Publications

In support of earthquake hazards and ground motion studies in the Pacific Northwest, three-dimensional P- and S-wave velocity (3D Vp and Vs) and density (3D rho) models incorporating the Cascadia subduction zone have been developed for the region encompassed from about 40.2°N to 50°N latitude, and from about -122°W to -129°W longitude. The model volume includes elevations from 0 km to 60 km (eleva

The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual

The County of Santa Cruz Department of Public Works and the County of Santa Cruz Redevelopment Agency requested the U.S. Geological Survey (USGS) Western Coastal and Marine Geology Team (WCMG) to provide baseline geologic and oceanographic information on the coast and inner shelf at Pleasure Point, Santa Cruz County, California. The rationale for this proposed work is a need to better understand t

Introduction Although effects of rotational motions due to earthquakes have long been observed (e. g., Mallet, 1862), nevertheless Richter (1958, p. 213) stated that: 'Perfectly general motion would also involve rotations about three perpendicular axes, and three more instruments for these. Theory indicates, and observation confirms, that such rotations are negligible.' However, Richter provide

The U.S. Geological Survey (USGS), established by an act of Congress in 1879, is the Nation's largest natural science and civilian mapping agency. The USGS works in cooperation with more than 2,000 organizations across the country to provide reliable, impartial scientific information. This information is used to minimize the loss of life and property from natural disasters, safeguard the Nation's

The layer-structure minerals serpentine, brucite, and talc are postulated to form in the mantle wedge above a subducting slab as a result of progressive hydration and silica metasomatism. Tectonic mixing at the slab-mantle interface generates serpentinite mélanges that contain blocks of high-pressure (HP) or ultrahigh-pressure (UHP) metamorphic rock derived from the subducting slab. Such serpentin

Landslides resulting from earthquakes can cause widespread loss of life and damage to critical infrastructure. The U.S. Geological Survey (USGS) has developed an alarm system, PAGER (Prompt Assessment of Global Earthquakes for Response), that aims to provide timely information to emergency relief organizations on the impact of earthquakes. Landslides are responsible for many of the damaging effect

INTRODUCTION An active rockslide in Merced River Canyon was first noticed on April 29, 2006 when a few rocks rolled onto Highway 140 between mileposts 103 and 104, compromising traffic on this highway and signaling the onset of renewed activity of the Ferguson rockslide. State highway 140 is one of the main entrances to Yosemite National Park and is the primary road for large commercial trucks

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

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

This DVD publication was prepared by an agency of the United States Government. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution imply any such warranty. The U.S. G