Systematic Exploration of Long-Period Seismicity During the 2004–2006 Mount St. Helens Volcanic Unrest

Session: Waveform Cross-Correlation-Based Methods in Observational Seismology [Poster]
Type: Poster
Date: 4/30/2020
Time: 08:00 AM
Room: Ballroom
Description: 

Volcanic unrest at Mount St. Helens, the most active volcano within the Cascadia volcanic arc, started in the fall of 2004, the first time since the 1980 eruption. Intense seismic activity accompanied observable surface deformation and growth of the lava dome, although there was ultimately no catastrophic eruption when seismic activity faded away in 2006. Seismic networks captured the drumbeat of long-period earthquakes, suspected to be the seismic signature of magmatic fluid movement within the volcanic plumbing system, throughout a majority of the volcanic unrest. The characteristic repetitive signature of these drumbeat events facilitates their detection through network waveform correlation, like a matched-filter search. Making use of multiple seismic networks with overlapping periods of operation, I systematically detect multiple sources of long-period seismicity. The timing and locations of these different long-period earthquake sources highlights a complex spatiotemporal image of magmatic fluid transport beneath Mount St. Helens during during its most recent period of unrest.

Presenting Author: William B. Frank

Authors