Kīlauea Weekly Report, July 7, 2021: Shifting Summit Inflation

Magma movement continues within Kīlauea volcano close to its summit, evidenced by its seismicity and gradual inflation on monitoring signals reported by the USGS Hawaiian Volcano Observatory this week. They also note that “the pattern of tilt and GPS motions indicates that the inflation center may have shifted slightly to the southern part of the caldera”, while recent gas emissions have been measured slightly higher at around 110 tonnes per day, but still within the recent background range. The shifting center of summit inflation could explain why the GPS cross-caldera distance, which had been increasing since the recent eruption, shows little change over the past two weeks, mainly mirroring the larger Deflation-Inflation signals that also dominate the ground-tilt signal. However, in the last few days the spreading appears to have resumed, suggesting the inflation center could already be shifting back. Earthquakes continue to focus beneath the summit, and over this past week have resumed to the south beneath the upper east rift connector at slightly elevated levels. On the upper east rift and nearby south flank, seismic activity is lower than the previous weeks but still continues. Unrelated to the small volcanic earthquakes, two moderate tectonic events were felt on-island over the past week, a magnitude 5.2 just north of the island just offshore near Waipiʻo Valley on July 5, and two nearly coincident magnitudes 4.2 farther to the northwest on July 7. All in all, these are minor changes of interest that do not signify any imminent change in volcanic activity or hazard, yet offer clues about the subsurface dynamics and set the context for any future activity. As is typical, the slow adjustments continue. #Kilauea2021 Join our weekly live video review of Kīlauea and Maunaloa volcanoes, at 5pm Hawaiʻi time Thursdays! To support our productions please like, share and subscribe! Mahalo!