CODA-Q IN THE EASTERN CARIBBEAN, WEST-INDIES

Coda Q, Q(c), has been estimated from seismograms of local earthquakes recorded on short-period seismographs on some of the eastern Caribbean islands of the Lesser Antilles arc, West Indies, using the S-S single-scattering model. The region was subdivided into four distinct subregions in order to investigate lateral variations in Q(c). The Q(c) values exhibit a strong frequency dependence in the frequency band 1.5 to 16 Hz, with calculated coda Q at 1 Hz, Q(o), ranging from a minimum of 97 in the Dominica area to a maximum of 145 in the Leewards. The degree of frequency dependence is also largest in the Dominica area (n = 1.09) and smallest in the Leewards (n = 0.82). Although there appears to be some lateral and depth variation of both Q(o) and n in the region, this variation does not seem to be very significant.