Aftershocks and Intensity of the Managua Earthquake of 23 December 1972

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Science  10 Aug 1973:
Vol. 181, Issue 4099, pp. 545-547
DOI: 10.1126/science.181.4099.545


Two portable seismic stations and a fixed array of five seismometers were used to record aftershocks in the vicinity of Managua, Nicaragua, after the earthquake of 23 December 1972. Approximately 3000 aftershocks were recorded during a 20-day period in January 1973. Left lateral motion along at least two faults, both trending N40°E, is inferred from the seismic data. This is in good agreement with dislocations mapped at the surface in Managua. The data suggest that the shallow earthquakes of the Managua region are a consequence of north-south compressional stresses and east-west tensional stresses. This is consistent with regional plate movements deduced in other investigations.