The Commander Islands, Komandorski Islands, or Komandorskie Islands are a series of treeless, sparsely populated Russian islands in the Bering Sea located about 175 km (109 mi) east of the Kamchatka Peninsula in the Russian Far East. The islands consist of Bering Island, Medny Island and fifteen smaller ones, the largest of which are Tufted Puffin Rock , 15 ha, and Kamen Ariy, which are between 3 km (1.9 mi) and 13 km (8.1 mi) west of the only settlement, Nikolskoye. Administratively, they compose Aleutsky District of Kamchatka Krai in Russia.
The 1946 Aleutian Islands earthquake occurred near the Aleutian Islands, Alaska on April 1, 1946. The shock had a moment magnitude (Mw ) of 8.6, a tsunami magnitude Mt of 9.3, and a surface-wave magnitude (Ms ) of only 7.4, and a maximum Mercalli intensity of VI (Strong). It resulted in 165–173 casualties and over $26 million in damage. The seafloor along the fault was elevated, triggering a Pacific-wide tsunami with multiple destructive waves at heights ranging from 45–138 ft (14–42 m). The tsunami obliterated the Scotch Cap Lighthouse on Unimak Island, Alaska among others, and killed all five lighthouse keepers. Despite the destruction to the Aleutian Island Unimak, the tsunami had almost an imperceptible effect on the Alaskan mainland.
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 Aleutian Trench is an oceanic trench along a convergent plate boundary which runs along the southern coastline of Alaska and the Aleutian islands. The trench extends for 3,400 kilometres (2,100 mi) from a triple junction in the west with the Ulakhan Fault and the northern end of the Kuril–Kamchatka Trench, to a junction with the northern end of the Queen Charlotte Fault system in the east. It is classified as a "marginal trench" in the east as it runs along the margin of the continent. The subduction along the trench gives rise to the Aleutian Arc, a volcanic island arc, where it runs through the open sea west of the Alaska Peninsula. As a convergent plate boundary, the trench forms part of the boundary between two tectonic plates. Here, the Pacific Plate is being subducted under the North American Plate at a dip angle of nearly 45°. The rate of closure is 7.5 centimetres (3 in) per year.
The 1957 Andreanof Islands earthquake occurred at 04:22 local time on March 9 with a moment magnitude of 8.6 and maximum Modified Mercalli intensity of VIII (Severe). It occurred south of the Andreanof Islands group, which is part of the Aleutian Islands arc. The event occurred along the Aleutian Trench, the convergent plate boundary that separates the Pacific Plate and the North American plates near Alaska. A basin-wide tsunami followed, with effects felt in Alaska and Hawaii, and strong waves recorded across the Pacific rim. Total losses were around $5 million.
The 2006 Kamchatka earthquake occurred on . This shock had a moment magnitude of 7.6 and a maximum Mercalli intensity of X (Extreme). The hypocenter was located near the coast of Koryak Autonomous Okrug at an estimated depth of 22 km, as reported by the International Seismological Centre. This event caused damage in three villages and was followed by a number of large aftershocks. Two M6.6 earthquakes struck on April 29 at 16:58 UTC and again on May 22 at 11:12 UTC. These earthquakes caused no deaths; however, 40 people were reported injured.
The Queen Charlotte Fault is an active transform fault that marks the boundary of the North American plate and the Pacific plate. It is Canada's right-lateral strike-slip equivalent to the San Andreas Fault to the south in California. The Queen Charlotte Fault forms a triple junction south with the Cascadia subduction zone and the Explorer Ridge. The Queen Charlotte Fault (QCF) forms a transpressional plate boundary, and is as active as other major transform fault systems in terms of slip rates and seismogenic potential. It sustains the highest known deformation rates among continental or continent-ocean transform systems globally, accommodating greater than 50mm/yr dextral offset. The entire approximately 900 km offshore length has ruptured in seven greater than magnitude 7 events during the last century, making the cumulative historical seismic moment release higher than any other modern transform plate boundary system.
In seismology, a supershear earthquake is an earthquake in which the propagation of the rupture along the fault surface occurs at speeds in excess of the seismic shear wave (S-wave) velocity. This causes an effect analogous to a sonic boom.
The 2002 Denali earthquake occurred at 22:12:41 UTC November 3 with an epicenter 66 km ESE of Denali National Park, Alaska, United States. This 7.9 Mw earthquake was the largest recorded in the United States in 37 years. The shock was the strongest ever recorded in the interior of Alaska. Due to the remote location, there were no fatalities and only one injury.
The 1965 Rat Islands earthquake occurred at 05:01 UTC, on 4 February. It had a magnitude of 8.7 and triggered a tsunami of over 10 m on Shemya Island, but caused very little damage.
The 2012 Indian Ocean earthquakes were magnitude 8.6 and 8.2 Mw undersea earthquakes that struck near the Indonesian province of Aceh on 11 April at 15:38 local time. Initially, authorities feared that the initial earthquake would cause a tsunami and warnings were issued across the Indian Ocean; however, these warnings were subsequently cancelled. These were unusually strong intraplate earthquakes and the largest strike-slip earthquake ever recorded.
The 2014 Aleutian Islands earthquake occurred on 23 June at 11:53 HDT (UTC-9) with a moment magnitude of 7.9 and a maximum Mercalli intensity of VIII (Severe). The shock occurred in the Aleutian Islands – part of the US state of Alaska – 19 miles (31 km) southeast of Little Sitkin Island.
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.
On 9 December 2016 at 4:38 a.m. local time, the Solomon Islands region was rocked by an Mww 7.8 earthquake, centered 30 km off San Cristobal Island, about 61 km southwest of Kirakira, the capital of Makira-Ulawa Province. Initially registering magnitude 8.0, later downgraded to 7.8, the temblor prompted tsunami warnings that kept countries surrounding the Coral, Tasman and Solomon Sea on high alert, but was later cancelled. A large aftershock of magnitude 6.9 occurred shortly afterwards. This earthquake was largely felt, waking many residents who later ran to high ground for fears of a potential tsunami. The earthquake killed a child and affected some 34,000 people in Makira, South Malaita and Guadalcanal Island where many had lost their homes or had no access to basic needs. Earthquakes are common in this region, with little or no fatalities. This earthquake is tied with three other magnitude 7.8 earthquakes for the second largest earthquake of 2016. On 17 December, the Solomon Islands would be rattled again by a 7.9 magnitude earthquake, this time 54 km east of Taron, Papua New Guinea.
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 damages.
On April 13, 1923 at 15:31 UTC, an earthquake occurred off the northern coast of the Kamchatka Peninsula in the USSR, present-day Russia. The earthquake had a surface-wave magnitude (Ms ) of 6.8–7.3 and an estimated moment magnitude (Mw ) of ~8.2. This event came just two months after a slightly larger earthquake with an epicenter struck south of the April event. Both earthquakes were tsunamigenic although the latter generated wave heights far exceeding that of the one in February. After two foreshocks of "moderate force", the main event caused considerable damage. Most of the 36 casualties were the result of the tsunami inundation rather than the earthquake.
The 1585 Aleutian Islands earthquake is the presumed source of a tsunami along the Sanriku coast of Japan on June 11, 1585, known only from vague historical accounts and oral traditions. The event was initially misdated to 1586, which led to it being associated with the deadly earthquakes in Peru and Japan of that year. The source earthquake was later determined by modern seismological studies to have originated near the Aleutian Islands in the North Pacific Ocean. Paleotsunami evidence from shoreline deposits and coral rocks in Hawaii suggest that the 1585 event was a large megathrust earthquake occurring on the Aleutian subduction zone with a moment magnitude (Mw ) as large as 9.25.
An earthquake occurred off the coast of the Alaska Peninsula on July 28, 2021, at 10:15 p.m. local time. The large megathrust earthquake had a moment magnitude of 8.2 according to the United States Geological Survey (USGS). A tsunami warning was issued by the National Oceanic and Atmospheric Administration (NOAA) but later cancelled. The mainshock was followed by a number of aftershocks, including three that were of magnitude 5.9, 6.1 and 6.9 respectively.
The 2021 South Sandwich Islands earthquakes were a pair of powerful earthquakes, followed by many strong aftershocks which struck along the South Sandwich Trench in August 2021. The quakes measured 7.5 and 8.1 on the moment magnitude scale, according to the United States Geological Survey. The mainshock is tied with another event in 1929 as the largest earthquake ever recorded in this region and the Atlantic Ocean as a whole, and is tied with the 2021 Kermadec Islands earthquake as the second largest earthquake of 2021.
The 1979 Saint Elias earthquake occurred near noon local time on the 28th of February. It measured Mw 7.4–7.6. Though the maximum recorded Modified Mercalli intensity was VII, damages were minimal and there were no casualties due to the remoteness of the faulting. The epicenter lies near the Alaskan border between America and Canada.
