HILO, Hawai'i — A small explosion late last night added to the excitement at Halema'uma'u by tossing a few hot rocks about 230 feet up to the rim of the crater.

Hawaii Volcanoes National Park was closed at the time because of fumes from Halema'uma'u, but the park reopened hours after the explosion.

Scientists with the U.S. Geological Survey said the blast apparently enlarged the new vent in the wall of the crater by 15 to 30 feet, but said the explosion was considerably smaller than a similar blast on March 19.

Scientists found lava splatters and rocks that were ejected by the blast, including one block that was about 14 inches tall and eight inches wide. Scientists said some ash from the blast apparently drifted on the wind about 19 miles to the Pahala area.