Large E., Huyghe P., Mugnier J. L., Guillier Bertrand, Taral S., Gyawali B. R., Chabraborty T. (2022). Distribution of active tectonics in the Himalayan piedmont (Darjeeling, eastern India) inferred from Horizontal-to-Vertical spectral ratio analysis of passive seismic records. Terra Nova, 34 (6), 535-542. ISSN 0954-4879.
Titre du document
Distribution of active tectonics in the Himalayan piedmont (Darjeeling, eastern India) inferred from Horizontal-to-Vertical spectral ratio analysis of passive seismic records
Large E., Huyghe P., Mugnier J. L., Guillier Bertrand, Taral S., Gyawali B. R., Chabraborty T.
Source
Terra Nova, 2022,
34 (6), 535-542 ISSN 0954-4879
The pattern of active deformation of frontal structures in Darjeeling Himalaya is complex with out-of-sequence reactivations in the chain and development of scarps associated with earthquake ruptures reaching the surface in the piedmont. To clarify the distribution of active deformation in this area, we analyse passive seismic records by the Horizontal-to-Vertical Spectral Ratio method along three NS trending profiles. We image the Siwalik sedimentary rocks / recent deposits interface under the piedmont and show folded and faulted geometries. Two of these faults are located under scarps of about 10 m affecting the 3.7 +/- 0.7 ka old surface of the Tista megafan. Such features imply that about half of the convergence is expressed south of the Himalayan front while the other part occurs out-of-sequence in the chain, suggesting a very limited activity of the Main Frontal Thrust itself.
Plan de classement
Géologie et formations superficielles [064]
;
Géophysique interne [066]
