Source Characterization of Surface Events in the Pacific Northwest
Description:
The Pacific Northwest (PNW) is subject to various geohazards due to its active tectonics, volcanism, and surface processes. The Pacific Northwest Seismic Network (PNSN) monitors seismic activity in the PNW with a mandate to characterize tectonic earthquakes. Volcanoes are relatively well monitored by the PNSN in terms of determining source origin time, location, and magnitude for volcano-tectonic earthquakes. However, many other event types are labeled by seismic analysts as “surface events,” which are informally understood as being mass flows of snow or rock avalanches, rockfall, landslides, and debris flows but are not characterized further by analysts.
We collect seismograms from ~ 8000 events with 5-10 seismic stations located on six PNW volcanoes; Mounts Hood, Rainier, St. Helens, Baker, and Adams, with the goal to further characterize these surface events. We use an ensemble deep-learning phase picker to pick the onset of the waveform, which helps determine where the emergent signal starts. We then calculate the signal-to-noise ratio (SNR) and only pick traces with sufficiently high SNR. We also pick the time of the peak amplitude in the envelope function to track the centroid time of the event. We locate event onsets and centroids using a simple grid-search algorithm. We estimate a potential direction of motion (flow) and velocity using 1) Doppler effects measured from the seismogram's spectral content and 2) the difference between the centroid and event onset times and locations. We analyze these directions and velocities relative to high-resolution digital elevation models and discuss the potential and limitations of this method as a prototype for detecting debris flow or lahar in the Cascades.
Session: Detecting, Characterizing and Monitoring Mass Movements - II
Type: Oral
Date: 5/2/2024
Presentation Time: 10:45 AM (local time)
Presenting Author: Marine
Student Presenter: No
Invited Presentation:
Authors
Marine Denolle Presenting Author Corresponding Author mdenolle@uw.edu University of Washington |
Francesca Skene fskene@uw.edu University of Washington |
Nicholas Smoczyk bluescale1999@gmail.com University of Minnesota |
Yiyu Ni niyiyu@uw.edu University of Washington |
Akash Kharita ak287@uw.edu University of Washington |
Stephen Malone smalone@uw.edu University of Washington |
Weston Thelen wthelen@usgs.gov U.S. Geological Survey |
Alexander Hutko ahutko@uw.edu Pacific Northwest Seismic Network |
Nathan Stevens ntsteven@uw.edu Pacific Northwest Seismic Network |
Renate Hartog jrhartog@uw.edu Pacific Northwest Seismic Network, Seattle, Washington, United States |
Source Characterization of Surface Events in the Pacific Northwest
Category
Detecting, Characterizing and Monitoring Mass Movements