How do volcanoes affect the weather and climate?

Topography indisputably influences the weather—that’s why precipitation is so much greater on the windward side of the island. But how much did Hawai‘i’s topography influence Iselle? Hurricane Iselle weakened to a tropical storm just as it reached the island, but still managed to make landfall. As it did, the bulk of the storm stalled on the east flank of Mauna Loa, but its weakened upper parts continued moving westward. [...]

Deep origins to the behavior of our volcanoes

Kīlauea volcano, on the Big Island of Hawaii, typically has effusive eruptions, where magma flows to create ropy pāhoehoe lava. But Kīlauea sometimes erupts more violently, showering scoria and blocks over much of the surface of the island. To explain the variability in Kīlauea’s eruption styles, a research team analyzed 25 eruptions that have taken place over the past 600 years. Their research shows that the ultimate fate of a magma at Kīlauea — that is if the eruption will be effusive or explosive — is strongly influenced by the variability in composition of the deep magma. In short, more gas-rich magmas produces more explosive eruptions. “Gas-rich magmas are ‘predisposed’ to rise quickly through the Earth’s mantle and crust and erupt powerfully,” Houghton explained. [...]