1999 Aïn Témouchent earthquake

Earthquake in Algeria 1999 Aïn Témouchent earthquake Algeria 1999-12-22 17:36:56 1658425 iscgem1658425 1999 12 22 18:36:56 5.6 w y 10 km mi 0 on 35.2 -1.35 region:DZ_type:event inline,title Reverse $60.93 million VII 22–25 dead 175 injured 15,000–25,000 displaced The 1999 Aïn Témouchent earthquake occurred on December 22 at 18:36:56 local time 17:36:56 UTC in northern Algeria. The dip-slip event had a moment magnitude of 5.6 and a maximum Mercalli intensity of VII (Very strong). At least 22 were killed, 175 were injured, and 15,000–25,000 were made homeless. The Belgian Centre for Research on the Epidemiology of Disasters' EM-DAT database and the USGS' National Geophysical Data Center both list financial losses of $60.93 million. Tectonic setting Aïn Témouchent lies within the Tell Atlas mountain range that runs southwest–northeast along the northern coast of Algeria. The current seismicity of the Tell Atlas is a result of continuing convergence of 3–6 mm per year between the African and Eurasian plates, in a northwest–southeast direction. The structures produced by the current phase of tectonics are reverse/thrust faults and fault-related folds. The Quaternary aged Tafna Basin lies to the south of Aïn Témouchent. It is deformed along its northwestern margin by the active Tafna Fault. An anticline is developed in the hanging wall (upper block) of the northwest-dipping Tafna Fault known as the Berdani Fold. Earthquake The earthquake had a magnitude of 5.6 w. The maximum felt intensity was VII on the Medvedev–Sponheuer–Karnik scale (MSK).The area affected by shaking of this level or greater was elongated southwest–northeast 42 km x 19 km across, including Aïn Témouchent at its northeastern end, and the epicenter as determined by the Center of Research in Astronomy, Astrophysics, and Geophysics (CRAAG). The focal mechanism is consistent with reverse faulting on a southwest–northeast trending fault. The earthquake was followed by a sequence of aftershocks, which lasted for the next 14 months. The most important of these were a M3.5 event on May 27, 2000, a M3.7 event on July 30, 2000, and a M3.1 event, followed by another of M2.9 on January 4, 2001. Due to the lack of any surface rupture that might constrain the causative fault, this has been investigated using Interferometric synthetic aperture radar (InSAR). The analysis used European Space Agency (ESA) ERS-2 SAR data. The observed fringes are consistent with a maximum displacement of 1 m on a 20 km long 32°-dipping blind thrust fault. Damage Severe damage was observed in the epicentral area (I≥VII MSK). In Aïn Témouchent the main hospital, several schools and the post office were amongst the buildings badly damaged. Older houses were the most severely affected, many being destroyed. The worst damage was concentrated in areas close to the river that runs through the town. The villages of Ain Allen, Ain Kihal and Ain Tolba were also severely affected. About 3,000 homes were destroyed and a total of 15,000–25,000 were made homeless Between 22 and 25 people were reported as being killed, with about a further 175 injured. Another three people were killed as a result of the M3.7 aftershock on July 30, 2000. See also List of earthquakes in 1999 List of earthquakes in Algeria References ISC-GEM Global Instrumental Earthquake Catalogue (1900–2012) http://www.isc.ac.uk/iscgem/index.php ISC 2016 International Seismological Centre Version 3.0 Significant Earthquake Database https://www.ngdc.noaa.gov/nndc/struts/form?t=101650&s=1&d=1 https://web.archive.org/web/20060929000601/http://www.ngdc.noaa.gov/nndc/struts/form?t=101650&s=1&d=1 dead September 29, 2006 National Geophysical Data Center / World Data Service (NGDC/WDS) National Geophysical Data Center, NOAA 10.7289/V5TD9V7K 1972 Data Set PAGER-CAT Earthquake Catalog https://earthquake.usgs.gov/static/lfs/data/pager/catalogs/ September 4, 2009 United States Geological Survey Version 2008_06.1 InSAR analysis of a blind thrust rupture and related active folding: The 1999 Ain Temouchent earthquake (M w 5.7, Algeria) case study Journal of Seismology 13 4 421–432 2009 Belabbès Samir Meghraoui Mustapha Çakir Ziyadin Bouhadad Youcef 10.1007/s10950-008-9135-x 2009JSeis..13..421B 67833926 https://hal.archives-ouvertes.fr/hal-00478440/file/PEER_stage2_10.1007%252Fs10950-008-9135-x.pdf The Ain Temouchent (Algeria) Earthquake of December 22nd, 1999 Pure and Applied Geophysics 161 3 607–621 2004 Yelles-Chaouche A. K. Djellit H. Beldjoudi H. Bezzeghoud M. Buforn E. 10.1007/s00024-003-2465-2 2004PApGe.161..607Y 10174/6286 free External links M5.6 – northern Algeria – United States Geological Survey 1658425 Aïn Témouchent earthquake Aïn Témouchent earthquake Category:December 1999 in Africa Category:Aïn Témouchent Province Category:Earthquakes in Algeria Category:Buried rupture earthquakes Aïn Témouchent earthquake