Algerian Earthquake: Geological setting, source mechanism, and some lessons for earthquake hazard in other African coastal cities (Cape Town included) C.J.H. Hartnady Cape Disaster Debrief 2004 DMISA Western Cape Branch, 2004 Feb 04 Algerian Earthquake : 2003 May 21 18h 44m 20.1s Statistics  Epicentre: 36.964ºN 3.634ºE  Magnitudes: Mw 6.7; MS 6.9; mb 6.5 (USGS)  Death toll: 2266+  Injured: 10261  Homeless: 150000  >1234 buildings damaged or destroyed Cost: US$100 million  (2 m tsunami damaged boats on Balearic Islands) Geotectonic Background Global Plate Tectonics  NB-EU-NA Plate Motions EU NA mas1 NB nklg hrao suth goug African Plate Neotectonics NB->EU NB->AR @ ~6 mm/yr @ ~7 mm/yr NB = Nubia  SM = Somalia  UN = Ukerewe  Nyanza RV = Rovuma  TG = Transgariep Stable NB  <0.5 mm/yr LW - Lwandle  TG->SM @ ~3 mm/yr Hartebeesthoek (HRAO) Motion GPS velocity of HRAO relative to ITRF2000 NB-EU Plate Kinematics Seismotectonic Framework Ba L Am GSHAP: Ibero-Maghreb region G lobal S eismic H azard A ssessment P 1365 rogram 1755 1980 El Asnam Historic earthquake disasters 1960 Agadir Lisbon – 1 November 1755 Death toll > 50000 St Alexius Estimated Magnitude ~ M 9 w