Fractal Analysis of Clustered Seismicity in and Around Central Himalaya

In this study, two statistical parameters of seismicity, correlation fractal dimension and b-values are estimated for a comprehensive database spanning approximately 60 years, from 1964 to 2023. The study covers the geographic range of ~26.0°N to 31°N latitude and ~80°E to 89°E longitude. The region is divided into five clusters using the K-Means clustering algorithm: Cluster 1 covers the area around the Doti region in western Nepal, while Cluster 2 encompasses the 2015 Gorkha earthquake region. Cluster 3 lies entirely within adjoining Tibet region, Cluster 4 is centered around the Kali Gandaki region, and Cluster 5 spans from the Koshi to Mechi regions. The b -values are estimated as 0.96±0.06, 1.09±0.08, 1.01±0.07,0.89±0.07, 0.81±0.06 and correlation fractal dimension value as 1.81±0.01, 1.34±0.03, 1.65±0.03, 1.58±0.02, 1.76±0.01. The spatial correlation fractal dimension and the b-value vary with the size of the clusters, and their relationship is negatively correlated, with a correlation coefficient of -0.66. Analyzing b-values reveals regions with varying stress levels, while high Dc values indicate diffuse seismicity and widespread faulting. Together, these findings help identify potential zones of future seismic activity and improve seismic hazard assessment.