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Research about Kern County, California

Source-linked reports with geographic coverage including Kern County, California.

35 records · Page 2Linked to original sources
USGS1997

Geodetic measurements of horizontal strain near the White Wolf fault, Kern County, California, 1926-1993

The White Wolf fault, located north of the Big Bend segment of the San Andreas fault, is the NE‐SW trending, left lateral‐oblique reverse fault responsible for the M s =7.8 1952 Kern County earthquake. We combined Global Positioning System (GPS) measurements with historical triangulation and trilateration data to determine changes in the strain rate over 7 decades (1926–1993). We reanalyzed the historical geodetic data and calculated an elevated preseismic (1926–1952) maximum shear strain rate of 0.62±0.16 μstrain/yr across the White Wolf fault. The maximum shear strain rate decreased with distance toward the Garlock fault to 0.09±0.08 μstrain/yr. In the decade following the earthquake (1952–1963), the near fault was high (0.85±0.23μstrain/yr), and decreased to 0.23±0.13 μstrain/yr across the Garlock fault. In 1993, we resurveyed many of the same monuments with GPS receivers to estimate fault‐crossing and off‐fault strain rates for the preceding 30 years. Across the White Wolf fault, the maximum shear strain rate dropped to 0.19±0.07 μstrain/yr. The azimuths of the maximum principal strain rates (ϕ) for the 1963–1993 epoch rotate from a fault normal orientation (−57°±15°) across the White Wolf fault to 11°±3°E across the Garlock fault.

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USGS1986

Summary geochemical maps for samples of rock, stream sediment, and nonmagnetic heavy-mineral concentrate, Cypress Roadless Area, Kern County, California

The Cypress Roadless Area comprises approximately 3 square miles (1,949 acres) of Sequoia National Forest, Kern County, California. The area is at the southern end of the Sierra Nevada, approximately 30 miles east-northeast of Bakersfield, and 2.5 miles and 3.5 miles south-southeast of the communities of Bodfish and Lake Isabella, respectively (index map). Geochemical sampling was conducted during 1980 and 1981. This report summarizes the results of that investigation and provides details of the geochemical evaluation used in the final mineral resource assessment of the study area (Kennedy and others, 1983). Map A shows the locations of all sites sampled for this report and the distributions of anomalous concentrations of 4 elements in 33 samples of rock, 5 elements in 34 samples of minus-60-mesh stream sediment, and 11 elements in 33 samples of nonmagnetic heavy-mineral concentrate derived from stream sediment. Map B shows outlines of those drainage basins containing samples of stream sediment and concentrate with anomalous concentrations and also shows weighted values for each outlined basin based on the number of elements with anomalous concentrations in each stream-sediment and concentrate sample and on the degree to which these concentrations are anomalous in each sample.

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USGS1977

Ground water in the Koehn Lake area, Kern County, California

Hydrologic characteristics of the Koehn Lake area were investigated to determine the effects of external stresses on the system. Unconsolidated deposits are more than 900 feet thick in the central part of the basin. Cantil Valley fault, in the central part of the basin, acts as a barrier to the flow of ground water. Average annual recharge to aquifers from percolation of surface water and from underflow, between 1958 and 1976, was 10,200 acre-feet. Average annual consumptive use, between 1960 and 1976, was 32,000 acre-feet, 21,800 acre-feet more than the recharge, implying that average annual withdrawal from storage is about 22,000 acre-feet. Storage depletion in 1976 was 50,000 acre-feet, considerably higher than the average. The cumulative storage depletion has caused a decline in water levels and a pumping depression about 5 miles southwest of Koehn Lake. Ground water in storage in 1976 was about 4 million acre-feet, and ground water in storage above the 500-foot depth excluding the saline water under Koehn Lake was about 2 million acre-feet. Water samples were collected from 24 wells for chemical analysis. Comparison of analyses made during this study with historical water-quality analyses indicated no significant change. A recent reversal in ground-water gradient southwest of Koehn Lake may allow the saline water below Koehn Lake to invade the fresh-water aquifer.

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USGS1977

Microwave radiometric survey of the San Joaquin nuclear project site, Kern County, California

An airborne microwave survey was made in the region of the San Joaquin nuclear project site near Bakersfield, Calif. The purpose of the study was to determine if the variability of soil emissivity due to moisture content is a valid near-surface expression of buried fault systems. The results showed the existence of linear-emissivity anomalies paralleling, and to some extent, overlying the Greeley and Pond-Poso Creek faults. The anomalies seem to be direct expressions of silt-filled, northwesterly trending channels of the Pond-Poso Creek-Tulare Lake distributary system. The location, orientation, and linearity of the distributary channels suggest an association with buried faults, but no relationship has yet been determined.

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USGS1954

Studies on avian malaria in vectors and hosts of encephalitis in Kern County, California. I. Infections in avian hosts

An epizoological study of Plasmodium infections in wild birds of Kern County, California, in the years 1946 through 1951 greatly extended knowledge of the occurrence of these parasites and their behavior in nature. Examination of 10,459 blood smears from 8,674 birds representing 73 species resulted in the observation of Plasmodium spp. in 1,094 smears representing 888 individual birds of 27 species. Seven species of Plasmodium were found: relictum, elongatum, hexamerium, nucleophilum, polare, rouxi and vaughani. Plasmodium relictum was by far the most frequently observed species, occurring in at least 79 per cent of the infected birds. Twelve new host species are recorded for this parasite. Sufficient morphological variation was observed to indicate that two strains of this species probably exist in nature. Numerous new host records were made of plasmodia with elongate gametocytes. The finding of parasites believed to be P. rouxi in two new host species represents the first record of the occurrence of this Plasmodium outside of Algeria. Multiple smears were obtained from a number of individual birds over varying time periods. Evidence of prolonged parasitemia was unusual, but some individuals had parasitemia on consecutive months and even for three successive years. In most individuals, parasitemias were of short duration. The inoculation of blood from wild birds into canaries led to the demonstration of many infections not observed on blood smear examination of donors. Use of these two complementary techniques led to more complete host records and a truer picture of the prevalence of infection. Three age classes of birds were studied--nestling, immature (less than 1 year of age) and adult. Parasites were observed in all three groups but infections in the younger individuals were most susceptible to interpretation. As to time of onset, numerous records were obtained of infection in nestling birds. Prevalence rates in immature birds after a single season's exposure ranged from 64 to 100 per cent in the house finch and 17 to 68 per cent in the English sparrow in different areas and years. Marked differences were found in the prevalence rates in different summer months, years and areas. It is believed these differences reflect variation in a number of environmental factors. This study indicates the extensive distribution of Plasmodium infection in a wide range of wild avian hosts. The observations are of possible importance in epidemiological studies of other arthropod-borne diseases such as the viral encephalitides for which these birds serve as hosts.

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USGS1953

Rosamond Prospect, Kern county, California

Small quantities of autunite and gummite (?) occur in tuffaceous sedimentary rocks of the Rosamond formation of Miocene age at the Rosamond prospect. The property is about 10 miles south of Mojave, Jern County, California, in the western Mojave Desert. Examination of the propert in January 1952, by George W. Walker and Luther H. Baumgardner of the U.S. Geological Survey, indicates the the autunite occurs principally as coating on fracture and joint surfaces and, to a less extent, as disseminations in the tuffaceous rocks adjacent to faults. A waxy, reddish-brown, radioactive mineral, here called gummite (?), is found in small quantities on slickensided fault surfaces associated with iron oxides and chlorite (?). The uranium minerals are erratically distributed over an area of about 15 acres. Assay of 12 samples indicate a uranium content ranging from 0.002 to 0.59 percent and an average content of slightly less than 0.08 percent uranium.

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