Major Earthquakes around the World, 2008 The following table lists the date, location, and magnitude of major earthquakes around the world during 2008. DateLocationMagnitude1 Jan. 5Queen Charlotte Islands Region6.6 Jan. 10Off the coast of Oregon6.4 Feb. 20Simeulue, Indonesia7.4 Feb. 24Neveda6.0 Feb. 25Kepulauan Mentawai Region, Indonesia7.0 March 21Xinjiang-Xizang Border Region7.2 April 9Loyalty Islands7.3 April 18Illinois5.2 May 12China7.9 June 13Eastern Honshu, Japan6.9 July 19Honshu, Japan7.0 Oct. 6Kyrgyzstan6.6 Oct. 11Russia6.3 Oct. 29Pakistan6.4 Nov. 16Indonesia7.3 Dec. 20Japan6.3 Source:Incorporated Research Institutions for Seismology: Earthquake Events 2008: IRIS NOTE: A major earthquake is defined here as having a magnitude of 6.0 or more. 1. Unless otherwise indicated, magnitudes listed are moment magnitudes, the newest, most uniformly applicable magnitude scale.

Earthquakes and Volcanic Eruptions Here is information on significant earthquakes and volcanic eruptions going back as early asA.D.79 and through the present. A.D. 79 Aug. 24, Italy: eruption of Mt. Vesuvius buried cities of Pompeiiand Herculaneum, killing thousands. 856 Dec. 22, Damghan, Iran:earthquake killed 200,000. 893 March 23, Ardabil, Iran:earthquake killed about 150,000 people. 1138 Aug. 9, Aleppo, Syria:deadly earthquake claimed lives of 230,000 people. 1290 Sept., Chihli, China:earthquake killed about 100,000 people. 1556 Jan. 23, Shaanxi (Shensi) province, China:most deadly earthquake in history; 830,000 killed. 1667 Nov., Shemakha, Caucasia:earthquake killed about 80,000 people. 1693 Jan. 11, Sicily, Italy:earthquake killed about 60,000 people. 1707 Oct. 28, Japan:tsunami caused by an earthquake drowned 30,000. 1727 Nov. 18, Tabriz, Iran:about 77,000 victims killed in deadly earthquake. 1755 Nov. 1, Portugal:earthquake, fires, and Atlantic tsunami leveled Lisbon and was felt as far away as southern France and North Africa; 70,000 killed. 1782 South Sea, China:tsunami killed 40,000. 1783 Feb. 4, Calabria, Italy:series of 6 earthquakes over two-month period caused massive destruction, killing 50,000. One of first scientifically investigated earthquakes. June 8, Iceland:eruption of Laki volcano lasted until Feb. 1784. Haze from eruption resulted in loss of island's livestock and widespread crop failure; 9,350 deaths, mostly due to starvation. 1792 May 21, Kyushu Island, Japan:collapse of old lava dome during eruption of Unzen volcano caused avalanche and tsunami that killed an estimated 14,300 people. (Most were killed by the tsunami.) Japan's greatest volcano disaster. 1811 Dec. 16, Mississippi Valley, nr. New Madrid, Mo.:earthquake reversed the course of the Mississippi River. Fatalities unknown due to sparse population in area. Aftershocks and tremors continued into 1812. It has been estimated that three of the series of earthquakes had surface-wave magnitudes of 8.6, 8.4, and 8.8 on the Richter scale.It is the largest series of earthquakes known to have occurred in North America. 1815 April 5, 10–11, Netherlands Indies (Sumbawa, Indonesia):eruption of Tambora largest in historic times. An estimated 92,000 people were killed, about 10,000 directly as a result of explosions and ash fall and about 82,000 indirectly by starvation and disease. 1877 June 26, north-central Ecuador:eruption of Mt. Cotopaxi caused severe mudflows that wiped out surrounding cities and valleys; 1,000 deaths. 1883 Aug. 26–28, Netherlands Indies (Krakatau, Indonesia):eruption of Krakatau;violent explosions destroyed two-thirds of island and caused a tsunami on Java and Sumatra, killing more than 36,000. It was felt as far away as Cape Hornand possibly England. 1886 Aug. 31, Charleston, S.C.:magnitude 7.3 quake, killed 60 people and caused extensive damage. 1896 June 15, Sanriku, Japan:earthquake and tidal wave killed 27,000. 1902 May 7, St. Vincent, West Indies:Soufrière volcano erupted, devastating one-third of the island and killing some 1,680 people. May 8, Martinique, West Indies: Mt. Peléeerupted and wiped out city of St. Pierre; 40,000 dead. 1906 April 18, San Francisco:earthquake accompanied by fire razed more than 4 sq mi; estimates range from 700 to 3,000 dead or missing.For more, see The Great 1906 San Francisco Earthquake. 1908 Dec. 28, Messina, Sicily:city totally destroyed by earthquake. Estimated death toll, from quake and tsunami, 70,000–100,000 in Sicilyand southern Italy. 1915 Jan. 13, Avezzano, Italy:magnitude 7.5 earthquake left 29,980 dead. 1920 Dec. 16, Gansu province, China:magnitude 7.8 earthquake killed 200,000 in northwest China. 1923 Sept. 1, Japan:magnitude 7.9 earthquake destroyed one-third of Tokyo and most of Yokohama. More than 140,000 killed. 1927 May 22, nr. Xining, China:magnitude 7.9 earthquake claimed approximately 200,000 victims. 1932 Dec. 25, Gansu, China:magnitude 7.6 earthquake killed approximately 70,000. 1933 March 10, Long Beach, Calif.:117 left dead by earthquake. 1935 May 30, Pakistan:earthquake at Quettakilled 30,000–60,000. 1939 Jan. 24, Chile:earthquake razed 50,000 sq mi; about 30,000 killed. Dec. 27, northern Turkey:severe quakes destroyed city of Erzingan; about 30,000 casualties. 1948 Oct. 5, Ashgabat, Turkmenistan:magnitude 7.3 earthquake destroyed the city, killing 110,000. 1950 Aug. 15, India:earthquake affected 30,000 sq mi in Assam;1500 killed. 1960 Feb. 29, Agadir, Morocco:10,000–12,000 dead as earthquake set off tidal wave and fire, destroying most of city. May 22, Chile:strongest earthquake ever recorded (9.5 magnitude) struck near the coast, causing a tsunami that traveled as far as Hawaii, Japan, and New Zealand, killing 4,000–5,000.

Frequency of Earthquakes Worldwide The following table lists the frequency of earthquakes worldwide, according to magnitude and annual average. DescriptorMagnitudeAnnual average Great8 or higher11 Major7–7.9172 Strong6–6.91342 Moderate5–5.91,3192 Light4–4.9c. 13,000 Minor3–3.9c. 130,000 Very minor2–2.9c. 1,300,000 1. Based on observations since 1900. 2. Based on observations since 1990. NOTE: The NEIC estimates that several million earthquakes occur in the world each year. Many go undetected because they hit remote areas or have very small magnitudes. Source:National Earthquake Information Center, U.S. Geological Survey.

The Severity of an Earthquake Source:National Earthquake Information Center, U.S. Geological Survey Earthquakes are the result of forces deep within Earth's interior that continuously affect its surface. The energy from these forces is stored in a variety of ways within the rocks. When this energy is released suddenly—by shearing movements along faults in the crust of Earth, for example—an earthquake results. The area of the fault where the sudden rupture takes place is called the focus or hypocenter of the earthquake. The point on Earth's surface directly above the focus is called the epicenter of the earthquake. The severity of an earthquake can be expressed in terms of both intensity and magnitude. The two terms are quite different, however, and they are often confused. Intensity is based on the observed effects of ground shaking on people, buildings, and natural features. It varies from place to place within the disturbed region depending on the location of the observer with respect to the earthquake epicenter. Magnitude is related to the amount of seismic energy released at the hypocenter of the earthquake. It is based on the amplitude of the earthquake waves recorded on instruments, which have a common calibration. Magnitude is thus represented by a single, instrumentally determined value. The Richter Magnitude Scale Seismic waves are the vibrations from earthquakes that travel through Earth; they are recorded on instruments called seismographs. Seismographs record a zigzag trace that shows the varying amplitude of ground oscillations beneath the instrument. Sensitive seismographs, which greatly magnify these ground motions, can detect strong earthquakes from sources anywhere in the world. The time, location, and magnitude of an earthquake can be determined from the data recorded by seismograph stations. The Richter magnitude scale was developed in 1935 by Charles F. Richter of the California Institute of Technology as a mathematical device to compare the size of earthquakes. The magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded by seismographs. Adjustments are included in the magnitude formula to compensate for the variation in the distance between the various seismographs and the epicenter of the earthquakes. On the Richter Scale, magnitude is expressed in whole numbers and decimal fractions. For example, a magnitude of 5.3 might be computed for a moderate earthquake, and a strong earthquake might be rated as magnitude 6.3. Because of the logarithmic basis of the scale, each whole number increase in magnitude represents a tenfold increase in measured amplitude; as an estimate of energy, each whole number step in the magnitude scale corresponds to the release of about 31 times more energy than the amount associated with the preceding whole number value. Although the Richter Scale has no upper limit, the largest known shocks have had magnitudes in the 8.8 to 8.9 range. Why Are There So Many Earthquake Magnitude Scales? Earthquake size, as measured by the Richter Scale, is a well-known, but not well understood, concept. What is even less well understood is the proliferation of magnitude scales and their relation to Richter's original magnitude scale. Richter's magnitude scale was first created for measuring the size of earthquakes occurring in southern California, using relatively high-frequency data from nearby seismograph stations. This magnitude scale was referred to as ML, with the L standing for local. As more seismograph stations were installed around the world, it became apparent that the method developed by Richter was strictly valid only for certain frequency and distance ranges. In order to take advantage of the growing number of globally distributed seismograph stations, new magnitude scales that are an extension of Richter's original idea were developed. These include body-wave magnitude, “mb,” and surface-wave magnitude, “MS.” Each is valid for a particular frequency range and type of seismic signal. In its range of validity each is equivalent to the Richter magnitude. Because of the limitations of all three magnitude scales—ML, mb, and MS—a new, more uniformly applicable extension of the magnitude scale, known as moment magnitude, or “MW,” was developed. In particular, for very large earthquakes moment magnitude gives the most reliable estimate of earthquake size. New techniques that take advantage of modern telecommunications have recently been implemented, allowing reporting agencies to obtain rapid estimates of moment magnitude for significant earthquakes. So nowadays, when most seismologists announce a magnitude number, they are rarely referring to the Richter Scale. The Modified Mercalli Intensity Scale The effect of an earthquake on Earth's surface is called the intensity.

Tsunami in Japan 2011: Waves Stirred Up by Earthquake Cause Wide Destruction Learn about the science behind tsunamis and earthquakes Source: U.S. Geological Survey Tsunami. Relief Effort in Japan Tsunami in Japan Japanwas hit by a 9.0 magnitude earthquakeon March 11, 2011, that triggered a deadly 23-foot tsunami in the country's north. The giant waves deluged cities and rural areas alike, sweeping away cars, homes, buildings, a train, and boats, leaving a path of death and devastation in its wake. Video footage showed cars racing away from surging waves. The earthquake—the largest in Japan's history—struck about 230 miles northeast of Tokyo. The Pacific Tsunami Warning Center issued warnings for Russia, Taiwan, Hawaii, Indonesia, the Marshall Islands, Papua New Guinea, Australia, and the west coasts the U.S., Mexico, Central America, and South America. According to the official toll, the disasters left 15,839 dead, 5,950 injured, and 3,642 missing. Earthquake Causes Nuclear Disaster What's more, cooling systems in one of the reactors at the Fukushima Daiichi Nuclear Power Station in the Fukushima prefecture on the east coast of Japan failed shortly after the earthquake, causing a nuclear crisis. This initial reactor failure was followed by an explosion and eventual partial meltdowns in two reactors, then by a fire in another reactor which released radioactivity directly into the atmosphere. The nuclear troubles were not limited to the Daiichi plant; three other nuclear facilities also reported problems. More than 200,000 residents were evacuated from affected areas. On April 12, Japan raised its assessment of the situation at the Fukushima Daiichi nuclear power plant to Level 7, the worst rating on the international scale, putting the disaster on par with the 1986 Chernobyl explosion. Developed by the International Atomic Energy Agency (IAEA) along with countries who use nuclear energy, the scale defines level 7 as a nuclear accident that involves "widespread health and environmental effects" and the "external release of a significant fraction of the reactor core inventory." Almost two months later, the IAEA called the status of the Fukushima Daiichi nuclear plant "very serious." At a news conference on March 13, Prime Minister Naoto Kan, who later gave the disaster the name "Great East Japan Earthquake", emphasized the gravity of the situation: "I think that the earthquake, tsunami, and the situation at our nuclear reactors makes up the worst crisis in the 65 years since the war. If the nation works together, we will overcome." The government called in 100,000 troops to aid in the relief effort. The deployment was the largest since World War II. The tsunami in Japan recalled the 2004 disaster in the Indian Ocean. On Dec. 26, a 9.0 magnitude earthquake—the largest earthquakein 40 years—ruptured in the Indian Ocean, off the northwest coast of the Indonesian island of Sumatra. The earthquake stirred up the deadliest tsunamiin world history, so powerful that the waves caused loss of life on the coast of Africa and were even detected on the East Coast of the United States. More than 225,000 people died from the disaster, a half a million were injured, and millions were left homeless. Seestatistics on Deadliest Tsunamisand Deadliest Earthquakes. The Science of Tsunami A tsunami(pronounced soo-NAHM-ee) is a series of huge waves that occur as the result of a violent underwater disturbance, such as an earthquakeor volcanic eruption. The waves travel in all directions from the epicenter of the disturbance. The waves may travel in the open sea as fast as 450 miles per hour. As they travel in the open ocean, tsunami waves are generally not particularly large—hence the difficulty in detecting the approach of a tsunami. But as these powerful waves approach shallow waters along the coast, their velocity is slowed and they consequently grow to a great height before smashing into the shore. They can grow as high as 100 feet; the Indian Ocean tsunami generated waves reaching 30 feet. Tsunamiis the Japanese word for "harbor wave." They are sometimes mistakenly referred to as tidal waves, but tsunamis have nothing to do with the tides. Tsunamis have been relatively rare in the Indian Ocean, and are most common in the Pacific Ocean.