Publications

Diatoms from estuarine and marsh sediments can be used to evaluate a number of geological processes. Information on salinity, elevation, and substrate derived from modern assemblages have been used to determine local and regional Holocene sea level history, identify seismic and tsunami events, and aid in the recognition of regional variations in precipitation. In order to apply diatoms to these qu

Diatoms provide the chief Cenozoic biostratigraphic tool in marine sediments beneath high primary productivity zones, especially where calcareous fossils are rare or poorly preserved. Diatom biostratigraphy, which is based on originations and extinctions of unique taxa, is especially useful in circum-Antarctic, equatorial Pacific, and high latitude North Pacific marine successions, which are avail

Medicine Lake volcano has had 4 eruptive episodes in its postglacial history (since 13,000 years ago) comprising 16 eruptions. Time intervals between events within the episodes are relatively short, whereas time intervals between the episodes are much longer. An updated radiocarbon chronology for these eruptions is presented that uses paleomagnetic data to constrain the choice of calibrated ages.

Medicine Lake volcano (MLV) is a very large shield-shaped volcano located in northern California where it forms part of the southern Cascade Range of volcanoes. It has erupted hundreds of times during its half-million-year history, including nine times during the past 5,200 years, most recently 950 years ago. This record represents one of the highest eruptive frequencies among Cascade volcanoes an

Technical outreach — distinct from general-interest and K-12 educational outreach — for volcanic hazards is aimed at providing usable scientific information about potential or ongoing volcanic activity to public officials, businesses, and individuals in support of their response, preparedness, and mitigation efforts. Within the context of a National Volcano Early Warning System (NVEWS) (Ewert et a

The Purisima Formation is an important upper Miocene and Pliocene stratigraphic unit in central California, cropping out from the coast at Point Reyes north of San Francisco to more extensive exposures in the Santa Cruz Mountains to the south. The fine-grained rocks in the lower parts of the Purisima Formation record a latest Miocene transgressive event, whereas the middle and upper parts of the f

No abstract available

The Breccia Museo, a pyroclastic flow that crops out in the Campi Flegrei volcanic complex (Naples, Italy), contains alkali-syenite (trachyte) nodules with enrichment in Cl and incompatible elements (e.g., U, Zr, Th, and rare-earth elements). Zircon was dated at ≈52 ka, by U-Th isotope systematics using a SHRIMP. Scanning electron microscope and electron microprobe analysis of the constituent phas

The most recent episode in the ongoing Pu'u 'O'o-Kupaianaha eruption of Kilauea Volcano is currently producing lava flows north of the east rift zone. Although they pose no immediate threat to communities, changes in flow behavior could conceivably cause future flows to advance downrift and impact communities thus far unaffected. This report reviews lava flow hazards in the Puna District and discu

Geodesists are, for the most part, a patient and hardworking lot. A day spent hiking to a distant peak, hours spent waiting for clouds to clear a line-of-sight between observation points, weeks spent moving methodically along a level line – such is the normal pulse of the geodetic profession. The fruits of such labors are all the more precious because they are so scarce. A good day spent with an e

Summary of Volcano Hazards at Tanaga Volcanic Cluster The Tanaga volcanic cluster lies on the northwest part of Tanaga Island, about 100 kilometers west of Adak, Alaska, and 2,025 kilometers southwest of Anchorage, Alaska. The cluster consists of three volcanoes-from west to east, they are Sajaka, Tanaga, and Takawangha. All three volcanoes have erupted in the last 1,000 years, producing lava flow

High resolution diatom and pollen data from piston core TN062 0550 off northernmost California, and Kasten core WW7710A-26 off coastal Oregon, are compiled for the past 2,400 years. Diatom proxy data for Fall SST from both cores record warm SST's in the intervals from ca. AD 400 to 600, and from ca. AD 1050 to 1300 (later part of the Medieval Warm Period). The intervening AD 650 to 1000 interval,