4 research outputs found
The new Algerian Digital Seismic Network (ADSN): towards an earthquake early-warning system
Seismic monitoring in Algeria has seen great changes since the Boumerdes
earthquake of 21 May 2003. Indeed, the installation of a new digital
seismic network has resulted in a significant upgrade of the previous analog
telemetry network.
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During the last four years, the number of stations in operation has
increased substantially from 25 to 69, and 20 of these are broadband, 2 are
very broadband, 47 are short period. 21 are equipped with accelerometers.
They are all managed by Antelope software from Kinemetrics (US Cie), and
they are all connected in real time and use various modes of transmission
(e.g., satellite, internet, mobile phone). The spatial repartition of the
stations now cover most of northern Algeria. In addition, 70 GPS stations
have recently been added to this seismological network, most of them
collocated with the seismological stations.
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Since the installation of the network, the records of local or distant
events have improved significantly. The automatic processing of the data in a
few minutes allows alert messages to be distributed to Civil Defense and
other national authorities to react promptly to any emergency. The current
strategy is to improve the data quality, to increase the density of the
network by adding about 50 new stations, to reduce the processing time, and
to reduce the time needed to send out an alert message. The result should be
greatly improved network performance, which will lead to an effective
early-warning system
Strong Algerian earthquake strikes near capital city
International audienceOn 21 May 2003, a damaging earthquake of Mw 6.8 struck the region of Boumerdes 40 km east of Algiers in northern Algeria (Figure 1). The main shock, which lasted ∼36–40 s, had devastating effects and claimed about 2300 victims, caused more than 11,450 injuries, and left about 200,000 people homeless. It destroyed and seriously damaged around 180,000 housing units and 6000 public buildings with losses estimated at $5 billion. The main shock was widely felt within a radius of ∼400 km in Algeria. To the north, the earthquake was felt in southeastern Spain, including the Balearic Islands, and also in Sardinia and in southern France