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Lateral Variation in Coda Wave Attenuation in Sikkim Himalaya

Description: 

Spatial variations of coda wave attenuation (Q_c) have been investigated in the Sikkim Himalaya. We have used data from 2062 local earthquakes having an epicentral distance of 130 km that were recorded by a dense network of 27 broadband seismic stations across the entire Sikkim region between April 2019 and May 2022. Variations of Q_c with frequency suggest notable contrast across the region manifesting diverse tectonics beneath Sikkim Himalaya. A consistent high attenuation zone has been observed in central Sikkim, regions close to curvilinear trends of MCT, where seismicity is mostly concentrated. Northern Sikkim exhibits high Q values at all the frequencies where clear arrivals from Moho have been observed from receiver functions study for the seismic stations located in the north. The spatial distributions of Q₀ (Q_c ) structure of the region is further investigated to examine the detailed attenuation characteristics across the region. It shows the differences in the attenuation characteristics across the region. A high attenuation pocket is evident in the central segment while northern Sikkim shows less attenuative medium. Our results reflect less complex crustal architecture below the northern part compared to the central portion of the Sikkim Himalaya.

Session: How Well Can We Predict Broadband Site-Specific Ground Motion and Its Spatial Variability So Far? [Poster Session]

Type: Poster

Date: 5/1/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Abhisek

Student Presenter: No

Invited Presentation: 

Authors