Publications

The Hawaiian Volcano Observatory (HVO) summary presents seismic data gathered during the year. The seismic summary is offered without interpretation as a source of preliminary data. It is complete in the sense that most data for events of M≥1.5 routinely gathered by the Observatory are included. The HVO summaries have been published in various forms since 1956. Summaries prior to 1974...

No abstract available.

Locally, voluminous andesitic volcanism both preceded and followed large eruptions of silicic ash-flow tuff from many calderas in the San Juan volcanic field. The most voluminous post-collapse lava suite of the central San Juan caldera cluster is the 28 Ma Huerto Andesite, a diverse assemblage erupted from at least 5–6 volcanic centres that were active around the southern margins of the...

The 1912 Valley of Ten Thousand Smokes (VTTS) ignimbrite was constructed from 9 compositionally distinct, sequentially emplaced packages, each with distinct proportions of rhyolite (R), dacite (D), and andesite (A) pumices that permit us to map package boundaries and flow paths from vent to distal extents. Changing pumice proportions and interbedding relationships link ignimbrite...

During 1999 we designed and tested a thermal monitoring system to provide a cheap, robust, modular, real-time system capable of surviving the hostile conditions encountered proximal to active volcanic vents. In November 2000 the first system was deployed at Pu'u 'O'o (Kilauea, Hawai'i) to target persistently active vents. Aside from some minor problems, such as sensor damage due to...

Since 1988, Alaska Volcano Observatory (AVO) has been continually monitoring seismicity at active volcanoes in Alaska (Dixon et al., 2004). The AVO seismic network has grown from 27 stations on the Cook Inlet volcanoes (Augustine, Iliamna, Redoubt, and Spurr) to 160 stations on 27 volcanoes in 2004 (Figure 1). Each seismograph subnetwork on an individual volcano typically consists of...

Regional-scale triggering of local earthquakes in the crust by seismic waves from distant main shocks has now been robustly documented for over a decade. Some of the most thoroughly recorded examples of repeated triggering of a single site from multiple, large earthquakes are measured in geothermal fields of the western United States like Long Valley Caldera. As one of the few natural...

Anatahan island is 9.5 km east–west by 3.5 km north–south and truncated by an elongate caldera 5 km east–west by 2.5 km north–south. A steep-walled pit crater ∼1 km across and ∼200 m deep occupies the eastern part of the caldera. The island is the summit region of a mostly submarine stratovolcano. The oldest subaerial rocks (stage 1) are exposed low on the outer flanks and in the caldera...

The June 1912 eruption of Novarupta filled nearby glacial valleys on the Alaska Peninsula with ash-flow tuff (ignimbrite), and post-eruption observations of thousands of steaming fumaroles led to the name ‘Valley of Ten Thousand Smokes’ (VTTS). By the late 1980s most fumarolic activity had ceased, but the discovery of thermal springs in mid-valley in 1987 suggested continued cooling of...

The ion microprobe has the capability to generate high resolution, high precision isotopic measurements, but analysis of the isotopic composition of strontium, as measured by the 87Sr/86Sr ratio, has been hindered by isobaric interferences. Here we report the first high precision measurements of 87Sr/86Sr by ion microprobe in calcium carbonate samples with moderate Sr concentrations. We...

The first historical eruption of Anatahan volcano began on May 10, 2003. Samples of tephra from early in the eruption were analyzed for major and trace elements, and Sr, Nd, Pb, Hf, and O isotopic compositions. The compositions of these tephras are compared with those of prehistoric samples of basalt and andesite, also newly reported here. The May 2003 eruptives are medium-K andesites...

Within the Commonwealth of the Northern Mariana Islands (CNMI), Anatahan is one of nine active subaerial volcanoes that pose hazards to major air-traffic routes from airborne volcanic ash. The 2003-2004 eruptive activity of Anatahan volcano affected the region's aviation operations for 3 days in May 2003. On the first day of the eruption (10 May 2003), two international flights from...