Hiking the San Andreas Fault

Plenty of fine hikes right on our doorstep, but maybe you've done Prison Hill or Deadman's Creek and you're looking for something a little more exotic.

How about a stroll along the famous San Andreas Fault, the reason Bay Area people have nightmares now and then?

Yes, it's in the Bay Area, and yes that's about 225 miles, but it's a lot closer than the Great Basin National Park. The site, Los Transcos, is above Palo Alto in the open spaces preserve. The site is split by the fault, but of course you can't see the fault. It's underground, but the rangers there have built a trail that pretty much goes right along the course of the fault. No big, deep cracks, but a series of posts with yellow bands around the top mark the course of the San Andreas. White markings show minor fault breaks.

This is a fine interpretive moderate trail, about 1.5 miles long with some mild ups and downs, with posts with numbers 1 to 9 explaining the observation points marking the fault points.

At point No. 4, for example, a fence shows how wide the displacement of the land crated by the earthquake of 1906. One end of the fence is about 4 lateral feet from the other end (This is not a fence left from the quake but one rebuilt using wood left of a fence by the quake.).

At point No. 1 you can see Loma Prieta, a mountain 2.3 miles to the southeast near the site of the 1989 quake. Prieta is on the American tectonic plate, which underlies most of North America. But you're standing on the Pacific plate. Large boulders are scattered about; these were washed here by water about 2 million years ago. Quakes have moved the rocks to their present position.

At this point it might be well to mention how earthquakes come about. The 12 major tectonic plates that make up the crust of the earth, over the magma and core, are in constant motion, inches per year. As time goes by the plates rub against one another, with the friction creating boundary area of clay-rock. Kinetic energy is stored there and eventually when the stress becomes too great, the plates shift suddenly (just as they have been doing around Reno of late) and an earth temblor results.

The trail winds along on what seems to be a road but is actually where the plates shifted away from themselves, with dirt filling in the cracks. These are called benches and are typically found along fault lines. The plate shift varied geographically, with the north part of the San Andreas shifting 15 to 16 feet; the area between San Francisco and Portola moving about 7 to 9 feet, and here at Los Trancos about 3 to 4 feet.

At station 5 you can see a profusion of wildflowers, lot of orange California poppies growing there because the fault builds up a kind of clay dam which holds the water for the flowers. At station 6 you see sag ponds, created by tremors. And at station 7 there are two oak trees growing parallel with the ground, the limbs shaken down by the 1989 quake. While the parallel limbs continued to grow out, new limbs grew vertically.

There's lot more about this short hike that will help you to understand the phenomena of quakes. There's even a broad bench at the point where the trail splits, one leg dipping down and around and winding back to the bench.

Getting to Los Trancos parking lot is simple: Take I-280 West from Mountain View, Calif., and exit at Page Mill Road, 1.5 miles east of Skyline Boulevard. This is a winding, two-lane road thronged by bike riders on weekends. You won't have much time to look around as this is a twisting, dipping road. Call (650) 691-1200 or see info@openspace.org for a map.

HEAVENLY OPEN FOR MEMORIAL DAY

Heavenly Mountain Resort (www.skiheavenly.com) will open the Heavenly Gondola for sightseeing and adventure activities, including the new Heavenly Flyer cable ride, for the Memorial Day weekend May 23-26.

"Lake Tahoe is incredibly beautiful this time of year and just far enough away to really get that vacation feeling without spending your entire budget on travel," said John Wagnon, Heavenly's vice president of marketing.

The Heavenly Gondola will operate from 10 a.m. to 4 p.m. for sightseeing. The Adventure Peak activities area will operate the Heavenly Flyer zip line ride as well as a brand-new 25-foot-tall, multi-ability climbing wall from 11 a.m. until 3 p.m. Café Blue on the Observation Deck will be open for drinks and light snacks from 11 a.m. until 3 p.m.; as will the Adventure Peak BBQ and the Umbrella Bar at the top of the Gondola.

The Heavenly Flyer ZipRider cable ride is an exciting 3,300-foot ride, the longest zip line in the continental U.S. zooming at speeds up to 50 mph.

The Heavenly Flyer will operate from 11 a.m. until 3 p.m. with rides beginning on the hour. Flyers must check in at Mission Control at least 20 minutes prior to their scheduled flight time. Rides are $30 plus the cost of a Heavenly Gondola sightseeing ticket (adults $30). Heavenly season passholders ride the Gondola all summer long for free and receive a $10 discount on Heavenly Flyer rides.

• Contact Sam Bauman at Sbauman@nevadaappeal.com or 881-1236.

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