Earthquake Catalogue

Citation Author(s):
hanan
farghly
nriag
shimaa
Elkhouly
nriag
shaimaa
Maamoun Khaier
nriag
Submitted by:
hanan farghly
Last updated:
Thu, 12/19/2024 - 02:32
DOI:
10.21227/aazy-1n28
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Abstract 

        Northern Africa and the Eastern Mediterranean area has faced lots of natural catastrophes to earthquakes last decade. The primary active tectonic structure concentrated in Sub-Saharan Africa. A recent assessment of earthquake seismicity characteristics has been conducted in North Africa.The database of historical and instrumental earthquakes is one of the most crucial tools for evaluating the risk of earthquakes. As a result, a comprehensive and consistent earthquake catalog has been compiled that spans the years from 112 BC to March 2023 AD, including instrumental and historical seismic records. The instrumental seismicity is compiled from local and international sources .It covers the area between 20N˚ and 40N˚ and -20E˚ to 40E˚. Datasets containing all known earthquakes with a magnitude M ≥ 3 to emphasize that this catalog is not complete for all earthquakes M>3with a total number of 138886 earthquakes. Using the present knowledge available, duplicate events are found and eliminated. An orthogonal regression method was used to derive empirical relationships in order to determine the moment magnitude (Mw). The catalogue is de-clustered with two de-clustering algorithms in order to eliminate the dependent events. An update catalogue completeness test is conducted. The study analyzes seismic source zones, determining a-values, b-values, and maximum estimated magnitudes for 54 seismogenic zones of nine regions according to two types of declustring at estimated minimum magnitude 3.0 and 3.5. The highest b value is 1.09 in Shore Egypt/ Red Sea and the highest a value is 4.27 in Atlantic off shore.

Instructions: 

The most crucial and significant input parameter for modeling the seismicity parameters of North Africa is (a) the distribution of maximum observed magnitude and the level of seismicity deduced from the earthquake catalog; (b) the completeness of the gathered catalog; and (c) the knowledge currently available about the seismogenic source zones.