Seismotectonic Investigation of the Herat Fault System, Western Afghanistan

The western region of Afghanistan, particularly around the Herat (Harirud) fault system, is highly seismically active. This study investigates the tectonic earthquake potential of the Herat region using seismicity parameters and fractal analysis. Seismic data were collected from international catalogs and analyzed to determine the b-value and fractal dimension (D-value) of earthquake distribution. Remote sensing, GIS, and statistical methods were applied to identify fault structures and assess stress regimes. Results show that the Herat fault and its subsidiary faults exhibit high fractal dimensions, reflecting dense faulting and elevated seismic activity. Areas such as Pashtun Zarghoon, Farsi, Zagah, and Obeh are identified as high-stress zones with potential for future earthquakes. The b-value analysis indicates lower values along the Herat and Siakhobulak faults, corresponding to regions of higher stress accumulation and rupture probability. Stress inversion analysis confirms a convergent regime influenced by the ongoing collision between the Indian and Eurasian plates. These findings highlight the central role of the Herat fault system in regional seismicity and emphasize the need to update earthquake hazard maps for western Afghanistan. Understanding the relationship between fractal dimensions, b-values, and stress fields can contribute to better earthquake risk assessment and support safer construction practices in the region. Keywords: Herat fault, seismicity, fractal analysis, earthquake hazard, stress regime.