Attenuation of Intensity for the Zemmouri Earthquake of 21 May 2003 (Mw 6.8): Insights for the Seismic Hazard and Historical Earthquake Sources in Northern Algeria - Historical Seismology: Interdisciplinary Studies of Past and Recent Earthquakes - page 321

marshy deposits which extend over the most recent suburbs such as Bab Ezzouar and
Dar El Beida in the Algiers province. The early Quaternary (Villafranchian) alluvial
deposit made of sand or sand with other components (silt, clay, gravel, sandstone)
and the recent landfill, represented by sandy, silty or argillous deposits, cover the
area from Boumerdes to Zemmouri and Cap Djinet. To the south of the earthquake
area, the Isser, Si Mustapha and Bordj Menaiel cities have the same soil conditions.
4 Damage Assessment and Interpretation
The detailed damage description and other ground effects as well as the intensity
assessment are presented in a previous work by Harbi et al. (2007b). The results
of the macroseismic study of the Zemmouri earthquake, conducted at about 600
locations, allowed drawing with good constraint the spatial distribution of damage
in the form of an isoseismal map (Fig. 3). The NE-SW elongated isoseismals are
accentuated along the Mitidja basin mainly because of the lithological and structural
framework. It is worthwhile to note that the general shape of intensity distribution
appears to be primarily controlled by this sedimentary basin and the isoseismals
seems to be compressed in the SE direction. In some localities such as at Bordj
Menaiel, Baghlia and Bouira the intensities are influenced by smaller scale basins
Fig. 3 Isoseismal map of the Zemmouri earthquake of 21 May 2003 (Mw 6.8, I 0 X EMS), modified
from Harbi et al. (2007b) (Zem: Zemmouri, Z. Bah: Zemmouri Bahri, B. Kfane: Bordj El Kiffane,
BMN: Bordj Menaıel)