Читать книгу Afoot & Afield: Orange County. A Comprehensive Hiking Guide онлайн

17 страница из 92

The famous San Andreas Fault (which runs about 40 miles northeast of Orange County) is the principal division between the two plates. But earth movement can also take place along splinter faults south and west of the San Andreas. One such splinter fault, the Elsinore Fault, passes along the eastern base of the Santa Ana Mountains. Horizontal and vertical movements along this fault over the past 5 million years have shifted the Santa Ana Mountains northwest relative to the adjacent landforms to the east, and have raised and tilted the whole mountain block into its characteristic west-sloping orientation. Sudden earth movements along any of these faults have been and will again be responsible for most of Southern California’s devastating earthquakes.

The geologic history of Orange County is a fascinating one, and the diversity of landforms and rocks in Orange County and the Santa Ana Mountains is enough to pique the curiosity of most any amateur geologist. Refer to Appendix 2 for sources of additional information.