B021 Post‐Tsunami Helicopter‐Borne Electromagnetics Along the Coasts of Aceh, Indonesia

Abstract

After the earthquake and the tsunami‐event on December 26, 2004, the Indonesian and German governments decided to set up a project that was dedicated to re‐install the public life of the people in the coastal region of Aceh Province, Indonesia. As the tsunami waves caused large scale coastal salt‐water intrusions and destroyed thousands of shallow drinking water wells, the focal point was the water assessment in coastal areas of Aceh about nine months after the tsunami. The target areas are: Banda Aceh / Aceh Besar, the west coast between the towns of Calang (Aceh Jaya) and Meulaboh (Aceh Barat), and Sigli on the north‐east coast. A helicopter‐borne survey including five‐frequency electromagnetics (HEM), magnetics and gamma‐ray spectrometry was conducted by the BGR airborne group from August to October 2005. The northernmost survey area, Banda Aceh / Aceh Besar, comprises a 20 km by 50 km wide area that was surveyed within four weeks. The HEM survey revealed coastal saltwater occurrences caused by the tsunami, deep saltwater occurrences up to several kilometres inland, and several potential fresh‐water occurrences. Several requests for information on the geological/hydrogeological situation at sites for planned water wells were successfully evaluated.