Infrasound Metrology

This project will conduct research activities to support development of new acoustical measurement capabilities and services in the infrasonic regime (from 2 Hz to 20 Hz) to provide accuracy, traceability, and credibility in infrasonic measurements to meet industry and governmental needs. These needs are driven by the desire to study, detect, and warn of many important natural phenomena such as volcanic activity, hurricanes, tornadoes, landslides, earthquakes, meteors, atmospheric turbulence, and oceanic waves and man-made events such as rocket launches, airbag deployment, supersonic aircraft travel, explosions resulting from weapons tests, and tactical military operations involving vehicles and weapons also generate high-amplitude, low-frequency infrasound of great significance. Infrasonic measurements are important to the transportation industry, medical community, geophysical-science community, meteorology, and for agencies responsible for supporting the International Monitoring System (IMS).

Current monitoring systems for natural phenomena and high-amplitude man-made events typically rely on a combination of multiple types of sensing, including seismic, hydroacoustic, radionuclide, and infrasound.  Manufacturers of component infrasound transducers and systems also need the new NIST measurement capabilities and service for recognized, validated SI traceability.  Measurements of hazardous sounds with high-amplitude infrasonic components, such as those produced by automotive airbag deployment, would also be provided with improved accuracy, traceability, and credibility. In particular, the Society of Automotive Engineers (SAE) requires a more accurate calibration method and standard for measuring infrasound to influence the design and operation of automotive airbags and to protect the hearing of vehicle occupants during airbag deployment.