Semarang is one of the largest cities in Java Island that is very prone to tidal flood. In order to reduce the tidal flood risk, disaster managers and city planners need a well-planned natural disaster risk management method based on disaster risk map of the city area. Risk mapping alone is not enough; an efficient system to disseminate the result of risk mapping for general public is also needed. This work intends to solve a problem of arrangement and presentation of tidal flood risk mapping. In order to develop the disaster risk map, the validation and prediction of the tidal flood were done to produce a hazard map on the tidal flood. Subsequently, the maps of vulnerability and capacity of the study area were produced based upon VCA (Vulnerability Capacity Analysis) by using fuzzy logic and weighted method approaches. As a comparison to that, the calculation of tidal flood risk was also done by adopted to the Indonesian regulation of The Natural Disaster Risk Management Head PERKA BNPB No. 2 year 2012. Finally, the risk map online was designed and developed. This system has the function of information dissemination and spatial data download of the risk map result. The online map uses KML format for sharing spatial data attributes and uses Google Maps as the map engine. The online map also gets good responses through a usability test, where it can be concluded the onlin e map is effective, efficient, and satisfactory to users.

Abstract. The Land conversion can increase the risk of landslide disaster in Semarang Regency caused by human activity. Remote sensing and geographic information system to be used in this study to mapping the landslide areas because satellite image data can represent the object on the earth surface in wide area coverage. Satellite image Landsat 8 is used to mapping land cover that processed by supervised classification method. The parameters to mapping landslide areas are based on land cover, rainfall, slope, geological factors and soil types. Semarang Regency have the minimum value of landslide is 1.6 and the maximum value is 4.3, which is dominated by landslide prone areas about 791.27 km 2 . The calculation of the environmental vulnerability index in the study area is based on Perka BNPB No. 2/2012. Accumulation score of environmental vulnerability index is moderate value, that means environment condition must be considered, such as vegetation as ground cover and many others aspects. The range of NDVI value shows that density level in conservation areas (0.030 -0.844) and conservation forest (0.045 -0.849), which rarely until high density level. The results of this study furthermore can be assessed to reduce disaster risks from landslide as an effort of disaster preventive.

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Mount Merapi is one of the most active volcanoes in Indonesia. Seeing the status of Mount Merapi which until now is still quite active, disaster mitigation action efforts are needed. One of the disaster mitigation actions is by making the Risk Map. This study aims to provide an assessment of risk assessment of eruption of Mount Merapi in settlement areas so as to minimize losses that can occur. Mapping of eruption risk of Mount Merapi using two parameters, namely hazard and vulnerabilities. Risk assessment is derived from Matrix comparison of Risk Assessment. Making the risk map using processing method and spatial analysis of Geographic Information System (GIS) with scoring method, weighting, and overlay. The addition of settlement information was obtained using the Normalized Difference Built-up Index (NDBI) method to know total settlement areas. This research will produce a risk settlement area map of Mount Merapi eruption and conclusion that there is still a large risk that occurs in Sleman regency. And Remote sensing technology and GIS can answer challenges in providing disaster analysis with a fast response and better accuracy so that the need for other implementations in building disaster maps in other regions with this technology.

Semarang Regency is a region that is very vulnerable to landslides based on the spread of the wider area each year to the occurrence of landslides. The need for a proper assessment of the mapping of landslide hazard so that it can be used as decision making in the mitigation system in Semarang Regency. Geographical Information System (GIS) is the right method of mapping disaster-prone areas for a wide area with a relatively short time. This method is carried out as an effort to analyze risk and hazard mapping through the dissemination of hazard information so that it will accelerate the process of delivering information to the public and can improve preparedness in taking actions to reduce disaster risk. Then, various methods that can be used to obtain weighting and classification, one of which is to make a decision-making method using the Multi Criteria Decision Making (MCDM) method. One of the MCDM methods that can integrate with SIG is the Analytical Hierarchy Process (AHP). this research it can be concluded that the use of the AHP method to the GIS analysis of landslide mapping provides good accuracy with a value of 70.97% of the 31 validation points suitability. The results of this landslide map can be used as a basis for planning landslide disaster mitigation in Semarang Regency.