Local Explosion Detection and Infrasound Localization by Reverse Time Migration Using 3-D Finite-Difference Wave Propagation



Fee, David, Toney, Liam, Kim, Keehoon, Sanderson, Richard W, Iezzi, Alexandra M, Matoza, Robin S, De Angelis, Silvio ORCID: 0000-0003-2636-3056, Jolly, Arthur D, Lyons, John J and Haney, Matthew M
(2021) Local Explosion Detection and Infrasound Localization by Reverse Time Migration Using 3-D Finite-Difference Wave Propagation. FRONTIERS IN EARTH SCIENCE, 9. 620813-.

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Abstract

<jats:p>Infrasound data are routinely used to detect and locate volcanic and other explosions, using both arrays and single sensor networks. However, at local distances (&amp;lt;15 km) topography often complicates acoustic propagation, resulting in inaccurate acoustic travel times leading to biased source locations when assuming straight-line propagation. Here we present a new method, termed Reverse Time Migration-Finite-Difference Time Domain (RTM-FDTD), that integrates numerical modeling into the standard RTM back-projection process. Travel time information is computed across the entire potential source grid via FDTD modeling to incorporate the effects of topography. The waveforms are then back-projected and stacked at each grid point, with the stack maximum corresponding to the likely source. We apply our method to three volcanoes with different network configurations, source-receiver distances, and topography. At Yasur Volcano, Vanuatu, RTM-FDTD locates explosions within ∼20 m of the source and differentiates between multiple vents. RTM-FDTD produces a more accurate location for the two Yasur subcraters than standard RTM and doubles the number of detected events. At Sakurajima Volcano, Japan, RTM-FDTD locates the source within 50 m of the active vent despite notable topographic blocking. The RTM-FDTD location is similar to that from the Time Reversal Mirror method, but is more computationally efficient. Lastly, at Shishaldin Volcano, Alaska, RTM and RTM-FDTD both produce realistic source locations (&amp;lt;50 m) for ground-coupled airwaves recorded on a four-station seismic network. We show that RTM is an effective method to detect and locate infrasonic sources across a variety of scenarios, and by integrating numerical modeling, RTM-FDTD produces more accurate source locations and increases the detection capability.</jats:p>

Item Type: Article
Uncontrolled Keywords: infrasound, location, explosion, volcano, ground-coupled airwaves, numerical modeling
Divisions: Faculty of Science and Engineering > School of Environmental Sciences
Depositing User: Symplectic Admin
Date Deposited: 03 Sep 2021 07:28
Last Modified: 15 Mar 2024 08:47
DOI: 10.3389/feart.2021.620813
Open Access URL: http://10.0.13.61/feart.2021.620813
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3135724