Infrasound uncertainty propagation: Ensuring traceability from the laboratory to the field

Area of Science:

• Geophysics
• Acoustics
• Metrology

Background:

• Accurate infrasound measurements are crucial for the Comprehensive Nuclear-Test-Ban Treaty Organization's global monitoring network.
• Estimating measurement confidence requires analyzing the entire process, from lab calibration to field deployment, including associated uncertainties.

Purpose of the Study:

• To develop a methodology for traceable measurements of infrasound signal azimuth, trace velocity, and amplitude.
• To present an in situ calibration method for infrasound sensors to ensure field traceability under diverse environmental conditions.

Main Methods:

• Developed a methodology considering the traceability chain and various uncertainty sources in the infrasound measurement process.
• Implemented an in situ calibration method at IS26 (Germany), complementing the Gabrielson on-site calibration.
• Analyzed standard uncertainties in azimuth (0.05°–7°) and trace velocity (0.2–60 m/s), and amplitude (0.2 dB).

Main Results:

• Standard uncertainties in azimuth and trace velocity were primarily driven by Gabrielson phase uncertainty.
• Amplitude uncertainty was significantly influenced by temperature and pressure susceptibilities.
• The study quantifies uncertainties for infrasound measurements, crucial for treaty verification.

Conclusions:

• The presented methodology enhances the understanding of uncertainties in infrasound measurements.
• Improved uncertainty quantification leads to more accurate source yield and location estimations.
• This work supports the Comprehensive Nuclear-Test-Ban Treaty Organization's mission by increasing confidence in infrasound data quality.