Statistical analysis of earthquake catalogs for seismic hazard studies around the Karliova Triple Junction (eastern Turkey)

Ali, Sherif M.; Akkoyunlu, Mehveş Feyza

doi:10.1016/j.jafrearsci.2021.104436

Cited by 5 publications

(1 citation statement)

References 29 publications

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“…Another definition of Mc is the magnitude at which a seismic network provides complete event detection, meaning that no events are missed [32]. In other words, it is the smallest magnitude at which each earthquake in a space-time volume is successfully identified [33][34][35][36].…”

Section: Gr Relationship: MC and B-valuementioning

confidence: 99%

The Impact of Fractal Dimension, Stress Tensors, and Earthquake Probabilities on Seismotectonic Characterisation in the Red Sea

Ali,

Abdelrahman

2023

Fractal Fract

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The frequency–magnitude statistics of 6527 earthquakes with 1.0 ≤ ml ≤ 5.7 and focal depths between 0 and 49 km in the Red Sea region between 1980 and 2021 show that the threshold magnitude, above which most of the Red Sea earthquakes are precisely located, is 1.5. The b-value, which identifies regional stress situations and associated energy release modalities, has a value of 0.75, less than in historical data, and averages between 0.4 and 0.85 as it varies over time, indicating modest stress accumulation. We utilised these instrumental data to examine dynamic stress patterns in the Red Sea region, shedding light on the region’s geodynamics and providing a foundation for estimating the region’s seismic hazard. The computed fractal dimension (Dc) has a relatively high value of 2.3, which is significant for the Red Sea’s geological complexity and structural diversity. This result indicates the regular distribution of Red Sea earthquakes, which occur in clusters or along fault lines. The low b-value and comparatively high Dc were most likely due to major earthquakes in the past and the greater stress they caused. The focal mechanisms of the big earthquakes, predominantly normal solutions, are consistent with the movement and extensional regime. The pressure and tension (P-T) axes show a compression axis trending NW-SE and a tension axis trending NE-SW. According to the stress inversion results, the maximum principal stress (σ1) is oriented vertically, the minimum stress axis (σ3) is subhorizontal and strikes in the NE-SW direction, and the intermediate principal stress (σ2) is trending in the NE-SW direction. The variance in the region that characterises the homogeneity of stress directions within the range is 0.19. The stress ratio (R), which identifies the faulting type, is 0.76, suggesting a normal faulting pattern for the region. The hazard parameters are expressed by the probability of exceedance for 1-, 10-, 50-, and 100-year return periods. The highest probability that an earthquake will occur within a 50-year period is thought to be around 6.0. The largest observed catalogue and instrumental magnitudes in the area, 5.7 and 6.7, respectively, show average recurrence intervals of 36 and 142 years.

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Section: Gr Relationship: MC and B-valuementioning

confidence: 99%

The Impact of Fractal Dimension, Stress Tensors, and Earthquake Probabilities on Seismotectonic Characterisation in the Red Sea

Ali,

Abdelrahman

2023

Fractal Fract

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Seismic quiescence and b-value anomalies preceding the 6th February 2023 earthquake doublet (MW 7.8, MW 7.6) in Kahramanmaraş, Türkiye: a comprehensive analysis of seismic parameters along the East Anatolian Fault Zone

Sharma,

Biswas

2024

Acta Geophys.

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Earthquake Occurrences of the Major Tectonic Terranes for the Arabian Shield and Their Seismic Hazard Implications

Ali

Abdelrahman

2022

Front. Earth Sci.

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The Arabian Shield, which contains a group of diverse terranes accreted during the Late Proterozoic, has experienced considerable historical and recent earthquake activities. From north to south, the Midyan terrane, Tabuk-Neom area, Hijaz terrane, Jeddah terrane, and Asir terrane make up the western section of the Arabian shield. In order to determine the earthquake occurrences and earthquake recurrence characteristics in the study area, an earthquake dataset containing 2,991 seismic events recorded between 1941 and 2019 with magnitudes of 1.0 and 6.2 and depths between 0 and 50 km was examined. The data were compiled by combining phase readings and information, such as origin times, hypocenter parameters, and magnitudes reported by the International Seismological Centre. The maximum likelihood method has been applied to calculate the Gutenberg–Richter recurrence parameters (a- and b-values) and magnitudes of completeness (Mc). The range of b-values is 0.53–1.04, which indicates that the study region experienced different stress level accumulations that cause earthquakes with different magnitudes. The Hijaz terrane is characterized by a high b-value (1.04 ± 0.34), which indicates a relatively low stress regime that resulted from the earthquakes stress release. The Midyan terrane is characterized by a low b-value (0.53 ± 0.10), which could be indicative of a relatively higher stress regime associated with a dominantly extensional stress. Mc values were found to be 1.4 in Midyan and Jeddah terranes. The lower value of Mc at Midyan terrane demonstrates appropriate station distribution and high earthquake rates. However, at Jeddah terrane, the seismic activities are poorly detected that probably lead to the small value of Mc. Higher Mc are evident in Hijaz terrane (Mc = 2.3) and Tabuk-Neom (Mc = 2.4), where the station distribution is very poor. The maximum expected magnitudes (Mmax) are found to be 6.0 for Midyan terrane, 5.4 for Tabuk-Neom, 4.7 for Hijaz terrane, 4.8 for Jeddah terrane, and 7.7 for Asir terrane. The average recurrence intervals of earthquakes with the Mmax are ∼7, ∼20, ∼6, ∼120, and ∼200 years for each seismic terrain, respectively. The probability of occurrence and returned periods of different magnitudes in each region indicate that regions related to the Najd strike-slip fault system are the regions for large probable earthquake occurrences.

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Statistical analysis of earthquake catalogs for seismic hazard studies around the Karliova Triple Junction (eastern Turkey)

Cited by 5 publications

References 29 publications

The Impact of Fractal Dimension, Stress Tensors, and Earthquake Probabilities on Seismotectonic Characterisation in the Red Sea

The Impact of Fractal Dimension, Stress Tensors, and Earthquake Probabilities on Seismotectonic Characterisation in the Red Sea

Seismic quiescence and b-value anomalies preceding the 6th February 2023 earthquake doublet (MW 7.8, MW 7.6) in Kahramanmaraş, Türkiye: a comprehensive analysis of seismic parameters along the East Anatolian Fault Zone

Earthquake Occurrences of the Major Tectonic Terranes for the Arabian Shield and Their Seismic Hazard Implications

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