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Temporal Velocity Variations Associated With the 2020 Eruption of Kīlauea Volcano in Hawai'i, Revealed by Ambient Noise Cross-Correlation

Description: 

Detecting and understanding changes in the magmatic system that occur before/during an eruption is essential for forecasting volcanic eruptions, which cause extreme environmental and societal hazards. Seismic ambient noise analysis provides an approach to observing variations in the shallow velocity structure, and supplies information about perturbations in the interior of the volcano that can be challenging to resolve with ground deformation detection techniques. Cross-correlation of ambient noise has been used in various studies to examine pre-eruptive activity. Here we investigate temporal velocity variations before and during the 2020-2021 eruption of Kīlauea volcano in Hawai`i, which was the first major activity after the dramatic 2018 eruption and may provide insight into how a volcano readjusts itself after such a massive event. We download one-hour segments of continuous waveform data from the Incorporated Research Institutions for Seismology (IRIS) spanning 180 days before to 180 days after the onset of the eruption (December 20, 2020). We focus on data recorded by 9 broadband seismic stations in and around the summit caldera operated by the U.S. Geological Survey Hawaiian Volcano Observatory. After removal of trend, mean, and instrument response, the data are resampled to a uniform 100-Hz sample rate and bandpass filtered from 1 to 5 Hz. We calculate the cross-correlation functions of these hourly segments for the 36 station pairs and stack them for each day during the study time period. We apply a time-domain stretching method to the stacked function pairs and solve for the best-fitting set of velocity changes for the entire time period. We observe an overall velocity decrease of 2% about 10 days prior to the eruption, which may be related to magma or fluid/gas movement in the crust or an increase in pressure. Our study shows that cross-correlation of ambient noise continues to show promising results for revealing precursors of volcanic eruptions.

Session: Seismology's Role in Assessing Volcanic Hazard at Multiple Time Scales

Type: Oral

Date: 4/18/2023

Presentation Time: 10:30 AM (local time)

Presenting Author: Elizabeth Vinarski

Student Presenter: Yes

Invited Presentation: 

Authors