Tsunamite

Tsunamite refers to sedimentary deposits formed by the action of tsunamis. These deposits are distinct from those laid down by regular storm waves or riverine floods, possessing specific characteristics that allow geologists to identify ancient tsunami events. Key features of tsunamite deposits include their coarse grain size, often containing gravel and sand, sometimes interbedded with finer materials like silt and clay. They can exhibit evidence of extreme energy, such as overturned or jumbled bedding, rip-up clasts (fragments of pre-existing sediment), and distinct erosional bases.

The formation of tsunamite involves the rapid and powerful inundation of coastal areas by a tsunami wave, followed by its equally forceful withdrawal. The incoming wave can transport large volumes of sediment from the seafloor or offshore areas inland, depositing them as it loses energy. The receding wave then often erodes the newly deposited material and can transport it further inland or back out to sea. Identifying tsunamite deposits is crucial for understanding past seismic and volcanic activity that may have generated tsunamis, and for assessing tsunami hazard in coastal regions. Paleotsunami research, the study of ancient tsunami events through geological evidence, relies heavily on the analysis of these deposits.