Category: North America

THE SAN ANDREAS FAULT
The San Andreas Fault is part of the edge zone of the Pacific Ocean and thus belongs to the “Pacific fire belt”, in which around 80 percent of all tectonic earthquakes occur on earth. It stretches for almost 1300 kilometers from Mexico to Cape Mendocino north of San Francisco, where it descends north into the Pacific. The mainland is furrowed by a multitude of interconnected fractures and fault lines.

More than 20 million people live in the area of ​​the San Andreas Fault. There are two of the largest cities in the USA, San Francisco and Los Angeles (together around 17 million residents); In fact, San Francisco is in close proximity to the main fault. Although there have been repeated strong and devastating earthquakes in the region, further large earthquakes are predicted for the future and the movements of the earth’s crust can be seen in many places along the fault lines through offset streams, fields, roads, bridges or buildings, the settlements are growing and more new skyscrapers, bridges, highways, dams and reservoirs are being built.

GEOTECTONIC CONDITIONS
The earth’s body consists of a solid inner and a liquid outer core, a thin, hard crust and a less rigid, sluggishly flowing transition zone made of plastically deformable rock in between. The plates of the earth’s crust shift and change constantly at their common boundaries.

A long-term mean horizontal displacement of around 300 kilometers in 16 million years was calculated from the displacement of sedimentary and volcanic rock layers of the same age on both sides of the San Andreas Fault, which corresponds to an displacement of one to two centimeters per year. The current shift values ​​are even significantly higher. Geotectonically, the San Andreas Fault separates the western part of California, which is part of the North Pacific Plate, from the North American Plate.

In addition to the horizontal movements, there are also vertical shifts. The longest valley in California sinks continuously and absorbs sediments from the surrounding mountain ranges. For more information about the continent of North America, please check a2zgov.com.