Tsunamis and tsunami sedimentology

Tsunamis are one of the most catastrophic wave motions, which cover a large parts of the sea and behave intricately especially in coastal zones. Studies on tsunami sedimentology have revealed that tsunamis induce various types of sedimentation in marine, lacustrine, and onshore environments. Tsunami deposits are sedimentological evidence of tsunami events. This contribution describes the nature of tsunamis and of tsunami sedimentation as an introduction to this volume. Hydrodynamic aspects are introduced to explain the propagation of tsunamis. The diversity of tsunami deposits is illustrated on the basis of literature data. Onshore tsunami sedimentation is discussed in particular. Tsunami sedimentation appears to depend on the hydrodynamic and hydraulic character of the tsunami. The distribution pattern, grain-size variation, and many other sedimentological structures reflect the characters of the tsunami such as the height, current velocity, and period. Therefore, tsunami sedimentation should be interpreted based on careful consideration of the characteristics of tsunamis. This may result in a reliable reconstruction of ancient tsunami events.