Scientists can't know precisely when a volcano is about to erupt, but they can sometimes pick up telltale signs.
That happened two years ago with the world's largest active volcano . About two months before Mauna Loa spewed rivers of glowing orange molten lava, geologists detected small earthquakes nearby and other signs, and they warned residents on Hawaii's Big Island.
Now a study of the volcano's lava confirms their timeline for when the molten rock below was on the move.
"Volcanoes are tricky because we don't get to watch directly what's happening inside - we have to look for other signs," said Erik Klemetti Gonzalez, a volcano expert at Denison University, who was not involved in the study.
Upswelling ground and increased earthquake activity near the volcano resulted from magma rising from lower levels of Earth's crust to fill chambers beneath the volcano, said Kendra Lynn, a research geologist at the Hawaiian Volcano Observatory and co-author of a new study in Nature Communications .
