2003 Boumerdès earthquake
 Algiers
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| Date | May 21, 2003 |
|---|---|
| Origin time | 18:44:21 UTC |
| Magnitude | 6.8 Mw |
| Depth | 12 km (7.5 mi) |
| Epicenter | 36°55′N 3°43′E / 36.91°N 3.71°ECoordinates: 36°55′N 3°43′E / 36.91°N 3.71°E |
| Type | Dip-slip |
| Areas affected | Algeria |
| Total damage | $5 billion |
| Max. intensity | X (Extreme) |
| Peak acceleration | .58g |
| Tsunami | 3 m (10 ft) |
| Casualties | Approximately 2,266 dead and 10,261 injured. |
The 2003 Boumerdès earthquake occurred on May 21 at 19:44:21 local time in northern Algeria. The shock had a moment magnitude of 6.8 and a maximum Mercalli intensity of X (Extreme). The epicentre of the earthquake was located near the town of Thénia in Boumerdès Province, approximately 60 km east of the capital Algiers. The quake was the strongest to hit Algeria in more than twenty years – since 1980, when a magnitude 7.1 earthquake resulted in at least 2,633 deaths.
Northern Algeria is situated at the boundary between the African Plate and the Eurasian Plate, thus creating a zone of compression. This zone of compression manifests itself by several thrust and faults. Due to this location between two tectonic plates, many earthquakes occurred in the region. The mechanism of the earthquake on May 21 corresponds to a northeast-striking thrust fault named Zemmouri fault which was identified for the first time after this earthquake. According to the United States Geological Survey,
The earthquake occurred in the boundary region between the Eurasian plate and the African plate. Along this section of the plate boundary, the African plate is moving northwestward against the Eurasian plate with a velocity of about 6 mm per year. The relative plate motions create a compressional tectonic environment, in which earthquakes occur by thrust-faulting and strike-slip faulting. Analysis of seismic waves generated by this earthquake shows that it occurred as the result of thrust-faulting.
Approximately 2,266 people were killed, 10,261 injured, and 200,000 left homeless as a result of the earthquake. Reports indicate more than 1,243 buildings were completely or partially destroyed. Infrastructure was predictably damaged in Algiers, Boumerdès, Réghaïa and Thénia; roads in Algeria are generally of high quality, but many city streets and local roads were difficult to traverse because of debris from collapsed buildings. Bridges are constructed similarly to those in the US, with precast steel girders supporting a concrete deck. A few days after the earthquake, three major highway bridges were still closed. The last highway bridge to open was the Hussein Dey Bridge on July 5.
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Wikipedia