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During the past several years the Viking project developed plans to use Viking orbiter instruments and Earth-based radar to certify the suitability of the landing sites selected as the safest and most scientifically rewarding using Mariner 9 data. During June and July 1976, the Earth-based radar and...

Seismic ray tracing is used to relocate a set of local earthquakes recorded by a dense seismic array in Bear Valley, California. The crustal velocity structure is two-dimensional and incorporates most of the known and inferred velocity differences in the region. Relocated hypocenters fall within the San Andreas fault zone,...

Geiger's method of locating local earthquakes has been extended to include the effect of P velocity variation along the ray paths in three dimensions. The crustal structure was modeled by rectangular blocks, and a parameter was assigned to each block describing the perturbation of P wave slowness...

No abstract available....

Regional linear carbonate shelf margins, or stratigraphic reefs, are postulated to have developed during Mississippian time along the eastern flank of the Cordilleran miogeosyncline in the Western United States. These shelf margins are analogous to well-documented ancient and modern geologic counterparts, such as the Guadalupian reef of the West Texas...

The Beartooth Mountains of south-central Montana and northwestern Wyoming are a northwesterly trending high rugged range made up mainly of Precambrian metamorphic rocks. The southeastern part of the range is characterized by extensive high-altitude flat or gently rolling plateaus separated by deep glaciated canyons. The plateaus along the crest...

Results of forest-trend modeling from one data set in the Atchafalaya River basin show that predicted forest acreage totals for 16 forest types agree within 30 percent of actual values in two-thirds of the comparisons. A forest-trend simulation model based on statistical regression relations of forest and hydrologic variables and...

Computer programs based on the exact calculations of the gravity and magnetic anomalies of polygonal prisms are faster in operation and more accurate than previous programs based on the numerical integration of polygonal laminas. The prism programs also are of more general application than existing computer programs that are based...

A general mathematical theory of line transects is develoepd which supplies a framework for nonparametric density estimation based on either right angle or sighting distances. The probability of observing a point given its right angle distance (y) from the line is generalized to an arbitrary function g(y). Given only that...

The Mississippian history of the northern Cordilleran region of the United States consists of two principal depositional cycles separated by a cycle of epeirogenic uplift and erosion. Each depositional cycle is divisible into phases that represent significant changes in depositional patterns. During Cycle I (early Kinderhookian-early Meramecian), predominantly carbonate and...

A previously developed analytical solution for two-dimensional dispersion is computed for various conditions. These results were then compared with solution of previously developed approximate models of transverse dispersion which were used to analyze experimentally derived concentration distribution. Comparison established that, whenever steady state was reached, the values of dispersion coefficient...

Double-mass-curve analysis of ground-water levels in Nassau County, Long Island, N.Y., shows that the average-weighted ground-water levels in a 32-mi2 (83-km2) segment of a sewered area declined 11.8 ft (3.6 m) relative to an adjacent unsewered area to the east during 1953-72. Electric-analog-model analysis indicates that 4.9 ft (1.5...

Ocher occurs widely In the Montezuma district as small sinters and as bedded deposits of bog iron and ocher-cemented conglomerates. The iron of the ochers is derived from pyrite-rich veins and from pyritic hydrothermally altered rocks. Trace amounts of ore metals in the ocher and its admixed detritus are...

An experiment in an oil field at Rangely, Colorado, has demonstrated the feasibility of earthquake control. Variations in seismicity were produced by controlled variations in the fluid pressure in a seismically active zone. Precise earthquake locations revealed that the earthquakes clustered about a fault trending through a zone of high...

Sedimentary records of Cenozoic history in southeastern New Mexico begin with the Ogallala Formation of Miocene and Pliocene age. Later records include the Gatuna Formation of early or middle Pleistocene age, Mescalero caliche, an informal term, of middle Pleistocene age, and fluvial deposits of late Pleistocene age but there are...

An injection of chloride, sodium, and stable strontium was made at a constant rate for 3 hours into Uvas Creek, Santa Clara County, Calif., to determine the mass transport processes in a small stream. Five observation points were selected within a 610-metre reach of the stream below the injection site....

Daytime roosting behavior of pallid bats (Antrozous pallidus) was studied in central Arizona. Bats were present in the area from March or April until November and roosted in cliffs in colonies generally including 20 or more individuals. Pallid bats were highly selective in their choice of roost sites...

No abstract available. ...

The virtually featureless Beringian shelf south of St. Lawrence Island is underlain structurally by at least 14 basins. Encompassing a total area of more than 300,000 sq km, most of the basins are either elongate structural sags, grabens, or half (asymmetric) grabens beneath the outer shelf. The regional trend of...

The eastern Bering Sea Basin, composed of the Aleutian and Bowers Basins, is flanked to the north by Mesozoic foldbelts that probably represent zones of plate subduction in Mesozoic time. Present plate subduction occurs 400 to 1,000 km farther south, at the Aleutian Trench. North-south magnetic lineations that formed at...

Electrical analog model simulations of hydraulic conditions in the Biscayne aquifer were made at proposed inland well-field sites in Dade County, Florida. Simulated drawdowns of water levels after 7 months of continuous pumping at 50, 100, and 150 million gallons per day were obtained at each site. Simultaneous pumping of...

The analog model of the Biscayne aquifer of southeast Florida was used to approximate the effects of two proposed water-management schemes. One involved adding a secondary control structure in a major canal which is controlled near the coast. In the model the controls were operated in accordance with canal water...

No abstract available....

This report is a program documentation to the latest revision (1975) of the unsteady open-channel flow simulation model by the method of characteristics, Version 13 in the program series, which employs a multiple-reach scheme treating each subreach as a prismatic shape. A long waterway of variable cross section, properties and...

Techniques have been developed for estimating future flood magnitudes having recurrence intervals as great as 100 years. Estimates for gaged sites were obtained by application of the log-Pearson Type III frequency distribution. Estimates for ungaged sites are defined by mathematical relations which may be solved using data from topographic maps....