Comparison of vertical GPS motion measured at station HUSB (top) with earthquake depth (bottom). Red line is a 60-day average of the cleaned GPS time series plotted in gray. Earthquakes are plotted with respect to their magnitudes. The swarm in 2004 represents the vast majority of earthquake in the vicinity of the deforming region.
Weston Thelen
I love earthquakes. I love volcanoes. And I know for a fact that volcano seismology is the best seismology.
As a research geophysicist at the Cascades Volcano Observatory, I undertake and facilitate research on Cascade Range Volcanoes; monitor seismicity on Cascade Range Volcanoes to assess volcanic hazard; and assist in planning, prioritization and execution of maintenance and growth of volcano monitoring networks in Oregon and Washington.
My education is in both geology and geophysics with a focus more recently on volcanoes. I have experience on both stratovolcanoes and basaltic volcanoes in Russia, Alaska, Washington, Oregon and Hawaii. I've worked in eruptive scenarios at Mount St. Helens in 2004-2008, Redoubt in 2008 and Kilauea from 2011 till 2020. In addition, I've held positions at the Nevada Seismological Network, the Pacific Northwest Seismic Network and the Hawaiian Volcano Observatory, which have all had components of network seismology to them.
Professional Experience
2011 - 2016, USGS Hawaiian Volcano Observatory Seismic Network Manager/ Supervisory Geophysicist
Responsibilities: Maintain and improve real-time monitoring and operations of the seismic network at the Hawaiian Volcano Observatory. Interpret seismic data for changes in volcanic activity. Analyze earthquake data.
Education and Certifications
2004: University of Nevada, B.S. in Geophysics with high distinction 2004
2004: University of Nevada, B.S. in Geology with high distinction 2004
2009: University of Washington, Ph.D in Geophysics
2009: University of Washington, Network Seismology, Post Doc
2010: USGS Cascade Volcano Observatory, Volcano Seismology, Post Doc
Science and Products
Relative seismic velocity variations correlate with deformation at Kilauea volcano, Hawaii
The dataset includes tiltmeter data at a sample rate of 1 sample per minute from a downhole tiltmeter at Uwekahuna Vault (UWE). Location is -155.291162, 19.420972 (NAD83), elevation 1257 m. Data has two orientations for each time sample (north and east). Each file contains a year of data. The original datasource removes the mean, so the ends of subsequent files will not align. The...
Laser Rangefinder Data for Surficial Mass Movements in the Cascades
A laser rangefinder was used to record surficial mass movements at Cascades volcanoes and an experimental debris flow flume. Mass movements such as large lahars and smaller seasonal debris flows can occur at volcanoes in the Cascades. A combination of seismic, infrasound, tripwires, and webcams can be used to detect and characterize these flows. A laser rangefinder can be placed on the...
High resolution earthquake catalogs from the 2018 Kilauea eruption sequence
The 2018 Kilauea eruption and caldera collapse generated intense cycles of seismicity tied to repeated large seismic (Mw ~5) collapse events associated with magma withdrawal from beneath the summit. To gain insight into the underlying dynamics and aid eruption response, we applied waveform-based earthquake detection and double-difference location as the eruption unfolded. Here, we...
Deformation and seismicity near South Sister during 2001-2022
Deformation and seismicity near South Sister during 2001-2022
Comparison of vertical GPS motion measured at station HUSB (top) with earthquake depth (bottom). Red line is a 60-day average of the cleaned GPS time series plotted in gray. Earthquakes are plotted with respect to their magnitudes. The swarm in 2004 represents the vast majority of earthquake in the vicinity of the deforming region.
Filter Total Items: 43
Long-lived partial melt beneath Cascade volcanoes
Quantitative estimates of magma storage are fundamental to evaluating volcanic dynamics and hazards. Yet our understanding of subvolcanic magmatic plumbing systems and their variability remains limited. There is ongoing debate regarding the ephemerality of shallow magma storage and its volume relative to eruptive output, and so whether an upper-crustal magma body could be a sign of...
Authors
Guanning Pang, Geoffrey A. Abers, Seth C. Moran, Weston A. Thelen
Seismic techniques and suggested instrumentation to monitor volcanoes
IntroductionChanges in the pressure or location of magma can stress or break surrounding rocks and trigger flow of nearby waters and gases, causing seismic signals, such as discrete earthquakes and tremor. These phenomena are types of seismic unrest that commonly precede eruption and can be used to forecast volcanic activity. Mass movements at the surface, including avalanches, debris...
Authors
Weston A. Thelen, John J. Lyons, Aaron G. Wech, Seth C. Moran, Matthew M. Haney, Ashton F. Flinders
Infrasound for volcano monitoring
IntroductionVolcanic eruptions produce acoustic waves when volcanic gases and hot material rapidly expand in the atmosphere. Volcanic activity can produce acoustic signals with a wide range of frequencies, from very long period (>10 seconds) to audible (>20 hertz [Hz]), but the most energetic band is typically in the infrasound from 0.5 to 20 Hz. Studies of volcanic infrasound and the...
Authors
John J. Lyons, David Fee, Weston A. Thelen, Alexandra M. Iezzi, Aaron G. Wech
Monitoring lahars
IntroductionLahars, or debris flows that originate from a volcano (Pierson and Scott, 1985; Pierson, 1995), are among the most destructive, far-reaching, and persistent hazards on stratovolcanoes. Lahars may be triggered by syneruptive rapid melting of snow and ice, lake breakouts, or heavy rains in conjunction with large eruptive columns. Alternatively, lahars can follow eruptions, when...
Authors
Weston A. Thelen, John J. Lyons, Alexandra M. Iezzi, Seth C. Moran
Debris-flow monitoring on volcanoes via a novel usage of a laser rangefinder
Mount Rainier has had at least 11 large lahars over the last 6,000 years, including one occurring without evidence of eruptive activity. This prompted the creation of a lahar detection system that uses a combination of seismic, infrasound, and tripwires. We test a laser rangefinder placed on a river channel bank for detecting and confirming mass movements flowing past a station as an...
Authors
Alexandra M. Iezzi, Emily H Bryant, Weston A. Thelen, Craig Gabrielson, Seth C. Moran, Matthew R. Patrick, Edward F. Younger, Maciej Obryk
Recent expansion of the Cascades Volcano Observatory geophysical network at Mount Rainier for improved volcano and lahar monitoring
The U.S. Geological Survey Cascades Volcano Observatory (CVO) recently expanded its continuous geophysical monitoring at Mount Rainier, an active stratovolcano in Washington state. CVO monitors volcanoes in Oregon, Washington, and Idaho to characterize volcanic systems and detect unrest. Mount Rainier has a history of large lahar occurrences in the Holocene, including at least one that...
Authors
Rebecca Kramer, Weston A. Thelen, Alexandra M. Iezzi, Seth C. Moran, Benjamin Pauk
Examining 22 years of ambient seismic wavefield at Mount St. Helens
An increase in seismic activity precedes most volcanic eruptions. Whereas event-based forecasting approaches have been successful, some eruptions remain unanticipated, resulting in casualties and damage. Our study leverages the recent advancements in ambient field seismology. We explore features extracted from continuous ambient fields using traditional methods, for example, peak ground...
Authors
Manuela Kopfli, Marine A. Denolle, Weston A. Thelen, Peter Makus, Stephen D. Malone
Explosive 2018 eruptions at Kīlauea driven by a collapse-induced stomp-rocket mechanism
Explosive volcanic eruptions produce hazardous atmospheric plumes composed of tephra particles, hot gas and entrained air. Such eruptions are generally driven by magmatic fragmentation or steam expansion. However, an eruption mechanism outside this phreatic–magmatic spectrum was suggested by a sequence of 12 explosive eruptions in May 2018 at Kīlauea, Hawaii, that occurred during the...
Authors
Joshua Allen Crozier, Josef Dufek, Leif Karlstrom, Kyle R. Anderson, Ryan Cain Cahalan, Weston A. Thelen, Mary Catherine Benage, Chao Liang
Dynamics of the December 2020 ash-poor plume formed by lava-water interaction at the summit of Kilauea Volcano, Hawaii
On 20 December 2020, after more than 2 years of quiescence at Kīlauea Volcano, Hawaiʻi, renewed volcanic activity in the summit crater caused boiling of the water lake over a period of ∼90 min. The resulting water-rich, electrified plume rose to 11–13 km above sea level, which is among the highest plumes on record for Kīlauea. Although conventional models would infer a high mass flux...
Authors
Ryan Cain Cahalan, Larry G. Mastin, Alexa R. Van Eaton, Shaul Hurwitz, Adam D. Smith, Josef Dufek, Stephen A. Solovitz, Matthew R. Patrick, Johanne Schmith, Carolyn Parcheta, Weston A. Thelen, Drew T. Downs
Seismometer records of ground tilt induced by debris flows
A change in surface loading causes the Earth’s surface to deform. Mass movements, such as debris flows, can cause a tilt large enough to be recorded by nearby instruments, but the signal is strongly dependent on the mass loading and subsurface parameters. Specifically designed sensors for such measurements (tiltmeters) are cumbersome to install. Alternatively, broadband seismometers...
Authors
Michaela Wenner, Kate E. Allstadt, Weston A. Thelen, Andrew Lockhart, Jacob Hirschberg, Brian W. McArdell, Fabian Walter
Revisiting the depth distribution of seismicity before and after the 2004–2008 eruption of Mount St. Helens
Hypocenter estimation at active volcanoes improves our understanding of their magmatic systems and indicates changing conditions at depth for continuously monitored volcanoes. The most active volcano in the Cascades Range, Mount St. Helens, has a multi-decadal earthquake catalog and it shows an apparent change in the depth distribution of seismicity before and after the 2004–2008 dome...
Authors
Han Zhang, Margaret Elizabeth Glasgow, Brandon Schmandt, Weston A. Thelen, Seth C. Moran, Amanda M. Thomas
Infrasound observations and constraints on the 2018 eruption of Kīlauea Volcano, Hawaii
The 2018 eruption of Kīlauea Volcano was a dynamic event involving explosions, collapses, and fountaining at multiple vents spread over tens of kilometers. The permanent infrasound network operated by the USGS Hawaiian Volcano Observatory (HVO) was well prepared to observe the collapse of the summit, and additional deployments permitted infrasound observations during fissuring in the...
Authors
Weston A. Thelen, Gregory P. Waite, John J. Lyons, David Fee
covdetect - network covariance event detector (Version 0.0.0)
The codes presented here combine modifications to the standard CovSeisNet package (providing estimates of seismic network covariance) with image processing to detect and classify volcanic seismicity. The codes are Python implementations and should work with standard Python distributions. In this case we use Anaconda and have verified that the codes work with Python 3.9 and 3.10. The...
Science and Products
Relative seismic velocity variations correlate with deformation at Kilauea volcano, Hawaii
The dataset includes tiltmeter data at a sample rate of 1 sample per minute from a downhole tiltmeter at Uwekahuna Vault (UWE). Location is -155.291162, 19.420972 (NAD83), elevation 1257 m. Data has two orientations for each time sample (north and east). Each file contains a year of data. The original datasource removes the mean, so the ends of subsequent files will not align. The...
Laser Rangefinder Data for Surficial Mass Movements in the Cascades
A laser rangefinder was used to record surficial mass movements at Cascades volcanoes and an experimental debris flow flume. Mass movements such as large lahars and smaller seasonal debris flows can occur at volcanoes in the Cascades. A combination of seismic, infrasound, tripwires, and webcams can be used to detect and characterize these flows. A laser rangefinder can be placed on the...
High resolution earthquake catalogs from the 2018 Kilauea eruption sequence
The 2018 Kilauea eruption and caldera collapse generated intense cycles of seismicity tied to repeated large seismic (Mw ~5) collapse events associated with magma withdrawal from beneath the summit. To gain insight into the underlying dynamics and aid eruption response, we applied waveform-based earthquake detection and double-difference location as the eruption unfolded. Here, we...
Deformation and seismicity near South Sister during 2001-2022
Deformation and seismicity near South Sister during 2001-2022
Comparison of vertical GPS motion measured at station HUSB (top) with earthquake depth (bottom). Red line is a 60-day average of the cleaned GPS time series plotted in gray. Earthquakes are plotted with respect to their magnitudes. The swarm in 2004 represents the vast majority of earthquake in the vicinity of the deforming region.
Comparison of vertical GPS motion measured at station HUSB (top) with earthquake depth (bottom). Red line is a 60-day average of the cleaned GPS time series plotted in gray. Earthquakes are plotted with respect to their magnitudes. The swarm in 2004 represents the vast majority of earthquake in the vicinity of the deforming region.
Filter Total Items: 43
Long-lived partial melt beneath Cascade volcanoes
Quantitative estimates of magma storage are fundamental to evaluating volcanic dynamics and hazards. Yet our understanding of subvolcanic magmatic plumbing systems and their variability remains limited. There is ongoing debate regarding the ephemerality of shallow magma storage and its volume relative to eruptive output, and so whether an upper-crustal magma body could be a sign of...
Authors
Guanning Pang, Geoffrey A. Abers, Seth C. Moran, Weston A. Thelen
Seismic techniques and suggested instrumentation to monitor volcanoes
IntroductionChanges in the pressure or location of magma can stress or break surrounding rocks and trigger flow of nearby waters and gases, causing seismic signals, such as discrete earthquakes and tremor. These phenomena are types of seismic unrest that commonly precede eruption and can be used to forecast volcanic activity. Mass movements at the surface, including avalanches, debris...
Authors
Weston A. Thelen, John J. Lyons, Aaron G. Wech, Seth C. Moran, Matthew M. Haney, Ashton F. Flinders
Infrasound for volcano monitoring
IntroductionVolcanic eruptions produce acoustic waves when volcanic gases and hot material rapidly expand in the atmosphere. Volcanic activity can produce acoustic signals with a wide range of frequencies, from very long period (>10 seconds) to audible (>20 hertz [Hz]), but the most energetic band is typically in the infrasound from 0.5 to 20 Hz. Studies of volcanic infrasound and the...
Authors
John J. Lyons, David Fee, Weston A. Thelen, Alexandra M. Iezzi, Aaron G. Wech
Monitoring lahars
IntroductionLahars, or debris flows that originate from a volcano (Pierson and Scott, 1985; Pierson, 1995), are among the most destructive, far-reaching, and persistent hazards on stratovolcanoes. Lahars may be triggered by syneruptive rapid melting of snow and ice, lake breakouts, or heavy rains in conjunction with large eruptive columns. Alternatively, lahars can follow eruptions, when...
Authors
Weston A. Thelen, John J. Lyons, Alexandra M. Iezzi, Seth C. Moran
Debris-flow monitoring on volcanoes via a novel usage of a laser rangefinder
Mount Rainier has had at least 11 large lahars over the last 6,000 years, including one occurring without evidence of eruptive activity. This prompted the creation of a lahar detection system that uses a combination of seismic, infrasound, and tripwires. We test a laser rangefinder placed on a river channel bank for detecting and confirming mass movements flowing past a station as an...
Authors
Alexandra M. Iezzi, Emily H Bryant, Weston A. Thelen, Craig Gabrielson, Seth C. Moran, Matthew R. Patrick, Edward F. Younger, Maciej Obryk
Recent expansion of the Cascades Volcano Observatory geophysical network at Mount Rainier for improved volcano and lahar monitoring
The U.S. Geological Survey Cascades Volcano Observatory (CVO) recently expanded its continuous geophysical monitoring at Mount Rainier, an active stratovolcano in Washington state. CVO monitors volcanoes in Oregon, Washington, and Idaho to characterize volcanic systems and detect unrest. Mount Rainier has a history of large lahar occurrences in the Holocene, including at least one that...
Authors
Rebecca Kramer, Weston A. Thelen, Alexandra M. Iezzi, Seth C. Moran, Benjamin Pauk
Examining 22 years of ambient seismic wavefield at Mount St. Helens
An increase in seismic activity precedes most volcanic eruptions. Whereas event-based forecasting approaches have been successful, some eruptions remain unanticipated, resulting in casualties and damage. Our study leverages the recent advancements in ambient field seismology. We explore features extracted from continuous ambient fields using traditional methods, for example, peak ground...
Authors
Manuela Kopfli, Marine A. Denolle, Weston A. Thelen, Peter Makus, Stephen D. Malone
Explosive 2018 eruptions at Kīlauea driven by a collapse-induced stomp-rocket mechanism
Explosive volcanic eruptions produce hazardous atmospheric plumes composed of tephra particles, hot gas and entrained air. Such eruptions are generally driven by magmatic fragmentation or steam expansion. However, an eruption mechanism outside this phreatic–magmatic spectrum was suggested by a sequence of 12 explosive eruptions in May 2018 at Kīlauea, Hawaii, that occurred during the...
Authors
Joshua Allen Crozier, Josef Dufek, Leif Karlstrom, Kyle R. Anderson, Ryan Cain Cahalan, Weston A. Thelen, Mary Catherine Benage, Chao Liang
Dynamics of the December 2020 ash-poor plume formed by lava-water interaction at the summit of Kilauea Volcano, Hawaii
On 20 December 2020, after more than 2 years of quiescence at Kīlauea Volcano, Hawaiʻi, renewed volcanic activity in the summit crater caused boiling of the water lake over a period of ∼90 min. The resulting water-rich, electrified plume rose to 11–13 km above sea level, which is among the highest plumes on record for Kīlauea. Although conventional models would infer a high mass flux...
Authors
Ryan Cain Cahalan, Larry G. Mastin, Alexa R. Van Eaton, Shaul Hurwitz, Adam D. Smith, Josef Dufek, Stephen A. Solovitz, Matthew R. Patrick, Johanne Schmith, Carolyn Parcheta, Weston A. Thelen, Drew T. Downs
Seismometer records of ground tilt induced by debris flows
A change in surface loading causes the Earth’s surface to deform. Mass movements, such as debris flows, can cause a tilt large enough to be recorded by nearby instruments, but the signal is strongly dependent on the mass loading and subsurface parameters. Specifically designed sensors for such measurements (tiltmeters) are cumbersome to install. Alternatively, broadband seismometers...
Authors
Michaela Wenner, Kate E. Allstadt, Weston A. Thelen, Andrew Lockhart, Jacob Hirschberg, Brian W. McArdell, Fabian Walter
Revisiting the depth distribution of seismicity before and after the 2004–2008 eruption of Mount St. Helens
Hypocenter estimation at active volcanoes improves our understanding of their magmatic systems and indicates changing conditions at depth for continuously monitored volcanoes. The most active volcano in the Cascades Range, Mount St. Helens, has a multi-decadal earthquake catalog and it shows an apparent change in the depth distribution of seismicity before and after the 2004–2008 dome...
Authors
Han Zhang, Margaret Elizabeth Glasgow, Brandon Schmandt, Weston A. Thelen, Seth C. Moran, Amanda M. Thomas
Infrasound observations and constraints on the 2018 eruption of Kīlauea Volcano, Hawaii
The 2018 eruption of Kīlauea Volcano was a dynamic event involving explosions, collapses, and fountaining at multiple vents spread over tens of kilometers. The permanent infrasound network operated by the USGS Hawaiian Volcano Observatory (HVO) was well prepared to observe the collapse of the summit, and additional deployments permitted infrasound observations during fissuring in the...
Authors
Weston A. Thelen, Gregory P. Waite, John J. Lyons, David Fee
covdetect - network covariance event detector (Version 0.0.0)
The codes presented here combine modifications to the standard CovSeisNet package (providing estimates of seismic network covariance) with image processing to detect and classify volcanic seismicity. The codes are Python implementations and should work with standard Python distributions. In this case we use Anaconda and have verified that the codes work with Python 3.9 and 3.10. The...