A little tsunami at Ras El-Bar, Nile Delta, Egypt; consequent to the 2023 Kahramanmaraş Turkey earthquakes

Abstract

From the 6th to 7th of February 2023, a storm surge struck Ras El-Bar, Nile Delta coast and attacked the resort facilities, with a wave height and velocity in deep water of 7.2 m and 12.7 m/sec respectively. The wind speed was 12.84 m/s, blowing from the NW and the WSW quadrants. This was an unwitnessed event revealed from the study of similar time interval from 1998 to 2022. Synchronizing with this event on the 6th of February 2023, was Kahramanmaraş Turkey Earthquakes. Consequently, the shoreline receded for about −30 m and with a drop in sea-level of about −40 cm. Furthermore, considerable changes in the beach morphology from a dissipative to a cuspate-related, intermediate tidal flat transverse bar with a rip profile. These are either related to the change in the morphodynamic or sedimentary budget, and resulting due to seawater scouring of bottom sediments for more than −30 cm. Two days preceding the Earthquakes an isostatic rise in sea-level (+20 cm) at the Turkish coast compared to the Mediterranean records, which is interpreted due to regional underwater seismic activities. The drop in the sea-surface height does not happen due to seawater outflow to the Atlantic Ocean. However, the sea-level regained its normal position because of the refill occurring from the Atlantic Ocean to the Mediterranean Sea. The pumice pieces, organic peat, and starfish distributed at Ras El-Bar coast, and thrown from the Northern Mediterranean indicate that the Egyptian coast was subjected to a little tsunami with average height of 14 cm. It is minimized due to enforced wave shifting from high pressure over Egypt to the low-pressure sinks.

Keywords

• Egypt
• Coasts
• Mediterranean
• Geomorphology
• Shoreline
• Sea-level