Akademik Veri Yönetim Sistemi
Eskişehir Teknik Üniversitesi Bilim Ve Teknoloji Dergisi - B Teorik Bilimler, cilt.6, ss.234-243, 2018 (Hakemli Dergi)
The use of highly accurate ground structure models in seismological studies has importance for the reliability of research findings
and results. A seismic velocity structure of the region with high accuracy was required for the determination of the locations of
Mw 5.4 Bala, Ankara earthquake (December 20th, 2007) and its aftershocks. In order to provide this requirement, one-dimensional
seismic velocity structure was determined by using data of 13 seismograph stations deployed in Central Anatolia. 2955 P- and S-
wave phases read from 652 earthquakes down to 30 km depth were used to determine the model. Two accuracy tests have been
applied to check the accuracy of the new model. One of them is the numerous shifting tests which are performed by shifting the
earthquake’s latitude, longitude and depth in different directions and quantities. The other one is the comparison of the travel time
residuals before and after the inversion for the model determination. The new model, assessed by accuracy tests, was used to
relocate the Bala earthquakes. Earthquake locations are also calculated simultaneously in the iterative inversion process in which
the new model is identified. The preliminary location parameters of the earthquakes calculated by using the previous velocity
models introduced by other researchers were accepted as the initial parameters for the inversion. The double difference method
which is based on the minimization of the residuals between the differences of the theoretical and observed travel times for
earthquake pairs was performed to relocate the earthquakes by using the new one-dimensional model. The average location error
is observed to be lower in the new model when compared to other seismic velocity models