A preliminary summary of a seismic-refraction survey in the vicinity of the Tonto Forest Observatory, Arizona
J.C. Roller, W. H. Jackson, D. H. Warren, J. H. Healy
1964, Crustal Studies Technical Letter 23
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...
Crustal structure between Lake Mead, Nevada, and Mono Lake, California
Lane R. Johnson
1964, Crustal Studies Technical Letter 22
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...
Seismic-refraction measurements of crustal structure between American Falls Reservoir, Idaho, and Flaming Gorge Reservoir, Utah
Ronald Willden
1964, Crustal Studies Technical Letter 21
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...
Variations in regional traveltimes
J. H. Healy
1964, Crustal Studies Technical Letter 16
Precise epicentral location of a seismic event is made difficult by variations in regional traveltimes. A discussion is presented on delays to be expected in the various segments of a generalized travel path of seismic waves. Traveltime variations caused by changes in crustal structure and velocity introduce a major part...
Preliminary report on some factors affecting shotpoint efficiency
W. H. Jackson, J. H. Healy
1964, Crustal Studies Technical Letter 17
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...
Compilation of seismic-refraction crustal data in the Soviet Union
Robert Rodriguez, William P. Durbin Jr., J. H. Healy, David H. Warren
1964, Crustal Studies Technical Letter 18
The U.S. Geological Survey is preparing a series of terrain atlases of the Sino-Soviet bloc of nations for use in a possible nuclear-test detection program. Part of this project is concerned with the compilation and evaluation of crustal-structure data. To date, a compilation has been made of data from Russian...
Continental crust
L. C. Pakiser
1964, Crustal Studies Technical Letter 20
The structure of the Earth’s crust (the outer shell of the earth above the M-discontinuity) has been intensively studied in many places by use of geophysical methods. The velocity of seismic compressional waves in the crust and in the upper mantle varies from place to place in the conterminous United...
Crustal structure in the eastern Colorado Plateaus Provence from seismic-refraction measurements
John C. Roller
1964, Crustal Studies Technical Letter 19
A reversed seismic-refraction profile was recorded in the Colorado Plateaus Province from Hanksville, Utah, to Chinle, Arizona, The velocity of Pg is 6.2 km/sec, and the true velocity of Pn is 7.8 km/sec, Waves identified as reflections indicate that an intermediate layer in the crust has a velocity of approximately...
Alaska's Good Friday earthquake, March 27, 1964, a preliminary geologic evaluation
Arthur Grantz, George Plafker, Reuben Kachadoorian
1964, Circular 491
The Hebgen Lake, Montana, earthquake of August 17, 1959
Water Resources Division, U.S. Geological Survey
1964, Professional Paper 435
Seismic-refraction measurements of crustal structure between Nevada Test Site and Ludlow, California
J. F. Gibbs, J.C. Roller
1964, Crustal Studies Technical Letter 26
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...
Preliminary study of first motion from nuclear explosions recorded on seismograms in the first zone
J. H. Healy, G. B. Mangan
1963, Crustal Studies Technical Letter 13
The U.S. Geological Survey has recorded more than 300 seismograms from more than 50 underground nuclear explosions. Most were recorded at distances of less than 1,000 km. These seismograms have been studied to obtain travel times and amplitudes which have been presented in reports on crustal structure and in a...
Crustal structure in the vicinity of Las Vegas, Nevada, from seismic and gravity observations
John C. Roller
1963, Crustal Studies Technical Letter 12
A seismic-refraction profile indicates that the crust of the Earth increases in thickness by as much as 5 km over a horizontal distance of less than 25 km northeast of Las Vegas, Nevada. This feature correlates with a decrease in the Bouguer anomaly and an increase in the average surface...
Crustal structure from San Francisco, California, to Eureka, Nevada, from seismic-refraction measurements
Jerry P. Eaton
1963, Crustal Studies Technical Letter 11
Seismic-refraction measurements from chemical explosions near San Francisco, California, and Fallon and Eureka, Nevada, were made along a line extending nearly 700 km inland from San Francisco across the Coast Ranges, Great Valley, Sierra Nevada, and Basin and Range Province. The velocity of Pg in the Basin and Range Province...
Traveltimes and amplitudes from nuclear explosions; Nevada Test Site to Ordway, Colorado
Alan Ryall, David J. Stuart
1963, Crustal Studies Technical Letter 10
This paper treats the results of a study of seismic waves generated by eight nuclear explosions and recorded at 31 locations between the Nevada Test Site (NTS) and Ordway, Colorado. The line of recording stations crosses the eastern part of the Basin and Range Province, the Colorado Plateau, the southern...
Crustal structure in the western United States; study of seismic propagation paths and regional traveltimes in the California-Nevada region
J.C. Roller, W. H. Jackson, J.F. Cooper, B.A. Martina
1963, Crustal Studies Technical Letter 9
The U.S. Geological Survey, with the assistance of United ElectroDynamics, Inc., completed ten weeks of seismic-refraction field work during the summer of 1962 in the southwestern part of the United States. This work was a continuation of a program initiated in 1961 to study traveltimes and seismic propagation paths in...
Structure of the crust and upper mantle in the western United States
L. C. Pakiser
1963, Crustal Studies Technical Letter 8
Seismic waves generated by underground nuclear and chemical explosions have been recorded in a network of nearly 2,000 stations in the western conterminous United States as a part of the VELA UNIFORM program. The network extends from eastern Colorado to the California coastline and from central Idaho to the border...
Preliminary report on seismic-reflection studies of crustal structure in the western, central, and southern United States
J.C. Roller, O.P. Strozier, W. H. Jackson, J. H. Healy
1963, Crustal Studies Technical Letter 14
During 1963 the U.S. Geological Survey, with the assistance of United ElectroDynamics, Inc., recorded five separate reversed seismic profiles. In addition to these profiles, the U.S. Geological Survey participated in a seismic-calibration program for the DRIBBLE experiment at Tatum Dome, Mississippi, a 20,000-pound shot near Dexter, Missouri, and in a...
A progress report on seismic model studies
J. H. Healy, G. B. Mangan
1963, Crustal Studies Technical Letter 15
The value of seismic-model studies as an aid to understanding wave propagation in the Earth's crust was recognized by early investigators (Tatel and Tuve, 1955). Preliminary model results were very promising, but progress in model seismology has been restricted by two problems: (1) difficulties in the development of models with...
Crustal structure in Nevada and southern Idaho from nuclear explosions
L. C. Pakiser, D.P. Hill
1962, Crustal Studies Technical Letter 4
The time of first arrival of seismic waves generated by 4 underground nuclear explosions at the Nevada Test Site (NTS) and recorded along a line extending north into southern Idaho is expressed as T0 = 0. 00 + Δ/3.0 (assumed), T1 = 0 .40 + Δ/6.03, and T2 = 6.15...
Digital processing of array seismic recordings
Alan Ryall, John Birtill
1962, Crustal Studies Technical Letter 2
This technical letter contains a brief review of the operations which are involved in digital processing of array seismic recordings by the methods of velocity filtering, summation, cross-multiplication and integration, and by combinations of these operations (the "UK Method" and multiple correlation). Examples are presented of analyses by the several...
Times and locations of explosions; U.S. Geological Survey 1962 field season
John C. Roller
1962, Crustal Studies Technical Letter 3
The U.S. Geological Survey detonated 86 large charges of chemical explosives in the western United States from 6 June to 9 August 1962, in a study of crustal structure in the western United States. This Technical Letter consists of two tables containing information about these explosions. Table I gives a...
Crustal structure along the coast of California from seismic-refraction measurements
J. H. Healy
1962, Crustal Studies Technical Letter 5
Two reversed seismic-refraction profiles were recorded between Los Angeles and San Francisco in 1961. The three shotpoints were located in Santa Monica Bay, offshore near San Francisco, and at Camp Roberts, about halfway between Los Angeles and San Francisco. The velocity of Pg along these profiles is 6.1 ± 0.1...
Fish kill from underwater explosions
David J. Stuart
1962, Crustal Studies Technical Letter 6
The U.S. Geological Survey has used 23 different shotpoints during two seasons of field work in our seismic study of crustal structure in western United States. Without exception, it has been found that under-water shotpoints result in a more efficient conversion of explosive energy into seismic energy than do drilled-hole...
Frequency of earthquakes for selected areas in the western United States for the period 1945-59
W.S. Twenhofel, R.A. Black, D.F. Balsinger
1962, Open-File Report 62-137
