| Propagating along the east side of the Peninsular Ranges,
the San Andreas fault moved north. Reaching the southern
boundary of the Sierra Nevada block, the San Andreas fault
stepped westward at a zone of crust weakened by the
Murray fracture zone. West of the Sierra Nevada, the
fault propagated north until reaching a similar zone of
crust weakened by the Mendocino fracture zone, where the
fault again stepped westward.
[Although this cartoon shows the entire course of the
San Andreas fault -- implying a fully formed fault --
the fault probably formed progressively
as the Gulf of California opened and Baja California moved
north.] |
