Publications

We use seismic, tilt, lidar, thermal, and gravity data from 32 consecutive eruption cycles of Lone Star geyser in Yellowstone National Park to identify key subsurface processes throughout the geyser's eruption cycle. Previously, we described measurements and analyses associated with the geyser's erupting jet dynamics. Here we show that seismicity is dominated by hydrothermal tremor (~5...

Twenty years of continuous Earth observation by satellite SAR have resulted in numerous new insights into active volcanism, including a better understanding of subsurface magma storage and transport, deposition of volcanic materials on the surface, and the structure and development of volcanic edifices. This massive archive of data has resulted in fundamental leaps in our understanding...

The seismic network operated by the U.S. Geological Survey’s Hawaiian Volcano Observatory (HVO) is the main source of authoritative data for reporting earthquakes in the State of Hawaii, including those that occur on the State’s six active volcanoes (Kīlauea, Mauna Loa, Hualālai, Mauna Kea, Haleakalā, Lō‘ihi). Of these volcanoes, Kīlauea and Mauna Loa are considered “very high threat” in...

Most nuclear powerplants in the United States are near rivers, large lakes, or oceans. As evident from the Fukushima Daiichi, Japan, disaster of 2011, these water bodies pose inundation threats. Geologic records can extend knowledge of rare hazards from flooding, storm surges, and tsunamis. This knowledge can aid in assessing the safety of critical structures such as dams and energy...

Dissected caldera structures expose thick intracaldera tuff and, uncommonly, cogenetic shallow plutons, while remnants of correlative outflow tuffs deposited on the pre-eruption ground surface record elements of ancient landscapes. The Middle Fork caldera encompasses a 10 km × 20 km area of rhyolite welded tuff and granite porphyry in east-central Alaska, ∼100 km west of the Yukon border...

The key parameters one needs to forecast outcomes of volcanic unrest are hidden kilometers beneath the Earth’s surface, and volcanic systems are so complex that there will invariably be stochastic elements in the evolution of any unrest. Fortunately, there is sufficient regularity in behaviour that some, perhaps many, eruptions can be forecast with enough certainty for populations to be...

The most voluminous of the Cascade volcanoes, northern California’s Mount Shasta, is a massive compound stratovolcano composed of at least four main edifices constructed over a period of at least 590,000 years. An ancestral Shasta volcano was destroyed by Earth’s largest known Quaternary subaerial debris avalanche, which filled Shasta Valley, northwest of the volcano. The Hotlum cone...

In order to better define the size of the thermal anomaly in the Raft River Valley, Idaho, the U.S. Geological Survey drilled a series of intermediate-depth (nominal 500-ft depth) wells in 1977 and 1978. This report presents geologic, geophysical, and temperature data for these drill holes, along with data for five wells drilled by the Idaho National Engineering Laboratory with U.S...

Long Valley Caldera is located in California along the eastern escarpment of the Sierra Nevada Range. The caldera formed about 760,000 years ago as the eruption of 600 km3 of rhyolite magma (Bishop Tuff) resulted in collapse of the partially evacuated magma chamber. Resurgent doming in the central part of the caldera occurred shortly afterwards, and the most recent eruptions inside the...

We present a combined 3-D P wave attenuation, 2-D S coda attenuation, and 3-D S coda scattering tomography model of fluid pathways, feeding systems, and sediments below Mount St. Helens (MSH) volcano between depths of 0 and 18 km. High-scattering and high-attenuation shallow anomalies are indicative of magma and fluid-rich zones within and below the volcanic edifice down to 6 km depth...

Lahars are rapid flows of mud-rock slurries that can occur without warning and catastrophically impact areas more than 100 km downstream of source volcanoes. Strategies to mitigate the potential for damage or loss from lahars fall into four basic categories: (1) avoidance of lahar hazards through land-use planning; (2) modification of lahar hazards through engineered protection...

Lava deltas, formed where lava enters the ocean and builds a shelf of new land extending from the coastline, represent a significant local hazard, especially on populated ocean island volcanoes. Such structures are unstable and prone to collapse—events that are often accompanied by small explosions that can deposit boulders and cobbles hundreds of meters inland. Explosions that coincide...