Strong shaking of aerial and subaqueous slopes triggered their failure, that produced avalanched or gravity flow deposits just below the slope. In marine environments, turbidites and subaqueous debris flow deposits may be formed. Tsunamis, associated with earthquakes, may deposit unusual coarse-grained strata. From the depositional ages of the event deposits, age and recurrence intervals of large earthquakes are inferred. For marine sediments, however, the difficulty to calbrate radiocarbon and calendar ages poses a problem to correlate evidence in marine sediments with the records in historical literature and archaeological sites with high accuracy.
Seamount subduction produces characteristic structures on forearc wedges.
A topographic swell and new backthrusts occur landward of a subducting seamount. Behind the seamount, a topographic depression with a scarp is formed at first, and landward dipping normal faults are produced when the seamount subduction proceeds further. Recently, the possibility that topographic highs on subducting plates act as seismogenic asperities is calling attention of many researchers. Another model postulates that subduction of oceanic plateaus and seamount chains increases seismic coupling. Based on precise bathymetry and seismicity data in the Middle America convergent margin off Costa Rica, however, it was proposed that subduction of rough seafloor could cause low interplate coupling along relatively small asperities compared with the regions of flat seafloor covered with sediments which could have large and strong contact zones.