Akademik Veri Yönetim Sistemi
21. TÜRKİYE JEOFİZİK KONGRE ve SERGİSİ, Ankara, Türkiye, 16 - 18 Ekim 2024, ss.1-2
The Turkish-Iranian
Plateau including Eastern Türkiye and NW Iranian in the Alpine-Himalayan
Orogenic Belt is a complex tectonic structure regarding historical and
instrumental seismicity. Eastern Türkiye and NW Iranian within the
Arabian-Eurasia collision zone represent a continental collision zone between
the Arabian and Eurasian plates with a 17 mm/yr convergence. Due to the
continuing collision and intra-continental deformations, the region has an average
height of 2 km, volcanic activity, and fault zones related to the N-S oriented
shortening. There are some important low- and high-angle transpressive,
transtensive, and reverse faults and fault zones in the NW-SW direction
including the Van Fault Zone, the Çaldıran Fault, the Maku Fault, the Başkale Fault,
the Guilato-Siahcheshmeh-Khoy Fault Zone, the Tasuj Fault, the Tabriz Fault
Zone, and the Salmas Fault. This region has produced large earthquakes in
instrumental and historical periods such as the 1780 Tabriz earthquake, the
1930 Salmas earthquake, the 1976 Çaldıran earthquake, etc. The last earthquake
that occurred on February 23, 2020, in the west of Khoy, revealed the
earthquake potential of this region. In this
study, we have studied the current seismic assessment of the
Turkish-Iranian Border using some seismotectonic parameters called b-value and Coulomb stress change. To
make a region-time-magnitude evaluation of the earthquake potential, a
homogeneous database according to Mw magnitude was obtained for the period
between 1930 and 2024. For the study region, the Coulomb stress changes are
also modeled and interpreted for the current seismic hazard. For this aim, 8
earthquakes with moment magnitudes greater than Mw≥5.3 are used.
The b-values change between 0.54 and 1.36.
Small b-values (<1.0) are observed
in the north, south, east, and northwest parts of the study region including the
Maku Fault, the Çaldıran Fault, the Başkale Fault, the Tasuj Fault, the Tabriz Fault
Zone, the Van Fault Zone and the Guilato-Siahcheshmeh-Khoy Fault Zone, while
large b-values (>1.0) are observed
in the west, southwest and southeast parts of the study region including the
Saray Fault and the Salmas Fault. Consistent and parallel with the b-value distribution results, the
Coulomb stress changes demonstrate positive stress lobes (> 0.0 in bar) in
the Guilato-Siahcheshmeh-Khoy and Çaldıran Fault Zones in the north, and the
Başkale and Tasuj Faults in the south. Conversely, negative Coulomb stress
changes are observed in the east and west parts of the study region. It is well
known that the areas with low b-value
and high-stress distribution are thought to be the most possible locations
where the next strong earthquakes will be expected to occur. Thus, several
anomaly areas of two seismotectonic variables are observed in the same parts of
the study region and earthquake hazard is high in these parts of the study
region. The results
suggest that the correlation between these parameters supplies a
better understanding of seismotectonic and structural properties in the region.