The latest event was preceded by gas-pistoning, in which gas accumulates at a lava column's top within a vent, on Tuesday.
The observatory said this process causes the lava surface to rise or piston. “Eventually, gas escapes as splatter/lava is erupted, and lave drains back into the vent,” the observatory wrote on its Facebook page.
These were occurring up to 10 times an hour, but increased in intensity until a small, sustained dome fountain began to feed flows to the crater floor a day later.
It is the 25th eruptive episode since the volcano on the southeastern part of the island began erupting Dec. 23. It has been pausing and resuming since.
Most of the eruptive episodes have spewed lava for about a day or less, with pauses between them generally lasting a few days.