Nicaragua’s Momotombo volcano, not far from the city of León, has erupted for the first time in over a century. This iconic fiery mountain last experienced a major eruptive event in 1905, but so far, the currently reported volcanic activity isn’t dangerous, Wired reports.
After a series of tremors, wherein shallow magma began to breach through the overlying rock and make its way to the surface, an impressive series of lava fountains and an accompanying, persistent, dark ash plume one kilometer (0.62 mile) high were seen rocketing above the peak of the volcano. Steam jets, produced when groundwater fluids percolate into the molten interior and explosively expand as they heat up, were also spotted by locals prior to the eruption.
Late on Monday night, glowing lava and glassy fragments began to cascade down its slopes; by Tuesday, things were calmer, although several steam jets were still seen emerging from the volcano. Ash has begun to fall on at least six local communities, but so far, it hasn’t been significant enough to warrant any sort of major evacuation.
Nicaragua’s Momotombo volcano has erupted for the first time in 100 years https://t.co/BXNNvF15AS pic.twitter.com/Dv5GPQ7Ltd
— WIRED (@WIRED) December 2, 2015
Momotombo is a stratovolcano, a type of volcanic formation that frequently contains highly viscous magma within a two-step magma chamber system: a deeper one with more “primitive” magma, and a shallower chamber containing more “evolved,” cooler magma.
This type of volcano can erupt in a variety of ways, from slow-moving lava flows trickling down its flanks, to much more violent and sustained explosions, induced by a sudden depressurization event. In this case, Momotombo is erupting in a “Strombolian” fashion, named after the Sicilian volcano which incidentally inspired Tolkien’s Mount Doom in the "Lord of the Rings" books.
These eruptions are essentially the volcanic version of a belch. Large slugs of gas pop at the vent, launching broiling magmatic particles, blocks and bombs into the sky and down onto the surrounding landscape. Whereas the Strombolian blasts that occur at the eponymous volcano are actually quite predictable – they’ve happened every 20-30 minutes for decades now – the behavior of Momotombo is slightly more chaotic, at least at the moment.
Nicaragua's #Momotombo volcano has its first big eruption in 100 years https://t.co/j6eddZL8PG pic.twitter.com/E11eAnZTGy
— Agence France-Presse (@AFP) December 3, 2015
Momotombo was far more violently active between 1849-1905, during which 10 incredibly dangerous explosive eruptions occurred. In 1610, the then-capital of the region, León Viejo, was abandoned due to highly damaging earthquakes; it was slowly buried by persistent, ash-spewing volcanic eruptions over time.
The volcano had been due for a small explosive eruption, as seismic tremors – indicating the upward movement of magma beneath the surface – had been ongoing since 2003. At present, it appears that the internal pressure of the volcano is being released relatively calmly, and it is therefore unlikely to become more violent in the near future.