Volcanoes as Agents of Change in Human History – Part 2

Earth Observatory Blog

Volcanoes as Agents of Change in Human History – Part 2


The Samalas volcano eruption in 1257 left a large caldera (lake Segara Anak) next to Rinjani volcano. (Source: Wikipedia/Petter Lindgren)

The previous post focused mainly on the 1991 Pinatubo eruption and how it affected humans and history (scientific in this case). Today’s post will cover a historic eruption that changed the course of history on one Indonesian island, and around the world. No, it isn’t the 1815 Tambora eruption. Although that was an amazing eruption with respect to global impacts, today we will cover the lesser known 1257 Samalas eruption.

Samalas volcano today, Lambok Island, right next to Bali, Indonesia (Source: Google Earth)

1257 Samalas – Lombok, Indonesia


Samalas is located on the island of Lombok in Indonesia. Pyroclastic flows descended from the summit to the southeast, southwest, and nearly wiped out the north coast. Ash deposits provide evidence for an ash plume reaching between 39 and 43 kilometres (km) in altitude. The high altitudes allows for wide dispersal of the ash plume and sulfate deposited on the Greenland and Antarctic ice sheets. Historic accounts and ash dispersal models indicate the eruption likely occurred between May and October 1257. The minimum volume erupted from the volcano is 10 km3, making this eruption a VEI 7 (roughly an order of magnitude larger than the Pinatubo eruption). Although there are historic accounts of this eruption, they are limited. There certainly wasn’t volcano monitoring at the time. However, current research of this eruption will lead to new ideas of what triggered the eruption and how the hazards can be mitigated.

Experts believe that the Samalas eruption was so destructive, it left Lombok Island, Bali and other surrounding areas uninhabitable for generations. (Source: Lavigne et al. 2013)



The Babad Lombok is an historic account of the eruption and its aftermath. It records the destruction of the local culture on Lombok by the sweeping pyroclastic flows. Indeed, political and economic upheaval results from the likely destruction of Pamatan, the royal seat for Lombok. When the ash settled, it likely ruined the local and regional (as far as Sumbawa Island) agriculture for years. Historians propose these outcomes as an explanation for the lack of resistance when the Javanese invaded Lombok later in the 13th century.


The large scale of the Samalas eruption certainly had a global effect on climate. Like the Pinatubo eruption, ash dispersal was extensive. Global temperatures also dropped due to the reduced reflectivity of the earth. The temperatures dropped so much that summers were cooler and wetter than normal in northern Europe, causing crop failures. Famines and epidemics resulted from these conditions. The eruption may have contributed to similar weather and social conditions reported in eastern Asia and the Middle East, as well.

After reconstructing the volcanic cone to its pre-eruption shape (bottom), scientists estimated the eruption to be more powerful than Krakatoa in 1883. (Source: Science/Lavigne et al. 2013)

Patterns emerge when looking at these two eruptions. Clearly, the size of the eruption affects the aftermath. Bigger eruptions have larger reach. The impact of eruptions seems to be related to wide scale temporary climatic changes which affects people worldwide. However, there are always ‘local’ impacts, regardless of the eruption size. Even though these very large eruptions are fascinating, smaller eruptions occur more frequently. Thus, we mustn’t forget to study those as well.

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