ABSTRACT
The site effects relating
to the amplification of ground motion under earthquake loading are strongly influenced by both the
subsurface soil condition and the geologic structure. In this study, for site
characterization at the Imam Khomeini International Airport (IKIA) area in
south of Tehran, in-situ seismic refraction tomography were
carried out as a part of site investigations project, in addition geologic setting, borehole
drilling, ground waters information and measurements. Based on seismic refraction studies,
three layers are separable which with increasing in depth the S and P wave
velocity is increased and this indicates increasing in compaction of soil and
geologic materials. In the second and third separated layers, the zones with
low and high seismic shear wave velocity is approximately equal, and northeast
and southwest of the airport site has the low velocities, in addition to
containing loose soils, highly weathered stones, and low depth to groundwater.
In terms of Poisson’s ratio, the most important and key installations of
airport site are located in suitable positions. According to Iranian Seismic
Code, most of the lands around the airport are in class 2 and 3. It seems that
a fault or a discontinuity is passed from northwest to the southeast of the
study area. This site, according to geological, subsurface geophysical, and
geotechnical boreholes studies, is high risk-earthquake prone.