Local explosion detection and infrasound localization by reverse time migration using 3-D finite-difference wave propagation
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Abstract
Infrasound data are routinely used to detect and locate volcanic and other explosions, using both arrays and single sensor networks. However, at local distances (<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 (<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.
Suggested Citation
Fee, D., Toney, L., Kim, K., Sanderson, R., Iezzi, A., Matoza, R.S., DeAngelis, S., Jolly, A., Lyons, J.J., Haney, M.M., 2021, Local explosion detection and infrasound localization by reverse time migration using 3-D finite-difference wave propagation: Frontiers in Earth Science, v. 9, 620813, 14 p., https://doi.org/10.3389/feart.2021.620813.
ISSN: 2296-6463 (online)
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Local explosion detection and infrasound localization by reverse time migration using 3-D finite-difference wave propagation |
| Series title | Frontiers in Earth Science |
| DOI | 10.3389/feart.2021.620813 |
| Volume | 9 |
| Publication Date | February 24, 2021 |
| Year Published | 2021 |
| Language | English |
| Publisher | Frontiers |
| Contributing office(s) | Volcano Science Center |
| Description | 620813, 14 p. |
| Country | United States, Japan, Vanuatu |
| State | Alaska |
| Other Geospatial | Sakurajima Volcano, Shishaldin Volcano, Yasur Volcano, Vanuatu |