Several large shallow earthquakes (Ms>7.0) have occurred along the Middle American Trench since the installation of the WWSSN network. Included are the 1965, 1968, and 1978 Oaxaca events, the 1970 Chiapas event, the 1973 Colima event, and the 1979 Petatlan event. These earthquakes have been studied in an attempt to identify similarities and differences between them that may lead to a better understanding of fracture and subduction processes. The events have seismic moments ranging from 1.0¿1027 dyne cm for the 1968 event to 3.2¿1027 dyne cm for the 1978 event. All events are of predominantly thrust type, consistent with subduction to the northeast of the Cocos plate. Body waves for the 1965, 1968, 1978, and 1979 events along the trench indicate rather simple faulting processes. These events all had focal depths of 15 to 20 km and stress drops of the order of 10 bars. The 1970 and 1973 events, the easternmost and westernmost, respectively, of the events studied here, are located close to triple junctions for the Cocos-North American-Caribbean plates (1970) and the Cocos-North American-Rivera plates (1973). These two events generated more complex body waves than the Oaxaca and Petatlan quakes. This source complexity may have been related to the more complicated tectonics near the 1970 and 1973 epicenters. This may offer a new perspective to viewing souce complexity in relation to subduction zones.