Maunaloa Weekly Report: June 17, 2021

Underground adjustments on Maunaloa volcano continue this week, with an uptick in small earthquakes on its southeast flank augmenting the activity beneath the summit, northwest and west flanks reported by the USGS in this week’s update. The southeast flank contributes 89 of this week’s total of 195 events less than magnitude 2.6, with another 46 under the summit and upper elevation flanks maintaining the low background rates in that area that have been evident in the past three quiet weeks, when that was the only seismicity noted on the volcano. Previously, over 100 earthquakes were reported every week between February 12th to May 20th by the USGS, over a total of 14 weeks. Episodic seismic movement of the flanks, as is happening now, appears to relieve pressure from magma build-up within the volcano, the latter sometimes associated with high earthquake rates beneath its summit and upper elevations. While most of the movement occurs on Maunaloa’s southeast flank, the southwest flank continues to exhibit slow signs of adjustment since January, with the region averaging 3 earthquakes per month between magnitudes 1.2 and 3.2, including a magnitude 2.6 and a 1.8 within the past week. This same area averaged just over 1 earthquake per month during 2020, based on the USGS Earthquakes page. There continue to be no significant changes reported by the USGS from GPS and ground tilt stations on the summit, as well as gas, temperature and visual monitors. Satellite measurements of the summit region between April 16th and May 28th have also been shared by the USGS on Twitter, showing “no deformation of note.” Nonetheless, the volcano remains at alert level “Advisory”, the second lowest of the four tiers, due to slightly elevated unrest above long-term background levels. Tracking the volcano’s data is interesting in surmising its inner workings, but most importantly there is no indication of increased volcanic hazard to people and their communities at this time. Join our weekly live video review of Kīlauea and Maunaloa volcanoes, at 5pm Hawaiʻi time Thursdays as of June 2021! To support our productions please like, share and subscribe! Mahalo! #Maunaloa Image caption via USGS Volcanoes Twitter: "Attached is a Sentinel interferogram spanning April 16 - May 28. No deformation of note (fringes around the mountain are atmospheric anomalies). The last couple of months have been relatively quiet in terms of deformation up there."