Infrasound Flashcards
1
Q
Uses of infrasound
A
Forensics (Seismology)
- Monitoring Nuclear tests
2
Q
Infrasound frequency range
A
- 003 - 20 Hz (Below audible range)
- Characterised by low frequency, long wavelengths (100 - 10000 m)
3
Q
What is the pressure of an adiabatic gas?
A
p = k*(rho^gamma)
4
Q
What is a ray
A
Direction acting normal to the wavefront
5
Q
What is a waveguide
A
A device for guiding the propagation of waves
Examples include:
- Stethoscopes
- Ear canal
- Ventilation ducts
- Layers of Earth’s atmosphere (Thermosphere, Stratosphere and Troposphere)
6
Q
How are pressure fluctuations generated by distant sources recorded and how are they made accurate
A
Microbarometer
- Filters are used to remove noise from wind
- Arrays across a region give result coherence (requires aligning to account for time difference)
- Statistical signal processing to identify probably signals
7
Q
Name some sources of infrasound
A
Volcanoes, Supersonic aircraft, Earthquakes and Explosions