Anak Krakatau
Interesting facts
- After the 1883 eruption, the Dutch geologist Rogier Verbeek predicted that new activity would appear between the vanished peaks of Perboewatan and Danan, exactly where Anak Krakatau rose.
- The island that finally survived in 1930 did so because its lava flows built new land faster than the waves could wear it away.
- Until 2018 the summit rose by an average of about 7–9 metres every year.
- Scientists had modelled a flank collapse and tsunami six years before 2018 and had pinpointed the flank of the cone most likely to fail.
- For about eight hours before the 2018 collapse, sensors are believed to have picked up a sustained infrasound signal from the volcano.
- The 2018 tsunami, with waves up to five metres high, struck more than 300 km of coastline on Java and Sumatra.
- Immediately after the collapse its vent erupted from underwater in Surtseyan style, named after the Icelandic island of Surtsey, until a new crater rim closed off the sea.
- An eruption in April 2020 could be heard in Jakarta, more than 150 km away.
- Its eruptions have repeatedly damaged the forest on neighbouring Rakata, which had regrown on bare ash after 1883 from seeds carried by sea and birds.
Why it is worth it
Anak Krakatau — "child of Krakatoa" — is one of the few places where a visitor can stand on land younger than their grandparents. After the cataclysmic eruption of 1883 blew away most of Krakatoa island and left a drowned caldera in the Sunda Strait between Java and Sumatra, the sea stayed empty for more than forty years. In December 1927 new activity broke the surface; several small islands rose and were torn down by waves over the next three years, until in August 1930 a cone held above the water for good and received its name.
Since then it has grown in fits and starts, an almost textbook stratovolcano built of andesite, dacite and basalt, rising by several metres a year for decades until it reached about 338 metres. On 22 December 2018 its south-western flank collapsed into the sea and set off a tsunami that struck the coasts of Java and Sumatra and killed several hundred people. The volcano lost around two-thirds of its volume, the summit dropped to little more than a hundred metres, and within weeks new eruptions began to rebuild the crater rim. That cycle of building, collapse and rebuilding is exactly what makes the island so closely watched by volcanologists.
What the eye takes in is the setting as much as the cone: a ring of older islands — Rakata to the south, Sertung to the west, Panjang to the east — that are the surviving walls of the 1883 caldera, with Anak Krakatau steaming in the middle. The whole group lies within the Ujung Kulon National Park and belongs to the Pacific Ring of Fire.
Getting there
The island lies in the Sunda Strait, about 54 km from the town of Labuan on the Banten coast of Java. Boat excursions leave from Carita beach on the Java side, a crossing of about an hour and a half by speedboat, and from Canti harbour in Lampung on the Sumatran side, usually via Sebesi Island. The nearest airport is Radin Inten II (TKG) in Lampung, about 98 km away; Carita is also reached by road from Jakarta.
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From the encyclopaedia
Anak Krakatoa, or Anak Krakatau, is a volcanic island in Indonesia. On December 29, 1927, Anak Krakatoa first emerged from the caldera formed by the explosive volcanic 1883 eruption of Krakatoa that destroyed the island of Krakatoa. Sporadic eruptive activity has occurred at the site since the late 20th century. A large sector collapse of the volcano occurred on December 22, 2018, causing a deadly tsunami — the 2018 Sunda Strait tsunami. There has been subsequent activity since. Owing to its young age, the island of Anak Krakatoa is one of several in the area which are of interest to, and the subject of extensive study by, volcanologists.
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