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
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.