Thursday, July 25, 2013

San Andreas Fault: fear is always latent

SCIENCE

Human civilization, as modern and boastful, forgets, sometimes, the destructive power of nature. In Culture in 10 already discussed when studying volcanoes and tornadoes. Today, we present the San Andreas Fault, causing a most seismically active region of the world and they demonstrated throughout history its destructive power to the point that one day "the island of Baja California", will be separated from the Americas.

Falla de San Andres terremoto californiaThe San Andreas fault is located in a depression in the ground on a transform boundary area, right-shift between the North American plate and the Pacific plate. This transform fault is famous for producing large and devastating earthquakes. This system has a length of about 1,286 km and passes through the state of California, in the United States, and Baja California in Mexico. The system is composed of numerous faults or segments. In the south are notable failures San Jacinta, Imperial and Cerro Prieto. To the south the system ends San Andreas fault in the Gulf of California.

Falla de San Andres terremoto californiaSan Andreas Fault earthquake california due to the Pacific plate enters the Gulf of California and to the north of the San Andreas fault in the next 50,000 years, the Baja California peninsula of Mexico will be separated and converted into an island, will move northward. It is estimated to arrive off Alaska in about 50 million years. Each year approximately Baja California peninsula separates 6 cm.

It is considered that the Baja California peninsula formed by this fault. This same process is moving to the city of Los Angeles toward San Francisco Bay (both are on the same side of the fault) at a rate of about 4.5 cm per year. This can not be perceived with the naked eye, but has caused extensive damage to engineering works such as aqueducts, roads and farms. As a result of this failure numerous earthquakes originate, having befallen some of considerable magnitude as those of 1857, extending from Parkfield to El Cajon (estimated magnitude: 8.0), the San Francisco of 1906 (estimated magnitude 7.2) , or the Loma Prieta earthquake of 1989, near Santa Cruz, California (magnitude 7.1) and El Centro in 1940.


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