Earthquakes in Indonesia cause major damages to buildings and infrastructure every year. Besides the structural design building ground conditions play a markedly important role in seismically active regions. In case of an earthquake soil type and stratification have a significant influence on the shaking intensity.On the 27th of May 2006, an earthquake with a magnitude of Mw=6.3 hit the southern coast of Java and highly affected Kabupaten Bantul in Yogyakarta Province. More than 5700 people have been killed, tens of thousands got injured and became homeless. Almost 80 % of the buildings in Bantul collapsed, leaving behind 127,000 destroyed houses and an additional 451,000 damaged.

Getting to the bottom of the local site effects the Center for Environmental Geology (Department of Badan Geologi) has carried out a comprehensive engineering geological and seismic building ground suitability assessment in the area of Bantul using the digital Information System Engineering Geology (ISEG). ISEG is a 2.5D-GIS/database-based multi component expert system for collecting, storing, managing, analyzing and presenting spatial related engineering geological information and has been developed by BGR Germany.Results from spatial building ground assessment allow comparability of building ground suitability among settlement areas, thus providing spatial planners with a valuable decision support tool. ISEG provides geohazard information, which in the scope of disaster mitigation is crucial to be considered and implemented in medium and long-term spatial planning processes.

The initiative is based on the cooperation of the Georisk-Project (Badan Geologi, BGR and GTZ) with Bappeda Kabupaten Bantul. Data acquisition and integrated analysis of spatial subsurface information using ISEG software is done by the Center for Environmental Geology.ISEG (Information System Engineering Geology) has been developed by BGR Germany and is exclusively designed for spatial planning purposes.

• Map Compilation: Building Ground Assessment for Spatial Planning Purposes, 1:50.000 (Soil Classification, Liquefaction, Settlement Susceptibility, Bearing Capacity, Building Ground Classification, Building Ground Suitability)
• Compilation of Building Ground Information (Lithology, Sounding)
• Consultancy for Bappeda Bantul
• Consultancy for External Spatial Planning Consultants of Bappeda Bantul
• Building Ground Assessment as Input to Spatial Planning Documents (e.g. RDTRK)
• Handbook on Safer Housing in Liquefaction Prone Areas