(a) Seismographs shall be provided, operated and maintained to measure, record, analyze, and report ground vibration and air overpressure resulting from blasting. A sufficient number of seismographs shall be provided to monitor the number of separate locations specified.
(b) Seismographs shall measure and digitally record the three components of the particle velocity waveform (vertical, longitudinal, and transverse), and the air blast waveform.
(c) Seismographs shall conform to the following minimum requirements:
(1) Sampling rate: 1024 samples per second, each channel.
(2) Frequency range: 2 to 250 Hz, linear within +/-3 dB.
(3) Seismic velocity range: 0.01 to 5 inches per second.
(4) Sound pressure level range: 90 to 140 dB linear.
(5) Recording time equal to the maximum duration of the longest blast plus one second.
(6) Sound pressure level microphone shall be equipped with windscreen.
(d) Seismographs shall be capable of providing event reports showing the following; serial number of device; date and time of event; peak sound pressure level, peak particle velocity in each of three directions, predominant frequency of each, and time of occurrence relative to trigger; time histories of sound pressure level and particle velocity (each direction).
(e) Seismographs shall be calibrated according to manufacturer's recommendations as often as necessary, but at least once every 12 months.
(Ord. 2005-5-4. Passed 5-3-05.)