Publications

The 2005–6 eruption of Augustine Volcano produced tephra-fall deposits during each of four eruptive phases. Late in the precursory phase (December 2005), small phreatic explosions produced small-volume, localized, mostly nonjuvenile tephra. The greatest volume of tephra was produced during the explosive phase (January 11–28, 2006) when 13 discrete Vulcanian explosions generated ash plumes between

During and after the 2006 eruption of Augustine Volcano, we compiled a geologic map and chronology of new lava and flowage deposits using observational flights, oblique and aerial photography, infrared imaging, satellite data, and field investigations. After approximately 6 months of precursory activity, the explosive phase of the eruption commenced with two explosions on January 11, 2006 (events

Dissemination of volcano-hazard information in coordination with other Federal, State, and local agencies is a primary responsibility of the Alaska Volcano Observatory (AVO). During the 2005-6 eruption of Augustine Volcano in Alaska, AVO used existing interagency relationships and written protocols to provide hazard guidance before, during, and after eruptive events. The 2005-6 eruption was notabl

Each of the three phases of the 2006 eruption at Augustine Volcano had a distinctive eruptive style and flowage deposits. From January 11 to 28, the explosive phase comprised short vulcanian eruptions that punctuated dome growth and produced volcanowide pyroclastic flows and more energetic hot currents whose mobility was influenced by efficient mixing with and vaporization of snow. Initially, hot

The petrology and geochemistry of 2006 eruptive products of Augustine Volcano, Alaska, have been investigated through analyses of whole-rock samples, phenocrysts, silicate melt inclusions, and matrix glasses to constrain processes of magma evolution, eruption, and degassing. Particular attention was directed toward the concentrations and geochemical relationships involving the magmatic volatile co

Deposits from the 2006 eruption of Augustine Volcano, Alaska, record a complex history of magma mixing before and during the eruption. The eruption produced five major lithologies: low-silica andesite scoria (LSAS; 56.5 to 58.7 weight percent SiO2), mostly during the initial explosive phase; high-silica andesite pumice (HSA; 62.2 to 63.3 weight percent SiO2), prevalent during the continuous phase;

For the first time in the United States, a modern geodetic network of continuously recording Global Positioning System (GPS) receivers has measured a complete eruption cycle at a stratovolcano, Augustine Volcano in Alaska, from the earliest precursory unrest through the return to background quiescence. The on-island network consisted of five continuously recording, telemetered GPS stations, four c

This chapter describes a two-step technique for determining earthquake hypocenters at Augustine Volcano. The algorithm, which was originally developed in the mid-1970s, was designed both to overcome limitations in the standard earthquake-location programs available at the time and to take advantage of the detailed seismic-velocity information obtained at Augustine Volcano. Hypocenters are calculat

Clustered earthquakes located 25 km northeast of Augustine Volcano occurred more frequently beginning about 8 months before the volcano’s explosive eruption in 2006. This increase in distal seismicity was contemporaneous with an increase in seismicity directly below the volcano’s vent. Furthermore, the distal seismicity intensified penecontemporaneously with signals in geodetic data that appear to

A series of 13 explosive eruptions occurred at Augustine Volcano, Alaska, from January 11–28, 2006. Each lasted 2.5 to 19 minutes and produced ash columns 3.8 to 13.5 km above mean sea level. We investigated various parameters to determine systematic trends, including durations, seismic amplitudes, frequency contents, signal characteristics, peak acoustic pressures, ash column heights, lightning o

We use seismic b-values to explore physical processes during the Augustine Volcano 2005–6 preeruptive earthquake swarm. The preeruptive earthquake swarm was divided into two parts: the “long swarm,” which extended from April 30, 2005, to January 10, 2006; and the "short swarm," which started 13 hours before the onset of explosive activity on January 11, 2006. Calculations of b-value for each of th

The 2006 eruption of Augustine Volcano, Alaska, generated more than 3,500 earthquakes in a month-long time frame bracketing the most explosive period of activity. We examine two quantitative tools that, in retrospective analysis, were excellent indicators of imminent eruption. The first tool, referred to as the frequency index (FI), is based on a simple ratio of high- and low-frequency energy in a