Journal
GEOPHYSICAL JOURNAL INTERNATIONAL
Volume 228, Issue 2, Pages 1038-1053Publisher
OXFORD UNIV PRESS
DOI: 10.1093/gji/ggab380
Keywords
Mantle processes; Inverse theory; Tomography; Seismic attenuation; Rheology: crust and lithosphere
Categories
Funding
- Ministry of Earth Sciences, Govt. of India [MoES/P.O/Seismo/1(318)/2017(SDH)]
Ask authors/readers for more resources
The 2-D Sn attenuation tomographic model in southeastern Tibet near Namche Barwa reveals high attenuation in the central region, with low attenuation observed in the southern part and some small regions beneath the northern side of the study area. The observed Q(Sn) values indicate significant Sn wave energy dissipation due to structural heterogeneity in the uppermost mantle, possibly resulting from the break-up of the subducting Indian Plate.
We have formulated a 2-D Sn attenuation tomographic model to investigate the uppermost mantle shear wave Q and its tectonic implications beneath southeastern Tibet near Namche Barwa. To achieve our objective, we first compute interstation Q values using the two station method (TSM) analysis on 618 station pairs obtained from 26 regional earthquakes (M-w >= 5.5) with epicentral distances ranging from 5 degrees to 15 degrees recorded at 47 seismic stations belonging to the Namche Barwa network (XE network, 2003-2004). Furthermore, the Q(Sn) tomographic model is generated by utilizing these interstation Q values. Q(Sn) values are varying from 101 to 490 in the region. The tomography image reveals high attenuation (<= 200 Q values) in the central region. Regions of low attenuation (>200 Q values) are observed in the southern part and in some small regions beneath the northern side of the study area. Consecutive high-low-high Q(Sn) values have been observed in the south part of the Lhasa block. The obtained Q(Sn) values, along with the prior isotropic Pn velocity model of the study area, indicate that the scattering effect is causing significant Sn wave energy dissipation due to structural heterogeneity present in the uppermost mantle beneath the region. This may be the result of the break-up of the subducting Indian Plate beneath the area.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available