The city of Banda Aceh stands on Holocene fluvial basin sediment, surrounded by the Aceh and Seulimeum fault segments where large magnitude earthquakes can occur at any time. Such earthquakes could cause extensive physical infrastructure damages, injuries, and economic loss. This research aims to produce several earthquake scenarios, to determine the damage ratio of the buildings and its distribution in these different scenarios and to estimate the number of potential casualties and economic loss. Data analysis in this research includes modelling an earthquake by applying a ground motion model for shallow crustal earthquakes to yield an intensity map after the correction for site effects. The damage ratios for different types of buildings were calculated using the fragility curves of buildings that were developed by other researchers. Building occupants at different times, building damage ratios, and injury ratios were used to determine the number of injured residents in the earthquake scenario. The results show that Banda Aceh could be potentially experience earthquake ground motion within the intensity range from MMI VII to IX due to earthquakes of Mw 6.5 to Mw 7.0. The Mw 7.0 earthquake on the Aceh segment is the worst case scenario, causing building damage throughout Banda Aceh with casualty rates of 3.5-20% of the population in buildings in general if it happened during daytime, with economic loss about 3320 million USD. Mitigation and preparedness programs for the Banda Aceh community are therefore very important in order to reduce the potential level of damage, personal injury, and economic loss due to future earthquakes.

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Illegal gold mining has increased significantly in Keude village of Krueng Sabee Aceh Jaya subdistrict. This causes environmental damage in the form of waste mercury pollution in the area. Environmental pollution caused by waste needs to be addressed. However, it needs to determine the appropriate method to overcome it by knowing the depth and the spread of mercury waste. This study aims to visualize subsurface conditions in the area of Krueng Sabee to provide information and data on the spread of mercury wastes. By using the method of geoelectric resistivity Schlumberger array, the contamination can be seen below the surface by the resistivity value of the sites. Results from these measurements after inverted using Earth Imager software of Res2Dinv can get a picture and visualize the location of subsurface conditions of the study. The results show that the resistivity value of waste mercury-contaminated soil at the study site ranged from 2–5 Ωm, and waste mercury contamination occurs vertically to a depth of 3 meters.