Sunda Strait tsunami 2018

On 22 December 2018, a tsunami that followed an eruption and partial collapse of the Anak Krakatau volcano in the Sunda Strait struck several coastal regions of Banten in Java and Lampung in Sumatra, Indonesia. At least 437 people were killed and 1,459 were injured. The tsunami was caused by an undersea landslide that followed an eruption of Anak Krakatau, the "Child of Krakatoa". On 23 December, it was found that much of the island of Anak Krakatau had collapsed into the sea.
Background
Lying on the Ring of Fire, Indonesia experiences a high frequency of earthquakes and is home to 127 active volcanoes. One of these volcanoes is Anak Krakatau (literally "Child of Krakatau"), an active volcano in the Sunda Strait. Anak Krakatau emerged from the sea in 1927, some time after the 1883 eruption of Krakatoa, one of the most violent eruptions in recorded history. Via tsunamis and ash fall, the 1883 eruption of Krakatoa killed more than 36,000 people, many of whom lived then in the same regions where the 2018 tsunami struck.
In the months leading up to the 2018 tsunami, Anak Krakatau had seen increased activity, with an eruption on 21 December lasting more than two minutes, and producing an ash cloud 400 metres (1,300 ft) high.[6]
A catastrophic tsunami in 2004 happened around the same time of year, occurring on 26 December after an undersea megathrust earthquake near the other end of Sumatra. That tsunami caused more widespread damage throughout the rim of the Indian Ocean, with countries such as Thailand and Sri Lanka being affected.

Tsunami
The Volcanological Survey of Indonesia (PVMBG) recorded a tremendous increase of activity of Anak Krakatau. On 22 December, from 12.00 to 18.00 local time, a total of 423 eruptions were recorded by the agency. The danger level of the volcano had been increased to Level 2. Authorities had warned people not to conduct any activities within 2 km of the volcano.

On 22 December 2018, at 21:03 local time (14:03 UTC), Anak Krakatau erupted and damaged local seismographic equipment, though a nearby seismographic station detected continuous tremors. The eruption caused the collapse of the southwest portion of the volcano, which triggered a tsunami. Officials stated that approximately 64-hectare of the volcano collapsed onto the ocean. The collapse caused the height of the volcano to be reduced from 338 m to 110 m.

The Meteorology, Climatology, and Geophysical Agency (BMKG) detected a tsunami event around 21:27 local time (14:27 UTC) at the western coast of Banten, but the agency had not detected any preceding tectonic events. The Indonesian National Agency for Disaster Countermeasure (BNPB) spokesman Sutopo Purwo Nugroho said, "Dozens of buildings were destroyed by the wave, which hit beaches in Lampung and Banten about 21:30 local time (14:30 UTC) on Saturday".According to The Jakarta Post, authorities said the tsunami "may have been triggered by an abnormal tidal surge due to a full Moon and an underwater landslide following the eruption of Anak Krakatau". The Agency initially refused to label the event as a tsunami, claiming that it was a "normal" high tide event and that no tsunami had occurred on the coast of Banten.

Previously, BMKG had issued a high wave warning for the waters surrounding the strait. Tide gauge for the tsunami measured around 90 centimetres (35 in) in Serang and 30 centimetres (12 in) in Lampung,[16] on top of the two-metre (6 ft 7 in) high tides. While Indonesia possessed a tsunami warning system for tsunamis caused by earthquakes, there were none in place for volcanic tsunamis, and hence there were no early warnings. On 23 December, it was confirmed via satellite data and helicopter footage that the southwest sector of the volcano had collapsed, which triggered the tsunami, and the main conduit was erupting from underwater, producing Surtseyan-style activity.

The waves struck about 312.75 kilometres (194.33 mi) of coastline with various heights. In Carita, the waves reportedly struck with a height of at least 2 m, while in Tanjung Lesung a height of more than 5 m was reported. Further survey conducted by the Ministry of Maritime Affairs and Fisheries, with assistance from Tohoku University and Chuo University on 31 December revealed that the tsunami struck the coastline of Banten and Lampung at a height of 13 m.

Casualties
The Indonesian National Board for Disaster Management (BNPB) initially reported 20 deaths and 165 injuries. By the following day, the figure had been revised to 43 deaths — 33 in Pandeglang, seven in South Lampung, and three in Serang Regencies, with 584 injured, and two missing; most of the injuries recorded (491) also occurred in Pandeglang. The areas of Pandeglang Regency struck by the wave included beaches that are popular tourist destinations, such as Tanjung Lesung. The tsunami struck during peak season, where hundreds had arrived to celebrate the Christmas and New Year holiday. The death toll was further updated to 62 with 20 missing persons later that day. Missing persons were also reported from small islands that are part of Pandeglang Regency. By 13:00 local time on 23 December, BNPB had confirmed 168 fatalities and 745 injuries with 30 having been reported as missing,[6] and the figure was further increased to 281 dead and 1,016 injured. As of 31 December, the death toll was 437, with 14,059 reported injured and 24 missing.
Indonesian officials stated that most of those who died were found inside villas and hotels, especially those located at Carita Beach, Banten. At least 24 people were killed inside a single villa in Carita, with dozens more reportedly found inside other villas. Indonesian Navy stated that dozens of bodies were also recovered from the sea.
Among the victims were Aa Jimmy, an Indonesian actor and comedian, and several members of the Indonesian band Seventeen — bassist Awal "Bani" Purbani, guitarist Herman Sikumbang, road manager Oki Wijaya, and crewmember Ujang. After a few hours, drummer Windu Andi Darmawan and Dylan Sahara, wife of Seventeen's vocalist Ifan, were reported to have been found dead. A video circulated online showing the band's stage being struck by the tsunami in the middle of their show at Tanjung Lesung, causing it to collapse and the audience to flee. Officials confirmed that dozens of concert-goers had been killed by the tsunami.  Tour groups from state-owned company PLN and the Sports and Youth Ministry were also affected by the tsunami. It was confirmed that 260 people had attended the gathering event, where the Seventeen concert was being held. On 23 December, officials from the company stated that at least 14 people related to the PLN had been killed, 89 people from the company had been declared missing and more than 150 had been injured by the tsunami. This number later rose to 23 in the afternoon. On 25 December, it was announced that 43 people from PLN had been killed, while 156 others survived. Most of them were killed while watching the Seventeen concert

Resource: wikipedia & BNPB