It is particularly important for the tremor source studies to establish the role played by the attenuation in the modification of the spectral shape. The goal of this note is to contribute in this topic, trying to quantify the effect of the attenuation on the volcanic tremor waveforms recorded at Etna volcano. Our working hypothesis is that the tremor source is shallow and spatially coincident with the crater area, and that it radiates mainly surface waves. Data were recorded on Etna volcano during a pre-eruptive phase of activity. The level of tremor amplitude was particularly high and an approximately linear profile of five short-period seismic stations was set up for a deep seismic sounding experiment. Space attenuation was estimated through the "quality factor" Q estimated through the spectral amplitudes. The Q values found for the Etna tremor agree fairly well with those reported in literature for other volcanoes. Although the present study is a quite crude estimate of the attenuation for tremor, it could be very useful in correcting spectra for source studies.
|Titolo:||Attenuation of volcanic tremor at Mt. Etna, Sicily|
|Data di pubblicazione:||1989|
|Appare nelle tipologie:||1.1 Articolo in rivista|