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

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. <br>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. <br>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. <br>