Publications

The lack of information on mantle velocities and crustal structure of the U.S.S.R. has led to a preliminary examination of published Soviet earthquake bulletins in the hope of deriving useful velocity and structure information from the data they contain. Mantle velocities deduced from earthquake data on several Russian earthquakes are in excellent agreement with results of Soviet deep...

Several mathematical models were investigated to determine the capa-bilities of the magneto-telluric method for determining the resistivity structure of the earth's crust. The model parameters were based on the crust model proposed by Keller (1963). The mathematical technique used was developed by Cagniard (1953). The investigations indicate that a three-layer model approximation of the...

Whittier, Alaska, lying at the western end of Passage Canal, is an ocean terminal of The Alaska Railroad. The earthquake that shook south-central Alaska at 5:36 p.m. (Alaska Standard Time) on March 27, 1964, took the lives of 13 persons and caused more than $5 million worth of damage to Government and private property at Whittier. Seismic motion lasted only 2½-3 minutes, but when it...

Anchorage, Alaska’s largest city, is about 80 miles west-northwest of the epicenter of the March 27 earthquake. Because of its size, Anchorage bore the brunt of property damage from the quake; it sustained greater losses than all the rest of Alaska combined. Damage was caused by direct seismic vibration, by ground cracks, and by landslides. Direct seismic vibration affected chiefly...

This report covers the first 4 years (1952 through 1956) of a project to investigate landslides in the vicinity of the Fort Randall Reservoir in South Dakota and to determine the effects of the new reservoir on landslide activity.

Seismic-refraction measurements from nuclear and chemical explosions were made along a line from the Nevada Test Site (NTS) to Ludlow, California, and additional recordings from nuclear explosions were made southward toward Calexico, California. The time of first arrivals from the Ludlow shotpoint is expressed as T0 = 0.00 + Δ/2.50 (assumed), T1 = 1.00 + Δ6.10, T2 = 2.81 + Δ/6.80, and T3...

No abstract available.

Interpretation of a reversed seismic-refraction profile between Lake Mead, Nevada, and Mono Lake, California, indicates velocities of 6.15 km/sec for the upper layer of the crust, 7.10 km/sec for an intermediate layer, and 7.80 km/sec for the uppermost mantle. Phases interpreted to be reflections from the top of the intermediate layer and the Mohorovicic discontinuity were used with the...

The U.S. Geological Survey complete d a seismic-refraction survey in the vicinity of the Tonto Forest Seismological Observatory (T.F.S.O.) in April and May 1964. More than 1200 km of reversed profiles were surveyed to determine the crustal structure and crustal and upper mantle velocities in this area. The purpose of this work was to provide information on wave-propagation paths of...

Geologic and geophysical investigations of the Loveland Basin landslide, which formed at the cut for the east portal of the Straight Creek tunnel, were made by the U.S. Geological Survey in cooperation with the U.S. Bureau of Public Road and the Colorado Department of Highways. The investigations indicate that the slide has a probable minimum volume of 500,000 cubic yards weighing 1,000...

A study of first-arrival amplitudes from 6 water shotpoints and 7 drill-hole shotpoints in parts of central and western United States indicate a variation of over 100 to 1 between the best and poorest shotpoints. Water shotpoints are, in general, superior to drill-hole shotpoints; however, one drill-hole shotpoint produced higher signal amplitudes than more than half of the water...

Interpretation of a reversed seismic-refraction profile recorded between American Falls reservoir and Flaming Gorge reservoir in May 1963 indicates that the depth to the Mohorovicic discontinuity is about 31 km at American Falls and 37 km at Flaming Gorge. The existence of an intermediate crustal layer at a depth of about 19 to 21 km beneath the profile is well supported by refractions...