On 18 July 1979, a portion of the Iliwerung volcano on

Lembata Lembata is an island in the Lesser Sunda Islands, also known as Lomblen or Kawela; 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. Th ...

collapsed into the

Savu Sea The Savu Sea (or the Sawu Sea) (, , ) is a small sea within Indonesia named for the island of Savu (Sawu) on its southern boundary. It is bounded by Savu and Raijua to the south, the islands of Rote and Timor (split between East Timor and ...

, triggering a deadly

tsunami A tsunami ( ; from , ) 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 (including detonations, ...

that swept along the island's coastal villages. The tsunami was triggered by a

landslide Landslides, also known as landslips, rockslips or rockslides, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, mudflows, shallow or deep-seated slope failures and debris flows. Landslides ...

rather than a volcanic eruption. Estimates of the dead start at 539 while another 700 were reported missing. Many of the dead were never recovered.

Tsunami characteristics

Earlier reports suggested an eruption generated the tsunami which was ruled out as a translation mistake. The cause was later determined to be a landslide along a cape of the island's southern shore. This landslide may have been triggered by an earthquake of unknown magnitude recorded by a seismic observatory in

Kupang Kupang (, ), formerly known as Koepang, is the capital of the Indonesian province of East Nusa Tenggara. At the 2020 Indonesian census, 2020 Census, it had a population of 442,758;Badan Pusat Statistik, Jakarta, 2021. the official estimate as o ...

on 18 July at 00:42. Local newspapers ''Kompas'' and ''Suara Karya'' said the tsunami occurred at 01:00 local time. The tsunami inundated up to inland, sweeping across four settlements. The total landslide volume was estimated at 50 × 10 m³ which originated from the volcano's eastern portion; one-third of the volcano fell into the sea. Waves of swept into Labala and Waiteba Bays. The landslide crown is situated at an elevation of near the village of Atakore on Bauraja Hill. This hill represents an ancient volcanic crater of the Iliwerung volcano, and is especially vulnerable to landslides after heavy downpour. Remnants of the landslide are still visible via satellite imagery. In some areas, the tsunami deposited up to of sand on the affected villages.

Impact

News of the tsunami reached Jakarta three days later due to the absence of well-established communication networks. The tsunami destroyed several settlements, some located inland. The lack of roads connecting the affected villages of Lembata made rescue works difficult. According to Ben Midol, the governor of

East Nusa Tenggara East Nusa Tenggara (; ) is the southernmost province of Indonesia. It comprises the eastern portion of the Lesser Sunda Islands, facing the Indian Ocean in the south and the Flores Sea in the north, with a total land area of 47,238.07 km2. It cons ...

, food and medical aid were quickly supplied to the region. The waves which destroyed the villages of Waiteba, Lebala and Bala struck when most of the population was asleep. In one area of the island, 60 bodies were discovered. On 23 July, the Indonesian military said the death toll could be between 650 and 750, though at the time, the death toll only stood at 155. The reported death toll rose to 539 the following day, though only 175 bodies were found by rescue workers. An additional 700 people were thought to be missing. Many of the estimated dead were people missing and presumed killed. Some people were also killed after being buried by the landslide. In addition to homes being razed, several primary schools and markets were also in ruins. Many of the victims were buried in mass graves. Thousands of panicked inhabitants from nine villages on the island abandoned their homes citing fear after the disaster. Despite the local authorities' efforts, they could not stop the mass evacuations. These villagers fled to Lewoleba in the central part of the island, causing housing concerns. A human body found inside a shark caught off

Rote Island Rote Island (, also spelled ''Roti'') is an island of Indonesia, part of the East Nusa Tenggara Provinces of Indonesia, province of the Lesser Sunda Islands. According to legend, this island got its name accidentally when a lost Portuguese people ...

one week after the disaster may have been a tsunami victim. According to ''Suara Karya'', citing a medican examiner, the body belonged to a male who had been dead for two days before being swallowed by the shark.

References

{{reflist 1979 in Indonesia Tsunamis in Indonesia 1970s tsunamis East Nusa Tenggara Volcanic tsunamis 1979 disasters in Asia Geography of the Lesser Sunda Islands July 1979 in Asia