Volcanic Avalanches Are Pretty Common ... and That Might Be a Problem

It has been a few weeks since the massive collapse of the Anak Krakatau cone that slid into the sea, generating the deadly tsunami that swept along both sides of the Sunda Strait in Indonesia. We’ve finally been able to see what occurred during that landslide and sure enough, most of the cone that was Anak Krakatau is gone (see below). In its place is, well, not much but open space that has seen seawater fill in. This volatile mix of water and erupting magma has meant that Anak Krakatau has been churning out tall steam-and-ash plumes that, at times, towered >10 kilometers (>30,000 feet) over the volcano. Luckily, the collapse of the cone will temporarily reduce the threat of another tsunami but as the cone builds back up over the years-to-decades, that threat will return because volcanic collapses and landslides are actually fairly common in the geologic record.