Seismicity and magnitude recurrence hazard assessment in Eastern Nepal, Northeast India and Tibet Himalaya. (October 2022)

• Record Type: Journal Article
• Authors: Yadav, R.B.S.; Tsapanos, Theodoros M.; Burton, Paul W.; Kumar, Rajiv; Sandhu, Manisha
• Is Part Of: Physics and chemistry of the earth. Volume 127(2022)
• Publication Date: 2022-10
• Subjects: Gumbel III distribution -- Northeast India -- Earthquake hazard parameters -- Magnitude recurrence maps -- Return periods; Geophysics -- Periodicals; Geochemistry -- Periodicals; Earth sciences -- Periodicals; Geodesy -- Periodicals; Astrophysics -- Periodicals; 550
• DOI: 10.1016/j.pce.2022.103158
• Languages: English
• ISSNs: 1474-7065

Abstract

Abstract: The regions of eastern Nepal, northeast India and Tibet Himalaya (26°-30°N, 85°-97°E) are one of the most earthquake hazardous areas in the Indian subcontinent. The seismicity of this region is analyzed using Gumbel's third asymptotic distribution ( GIII ) method of extreme values to assess the earthquake hazard. A uniform and complete seismic data covering the time span of 120 years (i.e. 1900-2019) is used for the appraisal of earthquake magnitude recurrence in different return periods. The expected largest earthquake magnitudes during the next 20 (M20 ), 50 (M50 ) and 100 (M100 ) years with their 90% probability of not being exceeded (PNBE) are spatially mapped to create a brief atlas of short- and long-term regional earthquake magnitude recurrence hazard maps. The obtained results of maximum magnitude during 20, 50 and 100-years are expected to exceed the values of Mw 7.1, 7.7 and 8.2, respectively in two prominent blocks of eastern Nepal and Arunachal Himalaya in the examined region. These blocks are also more prominent for the results of 20, 50 and 100 years earthquake magnitudes with 90% PNBE i.e. return periods of 190 (M190 ), 475 (M475 ) and 950 (M950 ) years along with two additional blocks in the Eastern Himalayan Syntaxis (EHS) and Yadong-Gulu rift near Lhasa in the Tibet Plateau. These earthquake magnitudes are expected to exceed Mw 8.5, 8.6 and 8.9 during the next 190, 475 and 950 years, respectively in these blocks. The spatial distribution of earthquake hazards in the region reveals the complex seismotectonic setup and high crustal heterogeneity. Highlights: Estimated earthquake magnitude recurrence in different return periods. Eastern Nepal and western Arunachal Himalaya show high value of recurrence. Four aseismic blocks of low earthquake hazard are observed in the region. Non-uniform variation of earthquake hazard is observed in the examined region.