eruption of the Merapi volcano, a strong tsunami with waves being reported as high as three meters (9 feet) in some areas, and 6 meters (18 feet) in others, struck the Mentawai archipelago and parts of Sumatra overnight. Currently there are reports of 108 dead and 502 missing. The area is a popular destination for surfers, and among the missing are 10 Australian surfers whose charter boat has been out of communication since the disaster. Due to the remoteness of the area and scale of the destruction the death toll is expected to rise.
CNN notes that one government representative stated that at least one village with a population of about 200 people had been swept away by the tsunami, and that only 40 people recovered. Several charter ships carrying tourists from Australia were docked in a port at Macaronis Bay. When the tsunami hit, the moorings on the ships broke and they collided. One ship caught fire while the captain of the other ship managed to steer his craft into deeper water. The crew on the burning vessel were forced overboard into the water. Several were carried by the surge up to 200 meters inland where they managed to climb into trees and then were forced to wait for the water to recede.
The tsunami was caused by a 7.7 magnitude earthquake, and a 6.6 magnitude aftershock that occurred in the Mentawai archipelago. The epicentre was located about 20 km (12.4 miles) off the coast of Sumatra and hit major cities along the coast of Sumatra and the Mentawai Islands and thousands of people fled into the streets in order to reach higher ground.
Initially, following the earthquake, a tsunami warning was issued, but it was then revoked by the Indonesian earthquake monitoring agency, an office designed to monitor seismic activity in the region. However, the tsunami warnings were later reissued and sirens sounded. I am not finding information, currently, on how much delay occurred between the initial revocation of the tsunami warning and its reactivation and whether this delay played a part in the death toll. I will definitely follow up on this if I find out more.