The glowing pond lies at the summit of the volcano and is fed by a cylindrical vent that slowly spews the molten lava.
The lake level has been rising and falling for months as magma levels have fluctuated within the volcano.
Over the past two weeks, it surged about 50 feet, reaching only 110 feet from the top of the nearly vertical vent.
This has provided a fiery light show for nighttime visitors to an overlook at the Jaggar Museum, inside the Hawaii Volcanoes National Park.
Even if the lava lake were to overflow, it would not pose an immediate threat to any populated areas.
Photo: U.S. Geological Survey