The hypocentral distribution and fault-plane solutions of intermediate-depth earthquakes in South Kyushu, Japan were investigated. The dipping seismic zone bends at a depth of 60--70 km and continues to a depth of 180 km and the majority of the source mechanisms are down-dip-extension (DE). Non-DE earthquakes are concentrated at depths of 100--120 km beneath the volcanic region, that is, upward and westward of the dipping seismic zone, and have vertical P- and horizontal T-axes. The occurrence of Non-DE earthquakes may be related to dehydration processes at the base of the mantle wedge. ¿ American Geophysical Union 1995