Publications

Methane emissions regulate the near‐term global warming potential of permafrost thaw, particularly where loss of ice‐rich permafrost converts forest and tundra into wetlands. Northern latitudes are expected to get warmer and wetter, and while there is consensus that warming will increase thaw and methane emissions, effects of increased precipitation are uncertain. At a thawing wetland...

Quaternary eruptive products in the Cascade arc include a variety of different basalt types. At Mount St. Helens (MSH), the most active volcano in the Cascades throughout the last 35 ka, three different mafic endmembers erupted at the end of the Castle Creek period (1900–1700 years B.P.): (1) high-field strength element (HFSE)-rich basalt enriched in K, Ti, P, and incompatible trace...

Tephra from the early Hawaiian fountaining episodes of the ongoing eruption of Pu'u 'Ō'ō in the East Rift Zone (ERZ) of Kīlauea provides an opportunity to study the vesicle microtextures of pyroclasts erupted from a single vent over a prolonged period of time. We report the results of microtextural analysis of pyroclasts from five of Pu'u 'Ō'ō's high (>200 m) Hawaiian fountaining...

Volcanoes are hazardous to local and global populations, but only a fraction are continuously monitored by ground-based sensors. For example, in Latin America, more than 60% of Holocene volcanoes are unmonitored, meaning long-term multi-parameter datasets of volcanic activity are rare and sparse. We use satellite observations of degassing, thermal anomalies, and surface deformation...

The Pleistocene Missoula floods through eastern and central Washington are by peak flow rate (discharge) the greatest freshwater cataclysms known on Earth. Newly explored features along the Wenatchee reach of Columbia valley give new evidence and revise earlier interpretations of size, frequency, and routing of megafloods. Crystalline-rock erratics derived far northeast lie scattered...

Volcanic ash is not only a hazard during an eruptive event; in strong winds, previously deposited loose volcanic ash can be picked up and reworked into dust clouds. Resuspension and transport of fine-grained volcanic ash from Katmai National Park and Preserve, Alaska has been observed and documented many times over the past several decades and has likely been occurring throughout the...

There are over 100 volcanoes in Alaska, 54 of which are considered historically active. A historically active volcano is one that fits one of the following criteria: a documented or strongly suspected eruption since the year 1700, persistent fumaroles near boiling point, significant deformation with a volcanic cause, or an earthquake swarm with a volcanic cause (Cameron and Schaefer...

Galeras - an andesitic stratovolcano part of the Galeras Volcanic Complex - is one of the most active volcanoes in Colombia. Historic activity is centered on a small-volume cone inside the youngest amphitheater, which breaches the west flank of the volcano. At least 30 confirmed eruption periods have been recorded in the past 480 years, with episodes of unrest ranging from weak fumarolic...

Background Volcanic plumes are complex environments composed of gases and ash particles, where chemical and physical processes occur at different temperature and compositional regimes. Commonly, soluble sulphate- and chloride-bearing salts are formed on ash as gases interact with ash surfaces. Exposure to respirable volcanic ash following an eruption is potentially a significant health...

Low-frequency earthquakes (LFEs) are small, rapidly recurring slip events that occur on the deep extensions of some major faults. Their collective activation is often observed as a semi-continuous signal known as tectonic (or non-volcanic) tremor. This manuscript presents a catalog of more than 1 million LFEs detected along the central San Andreas Fault from 2001-2016. These events have...

Most volcanoes worldwide are not monitored in real-time; for those that are, patterns of pre-eruptive earthquakes coupled with conceptual models of magma ascent enable short-term forecasting of eruption onset. Basic event locations, characterization of background seismicity, and recognition of changes in earthquake types and energy release are most important to successful eruption...

Kīlauea Volcano, Hawai‘i, is renowned as one of the most active and closely monitored volcanoes on Earth. Scores of seismometers and deformation sensors form an array across the volcano to detect subsurface magmatic activity, and ground observers track eruptions on the surface. In addition to this dense ground-based monitoring, remote sensing – both airborne and spaceborne – has become a...