An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. Earthquakes are recorded with a seismometer, also known as a seismograph. The moment magnitude of an earthquake is conventionally reported, or the related and mostly obsolete Richter magnitude, with magnitude 3 or lower: are earthquakes being barely felt and magnitude 7 causing serious damage over large areas. Intensity of shaking is measured on the modified Mercalli scale.
At the Earth's surface, earthquakes manifest themselves by shaking and sometimes displacing the ground. When a large earthquake epicenter is located offshore, the seabed sometimes suffers sufficient displacement to cause a tsunami. The shaking in earthquakes can also trigger landslides and occasionally volcanic activity.
The largest recorded earthquake in the United States was a magnitude 9.2 that struck Prince William Sound, Alaska on Good Friday, March 28, 1964 UTC.
2.The largest recorded earthquake in the world was a magnitude 9.5 (Mw) in Chile on May 22, 1960
3.Although both are sea waves, a tsunami and a tidal wave are two different unrelated phenomenon. A tidal wave is a shallow water wave caused by the gravitational interactions between the Sun, Moon, and Earth. A tsunami is a sea wave caused by an underwater earthquake or landslide (usually triggered by an earthquake) displacing the ocean water.
4.The hypocenter of an earthquake is the location beneath the earth's surface where the rupture of the fault begins. The epicenter of an earthquake is the location directly above the hypocenter on the surface of the earth.
5.It is estimated that there are 500,000 detectable earthquand akes in the world each year. 100,000 of those can be felt, 100 of them cause damage .
6. The magnitude of an earthquake is a measured value of the earthquake size. The magnitude is the same no matter where you are, or how strong or weak the shaking was in various locations. The intensity of an earthquake is a measure of the shaking created by the earthquake, and this value does vary with location.
7. Each year the southern California area has about 10,000 earthquakes. Most of them are so small that they are not felt. Only several hundred are greater than magnitude 3.0, and only about 15-20 are greater than magnitude 4.0.
8. From 1975-1995 there were only four states that did not have any earthquakes. They were: Florida, Iowa, North Dakota, and Wisconsin.
9. The world's deadliest recorded earthquake occurred in 1556 in central China. It struck a region where most people lived in caves carved from soft rock. These dwellings collapsed during the earthquake, killing an estimated 830,000 people. In 1976 another deadly earthquake struck in Tangshan, China, where more than 250,000 people were killed
*The average rate of motion across the San Andreas Fault Zone during the past 3 million years is 56 mm/yr (2 in/yr). This is about the same rate at which your fingernails grow. Assuming this rate continues, scientists project that Los Angeles and San Francisco will be adjacent to one another in approximately 15 million years.*
San Andreas Fault Line The San Andreas Fault is the sliding boundary between the Pacific Plate and the North American Plate. It slices California in two from Cape Mendocino to the Mexican border. San Diego, Los Angeles and Big Sur are on the Pacific Plate. San Francisco, Sacramento and the Sierra Nevada are on the North American Plate http://geology.com/articles/images/san-andreas-fault-map.jpg
Developed in 1935 by Charles Richter in partnership with Beno Gutenberg, both of the California Institute of Technology, the scale was intended to be used only in a particular study area in California, and on seismograms recorded on a particular instrument, the Wood-Anderson torsion seismometer
The Richter magnitude scale, assigns a single number to quantify the amount of seismic energy released by an earthquake. It is a base-10 logarithmic scale obtained by calculating the logarithm of the combined horizontal amplitude of the largest displacement from zero on a Wood–Anderson torsion seismometer output. So, for example, an earthquake that measures 5.0 on the Richter scale has a shaking amplitude 10 times larger than one that measures 4.0. The effective limit of measurement for local magnitude is about M L = 6.8.
10 Most Destructive Earthquakes Location Date Magnitude Chile May 22, 1960 9.5 Prince William Sound, Alaska March 28, 1964 9.2 Andréa of Islands, Aleutian Islands March 9, 1957 9.1 Kamchatka Nov. 4, 1952 9.0 Off western coast of Sumatra, Indonesia Dec. 26, 2004 9.0 Off the coast of Ecuador Jan. 31, 1906 8.8 Rat Islands, Aleutian Islands Feb. 4, 1965 8.7 Northern Sumatra, Indonesia March 28, 2005 8.7 India-China border Aug. 15, 1950 8.6 Kamchatka Feb. 3, 1923 8.5
The 1960 Valdivia earthquake or Great Chilean Earthquake of May 22 1960 is the most powerful earthquake ever recorded, rating 9.5 on the moment magnitude scale. It occurred in the afternoon around 2:11 pm local time and its resulting tsunami affected southern Chile, Hawaii, Japan, the Philippines, eastern New Zealand, south east Australia and the Aleutian Islands in Alaska.
The epicenter was near Canete about 435 miles south of Santiago although Valdivia, Chile was the most affected city. It caused tsunamis that severely battered the Chilean coast, with waves up to 82 feet. The main tsunami raced across the Pacific Ocean and devastated Hilo, Hawaii. Waves as high as 35 feet were recorded 6,000 miles from the epicenter, and as far away as Japan and the Philippines. The death toll and monetary losses arising from such a widespread disaster can never be precisely known. Various estimates of the total number of fatalities from the earthquake and tsunamis have been published, with the USGS citing studies with figures of 3000-5700 killed, and another source uses an estimate of 6000 dead. Different sources have estimated the monetary cost ranged from 400 million to 800 million US dollars. In 2005 terms adjusted for inflation about 2.6 to 5.2 billion
Footage From Valdivia Earthquake http://www. youtube .com/watch?v= vxXf -dYtG7Q&feature=related