21 May 2003 Boumerdès Earthquake: Numerical Investigations of the Rupture Mechanism Effects on the Induced Tsunami and Its Impact in Harbors

In order to obtain a fair and reliable description of the wave amplitude and currents in harbors due to the tsunami generated by the 21 May 2003 Boumerdès earthquake (Algeria), a numerical investigation has been performed with a standard hydraulic numerical model combined with various source fault models. Seven different rupture models proposed in literature to represent high frequency seismic effects have been used to simulate tsunami generation. The tsunami wave propagation across the Western Mediterranean Sea and in bays and harbors of the Balearic Islands is simulated, and results are checked against sea level measurements. All of them resulted in a significant underestimation of the tsunami impact on the Balearic coasts. In the paper the best fitting source model is identified, justifying the energy intensification of the event to account for low frequency character of tsunami waves. A fair correspondence is pointed out between damages to boats and harbor infrastructures, reported in newspapers, and wave intensity, characterized by level extremes and current intensity. Current speed and amplitude thresholds for possible damage in harbors suggested respectively by Lynett et al., doi.org/10.1002/2013GL058680, and Muhari et al., doi.org/10.1007/s11069-015-1772-0, are confirmed by the present analysis.

Nonlinear Deterministic Study of Seismic Microzoning of a City in North of Algeria

This paper presents also an overview of seismic microzonation studies of the city of Mohammadia-Algiers, which are important for a detailed ground movement modeling of urban cities. According to the seismic history of the city, one extraordinary earthquake event has been taken into consideration is Boumerdes earthquake (Algeria, May 21, 2003, magnitude Mw=6.5), that caused a huge damage. Thereby, the variability prediction of the seismic ground movement in a given built-up area, it is considered as an effective tool for planning appropriate urban development and understanding both seismic risk and damage pattern, caused by a strong movement event. We note that the shaking level is mainly described in terms of both maximum ground acceleration and visualized amplification by using response spectra. The study is carried out in two steps: - a detailed mapping of the geology and geotechnical properties of the area - numerical modeling of expected ground motions during earthquakes. A qualitative microzonation of the Mohammadia-Algiers city is presented, and it is discussed by comparing it to the historically reported damage of the 2003 Boumerdes earthquake. Finally, this study deals with the seismic microzonation map development, based on a SIG geological model.

Evolution of Soil Settlements under a Rockfill Dam Based on Potential Earthquake Harmfulness (PEH) 'Case of Boumerdes Earthquake, Algeria 2003'

Earthquakes are part of the natural cataclysms that are responsible for the destruction of entire cities, causing the deaths of millions of people and often have disastrous economic consequences. Therefore, it is important to consider measures of the intensity of seismic movement in risk analysis (Potential Earthquake Harmfulness ‘PEH’). The purpose of this study is to model the mass of soil under a rockfill embankment in order to evaluate the soil settlement under the effect of an earthquake of Boumerdes (Algeria 2003) using “plaxis” finite element code. The PEH characterizes in our study the Aria intensity IA(t) and the cumulative absolute velocity CAV(t), on the one hand, and on the other hand, empirical correlations between the indicators of harmfulness (PEH) and the settlements under the base of the dike. The correlations thus obtained (Uy-PEH) are slightly influenced by the gravitational loads and a tighter dispersion of the point cloud is observed on the correlations (Uy-IA).

Numerical Analysis of Keddara Dam under Seismic Motion

The Boumerdes earthquake of May 21, 2003 in Algeria, which widely felt within a radius of ~ 400 km, caused damage in five provinces. Numerous structures have been devastated, others suffered of damages. Keddara rockfill dam which is situated approximately at 20 km from the epicentre was strongly shaken during this seismic event and can undergo significant deformations. In this study, numerical analysis of Keddara rockfill dam under Boumerdes earthquake is performed. It is mainly focus on the seismic amplification at different level of the dam under the main shock with dominant frequency close to the natural frequency of the dam. The low coherence between the input and the structural output indicates the need of nonlinear analysis of the dam under the spatial variation in excitation. Furthermore, the effect of plasticity on the seismic response is investigated by using maximum acceleration which is one of the most important properties selected. The analysis of the dam under stochastic non-uniform excitation is conducted using a 2-D finite difference modeling by using the software Fast Lagrangian Analysis of Continua (FLAC). The final results obtained after successive analyses on the dam configuration incorporating the nonlinear soil properties are presented.

Analysis the dynamic response of earth dam in free vibration and forced by introducing the effect of the interaction dam foundation

The present study concerns the analysis of the dynamic response of earth dam, in free and forced vibration (under the effect of earthquake) using the finite element method. The analysis is carried out at the end of dam construction without filling. The behavior of the dam materials and the foundation is linear elastic. In free vibration, to better understand the effect of the dam foundation interaction, we will take into account different site conditions and see their influence on the free vibration characteristics of the dam. In forced vibration, to study the seismic response of the dam, the system is subjected to the acceleration of the Boumerdes earthquake of May 21, 2003 recorded at the station n ° 2 of the dam of Kaddara in the base, with a parametric study taking into account the influence of the main parameters such as the mechanical properties of the soil: rigidity, density.

Reuse Of Djenane Abd-El-Tif, An Emblematic Islamic Garden In Algiers

<p class="Keywords">Djenane Abd-el-Tif is an example of an Algerian summer residence dating from the Ottoman era. This type of building is not very well-known and remains marginalized in research that is more interested in the townhouses of the medina of Algiers. Yet, the gardens, the ingenious irrigation systems, fountains, and other patterns of Islamic gardens make of these <em>djenane</em> a unique typology worth exploring and preserving. Indeed, Islamic garden design is an art in itself and any restoration or conservation work should preserve the authenticity of its characteristics. The djenane Abd-el-Tif was fully restored following the damage caused by the Boumerdès earthquake in 2003. This led to the discovery of various elements that are particularly informative about its architecture and composition. It also highlighted the existence of valuable Islamic garden patterns, together with the djenane’s exceptional flora, which could provide added-value to the tourism potential of such residences. However, if restoration work has saved the djenane Abd-el-Tif, its garden with its Islamic design characteristics is not yet fully investigated nor listed as a cultural heritage. This article presents the djenane as a cultural heritage and argues that right restoration and reuse could contribute to enhancing knowledge about Islamic garden design in North Africa.</p>