Publications

This report provides a detailed picture of the rockslide-debris avalanche of the May 18, 1980, eruption of Mount St. Helens volcano. It provides a characterization of the deposit, a reinterpretation of the details of the first minutes of the eruption of May 18, and insight into the transport mechanism of the mass movement. Details of the rockslide event, as revealed by eyewitness photographs, are

The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska, Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained a program of seismic monitoring at potentially active volcanoes in the Cook Inlet region since 1988. The principal objectives of this program include the seismic sur

The Alaska Volcano Observatory (AVO) responded to eruptive activity or suspected volcanic activity (SVA) at 6 volcanic centers in 1995: Mount Martin (Katmai Group), Mount Veniaminof, Shishaldin, Makushin, Kliuchef/Korovin, and Kanaga. In addition to responding to eruptive activity at Alaska volcanoes, AVO also disseminated information for the Kamchatkan Volcanic Eruption Response Team (KVERT) on t

A proposed high‐altitude survey of the United States offers an exciting and cost effective opportunity to collect magnetic‐anomaly data. Lockheed Martin Missile and Space Company is considering funding a reimbursable ER‐2 aircraft (Figure 1) mission to collect synthetic aperture radar (SAR) imagery at an altitude of about 21 km over the conterminous United States and Alaska. The collection of tota

Earthquake focal mechanisms of events occurring between 1972 and 1992 in the south flank of Kilauea volcano, Hawaii, are used to infer the state of stress and strain as a function of time and space. We have determined 870 fault plane solutions from P wave first motion polarities for events with magnitudes ML ≥ 2.5 and depth ranging between 6 and 12 km. Faulting is characterized by a mixture of dec

The enactment of the Energy Policy Act of 1992 saw the assignment of definite responsibilities relating to hot dry rock (HDR) to the US Geological Survey (USGS). This mandate provided some explicit guidelines and individual tasks in areas in which the USGS already had close ties to the Department of Energy and a number of its national laboratories. This paper discusses various tasks in terms of pr

Reinterpretation of a voluminous regional ash-flow sheet (Masonic Park Tuff) as two separate tuff sheets of similar phenocryst-rich dacite erupted from separate source calderas has important implications for evolution of the multicyclic Platoro caldera complex and for caldera-forming processes generally. Masonic Park Tuff in central parts of the San Juan field, including the type area, was erupted

Published accounts of outburst floods from glacier‐dammed lakes show that a significant number of such floods are associated not with drainage through a tunnel incised into the basal ice—the process generally assumed—but rather with ice‐marginal drainage, mechanical failure of part of the ice dam, or both. Non‐tunnel floods are strongly correlated with formation of an ice dam by a glacier advancin

As a comparison to airborne infrared (IR) flux measurements, ground-based sampling of fumarole and soil gases was used to characterize the quiescent degassing of CO2 from Oldoinyo Lengai volcano. Aerial and ground-based measurements are in good agreement: ~75% of the aerially measured CO2 flux at Lengai (0.05-0.06 x 1012 mol yr-1 or 6000-7200 tonnes CO2 d-1) can be attributed to seven large crater

Isotope tracer methods were used to determine flow paths, recharge areas, and relative age for groundwater in the Kilauea volcano area of the Island of Hawaii. A network of up to 66 precipitation collectors was emplaced in the study area and sampled twice yearly for a 3-year period. Stable isotopes in rainfall show three distinct isotopic gradients with elevation, which are correlated with trade w

Numerical simulations of multiphase fluid and heat transport through a porous medium define combinations of rock properties and boundary conditions which lead to geyser‐like periodic discharge. Within the rather narrow range of conditions that allow geyser‐like behavior, eruption frequency and discharge are highly sensitive to the intrinsic permeabilities of the geyser conduit and the surrounding

Channel adjustments in the North Fork Toutle River and the Toutle River main stem were initiated by deposition of a 2.5km3 debris avalanche and associated lahars that accompanied the catastrophic eruption of Mount St. Helens, Washington on 18 May 1980. Channel widening was the dominant process. In combination, adjustments caused average boundary shear stress to decrease non-linearly with time and