This list of 20th-century earthquakes is a list of earthquakes of magnitude 6 and above that occurred in the 20th century. Sone smaller events which nevertheless had a significant impact are also included. After 1900 most earthquakes have some degree of instrumental records and this means that the locations and magnitudes are more reliable than for earlier events.
The 1868 Arica earthquake occurred on 13 August 1868, near Arica, then part of Peru, now part of Chile, at 21:30 UTC. It had an estimated magnitude between 8.5 and 9.3. A tsunami in the Pacific Ocean was produced by the earthquake, which was recorded in Hawaii, Japan, Australia, and New Zealand.
The 1730 Valparaíso earthquake occurred at 04:45 local time on July 8. It had an estimated magnitude of 9.1–9.3 and triggered a major tsunami with an estimated magnitude of Mt 8.75, that inundated the lower parts of Valparaíso. The earthquake caused severe damage from La Serena to Chillan, while the tsunami affected more than 1,000 km (620 mi) of Chile's coastline.
The 1868 Ecuador earthquakes occurred at 19:30 UTC on August 15 and 06:30 UTC on 16 August 1868. They caused severe damage in the northeastern part of Ecuador and in southwestern Colombia. They had an estimated magnitude of 6.3 and 6.7 and together caused up to 70,000 casualties. The earthquake of 15 August occurred near El Ángel, Carchi Province, close to the border with Colombia, while that of August 16 occurred near Ibarra in Imbabura Province. Reports of these earthquakes are often confused with the effects of the earthquake of 13 August at Arica.
The 1293 Kamakura earthquake in Japan occurred at about 06:00 local time on 27 May 1293. It had an estimated magnitude of 7.1–7.5 and triggered a tsunami. The estimated death toll was 23,024. It occurred during the Kamakura period, and the city of Kamakura was seriously damaged.
The 1877 Iquique earthquake occurred at 21:16 local time on 9 May. It had a magnitude of 8.5 on the surface-wave magnitude scale. Other estimates of its magnitude have been as high as 8.9 and 9.0 . It had a maximum intensity of XI (Extreme) on the Mercalli intensity scale and triggered a devastating tsunami. A total of 2,385 people died, mainly in Fiji from the tsunami.
The area around Constantinople was affected by a major earthquake in AD 447. It caused serious damage to the recently completed Theodosian Walls in Constantinople, destroying 57 towers and large stretches of the walls. The historical records contain no mention of casualties directly associated with this earthquake, although many thousands of people were reported to have died in the aftermath due to starvation and a "noxious smell".
The 1604 Arica earthquake is an earthquake that occurred at 1:30 pm on November 24, 1604, offshore Arica, Chile. The estimated magnitude range is 8.0–8.5 and up to 8.7–9.0 and 8.8–9.0. It had a destructive tsunami that destroyed moust of Southern Peru, including Arica and Arequipa. 1,200–2,800 km (750–1,740 mi) of coastline was affected by the tsunami. The recorded effects of this earthquake are very similar to those for the 1868 Arica event, suggesting a similar magnitude and rupture area of the megathrust between the subducting Nazca plate and the overriding South American plate. Tsunami deposits have been identified on the Chatham Islands that are likely to have been caused by a trans-Pacific tsunami caused by the 1604 earthquake.
During April 1819, the area around Copiapó in northern Chile was struck by a sequence of earthquakes over a period of several days. The largest of these earthquakes occurred on 11 April at about 15:00 local time, with an estimated magnitude of 8.5. The other two events, on 3 April between 08:00 and 09:00 local time and on 4 April at 16:00 local time, are interpreted as foreshocks to the mainshock on 11 April. The mainshock triggered a tsunami that affected 800 km of coastline and was also recorded at Hawaii. The city of Copiapó was devastated.
The 1657 Concepción earthquake occurred on March 15 at 20:00 local time off the coast of Concepción, Biobío Region in the Spanish Empire. The earthquake caused severe damage along the coast, and generated a large tsunami in the Bay of Concepción. At least 40 people were killed, the majority due to drowning from the tsunami. The town of Concepción was the hardest hit, with the earthquake and tsunami totally destroying it.
