Geoscience Reference
In-Depth Information
Chapter 15
Kerem Halicioglu and Haluk Ozener
INTRODUCTION
Both seismological and geodynamic research emphasize that the Aegean Region,
which comprises the Hellenic Arc, the Greek mainland, and Western Turkey is the
most seismically active region in Western Eurasia. The convergence of the Eurasian
and African lithospheric plates forces a westward motion on the Anatolian plate rela-
tive to the Eurasian one. Western Anatolia is a valuable laboratory for Earth Science
research because of its complex geological structure. Izmir is a large city in Turkey
with a population of about 2.5 million that is at great risk from big earthquakes. Un-
fortunately, previous geodynamics studies performed in this region are insufficient
or cover large areas instead of specific faults. The Tuzla fault (TF), which is aligned
trending NE-SW between the town of Menderes and Cape Doganbey, is an important
fault in terms of seismic activity and its proximity to the city of Izmir. This study aims
to perform a large scale investigation focusing on the TF and its vicinity for better
understanding of the region's tectonics. In order to investigate the crustal deformation
along the TF and Izmir Bay, a geodetic network has been designed and optimizations
were performed. This chapter suggests a schedule for a crustal deformation monitor-
ing study which includes research on the tectonics of the region, network design and
optimization strategies, theory, and practice of processing. The study is also open for
extension in terms of monitoring different types of fault characteristics. A one-dimen-
sional fault model with two parametersstandard strike-slip model of dislocation theory
in an elastic half-spaceis formulated in order to determine which sites are suitable for
the campaign based geodetic GPS measurements. Geodetic results can be used as a
background data for disaster management systems.
This study suggests a plan for a large scale crustal deformation monitoring project
including the relations between the global tectonics, the interpretation of seismicity
and tectonics of the study area, appropriate geodetic techniques for deformation moni-
toring, combination of different techniques, geodetic network design, and optimiza-
tion. Deformation measurements performed using geodetic techniques include some
critical steps in the processing and design stages. Moreover, other parameters such as
the location of deformed area or the deformation type should also be taken into consid-
eration. An appropriate technique should be chosen considering the deformation type,
the proximity of the deforming area or object to urban areas and suitable processing
techniques.
The Aegean Region and Western Anatolia are one of the most seismically active
and deforming parts of the Alpine-Himalayan orogenic belt. Consequently high seis-
mic activity has been observed in this region. An extensional deformation regime has
