LATERAL VARIATION AND FREQUENCY-DEPENDENCE OF CODA-Q IN THE SOUTHERN PART OF IBERIA

A method based on the coda attenuation law: Q = Q0(f/f0)v leads to the determination of the lateral variation of coda-Q in the southern part of the Iberian Peninsula using seismograms belonging to the seismological network of the Cartuja Observatory, located in Granada. The lateral variation of Q0 (Q value corresponding to a reference frequency f0 of 1 Hz) and its frequency dependence for the 1 to 5 Hz frequency range are, in general, in agreement with coda-Q values for frequencies less than about 1 Hz, previously determined in the region under study. To determine the coda-Q values analytical functions have been used to fit the magnification curves of the vertical component short-period seismographs belonging to the Cartuja network. The problem is solved by using least-squares techniques and non-linear inversion. The determined coda-Q0 values and its frequency dependence correlate well with several known geophysical parameters in the southern part of the Iberian Peninsula.