Earthquakes focal mechanism and stress field pattern in the northeastern part of Egypt

Mohamed, Emad K.; Hassoup, Awad; Elenean, K. M. Abou; Othman, Adel; Hamed, Diaa-Eldin M.K.

doi:10.1016/j.nrjag.2015.09.001

Cited by 20 publications

(16 citation statements)

References 25 publications

(28 reference statements)

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“…Southward, the stress field orientation shows a progressive clockwise rotation toward a NW-SE attitude along the Gulf of Aqaba. Overall, along this portion of the Sinai/Arabia plate boundary the stress field shows both normal and strike-slip faulting features with generally low R values (as indicated by the FPSs stress results) and therefore highlighting the coexistence of both faulting stress regimes in agreement with previous stress inversions [5,18,19] and with the extensional pattern of the geodetic strain-rates computed in this study (Figure 5). [25] pointed out that motion along the Dead Sea fault system primarily occurs under a primary left-lateral strike-slip faulting regime while the normal faulting regime reflects the extensional component of the fault system.…”

Section: Crustal Stress Fieldsupporting

confidence: 89%

“…Information on the stress field of the investigated area came from the intensive hydrocarbon exploratory drilling carried out in the last six decades [14,15] and earthquake fault plane solutions (FPSs) [15][16][17][18][19]. Achieved results highlighted a spatial variation of the stress field with (i) pure normal faulting mechanism to normal faulting with a secondary strike-slip component on the region comprised between Dahshour, western Cairo and the Gulf of Suez [15,[17][18][19], (ii) strike-slip faulting with a secondary normal slip component or normal faulting with a strike-slip component for the Gulf of Aqaba region [5,15,18,19] and (iii) strike-slip faulting for the surrounding Aswan region [15,17,19]. All these studies inferred a sub-horizontal extensional stress with roughly WSW-ENE orientations on both the Gulf of Suez and the Gulf of Aqaba and NNE-SSW orientations on Dahshour and Aswan regions.…”

Section: Introductionmentioning

confidence: 99%

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Crustal Strain and Stress Fields in Egypt from Geodetic and Seismological Data

et al. 2021

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The comparison between crustal stress and surface strain azimuthal patterns has provided new insights into several complex tectonic settings worldwide. Here, we performed such a comparison for Egypt taking into account updated datasets of seismological and geodetic observations. In north-eastern Egypt, the stress field shows a fan-shaped azimuthal pattern with a WNW–ESE orientation on the Cairo region, which progressively rotated to NW–SE along the Gulf of Aqaba. The stress field shows a prevailing normal faulting regime, however, along the Sinai/Arabia plate boundary it coexists with a strike–slip faulting one (σ1 ≅ σ2 > σ3), while on the Gulf of Suez, it is characterized by crustal extension occurring on near-orthogonal directions (σ1 > σ2 ≅ σ3). On the Nile Delta, the maximum horizontal stress (SHmax) pattern shows scattered orientations, while on the Aswan region, it has a WNW–ESE strike with pure strike–slip features. The strain-rate field shows the largest values along the Red Sea and the Sinai/Arabia plate boundary. Crustal stretching (up to 40 nanostrain/yr) occurs on these areas with WSW–ENE and NE–SW orientations, while crustal contraction occurs on northern Nile Delta (10 nanostrain/yr) and offshore (~35 nanostrain/yr) with E–W and N–S orientations, respectively. The comparison between stress and strain orientations over the investigated area reveals that both patterns are near-parallel and driven by the same large-scale tectonic processes.

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Section: Crustal Stress Fieldsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Crustal Strain and Stress Fields in Egypt from Geodetic and Seismological Data

et al. 2021

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“…4), as indicated by studies on the focal mechanism (e.g. Gu et al 1976;Sandu and Zaicenco 2009;Zeng et al 2013;Dologlou 2014;Mohamed et al 2015). Yet, the prerequisite of localised stress-accumulation on a fault-plane is the roughness or undulant shape of the plane, which determines the existence of the seismogenic zone.…”

Section: Model Of Fef and Its Relationship To Psea And Eqmentioning

confidence: 88%

“…2), geological studies on granite formation and distribution (Fig. 3), and seismological studies on the focal mechanism solutions (Gu et al 1976;Ekström and England 1989;Sipkin 1994;Sandu and Zaicenco 2009;Zeng et al 2013;Dologlou 2014;Mohamed et al 2015), we present a synthetic model to explain the seismogenic process of a causative fault and the correlation between the process and the geophysical phenomena observed on the ground surface, i.e., the PSEAs and the EQs.…”

Section: Model Of Fef and Its Relationship To Psea And Eqmentioning

confidence: 99%

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Fracture Electric Field: A Synthetic Model for Seismogenic Process and its Relationship with Preseismic Electric Anomalies and Earthquakes

Chen¹,

Chen²

2020

Preprint

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Unobservability of the seismogenic process in a causative fault that makes earthquake (EQ) prediction difficult. Although the relationship between the preseismic electric anomaly (PSEA) and the mainshock indicates that both the PSEA and EQ may originate from same course proceeding in the seismogenic zone, as evidenced by experiments on stressed granite, geological interpretation of those observations, and experiments was limited by the traditional granite formation theory. Based on new information from studies of granite genesis and geotransects, we present a synthetic model, the fracture electric field (FEF), to elucidate the seismogenic process on a causative fault and its logical linkage with the PSEA and EQ. The model is constrained with various data from the 1975 Haicheng EQ and verified by survey data from an FEF monitor station constructed in 2012 in Guangzhou, China. The main conclusions are as follows:(1) An uneven or undulant fault-plane is the prerequisite for stress-accumulation in the locality of the plane to form a seismogenic zone;(2) The position of the continental seismic layer corresponds to that of the crustal granite layer, suggesting that the seismogenic process of any causative fault in continents may produce the PSEA;(3) A normal FEF exists in a causative fault and can be measured beyond the preseismic situation. Thus, it is possible to detect the seismogenic process of a fracture through monitoring the variation of its FEF when the fracture enters a preseismic situation.

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Biochemical responses and antioxidant defense mechanisms in Channa Striatus exposed to Bisphenol S

Mohan,

Jacob,

Malini

et al. 2024

J Biochem & Molecular Tox

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Bisphenol S (BPS), a BPA analog and a safer alternative, is utilized in a diverse range of industrial applications, such as making polycarbonate plastics, epoxy resins, thermal receipt papers, and currency bills. Recently, the increased use of BPS in containers and packages for daily life has been interrogated due to its identical chemical structure and probable endocrine‐disrupting actions as BPA has. The present study aimed to evaluate the alterations in biochemical indices and antioxidant enzymes as certain indicators of the endocrine‐disrupting effect of BPS in Channa striatus, a freshwater fish. BPS‐exposed fish species were subjected to three sub‐lethal concentrations of BPS (1, 4, and 12 ppm) and observed after an interval of 7 and 21 days. Exposure to BPS caused a reduction in the level of protein in muscle, gonads and the liver due to an impairment of protein synthesis. Levels of cholesterol in the muscle, gonads, and liver of BPS‐exposed fish were found to be decreased after treatment, indicating either an inhibition of cholesterol biosynthesis in the liver or reduced absorption of dietary cholesterol. The levels of antioxidant enzymes such as superoxide dismutase, catalase, glutathione reductase and glutathione peroxidase showed remarkable increases, while the activity of glutathione S‐transferase decreased considerably, indicating the antioxidant defense mechanism to counteract the oxidative stress induced by BPS. Moreover, a significant increase was noted in the level of lipid peroxidation products, like malondialdehyde and conjugate diene, which represent biomarkers of oxidative stress. The histoarchitecture changes were also observed in the liver, muscle and gonads of BPS‐treated fish species. The present study showed that sub‐lethal exposure to BPS significantly influenced the activities of these enzymes and peroxidation byproducts. From this study, it is concluded that BPS‐caused toxic effects in fish species lead to an imbalance in the antioxidant defense system. It is clearly indicated that BPS toxicity could lead to susceptible oxidative stress in various tissues and could damage vital organs.

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Earthquakes focal mechanism and stress field pattern in the northeastern part of Egypt

Cited by 20 publications

References 25 publications

Crustal Strain and Stress Fields in Egypt from Geodetic and Seismological Data

Crustal Strain and Stress Fields in Egypt from Geodetic and Seismological Data

Fracture Electric Field: A Synthetic Model for Seismogenic Process and its Relationship with Preseismic Electric Anomalies and Earthquakes

Biochemical responses and antioxidant defense mechanisms in Channa Striatus exposed to Bisphenol S

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