Before-and-After Pics Show Dramatic Collapse of Tsunami-Causing Volcano in Indonesia

Left: Radar image of Anak Krakatau volcano before the eruption on December 22, 2018. Right: The volcano after the eruption on December 24, 2018.
Image: AP/JAXA/Geospatial Authority of Japan/Gizmodo

The entire southwest flank of Indonesia’s Anak Krakatau volcano is missing, as new radar imagery suggests. The erupting volcano triggered a massive landslide on December 22, generating a tsunami that has killed more than 420 people.

The dramatic radar images were taken by JAXA’s ALOS-2 satellite and subsequently analyzed by Japan’s Geospatial Information Authority, reports the Associated Press. Normal satellite photographs of the volcano haven’t been possible owing to incessant cloud cover in the region. The before image was taken two days before the eruption on August 20, 2018, and the after image was taken two days after on December 24, 2018.

Wide view of the area, with surrounding islands. The concentric circles in the “after” pic are waves causes by ongoing seismic activity at the volcano.
Image: AP/JAXA/Geospatial Authority of Japan

Looking at the photos, it seems the entire southwest flank of the Anak Krakatau island volcano has disappeared, likely the result of a cataclysmic landslide triggered by ongoing eruptions. The ensuing tsunami smashed into beaches along Indonesia’s Sunda Strait, killing hundreds.

As the images show, Krakatau is now significantly smaller than it was prior to the landslide. The concentric circles are waves moving away from the Anak Krakatau island volcano—a sign of seismic activity and eruptions, according to experts cited by the AP.

Indeed, ongoing eruptions have caused Indonesia’s disaster management agency to raise its alert level from two to three, the BBC reports. All flights around the volcano have been rerouted and a 5-kilometer (3-mile) exclusion zone implemented. Indonesian authorities are asking people to be on alert for another possible tsunami.


Anak Krakatau began to exhibit signs of renewed activity back in July, but it has been particularly active during the last couple of weeks. Very famously, an earlier iteration of the volcano produced a cataclysmic eruption in 1883, sending shockwaves around the planet, not once—but four times. The massive eruption affected global climate and caused temperature declines around the world.



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About the author

George Dvorsky

George is a senior staff reporter at Gizmodo.