Seismic unrest continues at the Kilauea Volcano on the Big Island of Hawaii, where USGS scientists are warning that an eruption could occur there with as little notice of only 1-2 hours. Kilauea is an active shield volcano located along the southeastern shore of Hawaii’s easternmost island; it last had an eruption in September.
“Episodic heightened unrest continues in the south summit area of Kilauea and an eruption in the region from Halemaʻumaʻu south to the December 1974 vents could emerge with little notice (1-2 hours) during peaks in this activity,” the Hawaiian Volcano Observatory (HVO) unit of USGS reported in today’s daily update. They add, “Inflation at the summit of Kīlauea remains at about its highest level in over 5 years and has nearly returned to the level seen just before the last eruption on September 10th.”
HVO scientists have been observing tiltmeter data to look for clues when the next eruption could occur. Tilt measurements have been used to monitor volcanoes in the United States since the founding of the Hawaiian Volcano Observatory in 1912. When magma accumulates beneath the ground, causing the surface above to inflate, the slope of adjacent areas will usually tilt away from the center of uplift. Conversely, if the ground deflates as a consequence of magma draining from a subsurface reservoir, the slope of adjacent areas will tilt toward the center of subsidence.
The Uēkahuna summit tiltmeter located north of the caldera recorded very slight inflation over the past 24 hours. According to HVO, the Sand Hill tiltmeter located just south of the caldera went off scale during the peak activity on October 6th, but has been reset and is showing continued inflation but at a lower rate than before the event. GPS units within the south end of the caldera and further south also show continued uplift of this region.
In addition to this apparent expansion and swelling of the volcano, there’s also been a significant uptick in earthquake activity in recent days. Elevated seismicity is being recorded beneath the south end of Kilauea caldera and extends to the southwest along the trend of December 1974 vents. Seismicity increased on October 4, peaked at over 250 earthquakes per day on October 5 and 6, and continues dispersed over this area. HVO says that over the past 24 hours, approximately 110 earthquakes were recorded in Kilauea summit region compared to about 125 earthquakes occurring over the previous day. Most of the earthquakes from the seismic swarm south of the caldera are at depths of around 1.5–2 miles below the surface.
With an increasing threat level at the volcano, the National Park Service has taken action to prevent visitors from entering in areas of greatest potential danger. “Hawaiʻi Volcanoes National Park is closely monitoring Kīlauea in collaboration with our colleagues at the USGS Hawaiian Volcano Observatory. The park is currently open, but visitors should be prepared and stay informed,” said the park service in an update posted online. Hilina Pali Road from Chain of Craters Road to Hilina Pali Overlook are now closed. The Pu’upua’i parking lot, Pu’upua’i Overlook, and the trail that connects it to Devestation Trail, including the Devastation Trail parking lot, are also closed. The Keanakako’i Overlook, the paved trail to/from Chain of Craters Road, and the nearby Crater Rim Trail are also closed as is the Maunaiki and Ka’u Desert Trails. The Kulanaokuaiki Campground has also been closed. The Visitors Center along with multiple viewing sites into the summit caldera crater remain open at the park.
This surge of activity at the volcano is occurring just weeks after another eruption at the summit ended. Back on September 16, HVO declared the eruption over. With the eruption over, the amount of volcanic gas spewing into the air was also significantly reduced, helping clear the air of many communities on the island which had harmful levels of volcanic-induced air pollution. On September 10, Kilauea exploded to life after an intense swarm of earthquakes near the summit. The lava put on quite the show for visitors who were able to safely observe the eruption inside the volcano caldera from above it at Hawaii Volcanoes National Park. The lava from that eruption never left the summit caldera.