Magnitude and intensity simulation of ground motion on near-fault areas: the case of Talysh (southern Azerbaijan)

In this research, we combine seismic and tectonic approaches in an attempt to apply the empirical relationships between fault parameters and earthquake magnitudes aiming to assess the maximum possible magnitude for the prediction of intensity ground motion in the areas close to active faults. The case we study is the Talysh area in southern Azerbaijan with the total area of 3960 km². It stretches to 38⁰54'N northern latitude and 48⁰35'E eastern longitude and spreads to the north through the Alborz mountains of Iran. The earthquakes with a higher depth are concentrated mainly in the central part of the Talysh zone (up to 70 km) and in the southwestern part of the Caspian Sea (up to 55 km), with the local magnitude range of up to M5.5.

The earthquake magnitudes calculated on the basis of the surface fault length were compared with the catalogued magnitudes. As a procedure, (1) a comprehensive catalogue of all available known faults was compiled; (2) earthquake magnitude is then derived from fault length; (3) the resulting fault-length-earthquake-magnitudes were compared by the mathematical difference with catalogued earthquake magnitudes; and (4) as a final, intensity simulation of ground motion on near-fault areas was plotted. The results show the approximate consistence of the calculated fault-length-earthquake-magnitude with the catalogued seismicity. The map shows that the highest intensity areas of VII are observed in the central and western parts of the zone. An intensity VI covers majority of the Talysh zone. The results will contribute to the implementing more solid analyses for advancing seismic hazard analysis. Our research emphasizes the seismotectonic areas in southern Azerbaijan where further comprehensive studies on faults are required.