Spectra of quarry blasts and microearthquakes recorded at local distances in Israel

In northern Israel, quarry blasts and microearthquakes occur in a region with complicated tectonics. Therefore correct event identification is essential for accurate and detailed seismotectonic studies. Spectral analysis of quarry blasts and microearthquakes recorded at local distances (5 < Δ < 2000 km) by stations of the Israel Seismograph Network revealed spectral characteristics in the frequency range less than 12.5 Hz that can be used routinely for event identification. The spectra of complete seismogram signals of 52 events recorded by the ISN at different distances and azimuths, including both microearthquakes and quarry blasts were compared. Consistent spectral modulation was found in a band from about 2 to 8 Hz for 18 of 21 reliably identified, i.e., reported, quarry blasts with time delays of 20 to 40 msec. -from Authors