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San Andreas Fault
The San Andreas Fault is easy to follow through California. From the Salton Sea, it runs northwest 800 miles before ending under the Pacific Ocean.
Geologists divide the San Andreas Fault into three parts and there are plenty of places to see in each one:
Southern San Andreas Fault
The San Andreas Fault begins near the Salton Sea, runs north along the San Bernardino Mountains, crosses Cajon Pass and then along the San Gabriel Mountains east of Los Angeles. The mud pots near the Salton Sea are a result of its action, but around Palm Springs is the best place to get a look at the San Andreas Fault in this area.
Continuing north, the San Andreas Fault crosses I-5 near Frazier Park and bends toward the north. Running between I-5 and US Hwy 101, it passes through the Carrizo Plain, one of the best places in the state to see the San Andreas Fault where its accompanying geological features are plainly visible - also a great place for bird-watching and spring wildflowers. The classic San Andreas... Fault view shown above was taken over it. If you're flying north-south above California, you can sometimes see this view and it's worth getting a window seat (not above the wing) and having your camera handy, just in case.
Central San Andreas Fault
A bend in the San Andreas Fault north of Frazier Park creates an earthquake about every 150 years. In Parkfield, you can see the results in a bent bridge. Parkfield is fun to visit, home to a deep well dug to explore the San Andreas Fault's behavior, but speaking of its title as Earthquake Capitol with tongue in cheek.
Northern San Andreas Fault
You can see results of the San Andreas Fault's movement at Pinnacles National Park, whose rocks hitched a ride from Los Angeles on the Pacific Plate to get here. Further north in San Juan Bautista, an old Spanish mission sits just above the San Andreas Fault, yet it has managed to survive.
The fault continues through the Santa Cruz Mountains, epicenter of the 1989 Loma Prieta earthquake, up the San Francisco Peninsula, where you can take a nice little hike to see along it at Los Trancos Open Space Preserve.
The fault turn offshore near Mussel Rock, the epicenter of the 1906 San Francisco earthquake. Several spots in San Francisco are reminders of that event. It comes back onshore north of Stinson Beach, goes underwater beneath Tomales Bay, crossing Point Reyes where you can take an interesting walk on the earthquake trail that includes a fence offset in the 1906 quake. Coming onshore for the last time near Fort Ross, it goes out to sea near Point Arena, runs up to Cape Mendocino, bends west and finally ends.Continue to 2 of 10 below.
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San Andreas Fault Near Palm Springs
Near Palm Springs, the San Andreas Fault is less well defined than further north, the monolithic geological feature fracturing into many smaller ones, running in various directions. Underground fissures caused by the faults give undergound water an easy route to the surface and are responsible for the many desert oases found along the east side of the Coachella Valley. You can see an oasis (and stand directly over the fault line) at 1000 Palms Canyon in the Coachella Valley Preserve (29200 1000 Palms Canyon Rd) in the town of Thousand Palms, on the east side of I-10 close to the Ramon Road exit.
All those little cracks also give rise to hot mineral springs, most of them located around the town of Desert Hot Springs.
An even better way to get up close to the fault near Palm Springs is to take a jeep tour with a knowledgeable guide. Our favorite is Desert Adventures' San Andreas Fault Adventure, which will take you through the desert and into the canyons and oases along the fault,... going right up to a spot where the Pacific and North American geological plates intersect (shown in the photo above). For even more fun, take their Nightwatch Adventure (summers only) which covers much of the same terrain and ends with a spectacular look at the evening sky.Continue to 3 of 10 below.
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San Andreas Fault in the Carrizo Plain
The picture above was taken above Soda Lake. The fault runs just at the bottom of the hillside beyond the water.
Situated between I-5 and US Hwy 101, the Carrizo Plain is one of California's least-visited sights, with many state residents unaware of its existence. Yet nearly everyone has seen the classic image of the San Andreas Fault taken from the air that's shown as the first page of this gallery - and it was taken directly above the Carrizo Plain.
Geologists swoon over this bit of California geology. Besides the dramatic fault itself, a bird's-eye view reveals streams beds offset by the fault's movement, hills torn apart in the middle and sagging bits of the earth's surface, but they're more subtle and harder to see on the ground. Nevertheless, the area is extraordinarily beautiful, especially during a good wildflower year and much is accessible by family sedan. The free self-guided geologic tour brochure available at the Visitor Center will help you get the... most out of your visit. Written for laymen, it includes a hike to a point atop the fault. You can also download self-guided tour brochures.
The Carrizo Plain is halfway between US Hwy 101 and I-5, accessible from either side. It's closer to Los Angeles than to San Francisco, but you can visit in a long day trip from either city.
The Carrizo Plain website warns not to rely on GPS systems or online mapping sites for directions because they'll get you lost, but it's easy to get there: Exit I-5 at CA Hwy 58 west near Buttonwillow, continue west through McKittrick and turn left onto Soda Lake Road or exit US Hwy 101 at CA Hwy 58 east near Santa Margarita, travel east and turn right onto Soda Lake Road. Soda Lake Road is paved from the north end to the visitor's center. It's also possible to get there from the south via CA Hwy 166 and Soda Lake Road north, but you'll drive on an unpaved, dirt road for 20 miles to reach the visitor center.
Carrizo Plain is very isolated, with no place to get food, water or gasoline for many miles in any direction. It's very hot and inhospitable in summer and the visitor center is only open from the beginning of December to the end of May. And to top it all off - there's no cellphone reception in the area, either. It's up to you to be prepared.
This area is also popular with birders and photographers. Following a rainy winter, wildflower displays are some of the state's best and docents lead special tours to see them. The nearest lodging is along the major highways, but they do have a campground. Check the Carrizo Plain National Monument website for more information.Continue to 4 of 10 below.
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San Andreas Fault at Parkfield
This tiny town sits nearly atop the San Andreas Fault and became quite famous when the United States Geological Survey observed that it had experienced six earthquakes at roughly 22-year intervals between 1857 and 1966. Based on that data, another quake was predicted for the early 1990s, the Geological Survey installed instruments to record it and in 2004, they drilled the San Andreas Fault Observatory at Depth, a hole almost 2 miles deep to get closer to the source of the movement. In the early '90s, we found a sign at the local cafe advising: "If you feel a quake or a shake, get under the table and eat your steak," but the 1990s came and went and interest waned. Finally, a magnitude 6.0 earthquake did occur on September 28, 2004.
Parkfield is just barely on the east side of the fault. The bridge shown above actually crosses the fault, with signs posted at both ends marking your transition between the Pacific and North American Plates. Since the first bridge was built here... in 1936, the Pacific plate has moved more than 5 feet (1.5 m) relative to the North American Plate - and the bridge has been rebuilt several times. This latest structure is built to slide atop concrete pillars as the fault moves, which it has. Sources say the bend in the metal railing was not there when it was first constructed.
In town, you'll find a cafe and a small inn that boasts: "Be here when it happens."Continue to 5 of 10 below.
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San Andreas Fault at the Pinnacles
The rocks shown above at Pinnacles National Park have been hitching a ride along the San Andreas Fault for eons. Because of unique rock formations found in only two places, they are believed to be part of the Neenach Volcano that occurred 23 million years ago near present-day Lancaster, California. The San Andreas Fault ripped the old volcano in half and they have traveled some 195 miles to reach their present location.
Pinnacles is east of US Hwy 101 and accessible from both the east and west. For easier access to the geological features, enter from the west through the town of Soledad. Read more about visiting Pinnacles National Park.Continue to 6 of 10 below.
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San Andreas Fault at San Juan Bautista
The old Spanish mission at San Juan Bautista sits just next to a small escarpment, and if you didn't know better, you probably wouldn't realize that the San Andreas Fault caused the little uplift in the earth's crust. A historic marker and geological exhibit call attention to what lies below the plowed field nearby. Surprisingly, the old adobe-brick Spanish mission building has been used continuously since 1812 and has never been toppled by an earthquake. However, in October 1798, the shaking was so bad that the missionaries slept outside for the whole month. There were as many as 6 tremors in one day, making huge cracks in buildings and in the ground.Continue to 7 of 10 below.
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San Andreas Fault along Trancos Ridge
On the peninsula south of San Francisco and near Palo Alto in the Los Trancos Open Space Preserve, you can take a mile-long, self-guided hike that runs over the San Andreas Fault. It's an easy, mile-long walk through some pleasant terrain, but the fault's features are subtle in this area: depressions that look like road beds, shallow sag ponds and gullies running the wrong way. Download their self-guided trail guide or you might miss them.
To get there, exit I-280 at Page Mill Road and follow the winding road west for 7 miles to the parking lot at the entrance of the Los Trancos Open Space Preserve. From there, the earthquake trail is well-marked by signs.Continue to 8 of 10 below.
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San Andreas Fault in San Francisco
By far the most famous victim of the San Andreas Fault, San Francisco has been rocked by two big earthquakes that began on it, in 1906 and 1989.
The bigger and more destructive of the two was the temblor which occurred at 5:12 a.m. on Wednesday, April 18, 1906. With an estimated magnitude of approximately 8, it was almost 10 times larger than the 7.1 magnitude quake in 1989. Centered about 2 miles offshore, it ruptured the San Andreas Fault for almost 300 miles and was felt from Oregon to Los Angeles. Devastating fires sprung up in its aftermath and well over 3,000 people died - the greatest loss of life from a natural disaster in California's history.
The statistics are eye-popping: 300,000 people homeless out of 410,000 - 25,000 buildings destroyed - $400 million in losses (equivalent to $5.67 billion in 2009 dollars). Surprisingly, the city got back on its feet in just a few years, in time to host the 1915 Panama-Pacific International Exposition.
Today, few landmarks remain where... you can see evidence of the 1906 quake. The picture above is Hotaling's warehouse in Jackson Square, used for storing whiskey, which survived the devastating fire while other, more puritanical structures did not, prompting poet and wit Charles Kellogg Field to write:
If, as they say, God spanked the town
For being over frisky,
Why did He burn the churches down
And save Hotaling's whiskey?Continue to 9 of 10 below.
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San Andreas Fault at Point Reyes
The 1906 earthquake caused more damage in San Francisco, but near Point Reyes, it generated the largest surface displacement ever recorded from an earthquake: 21 feet. The short Earthquake Trail leads from the parking lot near the Bear Valley Visitor Center to the spot shown above. Just before the big quake that shook San Francisco in April, 1906, this fence was continuous. Afterward, it had moved to where you see it today. More gradual movement along the fault moves the Point Reyes peninsula a little further north each year, separating it further from the Tehachapi Mountains (now 310 miles away) where it was once attached.Continue to 10 of 10 below.
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San Andreas Fault Map
This map shows the general path of the San Andreas Fault through the state of California. It is intended for general information only. You can find an interactive version of the base map here.