This story has been updated to reflect new details from the USGS Hawaiian Volcano Observatory.
(BIVN) – Following a noteable increase in shallow earthquake activity in lower Puna below Kilauea, Hawai‘i County Civil Defense has shut down the lava viewing area in Kalapana due to its proximity to the increased hazardous activity.
The increase in earthquakes in the Lower East Rift Zone began after the collapse of Puʻu ʻŌʻō on Monday.
Just after 2:00 p.m. on April 30, 2018, USGS Hawaiian Volcano Observatory scientists say “a marked increase in seismicity and ground deformation (change in ground surface shape) began at Puʻu ʻŌʻō on Kīlauea Volcano’s East Rift Zone. A few minutes later, a thermal webcam (PTcam) located on the rim of the Puʻu ʻŌʻō crater showed the first of two episodes of crater floor collapse; the second collapse began at 3:20 p.m. and lasted about an hour. Webcam views into the crater and surrounding area were frequently obscured by poor weather conditions. However, shortly after 4:00 p.m., the PTcam recorded images that were likely the signature of small explosions from the western side of the crater as the floor collapsed.”
On Tuesday morning, USGS issued a new Volcanic Activity Notice and later reported “an intrusion of magma occurred overnight in the lower East Rift Zone extending from the general area of Puʻu ʻŌʻō eastward at least as far as Highway 130. As of 8:30 this morning, the level of activity has decreased significantly, but it is too soon to know if this is merely a pause.”
The new Volcano Activity Notice also raised the possibility of a new outbreak along the rift zone if activity intensifies. “Residents of lower Puna should remain on alert and monitor Hawaii County Civil Defense messages,” scientists said.
“An outbreak of lava in a new location is one possible outcome,” USGS scientist-in-charge at Hawai’i Volcanoes Observatory, Christina Neal, said in statement. “At this time it is not possible to say with certainty if or where such an outbreak may occur, but the area downrift (east) of Puʻu ʻŌʻō is the most likely location, as this is where seismicity and deformation have been concentrated overnight.”
Also on Tuesday, scientists wrote that “HVO field crews attempting to reach Puʻu ʻŌʻō this morning were turned back by ash in the air above Puʻu ʻŌʻō, likely due to continuing collapse within the crater and vigorous gas emissions. Reddish ash was also noted in abundance on the ground around Puʻu ʻŌʻō. Seismicity remains elevated at Puʻu ʻŌʻō but tiltmeters near the cone show no significant deformation at this time.”
The county is already taking precautionary action. The Department of Parks and Recreation has shut down the lava viewing area in Kalapana due to the proximity to the increased hazardous activity.
“We don’t want people hiking in that area, which is downslope from the rift,” Parks and Recreation Deputy Director Maurice Messina said, adding that vendors at the viewing area were told to vacate the area. Messina noted that the lava viewing area can draw 500 to more than 2,000 visitors, depending on the level of volcanic activity.
A magnitude 4.0 earthquake just offshore of Puʻu ʻŌʻō occurred at 2:39 a.m. Tuesday morning, the largest of a sequence of tremors along the rift zone. There is no risk of tsunami at that magnitude, USGS reported.