Naslov
Lapse time dependent Qc-spectra observed in the Dinarides region

Autori
Herak, Marijan

Izvornik
Physics of the Earth and Planetary Interiors (0031-9201) 67 (1991); 303-312

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
coda waves; Q; seismicity

Sažetak
The paper presents results of the coda quality factor (Qc) measurements in the central Outer Dinarides and the central Adriatic Sea regions. The main objective of this study was to analyse quantitatively the frequently observed Qc increase with lapse time, t, 108 earthquakes were chosen for analysis, with lapse times between 30 and 130 s. After computing the coda amplitude spectra A(ƒ ; ) for 0.6 <= ƒ ; <= 5.0 Hz, the curve 1n(At) = a + btc was fitted to observed data for each earthquake and for each frequency. Denoting its slope by p(t), Qc was then estimated as a function of t as Qc(tƒ ; ) = -πƒ ; /p(t). In this way coda decay rate measurements were done in a consistent way, regardless of the lapse time window used. These individual values were then weighted and averaged in order to calculate the regional Qc(ƒ ; , t). The results indicate that in the region studied Qc increases both with frequency and lapse time, while the degree of frequency dependence decreases with lapse time. If Qc is expressed as Qc(t) = Q0(t) ƒ ; n(t) then for lapse times between 30 and 130 s Q0 increases from 45 to 275 while n decreases from 1.0 to 0.6.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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