The eruptions of Hawaii’s Kilauea volcano and Guatemala’s Fuego volcano are both devastating but in very different ways, reports the New York Times. The Kilauea eruption has been a slow-motion disaster, steadily destroying homes for a month but presenting little threat to people, while the Fuego eruption has been faster and fiercer, killing more than 100 thus far. Scientists say the volcanos have different underlying geology and magma viscosity. "The magma at Kilauea is quite runny, which means the gasses can easily escape," a volcanologist tells National Geographic. "At Fuego, the magma is stickier and more viscous." Fuego is belching what's called a "pyroclastic flow," a fast-moving noxious cocktail of rock and gas with temperatures topping 1,800 degrees Fahrenheit, per CNN.
By contrast, Kilauea’s lava flow is moving so slowly that people can easily walk away from it. "Lava flows rarely kill people," one volcano expert tells the Times, but "you will not survive a pyroclastic flow." The volcanos’ proximity to population centers has also made a difference: Kilauea is located in a national park, while Fuego is near densely populated areas that were quickly overtaken by ash and gas moving at more than 400 mph. Both regions will be uninhabitable for years, but according to one analyst, Fuego poses the additional challenge of volcanic mudflows that occur "when the loose debris mixes with rain/river waters."