Earthquakes are caused by movements within the Earth's crust and uppermost mantle. They range from events too weak to be detectable except by sensitive instrumentation, to sudden and violent events lasting many minutes which have caused some of the greatest disasters in human history. Below, earthquakes are listed by period, region or country, year, magnitude, cost, fatalities and number of scientific studies.
The 1868 Hayward earthquake occurred in the San Francisco Bay Area, California, United States on October 21. With an estimated moment magnitude of 6.3–6.7 and a maximum Mercalli intensity of IX (Violent), it was the most recent large earthquake to occur on the Hayward Fault Zone. It caused significant damage and a number of deaths throughout the region, and was known as the "Great San Francisco earthquake" prior to the 1906 San Francisco earthquake and fire.
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 1751 Port-au-Prince earthquake occurred at 12:50 UTC on 21 November in French Haiti, followed by a tsunami. Another earthquake was reported at the same location on 15 September of the same year and it is uncertain whether the two reports refer to the same event.
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 1935 Helena earthquake occurred at in Montana, with an epicenter near Helena. It had a magnitude of 6.2 on the surface wave magnitude scale and a maximum perceived intensity of VIII (Severe) on the Mercalli intensity scale. The temblor on that date was the largest of a series of earthquakes that also included a large aftershock on October 31 of magnitude 6.0 and a maximum intensity of VIII. Two people died in the mainshock and two others died as a result of the October 31 aftershock. Property damage was over $4 million.
The 1941 Andaman Islands earthquake struck the Andaman Islands on June 26 with a magnitude of 7.7 to 8.1. Details of this event are poorly known as much of Southeast Asia was in the turmoil of World War II. The quake caused severe damage in the Andaman Islands. The tsunami it triggered was reported along the Andaman and Nicobar Islands, India and British Ceylon. There may have been damage and deaths in Bangladesh, Myanmar, and Thailand due to the tsunami.
The 1615 Arica earthquake was a major earthquake centered near Arica in the Spanish colonial Viceroyalty of Peru, within the present day Arica y Parinacota Region of northwestern Chile.
The 1976 Sabah earthquake occurred at 10:56 am on 26 July near Lahad Datu in the eastern portion of Sabah, Malaysia. The moment magnitude 6.3 earthquake is one of the strongest in Malaysia to be recorded by seismic instruments. It had a focal mechanism corresponding to strike-slip faulting. While slightly larger than the 2015 Sabah earthquake, the 1976 event caused less extensive damage, in the form of cracks on several buildings and ground cracks.
The 2004 Baladeh earthquake occurred on May 28 in northern Iran. This dip-slip earthquake had a moment magnitude of 6.3 and a maximum Mercalli intensity of VIII (Severe). Total deaths for the event amounted to 35, with 278–400 injured, and $15.4 million in damage.
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 1941 Hyūga-nada earthquake occurred off the coast of Kyushu, Japan at 19:02 local time on November 19. The earthquake measured 8.0 Mw and had a depth of 35 km (22 mi). A JMA seismic intensity of 5 was observed in Miyazaki City and Nobeoka City in Miyazaki Prefecture, and Hitoyoshi City in Kumamoto Prefecture. Due to the earthquake, a tsunami with a maximum wave height of 1.2 m was observed in Kyushu and Shikoku. The tsunami washed away many ships. Twenty-seven homes were destroyed and two people were killed. In Miyazaki, Ōita and Kagoshima prefectures, telephone services were disrupted. Subsidence by 8 cm (3.1 in) was recorded at Hyūga, Miyazaki. At Nobeoka, stone walls and embankments were damaged while roads cracked. It was felt as far as central Honshu.
United States, south of Unimak Island, Alaska (Magnitude 8.6) April 1
Dominican Republic, Samaná Bay (Magnitude 7.5) August 4 1,790 deaths
