(BIVN) – A large crack has been discovered on the Kapoho lava delta, prompting a warning from state officials that part of the land mass could soon collapse into the ocean. 

The Hawaiʻi Department of Land and Natural Resources issued a warning to Hawaiʻi island residents and visitors on Monday, urging them use “extreme caution” when visiting the coastal areas of Puna impacted by the 2018 eruption of Kīlauea. 

The recent discovery of the crack – shown in an apparent cell phone video provided by the DLNR – “demonstrates the enduring instability that newly created land presents and may indicate signs of imminent collapse”, the department said. 

The warning includes, but is not limited to, “the communities of Kapoho, Pohoiki, Malama and Kalapana”, the DLNR says, 

The ocean below can be seen from between the cracks in the lava delta (image from Hawaiʻi DLNR video)

“The safety of our residents and visitors is our top priority, and we must emphasize that these newly created lands are not safe to traverse,” said DLNR Chair Dawn Chang in a news release. “The land is still settling and is unpredictable.”

From the Hawaiʻi DLNR:

Lava deltas are landforms built as hot lava enters and is cooled by the ocean. Deltas extend the island shoreline, but the terrain can be deceptive. Thin layers of molten rock appear as solid ground, but the new landforms are dynamic and inherently unstable. Vegetation may also conceal deep fissures and cracks.

There is little documentation as to the construction and subsequent destruction of this natural phenomenon, adding to its unpredictability. The U.S. Geological Survey notes that a collapsing delta can trigger explosive activity, hurling rocks and debris hundreds of yards inland and/or seaward.

“The report of the crack at Kapoho is a stark reminder that even years after eruption, areas in the lava flow hazard zones are active and can be dangerous,” Chang added. “Please exercise caution and remain alert when visiting these coastal areas.”