Villagers look on as Mount Sinabung volcano spews thick volcanic ash, as seen from Beganding village in Karo, North Sumatra province, on May 19, 2017. Sinabung roared back to life in 2010 for the first time in 400 years. After another period of inactivity, it erupted once more in 2013 and has remained highly active since. (Photo by Ivan Damanik/AFP Photo)

An Indonesian boy waits as he prepares to catch offerings released by Hindu devotees of the Tengger tribe during the Yadnya Kasada festival, on the crater of Mount Bromo in Probolinggo on July 21, 2016. During the annual Yadnya Kasada festival the Tenggerese climb Mount Bromo, an active volcano, and seek the blessing from the main deity Hyang Widi Wasa by presenting offerings of rice, fruit, livestock and other local produce. (Photo by Juni Kriswanto/AFP Photo)

A hiker admires the view as Mt. Etna, Europe's largest active volcano, erupts in the background, in the Bove Valley of Etna Park, on the eastern slope of Mt. Etna, in Sicily, southern Italy, Sunday, July 4, 2021. Since Feb. 16, 2021, Mt. Etna has begun a series of eruptive episodes. (Photo by Salvatore Allegra/AP Photo)

Indonesia's Mount Sinabung erupts, sending a column of volcanic materials as high as 16,000 feet into the sky on August 10, 2020. The volcano, one of two currently erupting in Indonesia, was dormant for four centuries before exploding in 2010, killing two people. Another eruption in 2014 killed 16 people, while seven died in a 2016 eruption. (Photo by Sutanta Aditya/Abaca/Sipa USA via AP Images)

A helicopter flies close to a volcanic eruption which has begun in Fagradalsfjall near the capital Reykjavik on March 20, 2021 in Fagradalsfjall, Iceland. On Friday the Icelandic meteorological office announced a volcano, referring to a mountain located south-west of the Capital Reykjavik has erupted after thousands of small earthquakes in the area over the recent weeks. A no-fly zone has been established in the area. (Photo by Vilhelm Gunnarsson/Getty Images)

A resident carries a gas canister as an ash cloud hovers above during an eruption of Mount Sinabung volcano at Tiga Serangkai village in Karo Regency, North Sumatra province, Indonesia June 24, 2015. More than 10,000 people from 12 villages, who are living around the slopes of Mount Sinabung, left their homes and moved to refugee camps, local media reported. (Photo by Reuters/Beawiharta)

Tourists gather to watch Mount Agung at Amed beach in Karangasem on Indonesia' s resort island of Bali on November 30, 2017. Thousands of foreign tourists were expected to leave Bali by plane on November 30 following a nearly three- day airport shutdown sparked by a rumbling volcano on the Indonesian holiday island. (Photo by Juni Kriswanto/AFP Photo)

Ngorongoro Crater (Tanzania). At 610m deep and 260 sq km, this is the largest unflooded caldera in the world. A blue-green vision from above it's a haven for engangered wildlife and Maasai livestock. The crater was formed three million years ago when a giant volcano, which could have been as high as Kilimanjaro, exploded and collapsed. The caldera formed the concentric fractures in the crust cracked down to a magma reservoir deep underground. (Photo by John Bryant/Getty Images)