Publications

During or immediately following the transit of Hurricane Andrew (August 23-24, 1992) across the northern part of the Great Bahama Bank, thin laminated beds of carbonate mud were deposited in high-energy subtidal channels (4 m depth) through the ooid shoals of south Cat Cay and Joulters Cays. During our reconnaissance seven weeks later, we observed lime-mud beds exposed in the troughs of submarine

The generation of seismically induced landslide depends on the characteristics of shaking as well as mechanical properties of geologic materials. A very important parameter in the study of seismically induced landslide is the intensity based on a strong-motion accelerogram: it is defined as Arias intensity and is proportional to the duration of the shaking record as well as the amplitude. Having a

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.

No abstract available.

In a handful of molten magma weighing about a pound, there is less than a tenth of an ounce, by weight, of idssolved gas-roughly the same weight as a pinch of table salt. Yet this tiny amount of gas produces spectacular lava foundations hundreds of meters high (see accompanying photograph). The fountain occurs as magma reaches the surface, because dissolved volcanic gases exolve and expand tremend

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 conduits tra

The Klamath Falls earthquakes caused landslides throughout an area of about 420 sq km and as far as about 29 km from the epicenter, a distribution that is typical for magnitude 6 earthquakes (see graphs on following pages). Most of the landslides were rock falls or shallow, highly disrupted rock slides from roadcuts, quarries, and steep bluff faces. Such landslides are also among the most common t

Slope instability along a new highway bypass in Golden, Colorado, became a major concern in 1993. Rains and snowmelt accelerated movement of a landslide that had begun to develop before the bypass was opened to traffic in July of 1991. The downslope movement of earth materials increased significantly in 1993. During the first few months of the year, the landslide pushed onto the west shoulder of t

The mammoth Slumgullion landslide in southwestern Colorado is the largest actively moving landslide in Colorado and, perhaps, the entire country. To learn more about how and why landslides move the way they do, scientists at the U.S Geological Survey (USGS) have observed and monitored the remarkably regular movement of this landslide for more than 30 years. Located near Lake City in the San Juan M

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 scientists

On June 27, 1992, the Crater Peak vent on the south side of Mt. Spurr awoke from 39 years of dormancy and burst into subplinian eruption after 10 months of elevated seismicity. Two more eruptions followed in August and September. The volcano lies 125-km west of Anchorage, which is Alaska's largest city and an important international hub for air travel. The Alaska Volcano Observatory (AVO) was able

Many landslides and debris flows have originated from Mount Rainier since the retreat of glaciers from Puget Sound about 10,000 years ago. The recurrent instability is due to several factors--height of the steep-sided volcanic cone, frequent volcanic activity, continuous weakening of rock by steam and hot, chemical-laden water, and exposure of unstable areas as the mountains glaciers have receded.