This study employs the classical approach of Probabilistic Seismic Hazard Analysis (PSHA) to explore the potential regional seismic hazard in Bejaia City and its surrounding regions in Algeria. The analysis explicitly focuses on individual active faults by integrating the fundamental concepts of the characteristic earthquake model. The research unfolds in three key phases: First, a comprehensive and homogeneous earthquake catalog was compiled and updated, following the methodology of the Unified Moment Magnitude (MW) parametric earthquake catalog for Algeria and adjacent regions (PECAAR). This updated catalog forms a consistent and a reliable basis for estimating the Gutenberg-Richter parameters. Second, active and potentially active fault networks were identified and characterized using seismotectonic data. Critical earthquake hazard parameters, such as the expected maximum magnitude (<InlineEquation ID="IEq1"> <EquationSource Format="TEX">${m}_{max}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>m</mi> <mrow> <mi mathvariant="italic">max</mi> </mrow> </msub> </math></EquationSource> </InlineEquation>), slip rate along the fault (<InlineEquation ID="IEq2"> <EquationSource Format="TEX">$\dot{s}$</EquationSource> <EquationSource Format="MATHML"><math> <mover accent="true"> <mi>s</mi> <mo>˙</mo> </mover> </math></EquationSource> </InlineEquation>), and rupture area (<InlineEquation ID="IEq3"> <EquationSource Format="TEX">${A}_{f}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>A</mi> <mi>f</mi> </msub> </math></EquationSource> </InlineEquation>), were estimated for each fault. These parameters provide a deeper insight into the region’s earthquake potential. Third, ground motion models (GMMs) were selected for the Bejaia region. The PSHA was conducted using these GMMs, and the results are presented as Peak Ground Acceleration (PGA) seismic hazard maps illustrating the spatial distribution of expected seismic hazard levels for two key return periods 475 years (10% probability of exceedance in 50 years) and 2475 years (2% probability of exceedance in 50 years. The findings highlight the Gulf of Bejaia as the most earthquake-prone area, with an estimated PGA value of 0.264 g for the 475-year return period and 0.400 g for the 2475-year return period. The Soummam basin follows with 0.236 g and 0.344 g, respectively, while the Western Offshore of Bejaia exhibits PGA values of 0.235 g and 0.380 g. The Djemila region records lower but still significant values of 0.229 g and 0.353 g for the respective return periods. These results emphasize the heightened seismic hazard in these areas, highlighting the importance of incorporating both standard maximum ground motions into seismic zoning updates and the design of earthquake-resistant structures to enhance regional safety and resilience.

Seismic hazard assessment for bejaia city and its surrounding regions: integrating characteristic earthquake model and tectonic considerations

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发表日期：

2025年8月23日

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Sara Idrissou,
Fouzi Bellalem,
Hocine Dehmous,
Abdelhak Talbi,
Said Maouche,
Yahia Mohammedi,
Billel Touati

摘要

This study employs the classical approach of Probabilistic Seismic Hazard Analysis (PSHA) to explore the potential regional seismic hazard in Bejaia City and its surrounding regions in Algeria. The analysis explicitly focuses on individual active faults by integrating the fundamental concepts of the characteristic earthquake model. The research unfolds in three key phases: First, a comprehensive and homogeneous earthquake catalog was compiled and updated, following the methodology of the Unified Moment Magnitude (M_W) parametric earthquake catalog for Algeria and adjacent regions (PECAAR). This updated catalog forms a consistent and a reliable basis for estimating the Gutenberg-Richter parameters. Second, active and potentially active fault networks were identified and characterized using seismotectonic data. Critical earthquake hazard parameters, such as the expected maximum magnitude ( ${m}_{max}$ $m_{\max}$ ), slip rate along the fault ( $\dot{s}$ $\dot{s}$ ), and rupture area ( ${A}_{f}$ $A_{f}$ ), were estimated for each fault. These parameters provide a deeper insight into the region’s earthquake potential. Third, ground motion models (GMMs) were selected for the Bejaia region. The PSHA was conducted using these GMMs, and the results are presented as Peak Ground Acceleration (PGA) seismic hazard maps illustrating the spatial distribution of expected seismic hazard levels for two key return periods 475 years (10% probability of exceedance in 50 years) and 2475 years (2% probability of exceedance in 50 years. The findings highlight the Gulf of Bejaia as the most earthquake-prone area, with an estimated PGA value of 0.264 g for the 475-year return period and 0.400 g for the 2475-year return period. The Soummam basin follows with 0.236 g and 0.344 g, respectively, while the Western Offshore of Bejaia exhibits PGA values of 0.235 g and 0.380 g. The Djemila region records lower but still significant values of 0.229 g and 0.353 g for the respective return periods. These results emphasize the heightened seismic hazard in these areas, highlighting the importance of incorporating both standard maximum ground motions into seismic zoning updates and the design of earthquake-resistant structures to enhance regional safety and resilience.