This study has attempted to define the seismic characteristics of El Salvador; based on a lack of accuracy in the data it was possible to state only preliminary conclusions. The major Salvadoran seismicity is apparently due to a subducting slab that defines a Benioff zone with relatively simple features: it begins at a depth of about 50 km., is some 40 km. thick, and dips some 45 degrees to the northeast. It follows the general pattern of the Middle America trench system. The temporal seismicity in the magnitude range of 4-5
