Spatio‐temporal variation in b‐value prior to the 26 November 2021 Mizoram earthquake of northeast India

Abstract

In this study, the variation in frequency magnitude distribution factor (b‐value) before the main shock has been assessed for the 26 November 2021 Mizoram earthquake (Mw 6.1) in northeast India. The study area covering the Indo‐Burma Ranges is divided into square grids of equal dimension and spatial mapping of the b‐value for each square grid has been carried out. The maximum likelihood method is implemented for the estimation of the b‐value of each grid. The epicentral location of the 26 November 2021 Mizoram earthquake (Mw 6.1) is found to be in the intermediate b‐value square grid. The temporal variation in the b‐value indicates a considerable decline in the b‐value before the occurrence of the main event. The depth‐wise variation in the b‐value suggests an antithetical relationship between the b‐value and crustal stress. The spatio‐temporal and depth‐wise fluctuation in the b‐value results have been strengthened by employing a non‐parametric Kolmogorov–Smirnov (K–S) test. Based on our study, we infer that interplate earthquakes occur mostly in the upper crust of the study region.

Introduction, Part 2—Geodynamic evolution of Eastern Himalaya and Indo‐Myanmar orogenic belts: Advances through interdisciplinary studies

“…Sharma and Biswas ( 2022 ) discussed the variation in frequency magnitude distribution factor ( b ‐value) before the main shock has been assessed for the 26th November 2021 Mizoram earthquake (Mw 6.1) in North‐east India. The study area covering the Indo–Burma Ranges is divided into square grids of equal dimension and spatial mapping of the b ‐value for each square grid has been carried out.…”

“…The Himalaya mountain belt is about 2500 km in length, from west to east, and is a classic example of an orogenic system created by the continent-continent collision between the Indian-Eurasian plates F I G U R E 2 Geological map of Eastern Himalaya, Indo-Myanmar orogenic belt, northern, Central Myanmar, and adjacent areas (modified after Mitchell et al, 2007;Searle et al, 2007;. Locations of study area presented in the issue include 1/S2: Kundu and Hazarika (2022); 2/S2: Y. R. ; 3/S2: Rawat and Luirei (2022) Chaubey et al (2022); 24/S2: ; Bora, Mukherjee, et al (2022); 25/S2: Khuman and Ibotombi (2022); 26/S2: Y. R. ; 27/S2: Thokchom and Kshetrimayum (2021); 28/S2: Barman et al (2022); 29/S2: V. Sharma and Biswas (2022) along the Indus-Tsangpo Suture Zone (ITSZ) $55 Ma ago (de Sigoyer et al, 2000;DeCelles et al, 2001;Yin, 2006). The southern parts of the Eurasian Plate mainly have the Trans-Himalaya, Ladakh batholith, Gangdese batholith, Lohit batholith, Karakoram Ranges, Ophiolites, Indus-Tsangpo Mélange zone, etc.…”

“…Geological map of Eastern Himalaya, Indo‐Myanmar orogenic belt, northern, Central Myanmar, and adjacent areas (modified after Mitchell et al, 2007; Searle et al, 2007; Y. R. Singh, Singh, Singh, et al, 2022). Locations of study area presented in the issue include 1/S2: Kundu and Hazarika (2022); 2/S2: Y. R. Singh, Singh, Singh, et al (2022); 3/S2: Rawat and Luirei (2022); 4/S2: Kayal et al (2022); 5/S2: Choudhury et al (2022); 6/S2: N. M. Sharma et al (2022); 7/S2: Goswami, Gogoi, et al (2022); 8/S2: Bikramaditya et al (2022); 9/S2: Goswami, Kalita, et al (2022); 10/S2: Joshi (2022); 11/S2: Jha and Sharma (2022); 12/S2: Shukla et al (2022); 13/S2: Khonglah et al (2022); 14/S2: Ali and Duarah (2022); 15/S2: Mohanty et al (2022); 16/S2: Chanu et al (2022); 17/S2: Majumdar, Gogoi, and Ghatak (2022); Majumdar, Gogoi, Ghatak, Saikia, et al (2022); 18/S2: Ding et al (2022); 19/S2: Ghose et al (2022); 20/S2: Hussain and Dey (2022); 21/S2: Ozukum et al (2022); 22/S2: Jamir et al (2022); 23/S2: Chaubey et al (2022); 24/S2: Bora, Borah, et al (2022); Bora, Mukherjee, et al (2022); 25/S2: Khuman and Ibotombi (2022); 26/S2: Y. R. Singh, Singh, Singh, et al (2022); 27/S2: Thokchom and Kshetrimayum (2021); 28/S2: Barman et al (2022); 29/S2: V. Sharma and Biswas (2022)…”

Unveiling Temporal Cyclicities in Seismic b-Values and Major Earthquake Events in Japan by Local Singularity Analysis and Wavelet Methods

“…Previous research suggests that the b-value can serve as a significant indicator of stress levels within a region [2][3][4][5], with its variations providing vital information about crustal stress accumulation and release [6,7]. Studies employing the b-value method on past seismic events indicate that temporal changes in the b-value can be considered precursors to major earthquake activity [8][9][10][11][12][13].…”