5000 Jahre Tsunami-Geschichte am Kap Pakarang (Thailand)
Neubauer, NP, Brill, D, Bruckner, H, Kelletat, D, Scheffers, S & Vott, A 2011, '5000 Jahre Tsunami-Geschichte am Kap Pakarang (Thailand)' Coastline Reports, vol. 17, pp. 81-98.
The 2004 Indian Ocean Tsunami (IOT), generated by an exceptionally strong rupture of the Sunda Arc, devastated vast coastal areas all around the Indian Ocean. Besides killing > 230,000 people and massively destroying human infrastructure its impact became particularly noticeable by erosion and deposition of coastal sediments. Since historical tsunami records are rare in the countries around the Indian Ocean, this geological evidence is of great importance to identify similar events which may have occurred in the past. We studied depositional features of the IOT at Cape Pakarang (SW Thailand) and used them as a reference for potential palaeoevents in the sedimentary record. Amongst others the 2004 tsunami left a sheet of sand commonly several centimeters thick in the coastal plain and dislocated boulders of up to 20 t. For the impact of potential palaeotsunamis we found two indicators: (1) the sediments of the coastal plain were sampled by means of vibra coring. We identified two allochthonous event layers, a homogeneous sandcap embedded in the deposits of a lagoon and a sheet of coral fragments, surrounded by shallow marine sand. For both, radiocarbon dating suggests an age of ca. 1100 cal BP. Due to correlation with contemporaneous palaeotsunami evidence from Northern Sumatra, India and Sri Lanka, the two event layers are interpreted as deposits of an 1100 year old palaeotsunami. (2) Dating 10 coral boulders on the reef platform produced 14C-age estimates between 4500 and 5300 cal BP, with two clusters at 5200 and 4700 cal BP. Additionally, all coral fragments from sediment cores revealed similar ages. Thus, the contemporaneous death of the dated corals point to the impact of two palaeoevents at 5200 and 4700 cal BP, which destroyed large parts of the former reef.