Arizona Republic from Phoenix, Arizona on April 4, 1969 · Page 23
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Arizona Republic from Phoenix, Arizona · Page 23

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Phoenix, Arizona
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Friday, April 4, 1969
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Page 23
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AI. Swingin? L.A. headed ior San Francisco, geologists report By GEORGE GETZE LM Angeles Times LOS ANGELES—Two field geologists suggested in 1953 that there has been a horizontal north-south movement of about 350 mjles on the San Andreas fault, which bisects California, in the last 135 million years. Their suggestion was made after years of studying offset stream beds and rock strata and has been generally accepted by geologists. It means that the site of Los Angeles is more than 300 miles farther north than in Jurassic times, 180 million years ago, and that in another 100 million or so years it may be somewhere west of whew San Francisco now is. This north-south movement is a peculiarity of the famous San Andreas fault, the longest, most exposed and most studied earthquake fault in the world. Most faults, when they move, have a vertical displacement. Land on one side moves up or down in relation to land on the other side of the fault. 12 The Arizona Republic Phoenix, Fri., April 4, m* The San Andreas fault, on the other hand, has more horizontal displacement than vertical. In the 1906 San Francisco earthquake there was a 20-foot horizontal displacement in many places but less than a two-foot vertical displacement and that only in a few places. One reason scientist? scoff at the prophecies of religious fantatics and soothsayers who pretend to know that that part of California will break off in a tremendous earthquake this month and fall into the ocean is that the pressure being exerted is all the other way, tending to hold coastal areas against the continent. Another reason they scoff, of course, is that nobody, not even seismologists and geophysicists, can predict the decade or year, much less the month, day or hour, that an earthquake will take place. All the scientists are able to do Is predict that future earthquakes will occur where earthquakes have occurred in the past. According to Mason Hill, former director of explorations for Atlantic-Richfield Co. and one of the geologists who advanced the idea that coastal California had moved 350 miles since Jurassic times, the evidence suggests that this movement has been consistent over the entire geologic history of the fault. The whole area has been in a constant state of geologic restlessness for millions of years and will continue restless for millions more. The San Andreas fault emerges from under the Pacific ocean north of San Francisco and runs southeastward through the extreme western section of that city. At its closest to the Los Angeles metropolitan district, just on the other side of the San Gabriel Mountains, it is about 30 miles from city hall. Many geologists now think the Gulf of California between the Mexican peninsula of Baja California and the rest of the country is th« result of millions of years of movement Along the fault, or tftat the fault and the gulf are both results of the same fundamental movement of the earth's crust. During future millions of years the crustal movement could continue to open up the gulf and eventually create an immense island consisting of Baja California and all that part of California west of the San Andreas fault. That is not a fantastic notion. That man will stay around for the ride is more doubtful than that the movement will continue. Most scientists doubt the human species will last that long, although they do not see earthquakes doing him in. The north-south displacement taking place in the present era amounts to about 2 inches a year. On those parts of the fault where there is no gradual movement, or "creep," the constantly increasing tension of this movement is relieved ever so often by a major earthquake. The most recent such adjustment on the San Andreas fault was in the Imperial Valley in southeastern California in 1940, when the biggest measurable displacement was 15 feet. In the 1906 earthquake on the northern section of the fault Ihe displacement measured 20 feet. HAGGAR HAGGAR PRE-CUFFS SPIRITED SLACKS IN DESERT COLORS Two great styles, two great slacks from Haggar. imperial styling, with Electromatic- prest feature for machine dry cleaning with no ironing required. $11. The Forevor-Presr Plus slack can be machine washed and dried, or machine dry cleaned. $13. Each in cactus green, copper, canyon brown, black, blue. Wais* liies 32-42, pre-cuffed lengths 28-33. Puritan shapes a full-fashioned Ban-Lon* shirt made of 100% nylon. Machine wash and dryable in cactus green, Spanish gold, black, blue, white. Sizes M.L.Xl. $11. Men's Sportswear. •Bancroft trade mark SHOP DIAMOND'S PARK CENTRAL, THOMAS ' 1 • -AJPR1I RS., URI. 9:30--9:30, TU EN STAMPS, TOOI

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