The Global Historical Megatsunamis Catalog (GHMCat) is a significant compilation of data on megatsunamis—extreme waves exceeding 35 meters in height—spanning from 1674 to 2024. The catalog, developed by researchers Mercedes Ferrer and Luis I. González-de-Vallejo, identifies 40 documented events and provides detailed analyses of their causes, impacts, and geographical distribution.
Megatsunamis differ from regular tsunamis in their scale and origin. While common tsunamis are caused by offshore earthquakes and dissipate over wide areas, megatsunamis are localized events triggered by massive geological disruptions, such as large landslides, volcanic eruptions, or asteroid impacts. These events often occur in confined environments, such as fjords, bays, or lakes, leading to concentrated destruction. For example, the 1958 Lituya Bay event in Alaska produced a wave that reached an unprecedented height of 525 meters.
The catalog reveals that regions like Alaska and Norway are particularly prone to these events due to their unique geological features. Most megatsunamis are associated with subaerial landslides, which generate massive waves through the rapid displacement of water. These findings help establish a clearer understanding of the conditions that lead to megatsunamis and highlight the importance of preparedness in high-risk areas.
This compilation aims to improve disaster prevention and risk management by identifying patterns and providing data critical for monitoring potential hazards. While megatsunamis are rare, their devastating effects necessitate awareness and ongoing scientific study.
For more information, the catalog can be accessed in GeoHazards 2024.
DAAD-Gastprofessorin at Julius-Maximilians-Universität Würzburg