It is speculated that the tsunami was caused by activity around a volcanic island in the strait, Krakatoa, which is 156 km west of the Indonesian capital of Jakarta.
On Saturday, disaster struck the coast of southern Sumatra and the western tip of Java when a volcano known as the "child" of Krakatoa erupted, which in turn, triggered a tsunami - in which powerful waves of a height of 30-90 centimetres (1-3 feet) lashed the area.