Highest alert level

Ruang volcano in Indonesia erupts again

The Ruang volcano hurled a column of ash, smoke and rock some 2000 meters high into the sky.(Bild: AFP/STR)

The Ruang volcano in Indonesia, which has been active for weeks, is not coming to rest. On Tuesday night (local time), the 725-metre-high mountain of fire in the Sangihe archipelago north of the island of Sulawesi hurled a column of ash, smoke and rock some 2,000 meters high into the sky.

This was "accompanied by thunderous noises and persistent tremors", reported the National Geological Agency. As a result, the authorities once again issued the highest alert level. Residents within a radius of six kilometers around the crater were asked to take shelter immediately and wear masks.

According to the Geological Agency, there has been a significant increase in both very deep and shallow volcanic tremors. This indicates a migration of magma from deep reservoirs to the surface, it said.

Two airports temporarily closed
Residents in a radius of initially six and later seven kilometers around the crater were asked to take shelter immediately and wear masks. The airport in Manado, the capital of Sulawesi province, and other airports in the region were temporarily closed.

People in the region should be vigilant for possible pyroclastic flows - streams of hot ash, rock and gas - and tsunamis that could be caused by boulders falling into the sea or the collapse of the entire volcanic body.

Eruptions since mid-April
There have been eruptions at Ruang since mid-April. On several occasions, the volcano spewed clouds of ash and rock up to 3,000 meters high. Air traffic in the region has been partially suspended. Last week, however, the alert level was initially lowered after the Ruang calmed down somewhat.

Collapse could trigger tsunami
Parts of the volcanic island were already threatening to collapse into the sea two weeks ago. According to the state-run Center for Meteorology, Climatology and Geophysics (BMKG), eruptions could cause the flanks of a volcano or, in the worst case, the entire mountain to collapse - triggering tsunamis with meter-high tidal waves and devastating consequences.

In 1871, an eruption of Mount Ruang triggered a tsunami with waves up to 25 meters high. Around 400 people died on the neighboring island of Tagulandang, around five kilometers away.

130 active volcanoes in Indonesia
The world's largest island nation, Indonesia, lies on the so-called Pacific Ring of Fire, the most geologically active zone on earth. Earthquakes and volcanic eruptions occur frequently along this belt. There are around 130 active volcanoes in Indonesia.