Publications

INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined...

The distribution of hydrothermal circulation within active volcanoes is of importance in identifying regions of hydrothermal alteration which may in turn control explosivity, slope stability and sector collapse. Self-potential measurements, indicative of fluid circulation, were made within the crater of Mount St. Helens in 2000 and 2001. A strong dipolar anomaly in the self-potential...

We present and analyze a chemical dataset that includes the concentrations and fluxes of HCO3−, SO42−, Cl−, and F− in the major rivers draining Yellowstone National Park (YNP) for the 2002–2004 water years (1 October 2001 – 30 September 2004). The total (molar) flux in all rivers decreases in the following order, HCO3− > Cl− > SO42− > F−, but each river is characterized by a distinct...

We analyze seismic data from the San Andreas Fault (SAF) near Parkfield, California, to test for annual modulation in seismicity rates. We use statistical analyses to show that seismicity is modulated with an annual period in the creeping section of the fault and a semiannual period in the locked section of the fault. Although the exact mechanism for seasonal triggering is undetermined...

Compositional data for >400 pumice clasts, organized according to eruptive sequence, crystal content, and texture, provide new perspectives on eruption and pre-eruptive evolution of the >600 km3 of zoned rhyolitic magma ejected as the Bishop Tuff during formation of Long Valley caldera. Proportions and compositions of different pumice types are given for each ignimbrite package and for...

Since 2003, 27 independent look angles have been acquired by ENVISAT’s Advanced Synthetic Aperture Radar (ASAR) instrument over the island of Hawai`i, allowing for the formation of thousands of interferograms showing deformation of the ground surface. On Kīlauea volcano, a transition from minor to broad-scale summit inflation was observed by interferograms that span 2003 to 2006. In...

We compare eruptive dynamics, effects and deposits of the Bezymianny 1956 (BZ), Mount St Helens 1980 (MSH), and Soufrière Hills volcano, Montserrat 1997 (SHV) eruptions, the key events of which included powerful directed blasts. Each blast subsequently generated a high-energy stratified pyroclastic density current (PDC) with a high speed at onset. The blasts were triggered by rapid...

The Yellowstone-Snake River Plain tectonomagmatic province resulted from Late Tertiary volcanism in western North America, producing three large, caldera-forming eruptions at the Yellowstone Plateau in the last 2 Myr. To understand the kinematics and geodynamics of this volcanic system, the University of Utah conducted seven GPS campaigns at 140 sites between 1987 and 2003 and installed...

This chapter contains sections titled: Introduction Geologic setting Field and Analytical Methods Results Discussion Conclusions

The National Volcano Early Warning System (NVEWS) is a proposed national-scale effort by the U.S. Geological Survey (USGS) Volcano Hazards Program and its affiliated partners in the Consortium of U.S. Volcano Observatories (CUSVO) (http://www.cusvo.org) to ensure that volcanoes are monitored at a level commensurate with the threats they pose. Roughly half of the Nation’s 169 young...

Mount Spurr, a 3,374-m-high stratovolcano in the Cook Inlet region of Alaska, showed signs of volcanic unrest beginning in 2004 and lasting through 2006. These signs included increases in heat flow, seismicity, and gas flux, which we interpret as the results of a magmatic intrusion in mid-2004. In response, debris-laden meltwater beneath the glacier in Mount Spurr's geothermally active...

To provide Yellowstone National Park (YNP) and its surrounding communities with a modern, comprehensive system for volcano and earthquake monitoring, the Yellowstone Volcano Observatory (YVO) has developed a monitoring plan for the period 2006-2015. Such a plan is needed so that YVO can provide timely information during seismic, volcanic, and hydrothermal crises and can anticipate...