A major earthquake swarm that had more than 1,500 quakes in recent days has subsided at the Kilauea Volcano on the Big Island of Hawaii. While this means the odds of a volcanic eruption have dropped there, that could change at any time. With the threat of an eruption lower than it has been, the National Park Service has re-opened roads and trails throughout the park that surrounds the active volcano that had been shuttered in recent days.
Over the last week, USGS Hawaiian Volcano Observatory (HVO) scientists and park staff monitored thousands of shallow low-magnitude earthquakes below the upper ERZ and just south of the summit caldera. According to USGS, the consistent decrease in both seismicity and ground deformation over the past 30 hours to background levels indicates that this pulse of unrest has ended…for now.
According to the Hawaiian Volcano Observatory of USGS, earthquake counts in the upper East Rift Zone have decreased to background levels with approximately 18 earthquakes over the last 24 hours compared to over 350 per day at the peak of the unrest. Earthquake locations remain focused primarily from the southeast side of Kilauea caldera extending to the Chain of Craters Road intersection with Hilina Pali Road. Earthquake depths remain unchanged, averaging 1.2-1.9 miles beneath the surface. Most of the earthquakes were less than a 1.0 magnitude with a 2.3 magnitude event as the maximum over the last day. More than 2,000 earthquakes were recorded during the heightened unrest from April 27 to May 03, with more than 1,800 of these earthquakes occurring beneath the upper East Rift Zone.
Seismic activity has simmered down at #Kilauea inside @Volcanoes_NPS, but plenty of steam still rises around the volcano from the hot rocks that are just below the surface. #HIwx pic.twitter.com/uZ4jc1aw6I
— the Weatherboy (@theWeatherboy) May 5, 2024
HVO says that ground deformation has also effectively ceased beneath Halemaʻumaʻu and the south side of Kalaupele and Keanakākoʻi crater with a little over 1 microradian inflation on both tiltmeters in the last 24 hours.. The Uēkahuna tiltmeter began recording mild inflation at approximately 4:30 AM today as part of a local deflation-inflation (DI) event beneath Halemaʻumaʻu. This is also reflected in the Sandhill tiltmeter, which has otherwise recorded little change in the past 48 hours.
Scientists at HVO studying this volcanic unrest say that it’s been driven by magma input to the main magma chamber, which lies beneath the area southeast of Kaluapele and south of Keanakākaoʻi crater. The significant drop in inflation rate, especially at the Sand Hill tiltmeter, suggests that the magma supply is greatly reduced and no longer pressurizing the magma chamber and producing seismicity. Magma input into the system has changed during the past year from relatively constant to occurring in pulses.
HVO warns that resumption of magma input could occur at anytime and build to another period of unrest, most likely in the upper East Rift Zone, within Kaluapele, or south of Kaluapele where the intrusion occurred in late January-early February. “Should volcanic activity change significantly, a Volcanic Activity Notice will be issued,” HVO wrote in a statement released today. “Hazards are still present on Kilauea. Residents and visitors should stay informed and follow County of Hawaii and Hawaii Volcanoes National Park guidelines. ”
“While the unrest appears to be over, Kilauea is one of the most active volcanoes on earth and conditions can change at any time,” a statement released by Hawaii Volcanoes National Park read. They add, “Chain of Craters Road and other previously closed sites are now open as unrest and seismicity return to normal levels in Kilauea volcano’s upper East Rift Zone and near its summit. Areas accessed by Chain of Craters Road, including coastal backcountry sites, Hilina Pali Road, Kulanaokuaiki Campground, Nāpau, and Pepeiao Cabin are now open. The Kaʻū Desert Trail is also open.”
