Renewed earthquake and deformation activity at Kīlauea summit - USGS HVO

(Official release from the USGS Hawaiian Volcano Observatory - Alert level is unchanged. Image: Last 24 hours of seismicity from USGS Earthquakes website.) Release Date: AUGUST 27, 2021 The US Geological Survey’s Hawaiian Volcano Observatory (HVO) detected a resumption in earthquake activity and ground deformation beneath the south part of Kīlauea summit caldera, within Hawaiʻi Volcanoes National Park. KĪLAUEA INFORMATION STATEMENT Kīlauea volcano is not erupting. The US Geological Survey’s Hawaiian Volcano Observatory (HVO) detected a resumption in earthquake activity and ground deformation beneath the south part of Kīlauea summit caldera, within Hawaiʻi Volcanoes National Park. The rate of ground deformation began increasing again around 6:00 p.m. HST on August 26 and was followed by increased earthquake activity after 8:30 p.m. The renewed activity occurred in approximately the same location as the August 23-25 earthquake swarm—within and south of Kīlauea caldera. The combination of these observations indicate a second pulse of intrusive activity. Most earthquakes in this renewed swarm were located 1–3 km (0.6–1.8 miles) beneath the surface, similar to the initial swarm. Approximately 200 earthquakes have been recorded since 8:30 p.m. on August 26, less than half of the number of earthquakes detected in the initial August 23–25 swarm. The largest recorded earthquake was magnitude 2.8, with the majority of earthquakes less than magnitude 1. Between 8:30 p.m. on August 26 and 5 a.m. on August 27, small earthquakes occurred at 16 detected earthquakes per hour, with a peak rate of 24 detected earthquakes per hour just after midnight. Since 5:00 a.m. on August 27, the average seismicity rate has dropped to about six detected earthquakes per hour. As of this statement, both earthquake and ground deformation rates in Kīlauea's summit region appear to be decreasing. In addition, there has been no indication of upward migration of earthquakes toward the surface or change in deformation that would indicate shallowing of the source intrusive activity. Accordingly, Kīlauea’s Volcano Alert Level and Aviation Color Code remain at ADVISORY/YELLOW. While the activity has slowed down as of the morning of August 27, additional intrusion pulses are possible. Any potential eruptive activity related to these events would be entirely within Hawaiʻi Volcanoes National Park and localized within undeveloped areas, well away from infrastructure such as roads. HVO continues to monitor this situation and will issue additional messages and Volcano Alert Level changes if warranted by changing activity.