Background On Earthquakes
An earthquake is caused by a sudden slip on a fault. Tectonic plates are always slowly moving, but they can get stuck at their edges due to friction. When the stress on the edge of a tectonic plate overcomes the friction, there is an earthquake that releases energy in waves that travel through the earth's crust and cause the shaking that is felt. For example, in California, there are two plates - the Pacific Plate and the North American Plate. The Pacific Plate consists of most of the Pacific Ocean floor and the California Coast line. The North American Plate comprises most of the North American Continent and parts of the Atlantic and Arctic Ocean floor. The primary boundary between these two plates is the San Andreas Fault. The San Andreas Fault is more than 800 miles long and extends to depths of at least 10 miles. Many other smaller faults like the Hayward (Northern California) and the San Jacinto (Southern California) branch join the San Andreas Fault Zone. The Pacific Plate grinds northwestward past the North American Plate at a rate of about two inches per year.
Read more about this topic: Earthquake Weather
Famous quotes containing the words background and/or earthquakes:
“Silence is the universal refuge, the sequel to all dull discourses and all foolish acts, a balm to our every chagrin, as welcome after satiety as after disappointment; that background which the painter may not daub, be he master or bungler, and which, however awkward a figure we may have made in the foreground, remains ever our inviolable asylum, where no indignity can assail, no personality can disturb us.”
—Henry David Thoreau (1817–1862)
“For nation will rise against nation, and kingdom against kingdom, and there will be famines and earthquakes in various places: all this is but the beginning of the birth pangs.”
—Bible: New Testament, Matthew 24:7,8.