Local Infrasound Variability Related to In Situ Atmospheric Observation. Issue 7 (6th April 2018)

• Record Type: Journal Article
• Authors: Kim, Keehoon; Rodgers, Arthur; Seastrand, Douglas
• Is Part Of: Geophysical research letters. Volume 45:Issue 7(2018)
• Page Start: 2954
• Page End: 2962
• Publication Date: 2018-04-06
• Subjects: explosion‐induced infrasound -- full‐waveform modeling -- finite difference method; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2018GL077124
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Local infrasound is widely used to constrain source parameters of near‐surface events (e.g., chemical explosions and volcanic eruptions). While atmospheric conditions are critical to infrasound propagation and source parameter inversion, local atmospheric variability is often ignored by assuming homogeneous atmospheres, and their impact on the source inversion uncertainty has never been accounted for due to the lack of quantitative understanding of infrasound variability. We investigate atmospheric impacts on local infrasound propagation by repeated explosion experiments with a dense acoustic network and in situ atmospheric measurement. We perform full 3‐D waveform simulations with local atmospheric data and numerical weather forecast model to quantify atmosphere‐dependent infrasound variability and address the advantage and restriction of local weather data/numerical weather model for sound propagation simulation. Numerical simulations with stochastic atmosphere models also showed nonnegligible influence of atmospheric heterogeneity on infrasound amplitude, suggesting an important role of local turbulence. Plain Language Summary: Energetic events near or above the Earth's surface can release explosion energy in the form of acoustic waves in the atmosphere. Local infrasound (low‐frequency acoustic wave) can contain valuable source information and becomes increasingly useful to constrain source parameters of the events (e.g., the size of chemical explosions and the erupted mass during volcanic explosions). Local weather conditions can also affect infrasound propagation, and these propagation path effects must be removed from the signals to obtain accurate source information. However, these atmospheric effects are often ignored by assuming oversimplified atmospheres in many applications due to the lack of quantitative understanding of it. In this study, we investigate atmospheric impacts on local infrasound propagation by using explosion experiment data and in situ atmospheric measurements. Full 3‐D waveform simulations are performed with local atmospheric data, providing quantitative information about the sound pressure variation due to atmospheric conditions. In addition, we simulate sound propagation with stochastic atmosphere models and show nonnegligible impacts of atmospheric heterogeneity on infrasound amplitude, suggesting an important role of local turbulence. Key Points: Local infrasound variability is studied by explosion experiments with local atmospheric measurements Sound pressure levels are predicted by full 3‐D waveform modeling using in‐situ atmospheric profile Waveform simulations suggest nonnegligible impacts of local atmospheric heterogeneity on infrasound