(AP) -- The summit of Hawaii's Kilauea volcano is glowing brightly as molten lava swirls 300 feet below its crater's floor, bubbling near the surface after years of spewing from the volcano's side.
The expanding vent of Halemaumau crater helps confirm scientists' belief that the lava is close to the surface of the summit, said Janet Babb, a geologist and spokeswoman for the U.S. Geological Survey's Hawaiian Volcano Observatory.
Park rangers have begun keeping the overlook at the Jaggar Museum open later at night to accommodate the growing number of visitors arriving at dusk or after dark to view the glow.
Kilauea has been erupting for more than 25 years, with its lava creating a plume of steam as it spills into the Pacific Ocean.
But this recent activity is coming from the top of the volcano, not its sea-level side. This is the strongest glow coming from the crater since October, but scientists don't know if lava will ever erupt in a fountain from within the crater, Babb said.
"There's no way to know if that will ever materialize," she said. "It would be grand to see some fountaining here."
The changes in the crater have not created any increased risk to visitors or park staff, she said.
Volcanic smog - known as vog - regularly emits from the crater, spreading a haze of toxic sulfur dioxide over the island. Sometimes, it has been thick enough to cause illnesses, kill crops and force school closures.
Measurements taken earlier this week showed that sulfur dioxide emissions remain similar to recent elevated levels, Babb said.
A non-lava eruption from the summit in March 2008 rained gravel-sized rocks onto a lookout, road and trail, forcing parts of the park to close.
Information from: West Hawaii Today, http://www.westhawaiitoday.com
©2009 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
Explore further: Study provides improved decision-making tools for oil well construction