Meet Weston (Wes) Thelen 

Wes Thelen is a research geophysicist, and more specifically, a Volcano Seismologist at the Cascades Volcano Observatory. Volcano seismologists use sensitive instruments called seismometers that measure the shaking of the ground and can record tiny volcanic earthquakes. Seismologists visit volcanoes and set up networks of seismometers around them to record and locate the earthquakes. A seismologist's job is then to analyze this ground motion data using modern computing methods. In his role, Wes monitors seismicity on Cascade Range Volcanoes to assess volcanic hazards. He also assists in the planning and implementation of the volcano monitoring networks in Oregon and Washington. His education is in both geology and geophysics with a focus on volcanoes. He has experience working at both the Hawaiian Volcano Observatory and CVO.

CVO Seismic Network 

Seismicity at Cascade volcanoes is monitored in partnership between the Pacific Northwest Seismic Network (PNSN) and the CVO, as well as EarthScope. There is significant variability in the number of stations at each volcano, which reflects the degree of difficulty in operating seismic stations in remote locations, proximity to population centers, recency of eruptive activity, and land-use permitting restrictions. Many of the volcanoes of the Pacific Northwest are within Congressionally designated Wilderness Areas. This makes them both incredibly pristine landscapes and very challenging environments to install and maintain monitoring equipment. Some stations, like those proposed for Glacier Peak, require up to a 2.5 day hike each way to access because helicopter use is not permitted. The National Volcano Early Warning System (NVEWS) is a national-scale plan to ensure that volcanoes are monitored at levels commensurate to their threats. The plan was developed by the U.S. Geological Survey (USGS) Volcano Hazards Program (VHP) and its affiliated partners in state and academic institutions. Since NVEWs was authorized in 2019, CVO has made substantial progress towards improving our monitoring capabilities through network expansion and updates at Mount Rainier, Mount St. Helens and Mount Hood. Additional installations are also planned for Mount Baker, Glacier Peak and Mount Adams.

Wes uses seismic data to keep a pulse on Cascade Volcanoes 

You can tell a lot about a volcano from seismic data. Small earthquakes are expected at volcanoes and are considered normal or “background” levels of seismicity. You can think about it sort of like the pulse of the volcanoes, letting us know they still have active systems even during times of quiet.  Wes and other CVO seismologists study the small earthquakes occurring in and around volcanoes to help understand how volcanoes work and where magma is moving underground. They can also use the seismic waves to image what volcanoes look like beneath the ground to better understand where magma is being stored. Between the USGS, the Pacific Northwest Seismic Network and other partners, we are lucky to have such a dedicated team of seismologists keeping an eye on our Cascade volcanoes.