OBSERVATIONS OF HIGH-FREQUENCY SCATTERED WAVES USING DENSE ARRAYS AT TEIDE VOLCANO

A study of the seismic coda of seven small earthquakes recorded on the Teide Volcano-Canary Islands (Spain) was carried out using a temporar y, small-aperture, 12-station, seismic array. The purpose was to measu re backazimuth, apparent velocity and the type of waves that compose t he coda in the frequency range 4 to 6 Hz. We used the zero-lag cross-c orrelation (ZLC) method to obtain the components of the wave vector an d three-component analysis techniques based on the covariance matrix o f the signal in the time domain to investigate the polarization proper ties of the signals. The results show that a great part of the coda si gnals in the analyzed frequency range are almost uncorrelated, while a low number of isolated correlated arrivals show an apparent slowness between 2 X 10(-3) and 2.5 X 10(-4) sec/m and an almost random distrib ution of backazimuths, The correlated arrivals have been interpreted a s generated by strong scatterers, probably related to the presence, in the study area, of surface topography irregularities (the volcanic co ne and the caldera rim). The wave type varies from pure S-type waves t o mixed surface waves with some Rayleigh components.