EGU22-4446, updated on 27 Mar 2022
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

2-D Sn attenuation tomography of Arunachal Himalaya

Sukanta Sarkar1, Chandrani Singh1, M. Ravi Kumar2, Ashwani Kant Tiwari1, Arun Kumar Dubey1, and Arun Singh1
Sukanta Sarkar et al.
  • 1Indian Institute of Technology, Kharagpur, Geology and Geophysics, India (
  • 2National Geophysical Research Institute, Hyderabad, India.

In this study, we have presented the first high-resolution 2-D Sn attenuation tomography image of
Arunachal Himalaya to enlighten the lithospheric structure of the area. The region is one of the
active segments of the Himalaya and least understood because of the inaccessibility and difficult
working conditions. 37 regional earthquakes within the epicentral distance of 250 - 1650 km were
recorded by 29 broadband seismic stations operated in Arunachal Himalaya covering the majority
portions of the eastern Himalaya are used in the present study.
Sn is the uppermost mantle refracted phase travelled with a velocity of 4.3 - 4.7 km/s. It
is highly sensitive to the velocity gradient and attenuation in the uppermost mantle. We have
categorised the propagation efficiencies of Sn as efficient, inefficient and blocked based on a
visual inspection. The inefficient and blocked Sn phases are observed mainly in the western side
of our study region. Further, we have obtained the Sn Q tomography model to examine lateral
variations in attenuation characteristics, employing the Two Station Method (TSM) using 567 station
pairs as input data. The central Arunachal Himalaya exhibits a low Q value (≤ 50) whereas
Tawang and the western part of Arunachal Himalaya show a high value of Q ≤ 300. The obtained
results are well correlated with the tectonic fabric of the area.

How to cite: Sarkar, S., Singh, C., Kumar, M. R., Tiwari, A. K., Dubey, A. K., and Singh, A.: 2-D Sn attenuation tomography of Arunachal Himalaya, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4446,, 2022.


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