Abstract: As high energy tsunami waves reach shallow near-shore environments, the height of the waves increasesand sea water propagates towards the land. During this movement, significant amounts of sediment are transportedinland from the nearshore, foreshore and beach. While a lagoon that is separated from the sea by a low, thin sandbarrier has a relatively calm depositional environment under normal conditions, during a tsunami the sea waterclimbs over the sand barrier and deposits material from the nearshore, foreshore and sand barrier onto inner partsof the lagoon. This phenomenon is the reason why investigation of sedimentary sequences in lagoons reveals thesedimentary traces of past tsunamis. In this study, the physical and geochemical properties of sediments in two ca.3.2 m-long cores collected from Karine Lagoon on the coast of Aydın-Söke (western Turkey) were investigated inorder to determine the traces of past tsunamis in the Aegean Sea. An ITRAX micro-XRF scanner was used to obtain0.2 mm-resolution radiographic images and 1mm-resolution XRF data from the cores. High-resolution analysis detected three heterogeneous and high-density intercalations within the relatively homogenous and occasionallylaminated background sediments. XRF data revealed that these intercalations had significantly higher Ca/Ti valuescompared to the background sediments, i.e. they were rich in carbonates. Observation under a stereo-microscopedetermined that while the background sediments contained fresh bivalve shells smaller than 1 cm in diameter, theintercalations contained weathered/broken bivalve shells approximately 4 cm in diameter. Considering the physicaland geochemical observations together, it was concluded that the intercalations containing relatively coarser andintensely-weathered bivalve shells are deposits that were transported from the sand barrier of the lagoon duringtsunamis. Radiocarbon dating shows that three intercalations in the sequence of Karine Lagoon were depositedduring the tsunamis, from AD 1956, 1650 and 1303.