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Sharp Changes of Crustal Seismic Anisotropy across the Central Tanlu Fault Zone in East China

Fenglin Niu, Wenpei Miao, & Haichao Chen

Submitted September 11, 2022, SCEC Contribution #11991, 2022 SCEC Annual Meeting Poster #183

We measured crustal and upper mantle seismic anisotropy using P-to-S converted waves at the Moho (Pms) and core-mantle boundary (SKS) recorded by broadband arrays deployed across the Weifang segment of the Tanlu fault zone. We gathered Pms geographically and measured crustal seismic anisotropy using a joint analysis of radial and transverse receiver functions. The measured crustal anisotropy inside the fault zone shows a fast direction of ~NNE, parallel to the fault orientation. Right east to the fault zone, the fast axis rotates by almost 90 to ESE. Meanwhile, SKS splitting data showed a consistent ESE fast direction, parallel to the absolute plate motion direction, suggesting that it is likely caused by asthenospheric flow and the frozen flow fabric of the contemporary mantle lithosphere. The crustal anisotropy within the fault zone could be caused by aligned microcracks and foliated minerals due to long-lasting shear motion within the fault zone.

Citation
Niu, F., Miao, W., & Chen, H. (2022, 09). Sharp Changes of Crustal Seismic Anisotropy across the Central Tanlu Fault Zone in East China. Poster Presentation at 2022 SCEC Annual Meeting.


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