Even tsunamis, a series of very long wavelength ocean waves caused by the sudden displacement of water, were typically attributed to earthquakes, the evidences collected in marine surveys imply that submarine mass movements such as landslides and submarine slumps are also responsible. They are important mechanism in shaping and moving vast quantities of sediment down continental slopes. Submarine landslides, which often accompany large earthquakes, as well as collapses of volcanic edifices, can also disturb the overlying water column as sediment and rock slump downslope and are redistributed across the sea floor. A landslide on the move leaves a void behind itself that the ocean instantly fills, possibly creating tsunami waves which may overrun nearby coastal areas in a matter of minutes and cause damage. By gaining an understanding of how mass movements occur, it may become possible to infer what triggered these failures, even speculate on their timing.

Mass movements are initially identified using the bathymetry data and bolstered using side-scan sonar data. However, it is difficult to determine whether a mass movement is a slump, debris flow, rockfall, etc. based solely on surficial morphology. Therefore seismic data is needed. All these tools allow us to make the morphometric measurements.

On the basis of multibeam bathymetric data collected by Turkish Navy, shallow and conventional seismic reflection profiles gathered by different institutions, slope failures in the eastern Marmara Sea were investigated.

As deducted from bathymetric and seismic data, the size of the slope failures is mainly controlled by tectonics, sedimentation, erosion patterns and slope. In the Çınarcık Basin, average slopes adjacent to slope failures are actually inclined 17° to the north and 7-10° to the south, which is extremely steep for submarine slopes. In addition, the sedimentation rate is much higher in the deep basins than those on the shelf area and push-ups.

Offshore Yalova, the landslides are disintegrative. They have characteristic scar morphology, but lack bathymetric evidence of failed material at the base of the failure. On the other hand, the slope failure deposits along the eroded continental slopes of the Istanbul shelf are cohesive landslides. They are associated with a particular scar directly up gradient. Their headscarps, steep upslope regions at the top of the scar, are generally integrated with the shelf edge as very well defined on shallow seismic data. The average gradients of the scar slope and the area adjacent to failure are not so different, making interpretation of multibeam bathmetry somewhat difficult. Landslides in weaker sediment, which are usually placed offshore drainage areas, are tend to be larger. In the Çınarcık Basin, the lowermost terminus of the landslides coincide with the very base of the slope where the 1150-1270 m deep flat base of the depression starts abruptly.