Crustal velocity structure for Northern Egypt using ambient noise tomography

Area of Science:

• Geophysics
• Seismology
• Tectonics

Background:

• Northern Egypt is part of the seismically active Eastern Mediterranean region with a complex tectonic setting.
• Previous investigations into the crustal structure of this region are limited.

Purpose of the Study:

• To investigate the crustal structure of Northern Egypt using Ambient Noise Tomography (ANT).
• To determine variations in seismic wave velocities and Moho depths across the study area.

Main Methods:

• Utilized one year of continuous data from 32 broadband seismic stations (Egyptian National Seismological Network and southern European regional stations).
• Applied Ambient Noise Tomography (ANT) by selecting ~300 dispersion curves based on signal-to-noise ratio and seasonal variations.
• Inverted selected dispersion curves to generate group velocity maps (5-25 s) and calculated Moho depths at nine sites.

Main Results:

• Identified significant lateral variations in group velocities across Northern Egypt.
• Observed low seismic velocities in the crust of the Northern Western Desert.
• Detected higher velocities in the Northern Eastern Desert and the Sinai Peninsula.
• Estimated Moho depths ranging from 31 km (near the Mediterranean coast) to 42 km (Western Desert).
• Calculated Moho depths beneath the Sinai Peninsula at 33-35 km.
• Determined the Conrad discontinuity depth between 10 and 16 km.

Conclusions:

• The study provides the first detailed crustal structure map of Northern Egypt using ANT.
• Results highlight significant variations in crustal thickness and seismic velocity, correlating with regional tectonic features.
• The findings contribute to a better understanding of the complex geodynamics of the Eastern Mediterranean region.