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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

Preliminary geomagnetic paleointensities from Long Valley Caldera, California Preliminary geomagnetic paleointensities from Long Valley Caldera, California

Paleointensities are being determined in order to characterize geomagnetic intensity variations during Quaternary time. Because the geomagnetic field acts as a shield against cosmic radiation, its intensity directly affects the production rate of radiocarbon (^C) in the upper atmosphere. Coe and others (1978) showed that the variation in dipole moment during Holocene time is nearly...
Authors
Edward A. Mankinen

Biogenic silica in Lake Baikal sediments: results from 1990-1992 American cores Biogenic silica in Lake Baikal sediments: results from 1990-1992 American cores

The Lake Baikal Paleoclimate Project is a joint Russian-American program established to study the paleoclimate of Central Asia. During three summer field seasons, duplicate Russian and American cores were taken at a number of sites in different sedimentary environments in the lake. Eight cores returned to the U.S. were quantitatively analyzed for biogenic silica using a single-step 5...
Authors
Susan J. Carter, Steven M. Colman

Antifouling leaching technique for optical lenses Antifouling leaching technique for optical lenses

The effectiveness of optical lenses deployed in water less than 100 m deep is significantly reduced by biofouling caused by the settlement of macrofauna, such as barnacles, hydroids, and tunicates. However, machineable porous plastic rings can be used to dispense antifoulant into the water in front of the lens to retard macrofaunal growth without obstructing the light path. Unlike...
Authors
William J. Strahle, C. L. Perez, Marinna A. Martini

New recording package for VACM provides sensor flexibility New recording package for VACM provides sensor flexibility

For the past three decades, the VACM has been a standard for ocean current measurements. A VACM is a true vector-averaging instrument that computes north and east current vectors and averages temperature continuously over a specified interval. It keeps a running total of rotor counts, and records one-shot samples of compass, vane position and time. Adding peripheral sensors to the data...
Authors
William J. Strahle, S. E. Worrilow, S. E. Fucile, Marinna A. Martini

Potential for seepage erosion of landslide dam Potential for seepage erosion of landslide dam

The failure potential of the debris-avalanche dam at Castle Lake near Mount St. Helens, Washington, by three processes of seepage erosion (1) Heave; (2) piping; and (3) internal erosion, is examined. Results indicated that the dam is stable against piping but potentially locally unstable against heave. -from Authors
Authors
W. Meyer, R. L. Schuster, M. A. Sabol

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

The importance of earthquake-induced landslides to long-term slope erosion and slope-failure hazards in seismically active regions The importance of earthquake-induced landslides to long-term slope erosion and slope-failure hazards in seismically active regions

This paper describes a general method for determining the amount of earthquake-induced landsliding that occurs in a seismically active region over time; this determination can be used as a quantitative measure of the long-term hazard from seismically triggered landslides as well as a measure of the importance of this process to regional slope-erosion rates and landscape evolution. The...
Authors
D. K. Keefer

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
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