|dc.description.abstract||The Alborz range is part of the Alpine-
Himalayan Orogenic belt, located in northern
Iran, between the South Caspian block and the
Central Iranian Block.
In this thesis I have chosen an area in Alborz
range which has experienced a surprising
earthquake (the Rudbar earthquake) that
occurred on a fault that was not previously
mapped. It could mean that there are other
unidentified active faults in Alborz Mountains;
therefore I did a comprehensive study of the
earthquake activity in this area.
For this purpose I went to Iran and got the
local seismic data from IIEES and did the
- I identified the first P-waves and Sg-phases
on my waveforms and I used four different
velocity models to locate events in my data
set, using single earthquake location method.
- I used the travel times of the phases to
comparison of existing models and conclusion on
crustal thickness. This comparison shows that
the velocity model which represents the Moho at
a depth of 58±2 km describes structures in the
Alborz Mountains better compared to other
- I also used the travel times of the phases to
develop velocity models by improving the
existing velocity model, using joint hypocenter
and velocity model inversion method. In this
thesis I improved the three initial models, but
I could not introduce a new model that works
better for this study area.
- I read amplitudes on vertical- and horizontal
components and made vertical to horizontal
comparison which shows horizontal components
are 1.48 larger than amplitudes on vertical
components on average. I used the amplitudes to
compute magnitudes and develop a magnitude
scale for the study area.
- I made the required observations (polarities
and amplitude ratios) to determine mechanisms,
using FOCMEC and HASH programs. I also used
Moment tensor inversion as the third method for
calculating the focal mechanisms where full
waveforms were used.
I used all the above to get an understanding of
tectonic setting in study area which
represented a complicated tectonic activity in