1980 El Asnam earthquake

1980 El Asnam earthquake
1980 El Asnam earthquake is located in Algeria
Algiers
Algiers
1980 El Asnam earthquake
Oran
Oran
UTC time1980-10-10 12:25:23
ISC event636856
USGS-ANSSComCat
Local dateOctober 10, 1980 (1980-10-10)
Local time13:25:23
Duration35 seconds
Magnitude7.1 Mw[1]
Depth10 km (6.2 mi)[1]
Epicenter36°12′N 1°22′E / 36.2°N 1.37°E / 36.2; 1.37[1]
FaultEl Asnam[2]
TypeDip-slip[3]
Areas affectedChlef Province
Algeria
Max. intensityMMI X (Extreme)[4]
Tsunami0.7 m (2 ft 4 in)[3]
Aftershocks6.2 Mw Oct 10 at 15:39 UTC[3]
Casualties2,633–5,000 dead[3]
8,369–9,000 injured[3]

The 1980 El Asnam earthquake occurred on October 10 at 13:25:23 local time with a moment magnitude of 7.1 and a maximum Mercalli intensity of X (Extreme). The shock occurred in the Algerian town of El Asnam (now known as Chlef). The shocks were felt over 550 km (340 mi) away, with the initial earthquake lasting 35 seconds.[5] It was the largest earthquake in Algeria, and was followed three hours later by a magnitude 6.2 aftershock. The earthquake created about 42 km (26 mi) of surface rupture and had a vertical slip of up to 4.2 m (14 ft). No foreshocks were recorded.[5] The earthquake was found to have occurred very close to the epicenter of the 1954 Chlef earthquake using joint epicenter determination techniques.[6][7] It occurred at a previously unknown reverse fault.[8]

The earthquake was the largest in the Atlas range since 1790.[6]

In addition to the earthquake, weak tsunami waves were recorded on tide gauges.[9]

The earthquake occurred at a populated region of Algeria, affecting 900,000 people. It destroyed 25,000 houses and made 300,000 inhabitants homeless.[6] In addition to destroying homes, the earthquake also demolished critical infrastructure, including the main hospital, the central mosque, and a girls' school. The hospital was damaged significantly enough that victims had to be transported more than 160 km (100 mi) away to the next nearest hospital. Both events caused considerable damage with at least 2,633 killed and 8,369 injured.[6][10] The earthquake caused approximately $5.2 billion in damage, which was 22% of Algeria's GDP at the time.[5]

  1. ^ a b c Cite error: The named reference ISC-GEM was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference yeats was invoked but never defined (see the help page).
  3. ^ a b c d e Cite error: The named reference PAGER-CAT was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference NGDC was invoked but never defined (see the help page).
  5. ^ a b c "El Asnam Algeria 1980 (CAR)". GEM ECD. Archived from the original on October 21, 2016. Retrieved October 21, 2016.
  6. ^ a b c d Ambraseys, Nicolas (1981). "The El Asnam (Algeria) earthquake of 10 October 1980; conclusions drawn from a field study". Quarterly Journal of Engineering Geology and Hydrogeology. 14 (2): 143–148. doi:10.1144/gsl.qjeg.1981.014.02.05. S2CID 140701882. Archived from the original on 27 February 2023. Retrieved 14 July 2009.
  7. ^ Cite error: The named reference geoscience was invoked but never defined (see the help page).
  8. ^ "Comments for the Significant Earthquake". NOAA. Archived from the original on December 16, 2022. Retrieved October 21, 2016.
  9. ^ "Comments for the Significant Earthquake". NOAA. Archived from the original on April 29, 2020. Retrieved October 21, 2016.
  10. ^ "Thousands feared dead in Algerian quake". BBC News. October 10, 1980. Archived from the original on August 7, 2009. Retrieved July 14, 2009.