Access Data

Special Data Sets

Compression Directions in Southern California

Last updated: April 9, 1997
Comments to wilde@gps.caltech.edu or jstock@gps.caltech.edu

These are results of observations from deviated boreholes in Southern California (from Santa Barbara to Los Angeles Basin). Borehole elongation in drill holes was used to infer breakout orientation and directions of maximum horizontal principal stress [Wilde and Stock, 1997]. These results are broadly consistent with results from focal mechanism studies [Hauksson, 1990] as well as breakout and focal mechanism data present in the world stress map database [Zoback, 1992]. Click on one of the next choices to see:

Map of Southern California showing stress directions from Wilde and Stock (1997), from Zoback (1992), and Mount and Suppe (1995).
Map of Upper Ojai Valley Area only
Map of Los Angeles Area only

Lower hemisphere stereographic projections of borehole elongation directions from all borehole studied, separated according to geographic region:

More Detailed Data for Each Borhole Studied

Table with list of all boreholes used in wilde-stock study with more information about each borehole
(latitude, longitude, township, range, section, mean breakout azimuth, depth range, breakout depth range).

Plots showing dipmeter data and processed results for one borehole as an example
(caliper data, bitsize, breakout and borehole azimuth, relative bearing, and borehole deviation; as a function of depth).