used to determine the gas compositions. In most samples, the...
Authors
Terrance M. Gerlach
Preventing volcanic catastrophe; the U.S. International Volcano Disaster Assistance Program Preventing volcanic catastrophe; the U.S. International Volcano Disaster Assistance Program
When the seismograph began to record the violent earth-shaking caused by yet another eruption of the Nevado del Ruiz volcano in Colombia, no one thought that a few hours later more than 23,000 people would be dead, killed by lahars (volcanic debris flows) in towns and villages several tens of kilometers away from the volcano. Before the fatal eruption the volcano was being monitored by...
Authors
J.W. Ewert, T.L. Murray, A. B. Lockhart, C.D. Miller
Chemical analyses of pre-Mazama silicic volcanic rocks, inclusions, and glass separates, Crater Lake, Oregon Chemical analyses of pre-Mazama silicic volcanic rocks, inclusions, and glass separates, Crater Lake, Oregon
No abstract available.
Authors
P. E. Bruggman, C. R. Bacon, J. S. Mee, S. T. Pribble, D. F. Siems