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Eruptive activity at Mount St Helens, Washington, USA, 1984-1988: a gas geochemistry perspective Eruptive activity at Mount St Helens, Washington, USA, 1984-1988: a gas geochemistry perspective

The results from two different types of gas measurement, telemetered in situ monitoring of reducing gases on the dome and airborne measurements of sulfur dioxide emission rates in the plume by correlation spectrometry, suggest that the combination of these two methods is particularly effective in detecting periods of enhanced degassing that intermittently punctuate the normal background...
Authors
K.A. McGee, A. J. Sutton

Chaotic deposition by a giant wave, Molokai, Hawaii Chaotic deposition by a giant wave, Molokai, Hawaii

A coral-basalt breccia-conglomerate is exposed >60m above present sea level and nearly 2km inland from the present shoreline on the southwest side of East Molokai Volcano. This deposits was apparently laid down by a giant wave that broke over an outer reef, similar to the present fringing reef, and advanced as a turbulent bore over the back-reef flat, picking up a slurry of carbonate...
Authors
J.G. Moore, W.B. Bryan, K.R. Ludwig

Stability of submerged slopes on the flanks of the Hawaiian Islands, a simplified approach Stability of submerged slopes on the flanks of the Hawaiian Islands, a simplified approach

Undersea transmission lines and shoreline AC-DC conversion stations and near-shore transmission lines are being considered as part of a system for transporting energy between the Hawaiian Islands. These facilities will need to be designed so that they will not be damaged or destroyed by coastal or undersea landslides. Advanced site surveys and engineering design of these facilities will...
Authors
Homa J. Lee, Michael Torresan, William McArthur

Channelized subglacial drainage over a deformable bed Channelized subglacial drainage over a deformable bed

We develop theoretically a description of a possible subglacial drainage mechanism for glaciers and ice sheets moving over saturated, deformable till. The model is based on the plausible assumption that flow of water in a thin film at the ice-till interface is unstable to the formation of a channelized drainage system, and is restricted to the case in which meltwater cannot escape...
Authors
J. S. Walder, A. Fowler

Deformation from 1973 to 1987 in the epicentral area of the 1959 Hebgen Lake, Montana, earthquake (Ms = 7.5) Deformation from 1973 to 1987 in the epicentral area of the 1959 Hebgen Lake, Montana, earthquake (Ms = 7.5)

A 40‐km aperture trilateration network centered on the 1959 Hebgen Lake earthquake epicenter has been surveyed in 1973, 1974, 1976, 1978, 1981, 1984, and 1987. The deformation inferred from those surveys is described roughly by a uniaxial, 0.266 ± 0.014 μstrain/yr, N15°E ± 1°extension that is uniform in both time and space. That extension is orthogonal to the strike (N78°W ± 5°) of the...
Authors
James C. Savage, Michael Lisowski, W.H. Prescott, A.D. Pitt

Klamath Falls earthquakes, September 20, 1993 — Including the strongest quake ever measured in Oregon Klamath Falls earthquakes, September 20, 1993 — Including the strongest quake ever measured in Oregon

Earthquakes struck the Klamath Falls area on Monday night, September 20, 1993, resulting in two deaths and extensive damage. The quakes were felt as far away as Coos Bay to the west, Eugene to the north, Lakeview to the east, and Chico, California, to the south. A foreshock recorded at 8:16 p.m. had a Richter magnitude of 3.9. The first of two main shocks, measuring 5.9 on the Richter...
Authors
T. J. Wiley, David R. Sherrod, David K. Keefer, Anthony Qamar, Robert L. Schuster, James W. Dewey, Matthew A. Mabey, Gerald L. Black, Ray E. Wells

Evolution of the caldera‐forming eruption at Crater Lake, Oregon, indicated by component analysis of lithic fragments Evolution of the caldera‐forming eruption at Crater Lake, Oregon, indicated by component analysis of lithic fragments

Crater Lake caldera (8 × 10 km), formed 6845 years B. P. (14C age) during the climactic eruption of the volcanic edifice known as Mount Mazama, is intermediate in size between small calderas associated with central vent eruptions and large calderas that have ring fracture vent systems. Our quantitative study of lithic fragments in the ejecta confirms the existing model of changes in vent
Authors
K. Suzuki-Kamata, H. Kamata, Charles R. Bacon

Anatomy of a basaltic volcano Anatomy of a basaltic volcano

Kilauea volcano, in Hawaii, may be the best understood basaltic volcano in the world. Magma rises from a depth of 80 km or more and resides temporarily in near-surface reservoirs: eruption begins when the crust above one of these reservoirs splits open in response to a pressure increase. Repeated rift-zone eruptions compress Kilauea's flanks; after decades of accumulation, the stress is...
Authors
Robert I. Tilling, J.J. Dvorak

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
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