The Indonesian volcano whose 1257 eruption formed the Samalas caldera on Lombok was Samalas.
Samalas, also known as Rinjani Tua, was part of the volcanic complex now dominated by Mount Rinjani. Its catastrophic 1257 eruption destroyed the volcano’s summit and created the Segara Anak caldera, which contains Lake Segara Anak. The eruption is generally rated VEI 7, placing it among the largest explosive eruptions of the Holocene.
Pyroclastic flows devastated much of Lombok and crossed surrounding seas. Ash reached Java, about 340 kilometres away, while sulfur aerosols spread globally and contributed to unusually cool conditions in the years after the eruption. Evidence from ice cores helped scientists identify the event before geological and historical research linked it to Samalas.
The main trap is confusing Samalas with Rinjani. Modern Mount Rinjani stands at the eastern edge of the caldera, but Samalas was the volcano that erupted and collapsed in 1257. Kelud and Agung are separate Indonesian volcanoes.