FN Archimer Export Format
PT J
TI Factors influencing seismic wave attenuation in the lithosphere in continental rift zones
BT 
AF DOBRYNINA, A. A.
   SANKOV, V. A.
   DEVERCHERE, Jacques
   CHECHELNITSKY, V. V.
AS 1:1,2;2:1,3,4;3:5;4:6;
FF 1:;2:;3:;4:;
C1 Institute of the Earth's Crust, Siberian Branch of RAS, Irkutsk, Russia
   Geological Institute, Siberian Branch of RAS, Ulan‐Ude, Russia
   Irkutsk State University, Irkutsk, Russia
   Irkutsk Scientific Center, Siberian Branch of RAS, Irkutsk, Russia
   Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, Domaines Océaniques, Plouzané, France
   Baikal Branch of Federal Research Center Geophysical Survey of RAS, Irkutsk, Russia
C2 RUSSIAN ACAD SCI, RUSSIA
   RUSSIAN ACAD SCI, RUSSIA
   UNIV IRKUTSK STATE, RUSSIA
   IRKUTSK SCIENTIFIC CENTER, RUSSIA
   UBO, FRANCE
   RUSSIAN ACAD SCI, RUSSIA
UM LGO
TC 3
UR https://archimer.ifremer.fr/doc/00638/75049/75658.pdf
LA English
DT Article
DE ;Baikal rift system;East African rift system;North American Basin and Range Province;attenuation of seismic waves;seismic quality factor;seismicity;coda waves;intrinsic attenuation;scattering attenuation;heat flow
AB Attenuation of seismic waves in the crust and the upper mantle has been studied in three global rift systems: the Baikal rift system (Eurasia), the North Tanzanian divergence zone (Africa) and the Basin and Range Province (North America). Using the records of direct and coda waves of regional earthquakes, the single scattering theory [Aki, Chouet, 1975], the hybrid model from [Zeng, 1991] and the approach described in [Wennerberg, 1993], we estimated the seismic quality factor (QC), frequency parameter (n), attenuation coefficient (delta), and total attenuation (QT). In addition, we evaluated the contributions of two components into total attenuation: intrinsic attenuation (Qi), and scattering attenuation (Qsc). Values of QC are strongly dependent on the frequency within the range of 0.2-16 Hz, as well as on the length of the coda processing window. The observed increase of QC with larger lengths of the coda processing window can be interpreted as a decrease in attenuation with increasing depth. Having compared the depth variations in the attenuation coefficient (delta) and the frequency (n) with the velocity structures of the studied regions, we conclude that seismic wave attenuation changes at the velocity boundaries in the medium. Moreover, the comparison results show that the estimated variations in the attenuation parameters with increasing depth are considerably dependent on utilized velocity models of the medium. Lateral variations in attenuation of seismic waves correlate with the geological and geophysical characteristics of the regions, and attenuation is primarily dependent on the regional seismic activity and regional heat flow. The geological inhomogeneities of the medium and the age of crust consolidation are secondary factors. Our estimations of intrinsic attenuation (Qi) and scattering attenuation (Qsc) show that in all the three studied regions, intrinsic attenuation is the major contributor to total attenuation. Our study shows that the characteristics of seismic wave attenuation in the three different rift systems are consistent with each other, and this may suggest that the lithosphere in the zones of these different rift systems has been modified to similar levels. 
PY 2017
SO Geodynamics & Tectonophysics
SN 2078-502X
PU Russian Acad Sciences, Siberian Branch, Inst Earths Crust
VL 8
IS 1
UT 000411206200005
BP 107
EP 133
DI 10.5800/GT-2017-8-1-0234
ID 75049
ER

EF