Coda Q in the eastern Caribbean, West Indies

Coda Q, Q,, 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,. The Qc values exhibit a strong frequency dependence in the frequency band 1.5 to 16 Hz, with calculated coda Q at 1 Hz, Qo, 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, and n in the region, this variation does not seem to be very significant. Key words: Caribbean, coda Q, earthquakes, seismograms.