A tsunami is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and underwater explosions above or below water all have the potential to generate a tsunami. Unlike normal ocean waves, which are generated by wind, or tides, which are in turn generated by the gravitational pull of the Moon and the Sun, a tsunami is generated by the displacement of water from a large event.
Mount Tambora, or Tomboro, is an active stratovolcano in West Nusa Tenggara, Indonesia. Located on Sumbawa in the Lesser Sunda Islands, it was formed by the active subduction zones beneath it. Before 1815, its elevation reached more than 4,300 metres high, making it one of the tallest peaks in the Indonesian archipelago.
A megatsunami is a very large wave created by a large, sudden displacement of material into a body of water.
On 26 December 2004, at 07:58:53 local time (UTC+7), a major earthquake with a magnitude of 9.2–9.3 struck with an epicentre off the west coast of northern Sumatra, Indonesia. The undersea megathrust earthquake, known by the scientific community as the Sumatra–Andaman earthquake, was caused by a rupture along the fault between the Burma Plate and the Indian Plate, and reached a Mercalli intensity up to IX in some areas.
Mount Rinjani is an active volcano in Indonesia on the island of Lombok. Administratively the mountain is in the Regency of North Lombok, West Nusa Tenggara. It rises to 3,726 metres (12,224 ft), making it the second highest volcano in Indonesia. It is also the highest point in the Indonesian province of West Nusa Tenggara. Adjacent to the volcano is a 6-by-8.5-kilometre caldera, which is filled partially by the crater lake known as Segara Anak or Anak Laut, due to the color of its water, as blue as the sea (laut). This lake is approximately 2,000 metres (6,600 ft) above sea level and estimated to be about 200 metres (660 ft) deep; the caldera also contains hot springs. The lake and mountain are sacred to the Sasak people and Hindus, and are the site of religious rituals. UNESCO made Mount Rinjani Caldera a part of the Global Geoparks Network in April 2018.
Anak Krakatoa is a volcanic island in Indonesia. On 29 December 1927, Anak Krakatoa first emerged from the caldera formed in 1883 by the explosive volcanic eruption that destroyed the island of Krakatoa. There has been sporadic eruptive activity at the site since the late 20th century, culminating in a large underwater collapse of the volcano, which caused a deadly tsunami in December 2018. There has been subsequent activity since. Owing to its young age the island is one of several in the area that are of interest to, and the subject of extensive study by volcanologists.
Lembata is an island in the Lesser Sunda Islands, also known as Lomblen island; it is the largest island of the Solor Archipelago, in the Lesser Sunda Islands, Indonesia. It forms a separate regency of the province of Nusa Tenggara Timur. The length of the island is about 80 km from the southwest to the northeast and the width is about 30 km from the west to the east. It rises to a height of 1,533 metres.
Iliwerung or Illiwerung is a complex volcano forming a prominent south-facing peninsula on Lembata Island in southern Indonesia. It contains north-south and northwest-southeast trending lines of craters and lava domes, with the summit dome having formed by a VEI-3 eruption in 1870.
Weh Island is a small active volcanic island to the northwest of Sumatra in Indonesia, also known as Sabang after the city situated on the northeast end of the island, whose area of 122.13 square kilometres (47.15 sq mi) includes the whole island as well as several offshore islets. It had a population of 43,527 at the official mid-2023 estimate. It is 45 minutes by fast regular ship or 2 hours by ferry from the mainland port of Banda Aceh. It was originally connected to the Sumatran mainland and became separated by sea after the stratovolcano's last eruption in the Pleistocene era. The island is situated in the Andaman Sea.
Ruang is the southernmost stratovolcano in the Sangihe Islands arc, North Sulawesi, Indonesia. It comprises an island 4 by 5 kilometres wide. The summit contains a partial lava dome and reaches some 725 metres (2,379 ft) in altitude. From its summit, Klabat's peak in the south, that of Siau to the north, and Ternate to the east can all be seen.
Tsunamis affecting Britain and Ireland are extremely uncommon, and there have only been two confirmed cases in recorded history. Meteotsunamis are somewhat more common, especially on the southern coasts of England around the English and Bristol Channels.
The 1883 eruption of Krakatoa in the Sunda Strait occurred from 20 May until 21 October 1883, peaking in the late morning of 27 August when over 70% of the island of Krakatoa and its surrounding archipelago were destroyed as it collapsed into a caldera.
The 2018 Sunda strait tsunami occurred on 22 December 2018 at around 21:38 local time after large parts of the southwestern side of Anak Krakatoa collapsed onto its caldera. The landslide spawned a massive tsunami wave that struck multiple coastal regions in Banten and Lampung, including the popular tourist destination of Anyer.
The island of La Palma in the Canary Islands is at risk of undergoing a large landslide, which could cause a tsunami in the Atlantic Ocean. Volcanic islands and volcanoes on land frequently undergo large landslides/collapses, which have been documented in Hawaii for example. A recent example is Anak Krakatau, which collapsed to cause the 2018 Sunda Strait tsunami.
On the morning of March 13, 1888, an explosion took place on Ritter Island, a small volcanic island in the Bismarck and Solomon Seas, between New Britain and Umboi Island. The explosion resulted in the collapse of most of the island and generated a tsunami with runups of up to 15 meters (49 ft) that caused damage more than 700 kilometers (430 mi) away and killed anywhere between 500 and 3,000 on neighboring islands, including scientists and explorers. This event is the largest volcanic island sector collapse in recent history.
The devastating eruption of Oshima–Ōshima began on 18 August 1741 and ended on 1 May the next year. Eleven days into the eruption, the Kampo tsunami with estimated maximum heights of over 90 m (300 ft) swept across neighboring islands in Japan and the Korean Peninsula. The eruption and its resulting tsunami killed at least 1,400 people. Damage was extreme along the coast of Japan, while in Korea, the tsunami damaged fishing boats.
A volcanic tsunami, also called a volcanogenic tsunami, is a tsunami produced by volcanic phenomena. About 20–25% of all fatalities at volcanoes during the past 250 years have been caused by volcanic tsunamis. The most devastating volcanic tsunami in recorded history was that produced by the 1883 eruption of Krakatoa. The waves reached heights of 40 m (130 ft) and killed 36,000 people.
In December 2021, an eruption began on Hunga Tonga–Hunga Haʻapai, a submarine volcano in the Tongan archipelago in the southern Pacific Ocean. The eruption reached a very large and powerful climax nearly four weeks later, on 15 January 2022. Hunga Tonga–Hunga Haʻapai is 65 kilometres (40 mi) north of Tongatapu, the country's main island, and is part of the highly active Tonga–Kermadec Islands volcanic arc, a subduction zone extending from New Zealand to Fiji. On the Volcanic Explosivity Index scale, the eruption was rated at least a VEI-5. Described by scientists as a "magma hammer", the volcano at its height produced a series of four underwater thrusts, displaced 10 cubic kilometres (2.4 cu mi) of rock, ash and sediment, and generated the largest atmospheric explosion recorded by modern instrumentation.
A volcanic landslide or volcanogenic landslide is a type of mass wasting that takes place at volcanoes.
