While current activity on Hawaii’s Kīlauea has captured media attention due to its impact on numerous residences, the eruption has been ongoing since 1983. We connected with Dr. Laszlo Kestay, Acting Director of the Astrogeology Science Center with the United States Geological Survey, to inquire into the story behind one of his stunning photos of the eruption.

West Kamokuna Skylight. Credit: Laszlo Kestay, USGS.

Taken on April 1, 1996 on the coastal flats below Pulama Pali, the photograph shows lava tubes reaching down to a skylight. Recently, it made waves on social media, with a viewer commenting that the “lava flow skylight looks like a portal to hell surrounded by [the] souls of the damned.”

Over the course of the 35-year eruption, lava has been flowing from the Puʻu ʻŌʻō to the ocean through lava tubes. The tubes began to form when knee-deep lava flows become engorged with yet more lava injected their still molten interior, expanding them so they were several meters thick. As some routes have hardened up, the lava has channelled into narrower and narrower pathways, or tubes.

In some locations, the roofs of the lava tubes have collapsed, providing skylights onto the river of flowing lava beneath that are invaluable for conducting scientific observations. This skylight in the picture was located on the coastal flats below Pulama Pali (see this link for a map from the USGS Hawaiian Volcano Observatory (HVO) archived by the Smithsonian Global Volcanism Project).

The photogenic fingers of pahoehoe lava frozen around the sides of the skylight were created by a flow of lava that had moved across the skylight and sent lava cascading back into the tube. Active lava flow over an active skylight is a rare coincidence—definitely worth taking a photo, even back in the days of film cameras with their limited numbers of shots, says Dr. Kestay.

These skylights can be dangerous to approach due to hot air blowing out and the possibility of further roof collapses. However, as HVO staff had become familiar with the long-lived lava tubes beneath, they were able to approach this skylight with relative safety. Hardhats being worn to work near explosions throwing rocks meters in the air could be confidently removed.

You can view the original image here.