GULLY TIED TO DESERT TEMBLORS : SCIENTISTS FIND TRACE OF STRONG QUAKES NEAR PALM SPRINGS.Byline: Jane E. Allen Associated Press Associated Press: see news agency. Associated Press (AP) Cooperative news agency, the oldest and largest in the U.S. and long the largest in the world. Geologists digging near Palm Springs have found evidence of some of the biggest displacements ever seen along the mighty San Andreas Fault San Andreas fault, great fracture (see fault) of the earth's crust in California. It is the principal fault of an intricate network of faults extending more than 600 mi (965 km) from NW California to the Gulf of California. : a 72-foot gap between edges of a stream channel likely created by two quakes. By digging trenches into soil and rock, the geologists believe they've discovered that very strong quakes along the Mission Creek Fault segment of the San Andreas San Andreas is an Anglicisation of the Spanish language San Andrés (Saint Andrew, the Apostle). It may refer to:
At least two quakes - one about 300 years ago and another 250 to 400 years earlier - moved the earth that distance, geologists Thomas Fumal and Michael Rymer determined. For that to happen, each of the quakes would have to have been magnitude 7.7 to 7.8. Each also would have had to displace nearly 36 feet, ``about as large as we've seen before,'' in San Andreas quakes further north in an area called the Carrizo Plain The Carrizo Plain is a large enclosed plain, approximately 50 miles (80 km) long and up to 15 miles (24 km) across, in eastern San Luis Obispo County, California. It contains the 180,000 acre (728 km²) Carrizo Plain National Monument, and it is the largest single native , Fumal said in an interview. But there might have been additional quakes powering the 72-foot shift, stressed Dan Ponti, another geologist with the U.S. Geological Survey The term geological survey can be used to describe both the conduct of a survey for geological purposes and an institution holding geological information. A geological survey in Menlo Park Menlo Park. 1 Residential city (1990 pop. 28,040), San Mateo co., W Calif.; inc. 1874. Electronic equipment and aerospace products are manufactured in the city. Menlo College and a Stanford Univ. research institute are there. 2 Uninc. . ``We can see at least two. There may be another one or two in there. There's a whole lot of uncertainties in this stuff,'' Ponti said in an interview Friday. He said the preliminary findings at the Coachella Valley Coachella Valley (kō'əchĕl`ə), arid region, SE Calif., N of the Salton Sea. Water is brought into the region by artesian wells and by the Coachella Canal (123 mi/198 km long), a branch of the All-American Canal built between 1938 and site leave many unanswered questions. Ponti said there is good evidence that another quake occurred on the fault before water cut the channel - making for at least three quakes in the last 1,000 to 1,200 years. Ponti said the historic events seen in the layers are comparable to other large earthquakes on the San Andreas, like the 1857 Fort Tejon quake and the 1906 San Francisco quake, both below magnitude 8. From the new work, Ponti said scientists can infer that the Mission Creek segment probably breaks in fairly large earthquakes every several hundred years. If additional research supports the findings so far, ``we're probably looking at an average rate of recurrence of around 400 years.'' |
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