Why Indonesia's 'volcano tsunami' gave little to no warning

Unlike past disasters triggered by earthquakes, this week's deadly tsunami was likely sparked by unrest of the Anak Krakatau volcano.

A tsunami swept across Indonesia's islands of Sumatra and Java the night of December 22, just before 9:30 p.m. local time. There was no notice for the wall of water, which left devastation in its wake. Though casualties are likely to rise as missing people are located, at least 220 are confirmed dead and more than 800 are injured.

The reason behind the lack of warning is the surprise source of the waves: Unlike past events triggered by earthquakes, this tsunami was most likely caused by the collapse of an offshore volcano.

The geologic beast in question, Anak Krakatau, has been undergoing a stuttering eruption since June 18 of this year. While more detailed information about the

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