Relative seismic velocity variations correlate with deformation at Kīlauea volcano

Area of Science:

• Geophysics
• Volcanology
• Seismology

Background:

• Seismic noise interferometry enables continuous, real-time measurement of relative seismic velocity.
• Seismic velocity changes indicate volcanic system pressurization, making it a valuable monitoring tool.
• Previous studies lacked comprehensive short-term comparisons of seismic velocity with other geophysical data at active volcanoes.

Purpose of the Study:

• To comprehensively compare seismic velocity changes with other geophysical observables on a short-term timescale at Kīlauea volcano.
• To assess the potential of seismic noise interferometry as a volcano monitoring tool.

Main Methods:

• Utilized volcanic tremor (0.3-1.0 Hz) at Kīlauea as a passive source for interferometry.
• Cross-correlated vertical seismic records from ~230 station pairs over day-long intervals.
• Extracted coherent coda wave signals with time lags up to 120 seconds.

Main Results:

• Generated time series of relative seismic velocity changes.
• Observed a remarkable correlation between relative velocity and radial tilt at Kīlauea summit (June 2011-November 2015).
• Velocity decreased with deflation and increased with inflation events, consistent with crack closure/opening due to magma reservoir pressurization.

Conclusions:

• The strong correlation between seismic velocity and deformation validates seismic noise interferometry for volcano monitoring.
• This method enhances understanding of seismic velocity variations in volcanic edifices.
• Passive seismic interferometry shows significant potential for real-time monitoring of active volcanoes.