Small splatters of molten lava have been ejected from Halemaumau Crater for the first time since 1982.
Officials with the U.S. Geological Survey's Hawaiian Volcano Observatory say some of the particles — the largest of which measure four inches across — have landed on the rim of the crater.
They say geologists have discovered thin strands of volcanic glass known as "Pele's hair" along with small bits of volcanic glass known as "Pele's tears" in the crater overlook area.
Scientists say the gas from the new vent at Halemaumau is thick with ash, making the plume from the 100-foot-wide vent appear brown.
Officials are continuing to monitor the activity and say aviation agencies have been warned that the ash may threaten aircraft in the area.