Seismic B-Value Study in Southern Slope of Greater Caucasus (Azerbaijan) ^†

Abstract

In this study, there was an attempt to estimate seismic hazard in terms of b-value distribution over the southern slope of Greater Caucasus (Azerbaijan). The southern slope of Caucasus (Azerbaijan) is influenced by tectonic activity driven by Arabian and Eurasian plate tectonics. The differences between seismotectonic characteristics are considered for large tectonic zones within this southern slope (Balaken-Zagatala, Sheki-Oguz-Gabala, Ismailli-Shamakhi). The b-value is one of the important components in the Gutenberg–Richter empirical relation. This relation represents the frequency of occurrence of seismic events as a function of their magnitude. The a-value and the b-value in this relation are constants and they characterize the seismic features. The a-value describes the seismic activity in terms of spatial and temporal occurrences within a certain period, while the b-value measures the relation of strong to weak earthquakes. The b-value indicates the dynamics of the tectonic regime of the area. This constant demonstrates the distribution of low or high stresses. The data for this study has been extracted from the Azerbaijan seismological center (RCSS). Different relations have then been developed for each separate zone. Some studies revealed spatial and temporal variations of the b-value before large earthquakes during the last decades. The b-value distribution results show that a decrease is observed in the western part of the region (Zagatala, Sheki), in the Shamakhi area and in some areas of the northern part which is an indication of higher stress in those areas.