A study of Paleo-Mega tsunamis in the Sunda Trench using far- field signatures in coastal and near shore sedimentary archives of Sri Lanka.

Pradeep Nalaka Ranasinghage, Geology & Geophysics
Jeffrey P. Donnelly, Geology & Geophysics


Project summary

Recent tsunamis in Japan, Chille and Indonesia highlight the importance of better preparedness for this unpreventable natural hazard.  Recognizing Tsunami recurrence interval, using signatures of paleo-tsunamis preserved in sediments, is very important in planning for the next possible tsunami, but there are no well constrained tsunami recurrence intervals for some of the major subduction zones including the Indonesian subduction zone.  Recent work in far field locations including India and Sri Lanka could document evidence for several 2004-type mega tsunamis in the northern part of the Indonesian subduction zone.  However, the record is not complete probably due to ‘mega tsunami gaps” in the history or lack of sediments preserving paleo-tsunami signatures.

To address this critical data gap we will construct the recurrence interval of mega paleotsunamis in the northern part of the subduction zone from new offshore and onshore sedimentary environments around Sri Lanka.  Eastern and southeastern coast of Sri Lanka is ideal to study paleo-tsunamis because it is directly attacked by tsunamis generated in the northern part of the subduction zone.  Sediment cores will be collected from suitable environments and Laboratory studies will be carried out to distinguish tsunami sand layers and to age dating them.

Field work will be carried out in collaboration with the Geological Survey of Sri Lanka.  This project will open avenues for a comprehensive study with federal funding by providing basic data and making links with local geosciences institutes.