‘Increased seismicity’ likely at Newberry volcano as geothermal exploration work resumes, USGS advises public

VANCOUVER, Wash. (KTVZ) -- "Increased rates of seismicity" are likely at the Newberry volcano south of Bend as a private exploration company conducts geothermal work in coming weeks, the U.S. Geological Survey reported.

"The project is not expected to result in changes to Newberry's status or volcano hazard," USGS said in Wednesday's update on earthquake monitoring activity at the geothermal site, where Mazama Energy's renewed exploration project was announced earlier this year.

Here's the rest of Wednesday's USGS announcement of its earthquake monitoring plans:

Beginning on Sunday, Dec. 22 and continuing off-and-on for several weeks to months, a private exploration company called Mazama Energy will conduct geothermal exploration work near Newberry volcano.

As their geothermal work proceeds, many small magnitude, non-volcanic earthquakes will occur, which will be detected by the Newberry seismic network. During geothermal exploration activities at Newberry in 2012 and 2014, for example, hundreds of small earthquakes of magnitude M2.5 or less occurred while a company conducted its work.

Increased rates of seismicity will be closely monitored by the USGS Cascades Volcano Observatory and its monitoring partner the Pacific Northwest Seismic Network. The project is not expected to result in any changes to Newberry’s state of activity or potential volcanic hazards.

Newberry seismic network

Seismic monitoring at Newberry began in 2012 after CVO scientists installed an 8-station network of seismic and GPS sensors. Since that time, scientists have located an average of 15 earthquakes at Newberry each year.

CVO and PNSN monitoring networks are operating normally and seismologists will be able to differentiate volcanic earthquakes from those caused by geothermal exploration activity. 

Overview of Newberry’s eruptive history

Newberry volcano is a broad shield-shaped, composite volcano in central Oregon covering an area the size of Rhode Island. The central caldera is located approximately 25 miles (40 km) south of Bend, Oregon. Notable features include Paulina Lake, East Lake, Big Obsidian Flow, and the volcano’s highest point, Paulina Peak, 7,986 ft (2,434 m) in elevation on the south caldera rim. 

Throughout its 500,000-year eruptive history, Newberry has produced ash and tephra, pyroclastic flows, and lava flows that range in composition from basalt to rhyolite. Newberry last erupted about 1,300 years ago (the Big Obsidian Flow), and present-day hot springs, background levels of seismicity, and geologically young lava flows indicate that it is still an active volcano.

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