Crustal and upper mantle structure of the interior Arabian platform

The crustal and upper-mantle velocity structure of the interior Arabian platform is derived using the spectral analysis of long-period P-wave amplitude ratios. The ratio of the vertical to the horizontal component is utilized to obtain crustal transfer functions using the Thomson- Haskell matrix formulation for horizontally layered crustal models.20 earthquakes recorded at the long-period station RYD between azimuths N20'W and ti 150-E were selected for the analysis based on the following criteria: focal depths in the range 5 to 215 km, body-wave magnitudes greater than 5.0, and epicentral distances in the range 7' to 97'. V A careful quality check of the data left us with six events, out of 29, that had short epicentral distances (