Characterizing the Relationship between Sampling Rate and the Appearance of FIR Precursors Infornt of Local Earthquakes

Abstract

Precursory signalsadd an error in the exact time of the earthquake P-wave onset which leads to inaccurate determination of the event parameters; such as the hypocenter and magnitude of the event. These precursors had a fluctuation in the appearance before the P-wave.Thus,changingthe sampling rate will be studied to display whether it has aninfluence on the precursory signal occurrence or not. An experimental field testhas been establishedat New Abu-Dabbab station (NADB)using a portable station beside the fixed one. A portable station digitizer withtwo sampling rates (50, and 200 samples/s)beside the fixed station, which has a sampling rate of 100 samples/s.Successful 381 events have been recorded along 17 months. The three different sampling rates for one event response has been observed. These events are significantly displaying the interdependence between the sampling rate and the precursory segment occurrence. The results prove that the appearing of precursory signals increase whenthe sample rate decreases.

Keywords:Earthquake Early Warning (EEW),sampling rate, precursory segment, seismic nucleation phases, FIR filter.