Fresh lava fountains spewed in spectacular fashion from Hawaii's Kilauea volcano on Saturday, US vulcanologists said, marking nearly a year since one of the world's most active volcanoes began erupting.

"Sustained lava fountains approximately 50-100 feet (15-30 meters) in height are currently erupting from the north vent," the US Geological Services Hawaiian Volcano Observatory said in a statement, adding that "fountain heights are increasing rapidly."

The latest episode in the ongoing eruption -- the 38th such surge of molten rock and gases from deep underground -- began at 8:45 am local time (1845 GMT), USGS said.

Such activity has been intermittent since an eruption began on December 23, 2024, USGS said, and typically continues for "a day or less."

All the eruptive activity is "confined to Halema'uma'u crater within the Hawaii Volcanoes National Park," the service said, and local airports are not expected to be affected by volcanic gas or ash.

Officials are on watch for high levels of volcanic gas and a phenomenon called "Pele's hair," in which strands of volcanic glass "often produced by lava fountaining activity" are "carried well over 10 miles (15 kilometers) from the vent."

Hot glassy volcanic fragments "can fall on the ground within 1-2 miles (1-3 kilometers) of the eruptive vents." 

Kilauea has been very active since 1983 and erupts relatively regularly.

It is one of six active volcanoes located in the Hawaiian Islands, which also include Mauna Loa, the largest volcano in the world.

Kilauea is much smaller than neighboring Mauna Loa, but is far more active and regularly wows helicopter-riding tourists who come to see its red-hot shows.