Nāhuku Lava Tube In Hawaiʻi Volcanoes Nationwide Park Closed To Examine Its Stability

NPS geomorphologists set up a crackmeter inside Nāhuku in November 2019/NPS, J.Wei

Nāhuku lava tube in Hawaiʻi Volcanoes Nationwide Park is closed till additional discover whereas geologists research its stability within the wake of motion of a big rock slab within the tube.

The lava tube, also called the Thurston lava tube, has a crack that not too long ago narrowed. A “crackmeter” put in to watch a fracture close to a big overhanging rock slab on the apex of the lava tube detected that it had narrowed by 2.47 millimeters between Saturday and Monday.

The narrowing motion may point out the crack is adjusting in response to different fractures widening within the lava tube, making the big overhead chunk of rock unstable and doubtlessly harmful, a park launch mentioned. The slab measures about 2.16 x 3.23 meters (7.1 x 10.5 ft) and 20.3 centimeters (8 inches) thick. Additional monitoring is required to find out if the lava tube can safely reopen.

On Sunday, Nationwide Park Service geomorphologist Dr. Eric Bilderback alerted park administration that the crackmeter in the course of Nāhuku had moved 1.96 millimeters Saturday night time over the course of a number of hours, and had moved one other 0.51 millimeters by Monday morning. Park managers closed the lava tube Sunday. 

Bilderback mentioned whereas the motion is gradual and never accelerating, these actions of a big rock slab are uncommon within the monitoring report. A return of motion much like the earlier report would wish to happen earlier than the lava tube could be thought of secure to reopen. It’s not clear how lengthy that can take. 

Previous to the fractural modifications over the weekend, knowledge from the screens revealed little change to the cave’s structural integrity displaying lower than 1 millimeter of motion since November 2019. 

Massive rocks in Nāhuku have been dislodged throughout the 2018 eruption and summit collapse of Kīlauea volcano. Two crackmeters have been put in within the lava tube’s ceiling to watch their motion. 

The restrooms close to Nāhuku and the parking space stay open. 


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