As lava continued to pour vigorously from the ground through fissures at the foot of Kilauea Volcano, the month-old eruption on Hawaii's Big Island has entered a new, seemingly calmer phase inside the summit crater, government scientists said on Friday.
But vulcanologists monitoring and measuring Kilauea's every move during the past four weeks hastened to add the latest change in the volcano's behavior, while undoubtedly significant, leaves them uncertain about what will follow.
The summit crater, which began ejecting ash and volcanic rock in periodic, daily eruptions in mid-May, has largely fallen quiet since Wednesday, Kyle Anderson, a U.S. Geological Survey (USGS) geophysicist, told reporters in a conference call.
The apparent reason, newly revealed in footage recorded by drone aircraft flown over the summit, is that tons of rocky material shaken loose from the inside walls of the crater vent have plugged up the bottom of the void, Anderson said.
What happens next is unknown.
"It's possible that new explosions will blast through the rubble at the bottom of the vent, and these may or may not be larger than previous explosions," he said. "It's also possible that the vent could become permanently blocked, ending the explosions entirely."
In any case, the volcano's behavior ultimately hinges on the ebb and flow of huge rivers of molten rock called magma, the term for lava while it remains underground.