Azimuth Dependence in Topographical Site Effects: Case of ABZH Broadband Station (North of Algeria)

Layadi, Khalissa; Semmane, Fethi; Yelles‐Chaouche, Abdelkrim

doi:10.1007/978-3-030-73026-0_50

Cited by 4 publications

(3 citation statements)

References 6 publications

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“…The results of our analysis of seismic anisotropy of seismic stations installed in Tunisia region are plotted in Fig 3a The calculated 1D models beneath each station (example in [13]) are interpolated to create the 3D model and shown in V. DISCUSSION The average fast orientation of CABS and TAMR stations are the smallest compared to the rest of the stations. The general trend of the orientations is not uniform; it changes from a station to another (Fig 3).…”

Section: Resultsmentioning

confidence: 97%

“…At 50 km, this concentration is crossed by a high velocity zone of 5.5 km/s of NS direction, giving two separated low velocity zone of 4.5 km/s (Fig 4). This high-velocity entity may be created by the oceanic lithosphere subducting at around 30 Ma caused by the Africa-Iberia convergence conducted to the ALKAPECA terrane dispersion by transporting its various fragments to be collided at Betic, Calabria Alps, Rif, and Kabylie ([4], [13], [14]).…”

Section: Resultsmentioning

confidence: 99%

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Upper Mantle beneath Tunisia from Joint Shear-Wave Splitting and Rayleigh Wave Dispersion Analysis

2023

1st International Conference on Modern and Advanced Research Icmar 2023

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The current study aims to continue the analysis of the seismic anisotropy of Tunisia region and complete the previous studies of northwestern Africa, which helped to identify the deformations of the crust and the upper mantel, allowing us to obtain a geodynamic scenario for the southwestern Mediterranean. Tunisia is located on the boundary between the African and Eurasian plates. We used the method of splitting the shear wave SKS analysis of data from nine broadband seismic stations installed in Algeria, Tunisia, and the surrounding islands, Sardinia and Sicily, to explore the seismic anisotropy of this study area. We obtained 2D tomography of the shear wave velocity, Vs, structure of lithosphere and upper mantle depths ranging from 50 to 300 km using the Raleigh wave dispersion curve with the twostation technique in the 10-200 sec period domain. After analyzing hundreds of seismic data, we obtained the following results: multi-layer seismic anisotropy beneath TAMR and THTN seismic stations installed in northern Tunisia, while the southern station TATN has a single layer. The results of Vs-structure imaging of the second method also confirmed these results of the direction and depth of the deformed layers. Four distinct velocity bodies were found: two with low values (Vs is ~ 4 km/s) in the west and the east, and two with high values (Vs is ~ 5.5 km/s) in the north and the south of the study area.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Upper Mantle beneath Tunisia from Joint Shear-Wave Splitting and Rayleigh Wave Dispersion Analysis

2023

1st International Conference on Modern and Advanced Research Icmar 2023

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“…The engineering bedrock identified in the Chéliff region has a Vs of 1000 m/s ( [2]). Another analysis is mapped for the Algiers region by [8], where the explanation of the low frequency peaks was impossible by a bedrock Vs of 700 m/s, and the most adequate is that of a higher velocity, in the vicinity of 4000 m/s of Paleozoic metamorphosis outcrops in Bouzeréah Massif, Northern border of Mitidja Basin ( [9]) and Djurdjura Massif (Fig. 1).…”

Section: Study Of the Effects Of Sites Constructed In Algerian Urban ...mentioning

confidence: 99%

Synthesis on the Shear Wave Velocity of Engineering and Seismic Bedrocks in Northern Algeria based on Recent Experimental Investigations

2023

1st International Conference on Modern and Advanced Research Icmar 2023

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In the field of civil engineering, knowledge of good rocky ground resistant to collapse minimizes the level of seismic risk, often known as the "engineering bedrock". In lithology, it overlays a harder rock known as "seismic bedrock". The latter is a transition zone between the earth's crust and the surface layers. It is sometimes impossible to carry out deep drilling and investigation techniques to define the engineering substratum for the foundations; in this case we rely on the seismic regulations. In Algeria, after the 2003 Boumerdès earthquake, seismology studies were expanded in order to better understand the Algerian crust on both the marine and continental sides. Furthermore, studies on seismic risk reduction in urban environments are increasingly focusing on the phenomenon of site effects or local amplification. Several experimental studies conducted in Algeria as part of seismic microzoning programs have defined the existence of these two substrate interfaces by identifying the natural frequencies of the ground. In this work, we describe the findings of numerous key research that reached the seismic bedrock in Algeria. It is classified as having two geological natures: Mesozoic with a shear wave velocity, Vs, less than 3000 m/s, and metamorphosed Paleozoic with Vs greater than 3500 m/s.

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Site characterization of Algerian broadband seismic stations using earthquake and ambient vibration data: topographic and lithological site-effects investigation

et al. 2023

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Azimuth Dependence in Topographical Site Effects: Case of ABZH Broadband Station (North of Algeria)

Cited by 4 publications

References 6 publications

Upper Mantle beneath Tunisia from Joint Shear-Wave Splitting and Rayleigh Wave Dispersion Analysis

Upper Mantle beneath Tunisia from Joint Shear-Wave Splitting and Rayleigh Wave Dispersion Analysis

Synthesis on the Shear Wave Velocity of Engineering and Seismic Bedrocks in Northern Algeria based on Recent Experimental Investigations

Site characterization of Algerian broadband seismic stations using earthquake and ambient vibration data: topographic and lithological site-effects investigation

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