An earthquake – also called a quake, tremor, or temblor – is the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they cannot be felt, to those violent enough to propel objects and people into the air, damage critical infrastructure, and wreak destruction across entire cities. The seismic activity of an area is the frequency, type, and size of earthquakes experienced over a particular time. The seismicity at a particular location in the Earth is the average rate of seismic energy release per unit volume.
The San Andreas Fault is a continental right-lateral strike-slip transform fault that extends roughly 1,200 kilometers (750 mi) through the U.S. state of California. It forms part of the tectonic boundary between the Pacific Plate and the North American Plate. Traditionally, for scientific purposes, the fault has been classified into three main segments, each with different characteristics and a different degree of earthquake risk. The average slip rate along the entire fault ranges from 20 to 35 mm per year.
The 1811–1812 New Madrid earthquakes were a series of intense intraplate earthquakes beginning with an initial earthquake of moment magnitude 7.2–8.2 on December 16, 1811, followed by a moment magnitude 7.4 aftershock on the same day. Two additional earthquakes of similar magnitude followed in January and February 1812. They remain the most powerful earthquakes to hit the contiguous United States east of the Rocky Mountains in recorded history. The earthquakes, as well as the seismic zone of their occurrence, were named for the Mississippi River town of New Madrid, then part of the Louisiana Territory and now within the U.S. state of Missouri.
The New Madrid seismic zone (NMSZ), sometimes called the New Madrid fault line, is a major seismic zone and a prolific source of intraplate earthquakes in the Southern and Midwestern United States, stretching to the southwest from New Madrid, Missouri.
The Wabash Valley seismic zone is a tectonic region located in the Midwestern United States, centered on the valley of the lower Wabash River, along the state line between southeastern Illinois and southwestern Indiana.
The 1983 Coalinga earthquake struck at 4:42 p.m. Monday, May 2 of that year, in Coalinga, California.
The Qayen earthquake, also known as the Ardekul or Qaen earthquake, struck northern Iran's Khorasan Province in the vicinity of Qaen on May 10, 1997, at 07:57 UTC. The largest in the area since 1990, the earthquake registered 7.3 on the moment magnitude scale and was centered approximately 270 kilometers (170 mi) south of Mashhad on the village of Ardekul. The third earthquake that year to cause severe damage, it devastated the Birjand–Qayen region, killing 1,567 and injuring more than 2,300. The earthquake—which left 50,000 homeless and damaged or destroyed over 15,000 homes—was described as the deadliest of 1997 by the United States Geological Survey. Some 155 aftershocks caused further destruction and drove away survivors. The earthquake was later discovered to have been caused by a rupture along a fault that runs underneath the Iran–Afghanistan border.
The 1915 Pleasant Valley earthquake occurred at in north-central Nevada. With a moment magnitude of 6.8, a surface wave magnitude of 7.7, and a maximum Mercalli intensity of X (Extreme), it was the strongest earthquake ever recorded in the state.
The Ramapo Fault zone is a system of faults between the northern Appalachian Mountains and Piedmont areas to the east. Spanning more than 185 miles (298 km) in New York, New Jersey, and Pennsylvania, it is perhaps the best known fault zone in the Mid-Atlantic region, and some small earthquakes have been known to occur in its vicinity. Recently, public knowledge about the fault has increased, especially after the 1970s, when the fault's proximity to the Indian Point nuclear plant in New York was noted.
The 1867 Manhattan earthquake struck Riley County, Kansas, in the United States on April 24, 1867, at 20:22 UTC, or about 14:30 local time. The strongest earthquake to originate in the state, it measured 5.1 on a seismic scale that is based on an isoseismal map or the event's felt area. The earthquake's epicenter was near the town of Manhattan.
The 2010 Baja California earthquake occurred on April 4 with a moment magnitude of 7.2 and a maximum Mercalli intensity of VII. The shock originated at south of Guadalupe Victoria, Baja California, Mexico.
The 1916 Irondale earthquake struck in the north–central region of the U.S. state of Alabama on October 18. The strongest earthquake in state history, it registered an estimated Richter scale magnitude of 5.1 and resulted in minor damage. Damage was limited to Shelby and Jefferson counties and reached its maximum severity near the epicenter in the city of Irondale, including cracked windows, fallen chimneys, and dried-up wells. While there were no fatalities, the earthquake spawned widespread panic, prompting alarmed workers to evacuate tall buildings.
On August 23, 2011, a magnitude 5.8 earthquake hit the Piedmont region of the U.S. state of Virginia at 1:51:04 p.m. EDT. The epicenter, in Louisa County, was 38 mi (61 km) northwest of Richmond and 5 mi (8 km) south-southwest of the town of Mineral. It was an intraplate earthquake with a maximum perceived intensity of VIII (Severe) on the Mercalli intensity scale. Several aftershocks, ranging up to 4.5 in magnitude, occurred after the main tremor.
The 2011 Oklahoma earthquake was a 5.7 magnitude intraplate earthquake which occurred near Prague, Oklahoma on November 5 at 10:53 p.m. CDT in the U.S. state of Oklahoma. The epicenter of the earthquake was in the vicinity of several active wastewater injection wells. According to the United States Geological Survey (USGS), it was the most powerful earthquake ever recorded in Oklahoma until the 2016 Oklahoma earthquake. The previous record was a 5.5 magnitude earthquake that struck near the town of El Reno in 1952. The quake's epicenter was approximately 44 miles (71 km) east-northeast of Oklahoma City, near the town of Sparks and was felt in the neighboring states of Texas, Arkansas, Kansas and Missouri and even as far away as Tennessee and Wisconsin. The quake followed several minor quakes earlier in the day, including a 4.7 magnitude foreshock. The quake had a maximum perceived intensity of VIII (Severe) on the Mercalli intensity scale in the area closest to the epicenter. Numerous aftershocks were detected after the main quake, with a few registering at 4.0 magnitude.
The 2012 Shwebo earthquake occurred at 07:42 local time on 11 November in Myanmar. It had a magnitude of 6.8 on the moment magnitude scale and a maximum perceived intensity of VIII (Severe) on the Mercalli intensity scale. The epicenter was near the town of Male, 52 km NNE of the city of Shwebo, 64 km west of Mogok and 120 km north of Mandalay. Significant damage and possible casualties have been reported from near the epicenter, with up to 26 people dead and many more injured. Part of a bridge under construction fell into the Irrawaddy River near Shwebo and a gold mine collapsed at Sintku. An aftershock with a magnitude of 5.8 followed at 17:24 local time.
The Oklahoma earthquake swarms are an ongoing series of human activity-induced earthquakes affecting central Oklahoma, southern Kansas, northern Texas since 2009. Beginning in 2009, the frequency of earthquakes in the U.S. state of Oklahoma rapidly increased from an average of fewer than two 3.0+ magnitude earthquakes per year since 1978 to hundreds each year in the 2014–17 period. Thousands of earthquakes have occurred in Oklahoma and surrounding areas in southern Kansas and North Texas since 2009. Scientific studies attribute the rise in earthquakes to the disposal of wastewater produced during oil extraction that has been injected more deeply into the ground.
The 2000 Tottori earthquake occurred on 6 October 2000, at with a moment magnitude of 6.7 and a maximum Mercalli intensity of VIII (Severe). The epicenter was near Yonago and Matsue. About $150 million in damage was caused and between 130 and 182 people were injured.
The 2016 Sumatra earthquake was a 7.8 magnitude earthquake which struck on 2 March 2016 in the Indian Ocean, approximately 800 kilometers southwest of Sumatra in Indonesia. Tsunami warnings were issued for Indonesia and Australia, but were withdrawn two hours later. There were no deaths directly related to the earthquake.
The 2019 Cotabato earthquakes were an earthquake swarm which struck the province of Cotabato on the island of Mindanao in the Philippines in October 2019. Three of these earthquakes were above 6.0 on the moment magnitude scale with a Mercalli intensity of VIII. More than 40 people have been reported dead or missing and nearly 800 were injured as a result of these events.
The 1990 Panay earthquake occurred at 3:41 p.m. local time on 14 June 1990 with a moment magnitude of 7.1, leaving eight dead and 41 others injured. The epicenter was located at Culasi, Antique on Panay Island in the Philippines. The depth was computed to be 15 kilometers. It was generated by fault movement in the collisional zone off western Panay Island.
