Nazli Ismail, a researcher from Syiah Kuala University in Banda Aceh, announced the results of his analysis of sediment layers in Aceh's Lhoong Cave. "About 11 major tsunamis have taken place in Aceh in the past 7,500 years," he told Tempo three weeks ago.

In Lhoong Cave lay the mystery of ancient paleo-tsunamis from the Indian Ocean, Nazli said. Their traces were evident in sediment layers that now line the cave. Their patterns describe overlapping