Indication of Submarine Landslide along the Southern Coast of Ceram Island

Based on field survey data taken in 2006 and 2008 along the southern coast of Ceram, we found geological evidences of submarine landslide which is caused by earthquake occurred on 28 January 2006 with magnitude Mw 7.6 at 346.2 km depth under the seafloor.

Creeping indications are shown by damage on road construction forming letter-U (horseshoe) more than 500 meters length, coastal terrace, position of oblique tress are found along the coast from Amahai, Rutah, Nustetu, Upa, Tamilau, Namanan and Tehoru.

Indication of subsidence and slumping were found at Mahu village, Tehoru sub-district and Samasuru village, Amahai sub-district of Central Molluca district. Ground subsidence causing 13 houses destroy, coastal plain collapse causing 2 houses drown into the water, and shoreline retreat landward about 40 meters, while water depth getting shallower.

The same event is found at Weduar village, Kei Besar sub-district, Southeast Molluca district, such as ground settlement along the coast about 7 meters and caused damage on 10 houses.

Indication on topography is observed from bathymetry profil along the water off the southern coast of Ceram island, which has high morphology and steep slope.

This landslide has caused damage on public property such as the main road across Ceram and supposed to relocate the body of road far from the coastline.

The same event has ever happened in 1899, when an earthquake which is associated with Banda subduction zone and caused damage on buildings and settlement along the coast. This earthquake was followed by tsunami with height reaches 9 meters at some locations in Ceram island.

This submarine landslide is triggered by earthquake which is associated with Banda subduction zone and it is activated strike slip faults at Ceram island.