Q in southern Norway Available to Purchase

Q was determined for the southern Norway region using short-period data from local events. The spectral ratio and the coda decay method were used to determine Q as a function of frequency for P, S, and coda waves, respectively. Q(f) was generally found to fit the relationship Q = Q_of^m where f is the frequency and Q_o and m constants. The following results were obtained:

where Q_c, Q_p, and Q_s are coda Q, Q of P waves, and Q of S waves, respectively. There is a good agreement between coda Q and spectral ratio Q_s values, which supports the hypothesis that coda waves are backscattered S waves. The increase in coda Q as a function of window length is thought to reflect an increase of Q with depth, because coda waves for a longer time window will sample deeper parts of the crust. At higher frequencies (12 to 15 Hz), our results are quite similar to what has been found for the Canadian Shield area, but with a much stronger frequency dependence. This could be interpreted in terms of a stronger presence of scatterers in southern Norway as compared to the Canadian Shield.