International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B7. Istanbul 2004 
DSi in a depth of 60 m at 112 locations. The results were 
interpreted using the three-dimensional ^ Geographical 
Information System (GIS) method. 
Micro-zoning maps are used in determination of earthquake 
hazards in urban areas and industrial regions. Scenarios of 
earthquake hazards are drawn up and studies of micro-zoning 
are carried out based upon the technology of GIS. Analyses of 
satellite images acquired in September 1987 and in September 
1999 revealed that the construction work focuses on unstable 
grounds in Eskigehir (Nefeslioglu A. H. et all., 2003). 
A pilot region including 5 districts was selected in attempt to 
form a basis for micro-zoning studies. The number of the 
storeys was determined for the buildings in this region and their 
characteristic site periods were calculated in consideration of 
the number of storeys in accordance with the standards 
followed in the literature. Maps showing the characteristic site 
periods of the superstructure and the ground were compared 
numerically in order to form a basis for analyses and modelling 
studies using GIS techniques. A structure-ground relationship 
was investigated through interpreting the fundamental vibration 
period of the ground in addition to conducting a risk analyses 
with respect to resonance. 
2. FEATURES OF THE GROUND STUDIED 
The ground investigated in our study is inclusive of a certain 
part of Eskisehir, which is 25 km?. The elevation of this city 
varies from 779 m to 800 m from the sea level. The Porsuk 
River is located to the south of the study area, cuts the area in 
half in the direction of E-W. 
  
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Figure 1. Location map of the studied area 
2.1 Geology of the study area 
It is known that the new alluvium, over which SCPT 
applications have been carried out, has been determined to be 
made up of loose soil seen in the plain of Eskisehir, among the 
particles of which no cementation occurred (Ayday C. et all., 
2001). Generally, sand containing a high amount of silt is 
present below this level. In some parts, there is a thick layer of 
silt below the same level. As for the lower levels, there is sand 
and sand containing silt layers can be found. The percentage of 
sand increases towards the lower levels and gravelly sand start 
at the lowest level. The study area is also composed of old 
alluvium in North-West and rocks in South-East part of the city 
(Figure 2) (Ayday C. et all., 2001). 
  
  
Figure 2. Geology of the study area and the location of SCPT 
applications 
3. FIELD STUDIES 
3.1 SCPT Studies 
The Seismic Conic Penetration Test (SCPT) method is 
employed in analysing dynamic behaviours of the ground and 
in solving engineering problems (Campanella, R. G. et all., 
1986; Robertson P. K. and Campanella, R. G., 1984). The 
application of SCPT is made using the SCPT probe formed 
through addition of a seismic receptor to the tip of the cone 
according to the standard Conic Penetration Test (CPT). 
Recording numerical data of the seismic measurements is 
carried out in such a way that, the seismic signal received by 
the seismometer is converted into numerical values by means of 
a seismic cable that is penetrated through the drilling stem in 
the depths where the application made (Campanella, R. G. et 
all., 1989). 
The seismic energy is created by horizontally striking the 
sledgehammer upon the surface of the horizontally placed metal 
sign over the surface. By repeating this process with intervals of 
| m, interval speeds are calculated. Thus, the average speed is 
obtained using the first and last signals the reference levels. In 
an effort to measure the shear wave velocity (V. 32 
applications of SCPT were made in certain parts of the study 
area (Figure 2). 
3.2 Determination of the Number of Storeys of the 
Buildings in the Study Area 
A pilot region consisting of 5 districts was designated for as the 
study area. The number of the storeys of 1159 buildings in the 
pilot region, consisting of the districts of Thsaniye, Cumhuriye, 
Hayriye, Hacialibey and Haciseyit, was determined (Figure 3). 
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