Rashad Sawires currently works at the Department of Geology, Assiut University, Egypt. Rashad does research in seismotectonics, seismic hazard, and various applied geophysical topics. Current research projects include seismicity, seismotectonics and seismic hazard of Egypt, crustal stress and strain fields in Egypt, and seismic hazard of Western Mexico. Supervisors: Prof. Hamza Ahmed Ibrahim, Prof. Raafat El-Shafei Fat-Helbary, Prof. Jose Antonio Pelaez and Prof. Miguel A. Santoyo Phone: 00201223926828 Address: Department of Geology, Faculty of Science, Assiut University, 71516, Assiut, Egypt
Some Egyptian building codes have been published in Egypt during the last three decades. These co... more Some Egyptian building codes have been published in Egypt during the last three decades. These codes are the Regulations of the Egyptian Society of Earthquake Engineering (ESEE, 1988), and the Egyptian Codes for the Calculation of Loads and Forces (ECP-201: 1993, 2004, 2008, and 2011). Great variations in the representation and values of the seismic action parameters can be observed among them. The current representation of the seismic action (ECP-201, 2011), which is based mainly on the seismic hazard study done by Riad et al. (2000), and follows the same framework adopted in Eurocode 8 (2004), do not give a specific ground-motion value for each Egyptian city, but it just divides the whole territory of Egypt into six broad zones, assigning to each of them a unique seismic action value. For zones 1, 2, 3 and 4, the peak ground acceleration (PGA) values are 0.10, 0.13, 0.15 and 0.20 g, respectively. Zone 5 is subdivided into two sub-zones, 5a and 5b, with PGA values of 0.25 and 0.30 g, respectively. Recently, an updated probabilistic seismic hazard for Egypt, in terms of PGA and spectral acceleration (SA) values, for both rock and stiff-soil site conditions, has been assessed. Seismic hazard results have been computed for the whole territory, and specific seismic hazard values have been estimated in detail for mostly important cities in Egypt. Moreover, taking into account the noticeable differences among the input seismic actions in the previous building codes, a new approach for establishing the design spectra, using only two SA values for oscillation periods of 0.2 and 1.0 s, is suggested and recommended for the upcoming building code in Egypt. The procedure developed by Malhotra (2005) for the establishment of the design spectra was used here. The obtained design response spectra using this approach have been analysed, comparing it with the computed uniform hazard spectra and the ECP-201 (2011) design spectra for several selected Egyptian cities. It clearly appears that, for a specific location, it is a good approach to include a design spectra defined by only two values (the computed SA values for 0.2 and 1.0 s) in the building code.
In this study, a seismogenic source zone model for the Algeria-Morocco region is proposed for sei... more In this study, a seismogenic source zone model for the Algeria-Morocco region is proposed for seismic forecasting and seismic hazard studies. The delineation includes five zones based on available seismic and geological data. The zone model shown in figure 1, includes the Moroccan Meseta, the Rif, the Tell zone, the High Plateaux and the Atlas zone. Earthquake occurrence process in this region is modeled and analyzed using recent earthquake catalogs for northern Morocco and northern Algeria compiled in former studies (Peláez et al., 2007; Hamdache et al., 2010). For these catalogs, dependent events were identified and removed by adapting Gardner and Knopoff declustering procedure to the study region. Magnitudes of completeness were estimated using different methods, then the Poissonian character of the obtained sub-catalogs was analyzed. The b-value of the Gutenberg-Richter recurrence relationship, considered as an area specific seismic hazard parameter, was initially computed using the Weichert (1980) approach. In order to characterize each seismogenic zone we have introduced a new parameter named seismic activity, defined as the number of earthquakes with magnitude above MW 4.0 in each seismogenic zone since 1925 by each 10 years and 10000 km2. It can be derived that in the Tell seismogenic zone happens of the order of 2.6 events with magnitude above MW 4.0 from 1925, by each decade and by each square cell of 100 km side. The b-value estimation has been improved by using an extension of the Aki-Utsu b-value estimator for incomplete earthquake catalogs (Kijko and Smit, 2012). Taking into account that the maximum possible magnitude is an important parameter required by earthquake engineering community, disaster management agencies and insurance industry, a detailed analysis has been performed using different statistical methods related to the quality of the earthquake data file. As introduced by Kijko (2004) and Kijko and Singh (2011), these procedures are free from subjective assumptions and only depend on seismic data. From a statistical point of view, the estimation methods are divided into three classes: a) parametric procedures, b) non-parametric procedures, and c) based on the fit of the cumulative distribution function of earthquake magnitudes. Thus, the maximum possible magnitude is analyzed at each seismogenic zone and its probability distribution function is derived. Then, we derive the activity rate λ(m) for events above the magnitude m, and the return period for different magnitudes. The analysis has been performed at each seismogenic zone of the proposed model.
The present work concerns with using electrical resistivity, seismicity, and excavating data to i... more The present work concerns with using electrical resistivity, seismicity, and excavating data to investigate the subsurface geological characteristics and their structure and competence for construction purposes at a proposed site in Assiut New City, Egypt. The Dipole-pole configuration was used for the resistivity data acquisition. One-dimensional numerical inversion of individual DC resistivity was applied to enhance the processing of the results for better achievement of the study aims. Models obtained from the 2D inversion of each station for constructing geo-electric sections which exhibit the main geo-electric characteristics of the shallow geological units and their heterogeneities in the site. Furthermore, a proposed seismic source model and its related seismicity parameters have been employed in seismic hazard assessment study for the investigated area. The interpreted geoelectrical sections show three-four layers. Their structure and lateral variation were resolved. Also, the competence of layers for civil engineering foundation was revealed from seismicity parameters investigation.
In this study, a seismogenic source zone model for the Algeria-Morocco region is proposed for sei... more In this study, a seismogenic source zone model for the Algeria-Morocco region is proposed for seismic forecasting and seismic hazard studies. The delineation includes five zones based on available seismic and geological data. The zone model includes the Moroccan Meseta, the Rif, the Tell zone, the High Plateaux and the Atlas zone. Earthquake occurrence process in this region is modelled and analyzed using recent and updated earthquake catalogs for northern Morocco and northern Algeria compiled in former studies (Peláez et al. 2007; Hamdache et al. 2010). For these catalogues, dependent events were identified and removed by adapting Gardner and Knopoff declustering procedure to the characteristics of the study region. Magnitudes of completeness were estimated using different methods, then the Poissonian character of the obtained sub-catalogs was analyzed. The b-value of the Gutenberg-Richter recurrence relationship, considered as an area-specific seismic hazard parameter, was initially computed using the Weichert (1980) approach. In order to characterize each seismogenic zone we have used a new parameter named seismic activity, defined as the number of earthquakes with magnitude above Mw 4.0 in each seismogenic zone since 1925 by each 10 years and 10000 km 2. The obtained results show for example, in the Tell zone, the seismic activity is equal to 2.6 and1.91 in the Rif region. The b-value estimation has been improved by using an extension of the Aki-Utsu b-value estimator for incomplete earthquake catalogs (Kijko and Smit, 2012). Taking into account that the maximum possible magnitude is an important parameter required by earthquake engineering community, disaster management agencies and insurance industry, a detailed analysis has been performed using different statistical methods, free from subjective assumptions and only related to the quality of the earthquake data file. Thus, the maximum possible magnitude, using parametric and non-parametric procedures, is analyzed at each seismogenic zone and its probability distribution function is derived. Then, we derive the activity rate m for events above the magnitude m , the return period for different magnitudes and the probability of exceeding a magnitude m during a time period of T years. The analysis has been performed at each seismogenic zone of the proposed model.
Since October 2012 till now, more than 2200 low magnitude earthquakes have been located in the vi... more Since October 2012 till now, more than 2200 low magnitude earthquakes have been located in the vicinity of the towns of Torreperogil and Sabiote (Jaén), in the easternmost part of Guadalquivir Basin, Spain, an area considered of low seismic hazard. Specific tectonic studies in the region are barely available due to the scarce deformation of Mesozoic and Cenozoic cover. However, the re-interpretation of former seismic reflection profiles reveals blind faults in the Variscan basement that could host the swarm. In this work we show the characteristics of the seismic series, including the relocation of earthquakes with magnitude above m bLg 1.5 using the well-known HypoDD code. In addition to a disperse seismicity composed by very low magnitude events that could not be relocated, two clear seismicity clusters with different characteristics were observed. Both clusters showed an approximate N-S striking, probably related to two N-S striking structures. Additionally, we also assessed a statistical analysis of the sequence. The detailed survey carried out in the epicentral area verified the existence of some fault zones. Although it is also possible to observe dip-slip movements, the main zone shows a tectonic fabric with lateral sense of shearing. Their strike and kinematics are in agreement with one of the two nodal planes of the computed focal mechanism.
In this study, a seismogenic source zone model for the Algeria-Morocco region is proposed for sei... more In this study, a seismogenic source zone model for the Algeria-Morocco region is proposed for seismic forecasting and seismic hazard studies. The delineation includes five zones based on available seismic and geological data. The zone model shown in figure 1, includes the Moroccan Meseta, the Rif, the Tell zone, the High Plateaux and the Atlas zone. Figure 1. Map showing the five seismogenic zones included in the proposed model Earthquake occurrence process in this region is modeled and analyzed using recent earthquake catalogs for northern Morocco and northern Algeria compiled in former studies (Peláez et al., 2007; Hamdache et al., 2010). For these catalogs, dependent events were identified and removed by adapting Gardner and Knopoff declustering procedure to the study region. Magnitudes of completeness were estimated using different methods, then the Poissonian character of the obtained sub-catalogs was analyzed. The b-value of the Gutenberg-Richter recurrence relationship, considered as an area-specific seismic hazard parameter, was initially computed using the Weichert (1980) approach.
Probabilistic seismic hazard analysis in terms of peak ground acceleration (PGA) and spectral acc... more Probabilistic seismic hazard analysis in terms of peak ground acceleration (PGA) and spectral acceleration (SA) values was assessed for the Egyptian territory. Eighty-eight potential seismic sources (for shallow-and intermediate-depth seismicity) in and around Egypt were identified and characterized based on an updated and unified earthquake catalogue spanning the time period from 2200 B.C. until 2013. Earthquake recurrence rates were computed, from both instrumental and historical data, for the defined seismic sources. Six well-known ground motion attenuation models were selected to predict the ground motion for the different tectonic environments in and around Egypt. Finally, a logic tree approach was followed, after a sensitivity analysis, to consider the epistemic uncertainty in different inputs (b-value, maximum expected magnitude and ground motion attenuation model). In the present study, we show the seismic hazard deaggregation results, in terms of distance and magnitude, for the most important cities in Egypt to help understanding the relative contributions of the different seismic sources. Seismic hazard deaggregation for PGA, 0.2, 1.0 and 2.0 s SA, for 10% probability of exceedance in 50 years (return period of 475 years), was computed in detail. The deaggregation graphs were drawn considering bins of 0.5 for magnitude and 25 km for distance. The mean and modal values of magnitude and distance, to identify the distribution of control earthquakes that contribute to exceedance of the considered SA level were also computed. In general, the results at most of the cities, indicate that the distance to the seismic sources which mostly contributes to the seismic hazard is mainly controlled by the nearby seismic sources (especially for PGA). However, the more distant events contribute more to the hazard for larger spectral periods (for 1.0 and 2.0 s SA). For instance, the control earthquake for Cairo has a moment magnitude (MW) values in the range 5.0-5.5 and a focal distance between 0 and 25 km for PGA, 0.2, and 1.0 s SA, whereas for 2.0 s the distance remains the same but the magnitude become 6.0-6.5. However, for Port Said (located along the Mediterranean Sea coast), values of 7.0-7.5 MW and 375-400 km for the control earthquake has been obtained for all spectral periods. A significant result of this type of work is that seismic hazard deaggregation provides useful data on the distance and magnitude of the contributing seismic sources to the hazard in a certain place, which can be applied to generate scenario earthquakes and select acceleration records for seismic design.
Probabilistic seismic hazard analysis in terms of peak ground acceleration (PGA) and spectral acc... more Probabilistic seismic hazard analysis in terms of peak ground acceleration (PGA) and spectral acceleration (SA) values was assessed for the Egyptian territory. Eighty-eight potential seismic sources (for shallow-and intermediate-depth seismicity) in and around Egypt were identified and characterized based on an updated and unified earthquake catalogue spanning the time period from 2200 B.C. until 2013. Earthquake recurrence rates were computed, from both instrumental and historical data, for the defined seismic sources. Six well-known ground-motion attenuation models were selected to predict the ground motion for the different tectonic environments in and around Egypt. Finally, a logic-tree approach was followed, after a sensitivity analysis, to consider the epistemic uncertainty in different inputs (b-value, maximum expected magnitude and ground-motion attenuation model). In the present study, we show the seismic hazard deaggregation results, in terms of distance and magnitude, for the most important cities in Egypt to help understanding the relative contributions of the different seismic sources. Seismic hazard deaggregation for PGA, 0.2, 1.0 and 2.0 s SA, for 10% probability of exceedance in 50 years (return period of 475 years), was computed in detail. The deaggregation graphs were drawn considering bins of 0.5 for magnitude and 25 km for distance. The mean and modal values of magnitude and distance, to identify the distribution of control earthquakes that contribute to exceedance of the considered SA level were also computed. In general, the results at most of the cities, indicate that the distance to the seismic sources which mostly contributes to the seismic hazard is mainly controlled by the nearby seismic sources (especially for PGA). However, the more distant events contribute more to the hazard for larger spectral periods (for 1.0 and 2.0 s SA). For instance, the control earthquake for Cairo has a moment magnitude (MW) values in the range 5.0-5.5 and a focal distance between 0 and 25 km for PGA, 0.2, and 1.0 s SA, whereas for 2.0 s the distance remains the same but the magnitude become 6.0-6.5. However, for Port Said (located along the Mediterranean Sea coast), values of 7.0-7.5 MW and 375-400 km for the control earthquake has been obtained for all spectral periods. A significant result of this type of work is that seismic hazard deaggregation provides useful data on the distance and magnitude of the contributing seismic sources to the hazard in a certain place, which can be applied to generate scenario earthquakes and select acceleration records for seismic design.
Some Egyptian building codes have been published in Egypt during the last three decades. These co... more Some Egyptian building codes have been published in Egypt during the last three decades. These codes are the Regulations of the Egyptian Society of Earthquake Engineering (ESEE, 1988), and the Egyptian Codes for the Calculation of Loads and Forces (ECP-201: 1993, 2004, 2008, and 2011). Great variations in the representation and values of the seismic action parameters can be observed among them. The current representation of the seismic action (ECP-201, 2011), which is based mainly on the seismic hazard study done by Riad et al. (2000), and follows the same framework adopted in Eurocode 8 (2004), do not give a specific ground-motion value for each Egyptian city, but it just divides the whole territory of Egypt into six broad zones, assigning to each of them a unique seismic action value. For zones 1, 2, 3 and 4, the peak ground acceleration (PGA) values are 0.10, 0.13, 0.15 and 0.20 g, respectively. Zone 5 is subdivided into two sub-zones, 5a and 5b, with PGA values of 0.25 and 0.30 g, respectively. Recently, an updated probabilistic seismic hazard for Egypt, in terms of PGA and spectral acceleration (SA) values, for both rock and stiff-soil site conditions, has been assessed. Seismic hazard results have been computed for the whole territory, and specific seismic hazard values have been estimated in detail for mostly important cities in Egypt. Moreover, taking into account the noticeable differences among the input seismic actions in the previous building codes, a new approach for establishing the design spectra, using only two SA values for oscillation periods of 0.2 and 1.0 s, is suggested and recommended for the upcoming building code in Egypt. The procedure developed by Malhotra (2005) for the establishment of the design spectra was used here. The obtained design response spectra using this approach have been analysed, comparing it with the computed uniform hazard spectra and the ECP-201 (2011) design spectra for several selected Egyptian cities. It clearly appears that, for a specific location, it is a good approach to include a design spectra defined by only two values (the computed SA values for 0.2 and 1.0 s) in the building code.
In this study, a seismogenic source zone model for the Algeria-Morocco region is proposed for sei... more In this study, a seismogenic source zone model for the Algeria-Morocco region is proposed for seismic forecasting and seismic hazard studies. The delineation includes five zones based on available seismic and geological data. The zone model shown in figure 1, includes the Moroccan Meseta, the Rif, the Tell zone, the High Plateaux and the Atlas zone. Earthquake occurrence process in this region is modeled and analyzed using recent earthquake catalogs for northern Morocco and northern Algeria compiled in former studies (Peláez et al., 2007; Hamdache et al., 2010). For these catalogs, dependent events were identified and removed by adapting Gardner and Knopoff declustering procedure to the study region. Magnitudes of completeness were estimated using different methods, then the Poissonian character of the obtained sub-catalogs was analyzed. The b-value of the Gutenberg-Richter recurrence relationship, considered as an area specific seismic hazard parameter, was initially computed using the Weichert (1980) approach. In order to characterize each seismogenic zone we have introduced a new parameter named seismic activity, defined as the number of earthquakes with magnitude above MW 4.0 in each seismogenic zone since 1925 by each 10 years and 10000 km2. It can be derived that in the Tell seismogenic zone happens of the order of 2.6 events with magnitude above MW 4.0 from 1925, by each decade and by each square cell of 100 km side. The b-value estimation has been improved by using an extension of the Aki-Utsu b-value estimator for incomplete earthquake catalogs (Kijko and Smit, 2012). Taking into account that the maximum possible magnitude is an important parameter required by earthquake engineering community, disaster management agencies and insurance industry, a detailed analysis has been performed using different statistical methods related to the quality of the earthquake data file. As introduced by Kijko (2004) and Kijko and Singh (2011), these procedures are free from subjective assumptions and only depend on seismic data. From a statistical point of view, the estimation methods are divided into three classes: a) parametric procedures, b) non-parametric procedures, and c) based on the fit of the cumulative distribution function of earthquake magnitudes. Thus, the maximum possible magnitude is analyzed at each seismogenic zone and its probability distribution function is derived. Then, we derive the activity rate λ(m) for events above the magnitude m, and the return period for different magnitudes. The analysis has been performed at each seismogenic zone of the proposed model.
The present work concerns with using electrical resistivity, seismicity, and excavating data to i... more The present work concerns with using electrical resistivity, seismicity, and excavating data to investigate the subsurface geological characteristics and their structure and competence for construction purposes at a proposed site in Assiut New City, Egypt. The Dipole-pole configuration was used for the resistivity data acquisition. One-dimensional numerical inversion of individual DC resistivity was applied to enhance the processing of the results for better achievement of the study aims. Models obtained from the 2D inversion of each station for constructing geo-electric sections which exhibit the main geo-electric characteristics of the shallow geological units and their heterogeneities in the site. Furthermore, a proposed seismic source model and its related seismicity parameters have been employed in seismic hazard assessment study for the investigated area. The interpreted geoelectrical sections show three-four layers. Their structure and lateral variation were resolved. Also, the competence of layers for civil engineering foundation was revealed from seismicity parameters investigation.
In this study, a seismogenic source zone model for the Algeria-Morocco region is proposed for sei... more In this study, a seismogenic source zone model for the Algeria-Morocco region is proposed for seismic forecasting and seismic hazard studies. The delineation includes five zones based on available seismic and geological data. The zone model includes the Moroccan Meseta, the Rif, the Tell zone, the High Plateaux and the Atlas zone. Earthquake occurrence process in this region is modelled and analyzed using recent and updated earthquake catalogs for northern Morocco and northern Algeria compiled in former studies (Peláez et al. 2007; Hamdache et al. 2010). For these catalogues, dependent events were identified and removed by adapting Gardner and Knopoff declustering procedure to the characteristics of the study region. Magnitudes of completeness were estimated using different methods, then the Poissonian character of the obtained sub-catalogs was analyzed. The b-value of the Gutenberg-Richter recurrence relationship, considered as an area-specific seismic hazard parameter, was initially computed using the Weichert (1980) approach. In order to characterize each seismogenic zone we have used a new parameter named seismic activity, defined as the number of earthquakes with magnitude above Mw 4.0 in each seismogenic zone since 1925 by each 10 years and 10000 km 2. The obtained results show for example, in the Tell zone, the seismic activity is equal to 2.6 and1.91 in the Rif region. The b-value estimation has been improved by using an extension of the Aki-Utsu b-value estimator for incomplete earthquake catalogs (Kijko and Smit, 2012). Taking into account that the maximum possible magnitude is an important parameter required by earthquake engineering community, disaster management agencies and insurance industry, a detailed analysis has been performed using different statistical methods, free from subjective assumptions and only related to the quality of the earthquake data file. Thus, the maximum possible magnitude, using parametric and non-parametric procedures, is analyzed at each seismogenic zone and its probability distribution function is derived. Then, we derive the activity rate m for events above the magnitude m , the return period for different magnitudes and the probability of exceeding a magnitude m during a time period of T years. The analysis has been performed at each seismogenic zone of the proposed model.
Since October 2012 till now, more than 2200 low magnitude earthquakes have been located in the vi... more Since October 2012 till now, more than 2200 low magnitude earthquakes have been located in the vicinity of the towns of Torreperogil and Sabiote (Jaén), in the easternmost part of Guadalquivir Basin, Spain, an area considered of low seismic hazard. Specific tectonic studies in the region are barely available due to the scarce deformation of Mesozoic and Cenozoic cover. However, the re-interpretation of former seismic reflection profiles reveals blind faults in the Variscan basement that could host the swarm. In this work we show the characteristics of the seismic series, including the relocation of earthquakes with magnitude above m bLg 1.5 using the well-known HypoDD code. In addition to a disperse seismicity composed by very low magnitude events that could not be relocated, two clear seismicity clusters with different characteristics were observed. Both clusters showed an approximate N-S striking, probably related to two N-S striking structures. Additionally, we also assessed a statistical analysis of the sequence. The detailed survey carried out in the epicentral area verified the existence of some fault zones. Although it is also possible to observe dip-slip movements, the main zone shows a tectonic fabric with lateral sense of shearing. Their strike and kinematics are in agreement with one of the two nodal planes of the computed focal mechanism.
In this study, a seismogenic source zone model for the Algeria-Morocco region is proposed for sei... more In this study, a seismogenic source zone model for the Algeria-Morocco region is proposed for seismic forecasting and seismic hazard studies. The delineation includes five zones based on available seismic and geological data. The zone model shown in figure 1, includes the Moroccan Meseta, the Rif, the Tell zone, the High Plateaux and the Atlas zone. Figure 1. Map showing the five seismogenic zones included in the proposed model Earthquake occurrence process in this region is modeled and analyzed using recent earthquake catalogs for northern Morocco and northern Algeria compiled in former studies (Peláez et al., 2007; Hamdache et al., 2010). For these catalogs, dependent events were identified and removed by adapting Gardner and Knopoff declustering procedure to the study region. Magnitudes of completeness were estimated using different methods, then the Poissonian character of the obtained sub-catalogs was analyzed. The b-value of the Gutenberg-Richter recurrence relationship, considered as an area-specific seismic hazard parameter, was initially computed using the Weichert (1980) approach.
Probabilistic seismic hazard analysis in terms of peak ground acceleration (PGA) and spectral acc... more Probabilistic seismic hazard analysis in terms of peak ground acceleration (PGA) and spectral acceleration (SA) values was assessed for the Egyptian territory. Eighty-eight potential seismic sources (for shallow-and intermediate-depth seismicity) in and around Egypt were identified and characterized based on an updated and unified earthquake catalogue spanning the time period from 2200 B.C. until 2013. Earthquake recurrence rates were computed, from both instrumental and historical data, for the defined seismic sources. Six well-known ground motion attenuation models were selected to predict the ground motion for the different tectonic environments in and around Egypt. Finally, a logic tree approach was followed, after a sensitivity analysis, to consider the epistemic uncertainty in different inputs (b-value, maximum expected magnitude and ground motion attenuation model). In the present study, we show the seismic hazard deaggregation results, in terms of distance and magnitude, for the most important cities in Egypt to help understanding the relative contributions of the different seismic sources. Seismic hazard deaggregation for PGA, 0.2, 1.0 and 2.0 s SA, for 10% probability of exceedance in 50 years (return period of 475 years), was computed in detail. The deaggregation graphs were drawn considering bins of 0.5 for magnitude and 25 km for distance. The mean and modal values of magnitude and distance, to identify the distribution of control earthquakes that contribute to exceedance of the considered SA level were also computed. In general, the results at most of the cities, indicate that the distance to the seismic sources which mostly contributes to the seismic hazard is mainly controlled by the nearby seismic sources (especially for PGA). However, the more distant events contribute more to the hazard for larger spectral periods (for 1.0 and 2.0 s SA). For instance, the control earthquake for Cairo has a moment magnitude (MW) values in the range 5.0-5.5 and a focal distance between 0 and 25 km for PGA, 0.2, and 1.0 s SA, whereas for 2.0 s the distance remains the same but the magnitude become 6.0-6.5. However, for Port Said (located along the Mediterranean Sea coast), values of 7.0-7.5 MW and 375-400 km for the control earthquake has been obtained for all spectral periods. A significant result of this type of work is that seismic hazard deaggregation provides useful data on the distance and magnitude of the contributing seismic sources to the hazard in a certain place, which can be applied to generate scenario earthquakes and select acceleration records for seismic design.
Probabilistic seismic hazard analysis in terms of peak ground acceleration (PGA) and spectral acc... more Probabilistic seismic hazard analysis in terms of peak ground acceleration (PGA) and spectral acceleration (SA) values was assessed for the Egyptian territory. Eighty-eight potential seismic sources (for shallow-and intermediate-depth seismicity) in and around Egypt were identified and characterized based on an updated and unified earthquake catalogue spanning the time period from 2200 B.C. until 2013. Earthquake recurrence rates were computed, from both instrumental and historical data, for the defined seismic sources. Six well-known ground-motion attenuation models were selected to predict the ground motion for the different tectonic environments in and around Egypt. Finally, a logic-tree approach was followed, after a sensitivity analysis, to consider the epistemic uncertainty in different inputs (b-value, maximum expected magnitude and ground-motion attenuation model). In the present study, we show the seismic hazard deaggregation results, in terms of distance and magnitude, for the most important cities in Egypt to help understanding the relative contributions of the different seismic sources. Seismic hazard deaggregation for PGA, 0.2, 1.0 and 2.0 s SA, for 10% probability of exceedance in 50 years (return period of 475 years), was computed in detail. The deaggregation graphs were drawn considering bins of 0.5 for magnitude and 25 km for distance. The mean and modal values of magnitude and distance, to identify the distribution of control earthquakes that contribute to exceedance of the considered SA level were also computed. In general, the results at most of the cities, indicate that the distance to the seismic sources which mostly contributes to the seismic hazard is mainly controlled by the nearby seismic sources (especially for PGA). However, the more distant events contribute more to the hazard for larger spectral periods (for 1.0 and 2.0 s SA). For instance, the control earthquake for Cairo has a moment magnitude (MW) values in the range 5.0-5.5 and a focal distance between 0 and 25 km for PGA, 0.2, and 1.0 s SA, whereas for 2.0 s the distance remains the same but the magnitude become 6.0-6.5. However, for Port Said (located along the Mediterranean Sea coast), values of 7.0-7.5 MW and 375-400 km for the control earthquake has been obtained for all spectral periods. A significant result of this type of work is that seismic hazard deaggregation provides useful data on the distance and magnitude of the contributing seismic sources to the hazard in a certain place, which can be applied to generate scenario earthquakes and select acceleration records for seismic design.
Journal of Volcanology and Geothermal Research, 2019
Ceboruco volcano is one of the largest volcanoes of the Trans-Mexican Volcanic Belt (TMVB), which... more Ceboruco volcano is one of the largest volcanoes of the Trans-Mexican Volcanic Belt (TMVB), which extends along central Mexico. Among the western TMVB, Ceboruco Volcano comes in the second place after Colima Volcano in its activity. Also, it is considered as the only one that has historically-documented eruptions. Few geo-physical studies have been published with the aim of studying the internal structure of the volcano. In the current work, and throughout the support of the CeMIEGeo-P24 geothermal exploration project, we aim to de-lineate the possible subsurface structural trends, to determine the approximate depth to the basement surface, and to provide an illustrative 3D model for its subsurface structure. To achieve such goals, a detailed analysis of the aeromagnetic data for the volcano area was performed. 2D interpretation was carried out for the aeromagnetic data. Edge detection filters, such as Tilt Derivative, and Analytic Signal, were used to map the contact/faults within the study area. In addition, 3D inversion was used to image the subsurface structure of the volcano. Aeromagnetic data was inverted using the GMSYS-3D inversion program by applying Parker algorithm. Four subsurface layers at depths of 250, 500, 750 and 1000 m were assumed during the inversion process. Results indicate that the limits "boundary" of the subsurface magma chamber of the volcano can be traced easily from the first subsurface layer. A secondary structure line appears towards the east from the volcano boundary and it can be observed from the inversion of the second and third layers. This indicates that both, the base of the volcano and the structure line, stem from the same source. Finally, they disappear in the inversion results for the last layer, which concludes that we reach the basement above which the volcano is formed. Combination of all obtained results with the geological information, helped to understand the main structure of the Ceboruco volcano.
The study of groundwater potential in Wadi El-Assiuoti is of a prime importance for both current ... more The study of groundwater potential in Wadi El-Assiuoti is of a prime importance for both current and future development. In this paper the groundwater occurrences are investigated using integrated; 1) geophysical well logging (Self potential, Resistivity and Gamma Ray), 2) subsurface lithologic data and 3) hydraulic data (trans-missivity, transmissibility, hydraulic conductivity and storativity) in addition to reviewing all studies on Wadi El-Assiuoti. Different petrophysical parameters (formation water resistivity, formation factor, porosity, perme-ability, salinity and shale volume) are computed. These parameters are very necessary to identify the aquifers characteristics in the surveyed area. The integration between geophysical and hydrogeological data shows the possibility of two water bearing formation (Quaternary and Plio-Pleistocene). Generally, porosity and perme-ability values of these aquifers decrease toward the west. The aquifers exist under unconfined to semi confined conditions. The wide range values of both well efficiency and hydraulic conductivity indicate heterogeneity in the lithology and hydraulic characteristics of the aquifer materials. The computed transmissibility values indicate that the water-bearing sediments in the area under investigation are generally of high productivity. In some localities due to the heterogeneity of sediment, the water-bearing sediments are of moderate productivity. Recently , due to the increase of drilling activities at the middle part of the studied area some problems concerning the groundwater potential and high salinity in the area are happening.
Seismic hazard in terms of mean peak ground acceleration (PGA) and spectral acceleration (SA) val... more Seismic hazard in terms of mean peak ground acceleration (PGA) and spectral acceleration (SA) values has been computed for Egypt using both historical and instrumental earthquake data. For this purpose, an updated earthquake catalog, spanning the time period from 2200 B.C. to 2013, has been compiled for Egypt as well as its surrounding regions and is prepared to be used in a new probabilistic seismic-hazard assessment of Egypt. The earthquakes sizes were unified in terms of the moment magnitude scale. A new seismic source model for the seismic activity in and around Egypt, consisting of a total of 88 seismic zones (for shallow-and intermediate depth seismicity), was considered in this new assessment. The seismicity parameters have been specifically computed for 35 seismic sources covering the Egyptian territory and the Eastern Mediterranean region. A logic-tree design was set up to consider the epistemic uncertainty in the Gutenberg–Richter b-value, maximum possible magnitude (M max), and the selected ground-motion prediction equations. Seismic-hazard computations for rock-site conditions with 10% and 5% probability of exceed-ance in 50 years were carried out. In addition, uniform hazard spectra for twelve, among the most important and populated cities in Egypt, are computed and compared with the most recent Egyptian building code values. It is interesting to highlight that the maximum hazard values are observed at the Gulf of Aqaba region, specifically around the epicentral location of the biggest Egyptian recorded earthquake of 22 No-vember 1995 (M w 7.2) Aqaba earthquake. The obtained seismic-hazard values for Nuweiba city (located in this region) for mean PGA and SA (0.1 s) are 0:29g and 0:74g, respectively, for a return period of 475 years.
<p>The necropolis of Qubbet el-Hawa is located in West-Aswan, Upper Egypt. ... more <p>The necropolis of Qubbet el-Hawa is located in West-Aswan, Upper Egypt. It looks like a huge dune covering the massive Nubian Sandstone Group, hosting one of the most densely occupied cemeteries of Ancient Egypt, dating back to c. 2500 B.C. to the Roman Period. Here we present the used methodology and the conducted ground-penetrating radar (GPR) survey accomplished in the Qubbet El-Hawa site.</p><p>Three different geological formations have been differentiated in the studied area. From bottom to top, the Abu Agag, the Timsah and the Um Barmil formations, which mainly belong to the Nubian Sandstone Group. The conducted GPR survey was accomplished in the Timsah Formation, the most heterogeneous formation of all of them, in which along its outcrops can be observed several stratigraphic discontinuities, being usually the alternation of lutite (mainly claystone), sandstone, and iron oxides, arranged in alternating layers varied in thickness from 5 to 10 cm, and from 30 to 50 cm thick blocks.</p><p>The studied area, 20 m width × 45 m length, showing a near-constant slope of about 35°, was surveyed using 250 and 500 MHz shielded antennas in a dense array pattern. Although dry eolian sand and sandstone rocks do not display a clear difference in their electromagnetic characteristics, the conducted survey was able to discriminate/define the interface among the underlying sandstone and the sand cover. This good behavior could be attributed to the different overlapping layers including ferruginous sediments and claystone. This was possible even when the studied area exhibits a steep slope, as well as many loose rocks in some parts, coming from the outcrops, that made the measurement difficult to carry out in some cases.</p><p>The interface among the underlying sandstone formation and the sand cover is acceptably resolved, providing some very useful data to archaeologists about the near-surface shape of the bedrock and their possible willingness to host some graves.</p>
Workshop Alboran domain and Gibraltar Arc: geological research and natural hazards, Granada (Spai... more Workshop Alboran domain and Gibraltar Arc: geological research and natural hazards, Granada (Spain), 16-18 october, 2019
This file incorporates the final gathered and analyzed focal mechanisms for local earthquakes tha... more This file incorporates the final gathered and analyzed focal mechanisms for local earthquakes that present moment magnitudes equal to or greater than 3.0, and occurred from 1951 to 2020, in Egypt. The current dataset comprises a total number of 462 focal mechanism solutions covering the spatial region from 21° to 34°N latitudes and from 24° to 38°E longitudes. Reported parameters for each included earthquake in this dataset are the origin time (year-month-date) and date (hour-minute-second), coordinates in terms of longitude and latitude, depth and magnitude values, faulting parameters for the two nodal planes in terms of the strike, dip and rake angles, azimuth and plunge of the principal strain axes (P-,T-, and B-axes), as well as the faulting type (Normal "NF", Normal with strike-slip component "NS", Strike-slip "SS", Reverse "TF", Reverse with strike-slip component "TS", or Undefined "U" faulting).
This file incorporates the final gathered and analyzed focal mechanisms for local earthquakes tha... more This file incorporates the final gathered and analyzed focal mechanisms for local earthquakes that present moment magnitudes equal to or greater than 3.0, and occurred from 1951 to 2020, in Egypt. The current dataset comprises a total number of 462 focal mechanism solutions covering the spatial region from 21° to 34°N latitudes and from 24° to 38°E longitudes. Reported parameters for each included earthquake in this dataset are the origin time (year-month-date) and date (hour-minute-second), coordinates in terms of longitude and latitude, depth and magnitude values, faulting parameters for the two nodal planes in terms of the strike, dip and rake angles, azimuth and plunge of the principal strain axes (P-,T-, and B-axes), as well as the faulting type (Normal "NF", Normal with strike-slip component "NS", Strike-slip "SS", Reverse "TF", Reverse with strike-slip component "TS", or Undefined "U" faulting).
Focal mechanism solutions for earthquakes that taken place in Mexico during the period from 1963 ... more Focal mechanism solutions for earthquakes that taken place in Mexico during the period from 1963 to 2015.
Focal mechanism solutions for earthquakes that taken place in Mexico during the period from 1963 ... more Focal mechanism solutions for earthquakes that taken place in Mexico during the period from 1963 to 2015.
Earthquake and focal mechanism data have been compiled from various local, regional and internati... more Earthquake and focal mechanism data have been compiled from various local, regional and international sources. Large earthquake events (MW≥ 6.5) have been carefully revised for their epicentral locations and magnitudes from trusted publications. Different magnitude-conversion relationships, compatible with local and regional ones, has been established to obtain unified moment magnitude estimates for the whole catalog. Completeness periods for the declustered catalog were estimated for the definition of appropriate seismic source models for the whole territory. The final unified Poissonian earthquake catalog spans from 1787 to 2018, covering a spatial extent of 13⁰N to 33⁰N and 91⁰W to 117⁰W.
Earthquake and focal mechanism data have been compiled from various local, regional and internati... more Earthquake and focal mechanism data have been compiled from various local, regional and international sources. Large earthquake events (MW≥ 6.5) have been carefully revised for their epicentral locations and magnitudes from trusted publications. Different magnitude-conversion relationships, compatible with local and regional ones, has been established to obtain unified moment magnitude estimates for the whole catalog. Completeness periods for the declustered catalog were estimated for the definition of appropriate seismic source models for the whole territory. The final unified Poissonian earthquake catalog spans from 1787 to 2018, covering a spatial extent of 13⁰N to 33⁰N and 91⁰W to 117⁰W.
An updated and unified earthquake catalog for Mexico spans from 1787 to 2018, covering a spatial ... more An updated and unified earthquake catalog for Mexico spans from 1787 to 2018, covering a spatial extent of 13⁰N to 33⁰N and 91⁰W to 117⁰W.
An updated and unified earthquake catalog for Mexico spans from 1787 to 2018, covering a spatial ... more An updated and unified earthquake catalog for Mexico spans from 1787 to 2018, covering a spatial extent of 13⁰N to 33⁰N and 91⁰W to 117⁰W.
Independent/Poissonian earthquakes (Mw ≥ 6.5) for Mexico covering the spatial distribution betwee... more Independent/Poissonian earthquakes (Mw ≥ 6.5) for Mexico covering the spatial distribution between 91 to 117 W longitudes and 13 to 33 N latitudes during the time period of 1787 to 2018.
Independent/Poissonian earthquakes (Mw ≥ 6.5) for Mexico covering the spatial distribution betwee... more Independent/Poissonian earthquakes (Mw ≥ 6.5) for Mexico covering the spatial distribution between 91 to 117 W longitudes and 13 to 33 N latitudes during the time period of 1787 to 2018.
This dataset contains key characteristics about the data described in the Data Descriptor An upda... more This dataset contains key characteristics about the data described in the Data Descriptor An updated and unified earthquake catalog from 1787 to 2018 for seismic hazard assessment studies in Mexico. <br> Contents: <br> 1. human readable metadata summary table in CSV format 2. machine readable metadata file in JSON format <br> <br> Versioning Note:Version 2 was generated when the metadata format was updated from JSON to JSON-LD. This was an automatic process that changed only the format, not the contents, of the metadata.<br>
This dataset contains key characteristics about the data described in the Data Descriptor An upda... more This dataset contains key characteristics about the data described in the Data Descriptor An updated and unified earthquake catalog from 1787 to 2018 for seismic hazard assessment studies in Mexico. <br> Contents: <br> 1. human readable metadata summary table in CSV format 2. machine readable metadata file in JSON format <br> <br> Versioning Note:Version 2 was generated when the metadata format was updated from JSON to JSON-LD. This was an automatic process that changed only the format, not the contents, of the metadata.<br>
In this study, a seismogenic source zone model for the Algeria-Morocco region is proposed for sei... more In this study, a seismogenic source zone model for the Algeria-Morocco region is proposed for seismic forecasting and seismic hazard studies. The delineation includes five zones based on available seismic and geological data. The zone model includes the Moroccan Meseta, the Rif, the Tell zone, the High Plateaux and the Atlas zone. Earthquake occurrence process in this region is modelled and analyzed using recent and updated earthquake catalogs for northern Morocco and northern Algeria compiled in former studies (Peláez et al. 2007; Hamdache et al. 2010). For these catalogues, dependent events were identified and removed by adapting Gardner and Knopoff declustering procedure to the characteristics of the study region. Magnitudes of completeness were estimated using different methods, then the Poissonian character of the obtained sub-catalogs was analyzed. The b-value of the Gutenberg-Richter recurrence relationship, considered as an area-specific seismic hazard parameter, was initial...
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Conference Paper by Rashad Sawires