VOLCANO, Hawaii -- A gas explosion at Halema'uma'u Crater at the summit of Kilauea Volcano shook parts of the Big Island and scattered debris over 75 acres of Hawaii Volcanoes National Park early on Wednesday morning.

The U.S. Geological Survey's Hawaiian Volcano Observatory said the quake with a preliminary magnitude 3.7 was located in the volcano's upper east rift zone. About a dozen smaller quakes followed.

The burst, recorded shortly after 3 a.m., carved out a small crater along the east wall of Halema'uma'u Crater. It is the first explosion there since 1924.

Rock fragments now cover a portion of Crater Rim Drive, the crater trail and the parking area. No lava was seen on the floor of the crater.

"It was probably the result of the gasses escaping at a great rate, trying to clear the throat of the conduit out. So, right now, there are no rocks covering the surface of this vent, which is around 2o-30 meters in diameter. It's just an open conduit pushing out a bunch of surfur dioxide among other gasses," said Jim Kauahikaua of Hawaiian Volcano Observatory.

Big Island Civil Defense has been monitoring levels of sulfur dioxide since Halema'uma'u began its dramatic display about a week ago. Emissions are 10 times the normal output, but the county has not issued any health advisories. The area has been closed off to visitors.

Scientists said that sulfur dioxide emission rates are high near the crater rim and could pose a danger down wind at the road.

Increased sulfur dioxide gas emissions from the volcano led to the closure of 4 miles of Crater Rim Drive last month.