Publications

High fluoride (F) groundwaters (>1 mg/L) have been recognized as a water quality problem for nearly a century and occur in many countries worldwide. The affected aquifers can be sedimentary, metamorphic or igneous rocks, but the process giving rise to high-F concentrations has been studied with geochemical modeling and an examination of the rock sources. The association of high-F with silicic igne

The study of volcano deformation has grown significantly through they year 2020 since the development of interferometric synthetic aperture radar (InSAR) in the 1990s. This relatively new data source, which provides evidence of changes in subsurface magma storage and pressure without the need for ground-based equipment, has matured during the past decade. It now provides a means to address previou

Episodes of unrest are not as well documented as eruptions at most volcanoes globally. Iliamna is an andesitic stratovolcano in the Cook Inlet of Alaska that has experienced several episodes of unrest. Unrest in 1996 was previously studied. Here we present data from a minor period of unrest between 2002 and 2006, and a more significant period in 2012. None of the episodes led to an eruption. A dik

Volcano seismology has been fundamental to our current understanding of crustal magma migration and eruption. The increasing availability of portable seismic networks with the creative use of seismic sources and ambient noise has led to a better understanding of the volcanic structure of many volcanoes and is producing increasingly detailed images of the volcanic subsurface. The past decade (2010-

River deltas and their diverse array of aquatic environments are increasingly impacted by anthropogenic inputs of nitrogen (N). These inputs can alter the N biogeochemistry of these systems and promote undesirable phenomena including harmful algae blooms and invasive aquatic macrophytes. To examine N sources and biogeochemical processes in the Sacramento-San Joaquin Delta, a river delta located in

The 2018 Kīlauea caldera collapse produced extraordinary sequences of seismicity and deformation, with 62 episodic collapse events which significantly altered the landscape of the summit region. Despite decades of focused scientific studies at Kīlauea, detailed information about the internal structure of the volcano is limited. Recently developed techniques in seismic interferometry can be used to

If volcanic eruptions could be forecast from the occurrence of some external process, it might be possible to better mitigate risk and protect lives and livelihoods. Farquharson and Amelung1 suggested that the 2018 lower East Rift Zone (ERZ) eruption of Kīlauea Volcano—the most destructive eruption in Hawai‘i in at least 200 years2—was triggered by extreme precipitation, which caused increased por

Magmas with matrix glass compositions ranging from basalt to dacite erupted from a series of 24 fissures in the first two weeks of the 2018 Lower East Rift Zone (LERZ) eruption of Kīlauea Volcano. Eruption styles ranged from low spattering and fountaining to strombolian activity. Major element trajectories in matrix glasses and melt inclusions hosted by olivine, pyroxene and plagioclase are consis

In November 2019, the fourth meeting on Volcano Observatory Best Practices workshop was held in Mexico City as a series of talks, discussions, and panels. Volcanologists from around the world offered suggestions for ways to optimize volcano-observatory crisis operations. By crisis, we mean unrest that may or may not lead to eruption, the eruption itself, or its aftermath, all of which require anal

The advent of continuous digital recording of seismograph stations in Alaska did not occur until the fall of 2002. Continuous records of seismic waveforms prior to 2002 were recorded only in analog form. The Alaska Volcano Observatory (AVO) has a substantial archive of continuous analog records made on helicorders in a collection maintained by the University of Alaska Fairbanks Geophysical Institu

Volcanic fallout in polar ice sheets provides important opportunities to date and correlate ice-core records as well as to investigate the environmental impacts of eruptions. Only the geochemical characterization of volcanic ash (tephra) embedded in the ice strata can confirm the source of the eruption, however, and is a requisite if historical eruption ages are to be used as valid chronological c

No abstract available.