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Oxidized sulfur-rich mafic magma at Mount Pinatubo, Philippines Oxidized sulfur-rich mafic magma at Mount Pinatubo, Philippines

Basaltic fragments enclosed in andesitic dome lavas and pyroclastic flows erupted during the early stages of the 1991 eruption of Mount Pinatubo, Philippines, contain amphiboles that crystallized during the injection of mafic magma into a dacitic magma body. The amphiboles contain abundant melt inclusions, which recorded the mixing of andesitic melt in the mafic magma and rhyolitic melt...
Authors
J.C.M. de Hoog, K.H. Hattori, R. Hoblitt

Non-double-couple microearthquakes at Long Valley caldera, California, provide evidence for hydraulic fracturing Non-double-couple microearthquakes at Long Valley caldera, California, provide evidence for hydraulic fracturing

Most of 26 small (0.4≲M≲3.1) microearthquakes at Long Valley caldera in mid-1997, analyzed using data from a dense temporary network of 69 digital three-component seismometers, have significantly non-double-couple focal mechanisms, inconsistent with simple shear faulting. We determined their mechanisms by inverting P- and S-wave polarities and amplitude ratios using linear-programming...
Authors
G.R. Foulger, B.R. Julian, D.P. Hill, A.D. Pitt, P.E. Malin, E. Shalev

1999 Volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory 1999 Volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory

The Alaska Volcano Observatory (AVO) monitors 41 historically active volcanoes along the Aleutian Arc. Twenty are seismically monitored and for the rest, the AVO monitoring program relies mainly on daily analysis of satellite images, pilot reports, and observations of local residents and ship's crews. In 1999, AVO responded to eruptive activity or suspect volcanic activity at 7 volcanic...
Authors
Robert G. McGimsey, Christina A. Neal, Olga Girina

Debris flow Debris flow

No abstract available.
Authors
Richard M. Iverson

Large floods in the United States: Where they happen and why Large floods in the United States: Where they happen and why

The spatial distribution of large gaged floods throughout the United States shows that the locations of most of the largest flows are related to specific combinations of regional climatology, topography, and basin size. Key factors include the general northward trend of decreasing atmospheric moisture, proximity to oceanic moisture sources such as the Pacific Ocean and the Gulf of Mexico...
Authors
Jim E. O'Connor, John E. Costa

The Pu‘u ‘Ō‘ō-Kūpaianaha eruption of Kīlauea Volcano, Hawai‘i: The first 20 years The Pu‘u ‘Ō‘ō-Kūpaianaha eruption of Kīlauea Volcano, Hawai‘i: The first 20 years

The Pu'u 'O'o-Kupaianaha eruption started on January 3, 1983. The ensuing 20-year period of nearly continuous eruption is the longest at Kilauea Volcano since the famous lava-lake activity of the 19th century. No rift-zone eruption in more than 600 years even comes close to matching the duration and volume of activity of these past two decades. Fortunately, such a landmark event came...

When models meet managers: Examples from geomorphology When models meet managers: Examples from geomorphology

No abstract available.
Authors
Peter R. Wilcock, John C. Schmidt, M. Gordon Wolman, William E. Dietrich, DeWitt Dominick, Martin W. Doyle, Gordon E. Grant, Richard M. Iverson, David R. Montgomery, Thomas C. Pierson, Steven P. Schilling, Raymond C. Wilson

Prediction in geomorphology Prediction in geomorphology

No abstract available.
Authors
Peter R. Wilcock, Richard M. Iverson

Gravity-driven mass flows Gravity-driven mass flows

Gravity-driven mass flows, also known as sediment gravity flows, include a spectrum of phenomena in which more-or-less coherent mixtures of grains and intergranular fluid flow down slopes. At one end of this spectrum are dilute flows in which momentum is transferred mostly by fluid forces and sediment is largely a passive cargo that increases the effective fluid density. These dilute...
Authors
Richard M. Iverson
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