The frequently restive Kilauea volcano on the island of Hawaii spewed a plume of lava 50 metres tall, more than twice as high as molten rock shot into the sky when eruptions flared anew on Saturday.
As eruptions continued at two spots, seismic activity grew more vigorous and poisonous sulphur dioxide gas emissions peaked at 10,000 tons a day, over 30 times last weekend's levels, before dropping off again by more than half, according to scientists at the US Geological Survey.
No injuries or damage to residential property have been reported since Kilauea roared back to life on Saturday.
The 1100degC molten lava from Kilauea's summit and the newly ruptured Kamoamoa fissure have destroyed 30 hectares of rain forest since Saturday and buried 65 hectares of parkland.
The ground around the eruptions has continued to collapse, and forests downwind of the fissure were choked with volcanic fumes that are toxic to the vegetation, said Mardie Lane, an official at the Hawaii Volcano Observatory.
"We've been fortunate that we've had showers and rain," Lane told Reuters. "One of the biggest unknown dangers is the spread of sulphur dioxide gas. It's invisible, noxious and toxic. When our rangers are in the field, they use respirators to filter out the harmful gases."
Kilauea is one of five volcanoes that formed the Big Island, officially known as the island of Hawaii. Periodic eruptions of the volcano have destroyed 213 homes since the volcano emerged from a period of dormancy in 1983.