The Australian Standard for use of explosives (AS2187.2) provides guidelines for blast monitoring where the peak particle velocity (PPV) has a variable acceptance threshold based on the signal frequency. At 1Hz the acceptable threshold is as low as 5mm/s, rising (non-linearly) to 50mm/s at 100Hz. Historically the geophones used for blast monitoring have had a natural frequency of 4.5Hz, which is not sufficient for full spectral analysis of PPV.
The triaxial geophones we recommend are available with 1Hz and 2Hz low frequency response, and with noise levels as low as 0.01 mm/s and full scale ranges of up ±125 mm/s we have the full frequency and amplitude spectrum covered.
So, what do you need for a blast monitoring node? A typical monitoring system will record sound pressure as well ground motion, so you’ll need a multichannel data recorder, a triaxial geophone, a microphone, and a power supply. Portable systems using solar power and 3G communications make remote blast monitoring even easier, and you can even push your data in real time to a cloud-based server that can send you alerts when your stations detect an event.
For further information please contact us for a complete system quotation, or click on the images below for more information about the various system components.