Indonesia Raises Threat Level on Anak Krakatau Volcano as Lava Flow Enters Sea

The Anak Krakatau volcano in Indonesia spews a plume of ash into the sky as molten lava streams down from its summit on July 18, 2018. (Ferdi Awad/AFP/Getty Images)

Indonesia’s Geological Agency on April 24 raised the alert level for the erupting Anak Krakatau volcano to level three, requiring a danger zone of up to 5 kilometers (3.1 miles) as volcanic activity intensified.

The volcanic mountain began spewing ash clouds towering 3,000 meters from the peak in the past three days, according to the Center for Volcanology and Geological Hazard Mitigation (PVMBG).

Hendra Gunawan, head of the Volcanic Mitigation Division, said on April 25 that the PVMBG is coordinating with the relevant authorities on the potential secondary hazard, citing the eruption of Anak Krakatau in 2018.

The volcano’s massive eruption in 2018 triggered an underwater landslide, resulting in a tsunami that killed at least 430 people along the Sumatra and Java shores.

“We will assess the activity level of Mount Anak Krakatau, particularly in terms of secondary hazards, by observing both volcanic eruption and ground motion,” Hendra told Indonesian news outlet Detik News, according to a translation.

The PVMBG said in a statement that the volcanic activity at Anak Krakatau began intensifying on April 15 and spewing incandescent lava on April 17. The lava was observed entering the sea on April 23.

Over the course of 24 hours, the agency recorded 21 eruption shocks, 155 phreatic tremors, 14 harmonic tremors, 121 low-frequency earthquakes, 17 shallow volcanic earthquakes, and 38 deep volcanic earthquakes at the mountain.

“Seismic activity is characterized by continuous volcanic tremor, recorded on seismogram with a maximum amplitude of 55 millimeters,” the agency stated.

The geological agency stated that a safe zone had been established to block the public from going near the area.

In 1883, the volcano then known as Krakatoa erupted in one of the biggest blasts in recorded history, killing more than 36,000 people in a series of tsunamis and lowering the global surface temperature by one degree Celsius with its ash.

Anak Krakatau, or “Child of Krakatau,” is the island that emerged from the area in 1927 and has been growing ever since.

Reuters contributed to this report.