Spatial mapping of b-value and fractal dimension prior to November 8, 2022 Doti Earthquake, Nepal

Abstract

An earthquake of magnitude 5.6 mb (6.6 ML) hit western Nepal (Doti region) in the wee hours of wednesday morning local time (2:12 AM, 2022.11.08) killing at least six people. Gutenberg-Richter b-value of earthquake distribution and correlation fractal dimension (D2) are estimated for 493 earthquakes with magnitude of completeness 3.6 prior to this earthquake. We consider earthquakes in western Nepal Himalaya and adjoining region (80.0- 83.5°E and 27.3-30.5°N) for the period of 1964 to 2022 for the analysis. The b-value 0.68 ±0.03 implies a high stress zone and the spatial correlation dimension 1.81±0.02 implies a highly heterogeneous region where the epicenters are spatially distributed. Low b-values and high D2 values identify the study region as a high hazard zone. Focal mechanism styles and low b-values correlate with thrust nature of earthquakes and show that the earthquake's occurrence is associated with the dynamics of the faults responsible for generating the past earthquakes.