Samalas Erupts and Buries a Royal City on Lombok

In 1257, a tremendous volcanic explosion tore apart Mount Samalas on the Indonesian island of Lombok. With an estimated magnitude of 7, the blast ranks as one of the largest eruptions of the Holocene epoch. Before the disaster, Samalas may have risen about 4,200 meters above sea level, surpassing its modern neighbor Mount Rinjani. The cataclysm utterly destroyed this ancient peak, collapsing its bulk into a massive depression now known as the Segara Anak caldera, within which a two-hundred-meter-deep lake formed.

The eruption unfolded in distinct phases, driving immense eruption columns up to about forty-three kilometers high into the stratosphere. Boiling pyroclastic flows swept across the island, burying river valleys, incinerating vegetation, and leaving deposits up to 35 meters thick at the coast 25 kilometers from the volcano. Ash fell across Lombok and the neighboring islands of Bali and Sumbawa and most likely reached eastern Java. On Lombok itself, the catastrophic flows obliterated human settlements, including Pamatan, the capital city of a local kingdom.