PEND K: MAPPING THE RISK
In Chapter 4, it is seen that GIS is a powerful tool for the visualization of spatial in formation and the creation of data bank for an earthquake-resistant city. In this chapter, GIS lets interested people to explore and analyze data based on location, revealing hidden patterns, relationships and trends that are not apparent in databases or reports. By bringing all the information together, GIS can create intelligent, dynamic maps to solve the problems. Beyond mapping, spatial analysis provides advanced insight into authorities’ information, enabling them to make better recommendations, decisions and directions to the bureaus working under them.
Spatial analysis, which can be seen in the following pages, is a set of tools and procedures that help officials evaluate suitability and capability, estimate and predict, interpret and understand spatial information. Work with geographic data to answer questions as “Where is ...?”, “What is inside...?”, “What intersects...?” , “How much...?” and “What if..?” . Buffering- create a zone of a specified distance around geographic features (Using ArcView 3. ESRI, 1 996)- routing, network, service area, imagery, overlaying, dissolve, merge, clip, intersect and union operations are used to achieve optimal results. Many maps were prepared from the results of the queries for the professionals, routing and service area analyses were made for the experts and teams, detailed databases linked to maps were created for the other teams. The study of case area was examined in three scales like in Chapter 4, the queries and their results in whole Pendik District, in the neighborhoods scale and in one neighborhood-Bati. The maps and statistics were given to the experts to use and develop complicated and deep methods in their fields for an earthquake-resistant Pendik. 5.1 Queries In Macro Scale First queries depend on the geological structure of Pendik which is the most important parameter to consider for a future earthquake. Man-made features which are located in dangerous places were extracted for the managers to take precautions. Then the disasters following an earthquake such as tsunami or fire were thought and analyses were made according to them. The action plans of the municipality were examined. The service areas of the important facilities and some what-if scenarios for the network analysis were made. The first map, which can seen in Figure 5., was created by querying building theme to find buildings based on earthquake faults they intersect. 255 buildings are located just ON the earthquake faults. By a simple estimate, over 1 000 people’s lives are in danger now.  Figure 5. Buildings on earthquake faults in yellow color If the geological map is examined, three types of areas will be seen. The alluvial soft areas where water table is high, the stable areas formed in Silurian and Devonian ages but sometimes creeks can be found in these areas, the most stable rocks formed in Devonian ages. In geological terms, the fill areas, alluvium and neogene sediments are soft areas, the formations of Silurian and Ordovician ages are most stable areas including some creeks and the rocks formed in Devonian age are the most stable areas (Dolayoba, Gölda i, Aydost and Kurtköy formations, see Figure 5.2 and 5.3), (http://www.akut.org.tr, visited on 20.02.2000).  Figure 5.2 The blue fill area, red alluvium, black neogene sediments
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