Publications

Spectacular volcanic scenery and features were the inspiration for creating many of our national parks and monuments and continue to enhance the visitor experience today (Table 1). At the same time, several of these parks include active and potentially active volcanoes that could pose serious hazards - earthquakes, mudflows, and hydrothermal explosions, as well as eruptions - events that would pro

This region of Yellowstone National Park has been the active focus of one of the Earth's largest magmatic systems for more than 2 million years. The resulting volcanism has been characterized by the eruption of voluminous rhyolites and subordinate basalts but virtually no lavas of intermediate composition. The magmatic system at depth remains active and drives the massive hydrothermal circulation

Stratigraphic and chronologic information collected for Quaternary deposits in the Willamette Valley, Oregon, provides a revised stratigraphic framework that serves as a basis for a 1:250,000-scale map, as well as for thickness estimates of widespread Quaternary geologic units. We have mapped 11 separate Quaternary units that are differentiated on the basis of stratigraphic, topographic, pedogenic

Three Sisters is one of three potentially active volcanic centers that lie close to rapidly growing communities and resort areas in Central Oregon. Two types of volcanoes exist in the Three Sisters region and each poses distinct hazards to people and property. South Sister, Middle Sister, and Broken Top, major composite volcanoes clustered near the center of the region, have erupted repeatedly ove

No abstract available

The collection of nine papers that follow continue the series of U.S. Geological Survey (USGS) investigative reports in Alaska under the broad umbrella of the geologic sciences. The series presents new and sometimes preliminary findings that are of interest to earth scientists in academia, government, and industry; to land and resource managers; and to the general public. Reports presented in Geol

At 4392 m high, glacier-clad Mount Rainier dominates the skyline of the southern Puget Sound region and is the centerpiece of Mount Rainier National Park. About 2.5 million people of the greater Seattle-Tacoma metropolitan area can see Mount Rainier on clear days, and 150,000 live in areas swept by lahars and floods that emanated from the volcano during the last 6,000 years (Figure 1). These lahar

In most models of the flow of glaciers on till beds, it has been assumed that till behaves as a viscoplastic fluid, despite contradictory evidence from laboratory studies. In accord with this assumption, displacement profiles measured in subglacial till have been fitted with viscoplastic models by estimating the stress distribution. Here we present a model that illustrates how observed displacemen

No abstract available.

No abstract available.

During the past century, numerous observers have described the violent ejection of large blocks and bombs from volcanoes during volcanic explosions. Minakami (1942) mapped the locations of blocks ejected from Asama Volcano during explosions in 1937. He developed a mathematical expression relating initial velocity and trajectory angle of ejected blocks to the ejection distance, taking into account

Hydrologic data were collected during 1994-96 as part of the U.S. Geological Survey's long-term Volcanic Hazards Monitoring Program of the Long Valley Caldera, Mono County, California, and the Long Valley Hydrologic Advisory Committee monitoring program. Hydrologic data collected include continuous record of ground-water levels in 4 wells; instantaneous measurements of ground-water levels in 53 we