Akademik Veri Yönetim Sistemi
LATİN AMERİKA 8. ULUSLARARASI BİLİMSEL ARAŞTIRMALAR KONGRESİ, Habana, Küba, 1 - 05 Mayıs 2024, ss.1-11
Marmara Region, located at
the western end of the North Anatolian Fault Zone, is one of the most active regions
of Türkiye in terms of earthquake occurrences. The region was exposed both in
historical and instrumental periods to large/destructive earthquakes such as
the 1766 Marmara Sea (I=10), 1912 Mürefte-Şarköy (Mw=7.6), 1953 Yenice-Gönen
(Mw=7.2), 1999 İzmit and Düzce (Mw=7.6 and Mw=7.2) and is seismotectonically
under high earthquake hazard in recent years. December 4, 2023 Mudanya
earthquake (Mw5.1) and December 17, 2023 Çınarcık Basin earthquake (Mw=4.1)
clearly reveal earthquake potential of the region. On the other hand, Tekirdağ
Basin and its surroundings, located just west of the Central Marmara Basin, indicate
an important region for the next earthquake potential. Therefore, it is very
important to reveal the earthquake potential and hazard in and around Marmara
Region. In this scope, the b-value,
the basic parameter of earthquake statistics, return periods and occurrence
probabilities of earthquakes were calculated. Also, Coulomb stress changes of
the earthquakes that occurred both after 2000 in the Marmara region and
Mürefte-Şarköy, Yenice-Gönen and İzmit earthquakes that occurred in the
instrumental period were calculated. For the statistical analyses, a catalog,
including 119,029 earthquakes with magnitudes ranging from 1.0£Mw£7.6, covering the region between
39.0°N-42.0°N latitude and 25.5°E-31.0°E longitude, in the 110.89-year period
between 1912 and 2024, was used. Focal mechanism solutions of 37 earthquakes
were used for Coulomb stress analyses of earthquakes (Mw≥4.0) that occurred
after 2000. The study area was divided into different regions related to
tectonic structures, and b-value
changes between 0.78-1.04. The smallest b-values
were observed on Ganos, Saros, Tekirdağ, Kumburgaz, Avcılar, Adalar, Çınarcık,
Darıca, Karamürsel, Gölcük, İznik-Mekece and Geyve segments. In the vicinity of
Central Marmara Basin, positive stress values (≥1.0 bar) and relatively small b-values were calculated. According to
these values, the occurrence probability of a moderate earthquake in the intermediate
term changes between 64% and 98%. In addition, small b-values and relatively average stress values were observed in the
east of the Marmara Sea. Consequently, evaluating these parameters together in
revealing the earthquake hazard will lead to studies in the active earthquake
zones.