An intraplate earthquake occurs in the interior of a tectonic plate, in contrast to an interplate earthquake on the boundary of a tectonic plate. They are relatively rare compared to the more familiar interplate earthquakes. Buildings far from plate boundaries are rarely protected with seismic retrofitting, so large intraplate earthquakes can inflict heavy damage. Examples of damaging intraplate earthquakes are the devastating 2001 Gujarat earthquake, the 2011 Christchurch earthquake, the 2012 Indian Ocean earthquakes, the 2017 Puebla earthquake, the 1811–1812 New Madrid earthquakes, and the 1886 Charleston earthquake. An earthquake that occurs within a subducting plate is known as an intraslab earthquake.
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.
An interplate earthquake occurs at the boundary between two tectonic plates. Earthquakes of this type account for more than 90 percent of the total seismic energy released around the world. If one plate is trying to move past the other, they will be locked until sufficient stress builds up to cause the plates to slip relative to each other. The slipping process creates an earthquake with relative displacement on either side of the fault, resulting in seismic waves which travel through the Earth and along the Earth's surface. Relative plate motion can be lateral as along a transform fault boundary, vertical if along a convergent boundary or a divergent boundary, and oblique, with horizontal and lateral components at the boundary. Interplate earthquakes associated at a subduction boundary are called megathrust earthquakes, which include most of the Earth's largest earthquakes.
Many major earthquakes have occurred in the region of the Kamchatka Peninsula in far eastern Russia. Events in 1737, 1923 and 1952, were megathrust earthquakes and caused tsunamis. There are many more earthquakes and tsunamis originating from the region.
The 1918 Shantou earthquake occurred in Shantou, Guangdong, Republic of China. Serious damage and high casualty numbers were reported in Guangdong and the surrounding provinces. It also caused some damage in British Hong Kong.
The 1975 Morris earthquake occurred in western Minnesota on July 9 at 14:54:15 UTC, or 9:54 a.m. local time. The strongest instrumentally recorded rupture in the history of the state, it registered at magnitude 4.6 Mn and had a maximum Mercalli intensity of VI (Strong). It was the first earthquake to be recorded on any seismic instrument in the state since 1917. Tremors were felt over much of Minnesota, northern Iowa, and the eastern Dakotas.
The 2009 Swan Islands earthquake occurred on May 28 at with a moment magnitude of 7.3 and a maximum Mercalli intensity of VII. The epicenter was located in the Caribbean Sea, 64 kilometres (40 mi) northeast of the island of Roatán, 19 miles northeast of Port Royal, Isla de Bahias, 15 miles northwest of Isla Barbaretta, and 130 kilometres (81 mi) north-northeast of La Ceiba. Three aftershocks followed the earthquake within magnitude 4 range.
Seismicity of the New York City area is relatively low. New York is less seismically active than California because it is far from any plate boundaries. Large and damaging intraplate earthquakes are relatively rare. When they do occur in the Northeastern United States, the areas affected by them are much larger than for earthquakes of similar magnitude on the West Coast of the United States. The largest known earthquake in the greater New York City area occurred in 1884, probably somewhere between Brooklyn and Sandy Hook, and had a magnitude of approximately 5. The New York quakes in 2023 and 2024 were shallow quakes.
The 2011 Kütahya earthquake struck near a populous region of western Turkey at 23:15 EEST (20:15 UTC) on 19 May with a moment magnitude of 5.8 and a maximum Mercalli intensity of VII. With an epicenter just to the east of Simav, it occurred at an estimated depth of 9.1 kilometers (5.7 mi), resulting in strong shaking in much of Kütahya.
The 1963 Marj earthquake occurred on February 21 in northern Libya. The earthquake occurred at with a moment magnitude of 5.6 and a maximum Mercalli intensity of VIII (Severe). Financial losses totaled US$5 million, with 290–375 deaths, 375–500 injuries, and 12,000 people being rendered homeless.
At 02:10 PM local time (UTC-5) on 28 January 2020, an earthquake with a magnitude of 7.7 struck the north side of the Cayman Trough, north of Jamaica and west of the southern tip of Cuba, with the epicenter being 80 miles (130 km) east-southeast of Cayman Brac, Cayman Islands, and 83 miles (134 km) north of Montego Bay, Jamaica. Schools in Jamaica, as well as corporate and public buildings in Miami, were evacuated after shaking was experienced in parts of the U.S. state of Florida, a region not typically thought of in-relation to seismic activity. Light shaking was also reported on the Yucatán Peninsula in Mexico. The quake was the largest seismic event in the Caribbean since 1946. A tsunami warning for the Caribbean Sea was initially issued by the Pacific Tsunami Warning Center, later being withdrawn.
The 2013 Craig, Alaska earthquake struck on January 5, at 12:58 am (UTC–7) near the city of Craig and Hydaburg, on Prince of Wales Island. The Mw 7.5 earthquake came nearly three months after an Mw 7.8 quake struck Haida Gwaii on October 28, in 2012. The quake prompted a regional tsunami warning to British Columbia and Alaska, but it was later cancelled. Due to the remote location of the quake, there were no reports of casualties or damage.
A moment magnitude 6.3–6.4 earthquake affected southeastern Mexico, in the states of Puebla and Veracruz, on 3 January 1920 at 22:25 local time. A maximum Mercalli-Cancani intensity of XI–XII (Extreme) was recorded in the epicenter, between Chilchotla and Patlanalán. While estimates of the death toll vary across different sources, ranging from 648 to 4,000 fatalities, it is the second deadliest earthquake in Mexico, behind another earthquake in 1985 that killed more than 9,000 people. Many people died from mudslides that swept through settlements along the Huitzilapa and Pescado rivers. The cost of damage was estimated at US$25,000,000. The towns of Patlanalá, Barranca Grande, Cosautlán, Quimixtlán, Teocelo and Xalapa were severely affected, as many buildings were damaged or destroyed.
The 1947 Satipo earthquake was the largest earthquake in the sub-Andean region of Peru. It occurred on November 1 at 09:58:57 local time with an epicenter in the Department of Junín. The earthquake had an estimated moment magnitude (Mw ) of 7.7 and focal depth of 20 km (12 mi). Damage was severe in the towns of Satipo and La Merced, and at least 233 people died.
The 1979 Petatlán earthquake, also known as the IBERO earthquake occurred on March 14 at 05:07 local time in the Mexican state of Guerrero. The earthquake had a surface-wave magnitude of Ms 7.6 or moment magnitude of Mw 7.4 and maximum Modified Mercalli intensity of VIII (Severe). The epicenter, onshore, was located 12 km south southeast of Vallecitos de Zaragoza.
An earthquake struck approximately 53 kilometres SSE of the town of Mansfield, in the Victorian Alps of Australia on 22 September 2021, at 09:15 local time. The earthquake measured 5.9 on the moment magnitude scale. The earthquake caused minor structural damage in parts of Melbourne and left one person injured. The earthquake was also felt in New South Wales, Australian Capital Territory, South Australia and Tasmania. The earthquake was substantially stronger than the 1989 Newcastle earthquake that measured 5.6 and killed 13 people.
The 1983 Hindu Kush earthquake occurred south of Fayzabad, Badakhshan in northeast Afghanistan at 03:52 PST on December 31, 1983, near the border with Pakistan and the USSR. Striking 214.5 km beneath the Hindu Kush mountains, the moment magnitude 7.4 quake affected three countries, killing at least 26 people and injuring several hundred.
The 1870 Charlevoix earthquake occurred on 20 October in the Canadian province of Quebec. It had a moment magnitude of 6.6 Mw and a Modified Mercalli intensity rating of X (Extreme). The town of Baie-Saint-Paul was seriously damaged by the event, with the loss of six lives. Effects from the earthquake were felt as far as Virginia and along the New England coast of the United States.
The 1959 Coatzacoalcos earthquake occurred at 02:25 local time on August 26 near the Mexican state of Veracruz. The earthquake measured 6.4 Mw at a depth of 21 km (13 mi), and had a maximum Modified Mercalli intensity of VIII (Severe). It had an epicenter immediately off the coast of Coatzacoalcos. The shallow back-arc thrust faulting earthquake damaged the cities of Acayucan, Coatzacoalcos, Jáltipan and Minatitlán. A total of 25 people died, including 10 from Jáltipan while a further 200 were injured. The Middle America Trench, a subduction zone that borders the southwestern coast of Mexico and Central America, accounts for much of the seismicity in Mexico. The eastern side of the country near the Gulf of Mexico rarely experiences large earthquakes although they have been recorded around the Veracruz area, where seismicity is higher compared to other parts of the gulf. Seismicity in the gulf is attributed to back-arc compression due to subduction.
On 22 January 1988, a sequence of destructive earthquakes measuring 6.2, 6.3, and 6.6 struck southwest of Tennant Creek, Australia which was felt as far north as Darwin and in other regions of the country. The largest event of the sequence was the largest earthquake ever recorded in mainland Australia since records began in 1800. An intensity of IX (Violent) was observed. Despite the large magnitude of the earthquakes and a close proximity to a town, in a country where earthquakes of this size are not common, damages were limited. Thousands of aftershocks were reported and felt across the Northern Territory.
