Megathrust earthquakes occur at convergent plate boundaries, where one tectonic plate is forced underneath another. The earthquakes are caused by slip along the thrust fault that forms the contact between the two plates. These interplate earthquakes are the planet's most powerful, with moment magnitudes (Mw) that can exceed 9.0. Since 1900, all earthquakes of magnitude 9.0 or greater have been megathrust earthquakes.
The Motagua Fault is a major, active left lateral-moving transform fault which cuts across Guatemala. It forms part of the tectonic boundary between the North American plate and the Caribbean plate. It is considered the onshore continuation of the Swan Islands Transform Fault and Cayman trench, which run under the Caribbean Sea. Its western end appears not to continue further than its surface trace, where it is covered by Cenozoic volcanics.
The Sierra de Chuacús is situated in the central highlands of Guatemala, and runs southeast from El Quiché to Baja Verapaz. Its northwestern border is marked by the Chixoy River basin in Uspantán, which separates it from the Sierra de los Cuchumatanes. Its eastern border is marked by the Salamá River which separates it from the Sierra de las Minas. Its southeastern border is defined by the Motagua River valley.
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.
The Chixoy-Polochic Fault, also known as Cuilco-Chixoy-Polochic Fault, is a major fault zone in Guatemala and southeast Mexico. It runs in a light arc from the east coast of Guatemala to Chiapas, following the deep valleys of the Polochic River, Chixoy River and Cuilco River.
The 2012 Guerrero–Oaxaca earthquake struck southern Mexico with a moment magnitude of 7.4 at on Tuesday, 20 March. Its epicenter was near Ometepec, in the border between the states of Guerrero and Oaxaca. With a shallow focus of 20 km, the earthquake caused strong shaking over a large area along the Oaxaca–Guerrero border and the adjacent Pacific coastline. Significant tremors were felt in areas up to several hundred kilometers away, including Mexico City and also in Guatemala. Two people were killed and over 30,000 houses were damaged or destroyed.
The 1981 Playa Azul earthquake occurred on October 24, 1981, at 21:22 local time. It was located near Playa Azul, Michoacán, Mexico. The magnitude of the earthquake was 7.2, or 7.3. Three deaths were reported, two from Michoacán and one from Mexico City. Some buildings were damaged in both Michoacán and Mexico City. A small tsunami was registered in Acapulco with a maximum height of 9 cm.
The 1816 Guatemala earthquake occurred at 15:30 UTC on 22 July. It had an estimated magnitude of 7.5 to 7.75 on the and a maximum perceived intensity of IX (Violent) on the Mercalli intensity scale. The quake, at a depth of 30.0 km, was caused by movement on the Chixoy-Polochic Fault. The area affected by shaking up to intensity VII (Very strong) was at least 13,000 km2. At least 23 deaths were reported. The discovery of this earthquake 175 years after it occurred was based on study of historical documents, and is notable for showing that this portion of Guatemala, previously believed by many planners to be of low seismic risk, has experienced, and is at further risk of, very large earthquakes.
Lake Chichoj is located near the city of San Cristóbal Verapaz, in the department of Alta Verapaz, in Guatemala. It is 1 km (0.62 mi) long, 0.5 km (0.31 mi) wide, with an area of 0.5 km2 (0.19 sq mi), an average water volume of (4.8±0.1)×106 m3 [(1.7±0.04)×108 cu ft], and a maximum depth of 32 m (105 ft).
The Valparaíso earthquake of April 2017 was a strong earthquake that shook the cities of Valparaíso and Santiago on Monday, April 24, 2017, at 18:38 local time. Its epicenter was located off the coast of the Valparaíso Region and had a magnitude of 6.9 Mw. On the scale of Mercalli, the earthquake reached an intensity of VII.
The 1942 Ecuador earthquake or the Guayaquil earthquake occurred on 13 May at 21:13 local time with a moment magnitude of Mw 7.9. The temblor struck the coastal (Esmeraldas) region of Manabí Province, Ecuador. It caused damage mainly to cities including Guayaquil, Portoviejo and Guaranda. More than 300 people were killed and the total cost of damage was about US$2.5 million. Ecuador's largest city Guayaquil was the most affected despite the significant distantce from the epicenter. Many reinforced concrete structures in a particular area in the city were completely destroyed, contributing to fatalities.
An earthquake occurred on 26 August 2012 at 22:37 local time. The earthquake located off the coast of El Salvador measured 7.3 on the moment magnitude scale and had a focal depth of 16.0 kilometres (10 mi). No deaths were reported, however more than 40 people were injured when they were caught in a tsunami generated by the earthquake. Waves from the tsunami were unusually large for an earthquake of this size. The large waves were attributed to the earthquake's unique rupture characteristic. In addition to the absence of fatalities, damage caused by the earthquake and tsunami was minimal as a result of the sparse population around the affected region and the slow rupture characteristic of the event.
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.
The 1950 Calama earthquake occurred near the Argentina–Chile border with an epicenter near Calama, Chile in the Atacama Desert on December 9. The event had a hypocenter depth of 113.9 km, beneath the Caichinque volcanic complex. It measured magnitude Mw 8.2 on the moment magnitude scale, making it the largest intermediate depth earthquake ever recorded on Chilean soil. One person was killed and an unspecified number of people were injured in Calama.
The 2022 Guatemala earthquake occurred on the early morning of February 16, 2022 in the southern regions of Guatemala. The quake measured a moment magnitude of 6.2 and reached a peak intensity of VI (Strong) on the Modified Mercalli Intensity scale. Damage was widespread but light in and around the capital, Guatemala City, resulting mostly in cracked walls and rockslides.
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.
The 1706 Abruzzo earthquake, also known as the Maiella earthquake, occurred on November 3 at 13:00 CEST. The earthquake with a possible epicenter in the Central Apennine Mountains (Maiella), Abruzzo had an estimated moment magnitude of 6.6–6.84 Mw . It was assigned a maximum Mercalli intensity of XI (Extreme), causing tremendous destruction in Valle Peligna. At least 2,400 people were killed.
The 1917 San Salvador earthquake occurred on June 7 at 18:55 local time near the Salvadoran capital. The hypocenter of the Mw 6.7 was at a shallow depth of 15 km (9.3 mi), and occurred along a shallow crustal fault near San Salvador. The earthquake caused significant destruction of the city and left approximately 1,050 dead. It was followed by an eruption on San Salvador that killed another 1,100. Only behind the earthquake of 1986, it is the second deadliest in El Salvador's history.
The 1991 Guatemala earthquake occurred on September 18 at 3:48 a.m. local time. The epicenter was 60 miles southwest of Guatemala City. The shock was assigned a magnitude of 5.3 on the Richter scale, later assigned with a magnitude of 6.2. It caused 25 deaths, over 200 injuries and left 1,000 people without homes.
