J. W. Dewey 1991 <p>Joint epicenter determination of earthquakes that occurred in northern Algeria near Ech Cheliff (named Orleansville in 1954 and El Asnam in 1980) shows that the earthquake of 9 September 1954 (M=6.5) occurred at nearly the same location as the earthquake of 10 October 1980 (M=7.3). The 1954 main shock and earliest aftershocks were concentrated close to the boundaries of segment B (nomenclature of Deschamps et al., 1982; King and Yielding, 1984) of the 1980 fault system, which was to experience approximately 8 m of slip in the 1980 earthquake. Later aftershocks of the 1954 earthquake were spread over a broad area, notably in a region north of the 1980 fault system that also experienced many aftershocks to the 1980 earthquake. The closeness of the 1954 main shock and earliest aftershocks to the 1980 segment B implies that the 1954 earthquake involved either 1) rupture of segment B proper, or 2) rupture of a distinct fault in the hanging wall of footwall block of segment B.&nbsp;</p> application/pdf 10.1785/BSSA0810020446 en Seismological Society of America The 1954 and 1980 Algerian earthquakes: Implications for the characteristic-displacement model of fault behavior article