Publications

This document provides the requested vision for the future of the National Strong-Motion Program operated by the US Geological Survey. Options for operation of the program are presented in a companion document. Each of the three major charges of the EHRP, program council pertaining to the vision document is addressed here. The 'Vision Summary' through a series of answers to specific...

A severe storm on June 27, 1995 triggered hundreds of rock, debris and soil slides from the steep hillsides of Madison County, Virginia. Most of these transformed into debris flows that inundated areas downslope causing damage to structures, roads, utilities, livestock and crops. This report contains an analysis of areas susceptible to debris flows including an examination of source...

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Although the Hayward fault is a source of major earthquakes, it also creeps or slips aseismically, and has done so steadily for several decades (certainly since 1921 and probably since 1869). Most of the fault creeps between 3 and 6 mm/yr, except for a 4- to 6-km-long segment near its south end that creeps at about 9 mm/yr. We present results of our recent surveys to recover angles and...

An understanding of the formation of new continental crust provides an important guide to locating the oldest terrestrial rocks and minerals. We evaluated the crustal thicknesses of the thinnest stable continental crust and of an unsubductable oceanic plateau and used the resulting data to estimate the amount of mantle melting which produces permanent continental crust. The lithospheric...

Iron, manganese, and iron-manganese deposits occur in nearly all geomorphologic and tectonic environments in the ocean basins and form by one or more of four processes: (1) hydrogenetic precipitation from cold ambient seawater, (2) precipitation from hydrothermal fluids, (3) precipitation from sediment pore waters that have been modified from bottom water compositions by diagenetic...

The nature of the Great Valley basement, whether oceanic or continental, has long been a source of controversy. A velocity model (derived from a 200-km-long east-west reflection-refraction profile collected south of the Mendocino triple junction, northern California, in 1993), further constrained by density and magnetic models, reveals an ophiolite underlying the Great Valley (Great...

This dataset consists of polygons enclosing areas of landslide incidence and susceptibility for the conterminous United States.

On June 15, 1991, Mount Pinatubo in the Philippines exploded in the second largest volcanic eruption on Earth this century. This eruption deposited more than 1 cubic mile (5 cubic kilometers) of volcanic ash and rock fragments on the volcano's slopes. Within hours, heavy rains began to wash this material down into the surrounding lowlands in giant, fast-moving mudflows called lahars. In...