Geodetic measurement of tectonic deformation in the Santa Maria Fold and Thrust Belt, California

Journal Article · Sat Mar 10 00:00:00 EST 1990 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JB095iB03p02679· OSTI ID:5010058

Feigl, K L; King, R W; Jordan, T H ^[1]

---

1. Massachusetts Inst. of Tech., Cambridge (United States)

The authors have analyzed geodetic observations to resolve tectonic deformation across the Belt, northwest of Santa Barbara, California. The data include (1) historical triangulation from the 1880s, 1920s and 1950s; (2) electronic distance measurement trilateration from 1971 and 1985; and (3) Global Positioning System observations from 1986 and 1987. They combine the three different types of data to estimate two-dimensional station positions and strain rate parameters simultaneously. Using a model which constrains the relative velocity field to be linear in space and constant in time, they find significant strain rates. The maximum compressive strain is oriented N17{degree}E {plus minus} 5{degree}E, and the compressive strain rate in this direction is 0.13 {plus minus} 0.03 {mu}strain/yr. Under the assumption that the unresolved rotational component of the velocity field is zero, they estimate that the integrated rate of deformation across the basin is 7 {plus minus} 1 mm/yr oriented at N 03{degree}E {plus minus} 13{degree}. This vector can be decomposed into 6 {plus minus} 2 mm/yr of crustal shortening on the general structural trend of N 30{degree}E and 3 {plus minus} 1 mm/yr of right-lateral shear across this axis. On the basis of these values and earthquake focal mechanisms in the area, they infer that the deformation occurs on northwest trending folds and thrusts within the belt. These results are consistent with the rate and direction of deformation across the central California Coast Ranges inferred by balancing Pacific-North America plate motion against San Andreas slip and Basin and Range extension. They imply that the Santa Maria Fold and Thrust Belt is the primary active element in transforming motion from the Coast Ranges to the western Transverse Ranges and the Santa Barbara Channel.

• OSTI ID: 5010058
• Journal Information: Journal of Geophysical Research; (United States), Vol. 95:B3; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
CALIFORNIA
GEOLOGIC FORMATIONS
GEODETIC SURVEYS
TECTONICS
COMPRESSION
DATA ANALYSIS
DEFORMATION
GEOLOGIC STRUCTURES
HISTORICAL ASPECTS
MATHEMATICAL MODELS
ORIENTATION
PLATE TECTONICS
SATELLITES
SLIP
STRAIN RATE
TWO-DIMENSIONAL CALCULATIONS
DEVELOPED COUNTRIES
FEDERAL REGION IX
GEOPHYSICAL SURVEYS
NORTH AMERICA
SURVEYS
USA
580000* - Geosciences