WASHINGTON – Scientists can’t know precisely when a volcano is about to erupt, but they can sometimes spot telltale signs.

This happened two years ago with the the largest active volcano in the world. About two months before Mauna Loa Rivers of glowing orange molten lava spewed out, geologists detected small earthquakes nearby and other signs, and they warned residents on the Big Island of Hawaii.

Now, a study of the volcano’s lava confirms the timeline of when the molten rock was in motion.

“Volcanoes are tricky because we can’t directly observe what’s happening inside — we have to look for other signs,” said Erik Klemetti Gonzalez, a volcano expert at Denison University, who has not not participated in the study.

The rising ground and increased seismic activity near the volcano results from magma rising from lower levels of the Earth’s crust to fill chambers beneath the volcano, said Kendra Lynn, a research geologist at the Observatory. of Hawaii’s volcanoes and co-author of a new study in 2007. Natural communications.

When the pressure was high enough, the magma broke through the fragile surface rock and turned into lava – and the eruption began in late November 2022. Researchers later collected samples of the volcanic rock for analysis.

The chemical composition of some crystals in the lava indicated that about 70 days before the eruption, large quantities of molten rock had moved about 1.9 miles (3 kilometers) to 3 miles (5 kilometers) below the summit up to a mile (2 kilometers). or less below, depending on the study. This matched the timeline observed by geologists along with other signs.

Mauna Loa last erupted in 1984. Most of the U.S. volcanoes that scientists consider active are in Hawaii, Alaska, and the West Coast.

Worldwide, around 585 volcanoes are considered active.

Scientists can’t predict eruptions, but they can make a “prediction,” said Ben Andrews, who directs the Global Volcano Program at the Smithsonian Institution and was not involved in the study.

Andrews compared volcano forecasts to weather forecasts – informed “probabilities” that an event will occur. And better data on the past behavior of specific volcanoes can help researchers refine their predictions of future activity, experts say.

(asterisk) We can look for similar patterns in the future and expect there to be a higher probability of an eruption occurring,” Klemetti Gonzalez said.

___

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Science and Education Media Group. The AP is solely responsible for all content.