#CVO researchers detect subtle increase in the rate of uplift, 3 mi west of #SouthSister volcano, of #ThreeSisters in central Oregon. Episodes uplift observed in this area before. Volcano status unchanged. 1/6 volcanoes.usgs.gov/hans2/view/not… 
Between June 2020-Aug 2021, #satellite data show uplift of ~0.9 in (about the width of your thumb) over a broad area 12 mi in diameter, west of South Sister. On-the-ground GPS monitoring confirms, detecting ~0.2 in of uplift since Aug 2021. #ThreeSisters 2/6
Uplift has been occurring in same area for ~25 years. From 1995 to 2020, area rose ~12 in (height of 2L soda bottle) at its center. Current uplift rate is slower than max rate from past - but distinctly faster than rate observed before 2020. #ThreeSisters 3/6
Seismologists observed brief bursts of small #earthquakes in October 2021, December 2021, and January 2022. Most of these shallow earthquakes are too small to locate precisely; those located are inside the uplifted area. #ThreeSisters 4/6
Uplift attributed to small magma pulses accumulating ~ 4 mi below ground in an area west of South Sister. If magma accumulation continues and shows sign toward eruption, we will detect significant changes in activity (EQs, deformation, gas emissions). #ThreeSisters 5/6
CVO scientists will closely monitor data in the coming months and issue further updates as warranted. Sign up for VNS to receive email alerts. volcanoes.usgs.gov/vns2/ #ThreeSisters 6/6
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