An earthquake is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, from those that are so weak that 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 word tremor is also used for non-earthquake seismic rumbling.
Katla is a large volcano in southern Iceland. It is very active; twenty eruptions have been documented between 930 and 1918, at intervals of 20–104 years. It has not erupted violently for 105 years, although there may have been small eruptions that did not break the ice cover, including ones in 1955, 1999, and 2011.
In seismology, an earthquake swarm is a sequence of seismic events occurring in a local area within a relatively short period. The time span used to define a swarm varies, but may be days, months, or years. Such an energy release is different from the situation when a major earthquake is followed by a series of aftershocks: in earthquake swarms, no single earthquake in the sequence is obviously the main shock. In particular, a cluster of aftershocks occurring after a mainshock is not a swarm.
The Cascadia subduction zone is a 960 km fault at a convergent plate boundary, about 112-160 km off the Pacific Shore, that stretches from northern Vancouver Island in Canada to Northern California in the United States. It is capable of producing 9.0+ magnitude earthquakes and tsunamis that could reach 30m. The Oregon Department of Emergency Management estimates shaking would last 5-7 minutes along the coast, with strength and intensity decreasing further from the epicenter. It is a very long, sloping subduction zone where the Explorer, Juan de Fuca, and Gorda plates move to the east and slide below the much larger mostly continental North American Plate. The zone varies in width and lies offshore beginning near Cape Mendocino, Northern California, passing through Oregon and Washington, and terminating at about Vancouver Island in British Columbia.
The Dogger Bank earthquake of 1931 was the strongest earthquake recorded in the United Kingdom since measurements began. It had a magnitude of 6.1 on the Richter magnitude scale, and it caused a shaking intensity of VI (Strong) to VII on the Mercalli intensity scale. The location of the earthquake in the North Sea meant that damage was significantly less than it would have been had the epicentre been on the British mainland.
An earthquake occurred at on 8 October in Azad Kashmir. It was centred near the city of Muzaffarabad, and also affected nearby Balakot in Khyber Pakhtunkhwa and some areas of Jammu and Kashmir. It registered a moment magnitude of 7.6 and had a maximum Mercalli intensity of XI (Extreme). The earthquake was also felt in Afghanistan, Tajikistan, India, and the Xinjiang region. The severity of the damage caused by the earthquake is attributed to severe upthrust. Over 86,000 people died, a similar number were injured, and millions were displaced. It is considered the deadliest earthquake in South Asia, surpassing the 1935 Quetta earthquake.
The 2003 Hokkaidō earthquake, scientifically named the 2003 Tokachi-Oki earthquake, occurred off the coast of Hokkaidō, Japan on 26 September at 04:50 local time. At a focal depth of 27 km (17 mi), this great undersea earthquake measured 8.3 on the moment magnitude scale, making it the most powerful earthquake of 2003, as well as one of the most intense earthquakes to hit Japan since modern record-keeping began in 1900.
The 1783 Calabrian earthquakes were a sequence of five strong earthquakes that hit the region of Calabria in southern Italy, the first two of which produced significant tsunamis. The epicenters form a clear alignment extending nearly 100 km from the Straits of Messina to about 18 km SSW of Catanzaro. The epicenter of the first earthquake occurred in the plain of Palmi. The earthquakes occurred over a period of nearly two months, all with estimated magnitudes of 5.9 or greater. Estimates of the total number of deaths lie in the range 32,000 to 50,000.
The 1968 Illinois earthquake was the largest recorded earthquake in the U.S. Midwestern state of Illinois. Striking at 11:02 am on November 9, it measured 5.4 on the Richter scale. Although no fatalities occurred, the event caused considerable structural damage to buildings, including the toppling of chimneys and shaking in Chicago, the region's largest city. The earthquake was one of the most widely felt in U.S. history, largely affecting 23 states over an area of 580,000 sq mi (1,500,000 km2). In studying its cause, scientists discovered the Cottage Grove Fault in the Southern Illinois Basin.
The 2010 Central Canada earthquake occurred with a moment magnitude of 5.0 in Central Canada on 23 June at about 13:41:41 EDT and lasted about 30 seconds. The epicentre was situated in the area of Buckingham, Quebec, approximately 56 kilometres (35 mi) north of Ottawa, Ontario, closest to the settlement of Val-des-Bois, Quebec. Canada's capital, Ottawa, declared this earthquake as being its most powerful in 65 years.
The 1906 Swansea earthquake hit near the town of Swansea, Glamorgan, Wales on 27 June. It was one of the most damaging to hit Britain during the twentieth century, with a small area reaching an intensity of VII on the Medvedev–Sponheuer–Karnik scale.
The 2013 Bushehr earthquake occurred with a moment magnitude of 6.3 on April 9 in Iran. The shock's epicenter was in the province of Bushehr, near the city of Khvormuj and the towns of Kaki and Shonbeh. At least 37 people were killed, mostly from the town of Shonbeh and villages of Shonbeh-Tasuj district, and an estimated 850 people were injured.
The following is a timeline of the history of the city of Accra, Ghana.
A magnitude 5.7 earthquake struck India 20 km (12 mi) east north-east of Ambassa in the state of Tripura on 3 January 2017 with a maximum observed intensity of 6-7 EMS. It struck at 2:39 pm local time, and was centered in an isolated area. The estimated depth was 32.0 km.
On 18 June 2018, around 7:58 a.m. Japan Standard Time, an earthquake measuring 5.6 Mw on the moment magnitude scale struck in northern Osaka Prefecture, Japan. The earthquake's epicenter was near Takatsuki and occurred at a depth of approximately 13 kilometres (8.1 mi). The Japan Meteorological Agency reported a magnitude of 6.1 Mj and an intensity of 6 lower on the shindo scale.
At 2:10 p.m. local time (UTC-5) on 28 January 2020, an earthquake of 7.7 struck on 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) ESE of Cayman Brac, Cayman Islands or 83 miles (134 km) north of Montego Bay, Jamaica. Schools in Jamaica and buildings in Miami were evacuated after shaking was observed in parts of the U.S. state of Florida. Light shaking was also reported on the Yucatan peninsula in Mexico. It is the largest earthquake in the Caribbean since 1946. A tsunami warning for the Caribbean Sea was issued by the Pacific Tsunami Warning Center and later withdrawn.
An earthquake struck the Mexican state of Oaxaca at 10:29 local time on June 23, 2020, with a magnitude of 7.4 . The epicenter was 19 miles (31 km) from San Miguel del Puerto and 7.5 miles (12.1 km) south-southwest of Santa María Zapotitlán. The quake was felt by an estimated 49 million people in Mexico and Guatemala, with some tremors felt as far away as 640 kilometers (400 mi). Thousands of houses in Oaxaca were damaged and 10 deaths were reported. A tsunami warning was issued for southern Mexico, El Salvador, Guatemala, and Honduras.
The following is a timeline of the COVID-19 pandemic in Ghana from March 2020 to July 2020.
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.
