Nearly 30 small, shallow quakes rumble beneath Paulina Lake; seismologists see no cause for alarm
Still, it's the 'most significant seismic sequence' since sensors were installed in 2012
VANCOUVER, Wash. (KTVZ) -- Nearly 30 shallow earthquakes -- too small to be felt -- have occurred in the past week and a half beneath the eastern shore of Paulina Lake at Newberry Volcano, but U.S. Geological Survey seismologists said Monday they are not a cause for alarm and are "likely the result of fluids moving in the hydrothermal system."
In their information statement, the seismologists called it "a slight uptick in seismic activity" and said there were no signs of ground deformation or "other indications of unrest," so the alert level for the area remains at "normal."
It's been a decade since Cascades Volcano Observatory scientists installed eight seismic and GPS sensors in the dormant volcano. Several hundred quakes have been recorded by the Pacific Northwest Seismic Network since then, "making Newberry one of the more seismically active volcanoes in the Cascade Range."
The latest small quake swarm -- including over 100 even smaller quakes, too small to locate -- "is the most significant seismic sequence" at the site," in terms of longevity and event rate, since the gear was installed in 2022.
"However, given that Newberry has a relatively high background rate of seismicity, seismologists do not consider the current seismicity to be a significant departure from normal activity," they said, adding that they "will closely monitor data in the coming days and weeks and will issue further updates as warranted."
Here's the full statement, and links to more information.
CASCADES VOLCANO OBSERVATORY INFORMATION STATEMENT
U.S. Geological Survey
Monday, April 4, 2022, 11:31 AM PDT (Monday, April 4, 2022, 18:31 UTC)
NEWBERRY VOLCANO (VNUM #322110)
43°43'19" N 121°13'44" W, Summit Elevation 7986 ft (2434 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN
Starting on March 24, seismologists at the USGS Cascades Volcano Observatory (CVO) and the Pacific Northwest Seismic Network (PNSN) have observed a slight uptick in seismic activity at Newberry Volcano. From March 24 through April 3, the PNSN has located 29 shallow (less than 2 km (1 mile) deep) earthquakes beneath the eastern shore of Paulina Lake. The largest earthquake was a magnitude 1.7 that occurred at 8:57 PM PDT on March 24. None of the earthquakes have been large enough to be felt. No ground deformation has been recorded by CVO’s network of GPS stations at Newberry Volcano, and there are no other indications of unrest. The color code and alert level for Newberry Volcano remain at Green / Normal.
In addition to the 29 earthquakes located by the PNSN, over one hundred other earthquakes have occurred that are too small to locate, most of which have occurred since March 30. These small events are likely occurring in the same shallow region as the larger earthquakes. All of these earthquakes are occurring in an area under Newberry where earthquakes commonly occur and are likely the result of fluids moving in the hydrothermal system.
Seismic monitoring at Newberry began in 2012 when CVO scientists installed an 8-station network of seismic and GPS sensors. Several hundred earthquakes have been located by the PNSN since then, making Newberry one of the more seismically active volcanoes in the Cascade Range. The current seismicity is the most significant seismic sequence that has occurred at Newberry in terms of longevity and event rate since 2012. However, given that Newberry has a relatively high background rate of seismicity, seismologists do not consider the current seismicity to be a significant departure from normal activity.
Scientists at CVO and the PNSN will closely monitor data in the coming days and weeks and will issue further updates as warranted.
GEOLOGIC CONTEXT:
Newberry Volcano, situated east of the Cascade Range and south of nearby Bend, Oregon, is one of the largest volcanoes in the conterminous United States. The shield-shaped volcano and its extensive apron of lava flows cover almost 2,000 square kilometers (1200 square miles), extending approximately 120 kilometers (75 miles) north to south and 43 kilometers (27 miles) east to west. The most recent eruptive activity from Newberry was approximately 1300 years ago when an explosive eruption from the summit caldera area occurred, followed by extrusion of the Big Obsidian Flow, a popular visitor attraction. The volcano has been active for about 400,000 years and exhibits diverse volcanism ranging from basalt lava flows to huge caldera-forming explosive eruptions.
For more information:
Jensen, R.A., Donnelly-Nolan, J.M., 2017. Field-trip guide to the geologic highlights of Newberry Volcano, Oregon, USGS Scientific Investigations Report 2017-5022-J2, 30 pp.
Website Resources
CVO Newberry Webpage: https://www.usgs.gov/volcanoes/newberry
PNSN Newberry webpage: https://pnsn.org/volcanoes/newberry
CONTACT INFORMATION:
Jon Major, Scientist-in-Charge, Cascades Volcano Observatory, jjmajor@usgs.gov
General inquiries: vhpweb@usgs.gov
