LAUSR

The quality agents for P- and S-waves (Qp and Qs) were estimated for earthquakes that recorded by nine seismic stations (DHA, NUB, TR1, TR2, KAT, SH2, GRB, HRG and SFG) from the Egyptian National Seismological Network (ENSN). These stations are located at southern Sinai and northern Red Sea coast region. For Q-values estimation, one station spectral rate method was applied and the spectral amplitude rates have been calculated between 2‒20 Hz for this aim. The obtained Q-values prove that Qp and Qs increase as a follower of frequency according to the relation Q = Q0f n. By averaging Q-values which were calculated at all nine stations the median attenuation relations for Qp and Qs were obtained as: Qp = (13.15 ± 0.76) f 0.95±0.19 and Qs = (20.05± 0.79)f 1.03±0.04. These relations are helpful for respect of origin parameters of earthquakes and emulation of earthquake strong ground motions. The Qs/Qp ratio for KAT station is less than 1 at lower frequencies, whereas at HRG and SH2 stations Qs/Qp ratios are greater than 1.