Infrasound Propagation in Atmospheric Systems

Infrasound refers to acoustic waves with frequencies below 20 Hz that can propagate over thousands of kilometres in the atmosphere by interacting with layered wind and temperature fields. Energy launched by natural sources such as earthquakes, volcanic eruptions, bolide entries or by anthropogenic events including industrial blasts and explosions couples into atmospheric waveguides in the troposphere, stratosphere and thermosphere. Refraction by thermal inversions and wind shears can trap infrasound in discrete ducts, producing multiple arrivals at distant sensors. Atmospheric variability, turbulence and small‐scale structure introduce amplitude fluctuations and arrival‐time uncertainties that challenge both detection and localisation. Advances in sensor arrays, ray‐tracing models and signal‐processing techniques now allow high‐precision mapping of infrasound sources, underpinning global monitoring of naturally occurring hazards, compliance verification of treaties and emerging applications in planetary defence and hazard early warning.

Research from Nature Portfolio

Recent studies have shown how dense seismic‐infrasound networks deployed near conflict zones can automatically detect and locate low‐yield explosions in near real time by exploiting both seismic and infrasound signals, providing robust origin times and source magnitudes. In parallel, large‐N infrasound arrays combined with advanced beamforming algorithms have resolved individual tropospheric and stratospheric phases from local and regional earthquakes, extending the reach of infrasound monitoring to several hundred kilometres and complementing conventional seismic measurements. These developments illustrate the growing integration of infrasonic and seismic methods for comprehensive characterisation of ground‐motion sources and enhanced hazard surveillance.

Infrasound Propagation in Atmospheric Systems publication trend

The graph below shows the total number of articles in infrasound propagation in atmospheric systems across all publications each year (not limited to Nature Index journals).

Technical terms

Infrasound: Acoustic waves below 20 Hz that experience low atmospheric attenuation and can propagate over great distances.

Waveguide: A layer or combination of atmospheric layers that refract and trap infrasound, enabling ducted propagation.

Beamforming: Signal‐processing technique that aligns and combines signals from multiple sensors to isolate and image wavefronts.

Back‐azimuth: The horizontal angle between true north and the direction from a sensor array to an infrasound source.

Ray‐tracing: Computational method for modelling sound‐wave paths through atmosphere profiles, accounting for wind and temperature gradients.

References

1. Natural and Anthropogenic Sources of Seismic, Hydroacoustic, and Infrasonic Waves: Waveforms and Spectral Characteristics (and Their Applicability for Sensor Calibration). Surveys in Geophysics (2022).
2. Toward an Improved Representation of Middle Atmospheric Dynamics Thanks to the ARISE Project. Surveys in Geophysics (2017).
3. Identifying attacks in the Russia–Ukraine conflict using seismic array data. Nature (2023).
4. Remotely imaging seismic ground shaking via large-N infrasound beamforming. Communications Earth & Environment (2023).
5. The Utility of Infrasound in Global Monitoring of Extraterrestrial Impacts: A Case Study of the 2008 July 23 Tajikistan Bolide. The Astronomical Journal (2024).
6. Back-Azimuth Estimation of Air-to-Ground Coupled Infrasound from Transverse Coherence Minimization. The Seismic Record (2023).
7. Toward a Neural Network-Based Approach for Improved Atmospheric Infrasound Localization. IEEE Access (2025).