| Popis: |
Two powerful earthquakes struck southeastern Turkey on 6 February 2023 with the magnitudes of Mw = 7.8 and Mw = 7.5 in nine hours. In addition, a storm surge caused by the passage of a cyclone over the area coincided with the first earthquake. Field observations showed that the fault planes did not extend to the Mediterranean Sea; however, a weak tsunami was observed on several tide gauges in the northeastern Mediterranean. Historically, there were tsunamis in the Levantine Sea region caused by earthquakes on land within the East Anatolian Fault Zone and the Dead Sea, having a complex cause, i.e., earthquakes and associated landslides. Hence, we studied the origin of the generated waves. We separated and estimated various components of sea level oscillations from 1 to 8 February 2023, using spectral and f-t analyses and sets of narrow-band and high-frequency filters. The earthquake Mw = 7.8 on 6 February 2023 caused a weak tsunami with maximum amplitudes 15‒17 cm in Erdemli and Arsuz. We identified that the increase in sea level oscillations in Arsuz after 7 February was associated with the impact of the cyclone. The maximum amplitude of sea level oscillations, 22 cm, in Arsuz was observed on 7 February and is associated with infragravity waves caused by the influence of storm surge during the passage of the cyclone. In Erdemli, on the contrary, the influence of high-frequency waves of atmospheric origin is significantly lower, i.e., the amplitude of the sea level oscillations after 7 February was less than 10 cm. |
