How are Earthquakes measured

Earthquakes are measured by seismographs which record an earthquake, and how bad it is by sensing the vibrations in the ground. this is otherwise known as a ritcher scale. Seismographs can record final results of an earthquake in numbers, a severe city crumbling result from a seismograph would be 10.0, a little earthquake would have a reading of 1.4. Here are some of the worst earthquakes in the world that have happened.


San Francisco Earthquake (1906). Between 7.7 and 8.3 magnitudes; killed approximately 3,000 people and caused around $400 million in damage; most devastating earthquake in California and U.S. history.
Great Kantō earthquake (1923). On the Japanese island of Honshū, killing over 140,000 in Tokyo and environs.
Napier earthquake (1931). 256 dead.
1933 Long Beach earthquake
1935 Balochistan earthquake at Quetta, Pakistan measuring 7.7 on the Richter scale. Anywhere from 30,000 to 60,000 people died
1939 Erzincan earthquake at Erzincan, Turkey measuring 7.9 on the Richter scale.
Assam earthquake of 1950 (1950). Earthquake in Assam, India measures 8.6M.
Kamchatka earthquakes (1952 and 1737).
Great Kern County earthquake (1952). This was second strongest tremor in Southern California history, epicentered 60 miles North of Los Angeles. Major damage in Bakersfield, California and Kern County, California, while it shook the Los Angeles area.
Quake Lake (1959) Formed a lake in southern Montana, USA
Great Chilean Earthquake (1960). Biggest earthquake ever recorded, 9.5 on Moment magnitude scale, and generated tsunamis throughout the Pacific ocean.
Skopje earthquake of 1963, measuring 6.1 on the Richter scale kills 1,800 people, leaves another 120,000 homeless, and destroys 80% of the city.
Good Friday Earthquake (1964) In Alaska, it was the third biggest earthquake recorded, measuring 9.2M. and generated tsunamis throughout the Pacific ocean.
Ancash earthquake (1970). Caused a landslide that buried the town of Yungay, Peru; killed over 40,000 people.
Sylmar earthquake (1971). Caused great and unexpected destruction of freeway bridges and flyways in the San Fernando Valley, leading to the first major seismic retrofits of these types of structures, but not at a sufficient pace to avoid the next California freeway collapse in 1989.
Managua earthquake (1972), which killed more than 10,000 people and destroyed 90% of the city. The earthquake took place on December 23 1972 at midnight.
Friuli earthquake (1976), Which killed more than 2.000 people in Northeastern Italy on the 6th of May
Tangshan earthquake (1976). The most destructive earthquake of modern times. The official death toll was 255,000, but many experts believe that two or three times that number died.
Guatemala 1976 earthquake (1976). Causing 23,000 deaths, 77,000 injuries and the destruction of more than 250,000 homes.
Coalinga, California earthquake (1983). 6.5 on the Richter scale on a section of the San Andreas Fault. Six people killed, downtown Coalinga, California devastated and oil field blazes.
Great Mexican Earthquake (1985). Killed over 6,500 people (though it is believed as many as 30,000 may have died, due to missing people never reappearing.)
Great San Salvador Earthquake (October 10, 1986). Killed over 1,500 people.
Whittier Narrows earthquake (1987).
Armenian earthquake (1988). Killed over 25,000.
Loma Prieta earthquake (1989). Severely affecting Santa Cruz, San Francisco and Oakland in California. This is also called the World Series Earthquake. It struck as Game 3 of the 1989 World Series was just getting underway at Candlestick Park in San Francisco. Revealed necessity of accelerated seismic retrofit of road and bridge structures.
Luzon Earthquake (1990). On 16 July 1990, an earthquake measuring 7.7 on the Richter scale struck the island of Luzon, Philippines.
Landers, California earthquake (1992). Serious damage in the small town of Yucca Valley, California and was felt across 10 states in Western U.S. Another tremor measured 6.4 struck 3 hours later and felt across Southern California.
August 1993 Guam Earthquake, measuring 8.2 on the Richter scale and lasting 60 seconds.
Northridge, California earthquake (1994). Damage showed seismic resistance deficiencies in modern low-rise apartment construction.
Great Hanshin earthquake (1995). Killed over 6,400 people in and around Kobe, Japan.
Athens earthquake (1999). 5.9 on the Richter scale, it hit Athens on September 7. Epicentered 10 miles north of the Greek capital, it claimed 143 lives.
Chi-Chi earthquake (1999) Also called the 921 earthquake. Struck Taiwan on September 21 1999. Over 2,000 people killed, destroyed or damaged over ten thousand buildings. Caused world computer prices to rise sharply.
Armenia, Colombia (1999) 6.2 on the Richter scale, Killed over 2,000 in the Colombian Coffee Grown Zone.
1999 İzmit earthquake measuring 7.4 on the Richter scale and killed over 17,000 in northwestern Turkey.
Hector Mine earthquake (1999). 7.1 on the Richter scale, epicentered 30 miles east of Barstow, California, widely felt in California and Nevada.
1999 Düzce earthquake at Düzce, Turkey measuring 7.2 on the Richter scale.
Baku earthquake (2000).

21st century
Nisqually Earthquake (2001).
El Salvador earthquakes (2001). 7.9 (13 January) and 6.6 (13 February) magnitudes, killed more than 1,100 people.
Gujarat Earthquake (26 January 2001).
Hindu Kush earthquakes (2002). Over 1.100 killed.
Molise earthquake (2002) 26 killed.
Bam Earthquake (2003). Over 40,000 people are reported dead.
Parkfield, California earthquake (2004). Not large (6.0), but the most anticipated and intensely instrumented earthquake ever recorded and likely to offer insights into predicting future earthquakes elsewhere on similar slip-strike fault structures.
Chuetsu Earthquake (2004).
Sumatra-Andaman Earthquake (26 December 2004). Second largest earthquake in recorded history registering a moment magnitude of 9.3. Epicentered off the coast of the Indonesian island of Sumatra, this massive temblor triggered a series of gigantic tsunamis that smashed onto the shores of a number of nations, causing more than 285,000 fatalities.
Sumatran (Nias) Earthquake (2005).
Fukuoka earthquake (2005).
Kashmir earthquake (2005) (also known as the Great Pakistan earthquake). Killed over 79,000 people; and many more injured.
Lake Tanganyika earthquake (2005).
May 2006 Java earthquake (2006).
July 2006 7.7 magnitude Java earthquake which triggered tsunamis (2006).
September 2006 6.0 magnitude Gulf of Mexico earthquake (2006).
October 2006 6.6 magnitude Kona, Hawaii earthquake (2006).
November 2006 8.1 magnitude north of Japan (2006).
December 26, 2006, 7.2 magnitude, southwest of Taiwan (2006).
February 12, 2007, 6.0 magnitude, southwest of Cape St. Vincent, Portugal (2007).
Sumatra Earthquakes March 06, 2007, 6.4 and 6.3 magnitude, Sumatra, Indonesia (2007).
March 25, 2007, 6.9 magnitude, off the west coast of Honshū, Japan (2007).
April 1, 2007, 8.1 magnitude, Solomon Islands (2007).
2007 Guatemala Earthquake 6.7 magnitude (2007)