This map shows the surface traces of most of the major faults of southern California, color-coded by slip rate. Blind thrust faults are shown by dotted lines which mark the upper terminus of the fault. The color scale used is shown at upper right. Because the distribution of slip rates is far from linear, the color scale used here is not a linear scale.
When studying this map, keep in mind that this figure is meant for qualitative, not quantitative, analysis. The slip rates given here are not meant to represent exact figures, but rather a good estimate, often based on several different studies using different methods to determine the rate. Also, the slip rates for many of these faults are unknown, or are likely inaccurate, and there is no information given on the map that applies to the uncertainties in the slip rates given. When insufficient data was available, reasonable assumptions were made to fill in these parts of the diagram. Most commonly, small slip rates were assigned to faults that may be inactive, but for which no slip rate studies existed. Therefore, some faults with slip rates shown as below 0.4 mm/year may in fact be totally inactive. In addition, due to the nature and comparitively small number of slip rate studies, the resolution of this map is very low. This means that minor changes in slip along the length of a fault, or along branches of a fault zone, are not always represented. Thus, parallel branches of the same fault zone are generally shown using the same color, even though slip is partitioned among them (and would therefore be lower along each individual branch).
Studying this figure, you can see the dominance, in terms of slip rate, of the major fault systems in southern California -- the San Andreas fault zone, the San Jacinto fault zone, and the Garlock fault zone. Smaller faults branching off from these tend to have moderate slip rates, which decrease with distance from the major fault zones. You may also note that the Transverse Ranges and the Los Angeles Basin area are marked by moderate slip rates, typically along reverse (including thrust and blind thrust) faults.