Kocaeli Üniversitesi

Micro Seismic Activity of The Mid-Marmara Region is Being Monitored

Seismic risk of Istanbul and its surrounding area has increased right after the 1999 earthquakes and many speculations have been published in the media about forthcoming events. In order to have enough information about forthcoming earthquakes, a seismic network should be installed and operated continuously via online communication. Researchers at the Research Center of Earth and Space Sciences of Kocaeli University (YUBAM), in cooperation with the scientists from GFZ (GeoForschungZentrum), installed a local seismic network consisting of 25 seismic stations to monitor micro-earthquake activities of the mid-Marmara region and collect information for the next probable large earthquake in this region.

The network which is called ARNET is the densest local network with the highest number of seismic stations in Turkey and covers the districts Yalova-Armutlu-Gemlik and its surrounding areas. It is also the biggest seismic network operated by universities in Turkey with its 25 seismic stations. The map below shows the distribution of ARNET seismic stations. This network was initially set up as a 10-station local network in September 2005 and the number of the stations reached 25 during the years 2006 and 2007.


Recently, 15 stations of this network have been connected to the data centre on Umuttepe Campus of Kocaeli University via online communication systems and micro-earthquake activities occurring in the Marmara Region have started to be recorded at our data centre. The network has many specifications with the most dense and largest number of seismic stations, and one of the stations located in 25 different sites has a borehole seismometer at 100 m depth, 15 broadband seismometers and 10 short period seismometers. In addition, six accelerometers have been installed nearby faults and densely-populated areas in order to monitor acceleration of mid-size and large earthquakes. Since the region being monitored is characterized by geothermal activity and higher tectonic deformation, we have also installed geochemical sensors to the cold and hot water well stations for pressure changes, conductivity, temperature changes and leveling in order to understand the relation between micro-earthquake activities with hydrothermal potential. This observation will enable us to catch some geochemical precursory phenomena noticed prior to some large earthquakes during earthquake prediction studies. These observations will enable us to study possible interactions between earthquakes and the fluids with special focus on earthquake-related pore-pressure variations in geothermal systems. These observations are conducted at 22 different locations of the study area and Bursa city. At each site, different kinds of geochemical parameters are being monitored. Geochemical observations are conducted together with the Kandilli Observatory and Earthquake Research Institute.

Offline and online data is recorded with the updated software at our center (YUBAM), and data processing is automatically and manually realized by our researchers and students. The data obtained by ARNET is used for education and research purposes and conducting different kinds of researches on Seismology. The information and some of the results obtained from ARNET data has been submitted and shared in several international symposiums, workshops and conferences. At present, the data of the network is under process in different scientific studies. Among some of these studies are 3-dimensional seismic tomography, local stress distribution analysis, recognition of seismicity patterns, moment tensor analysis and accurate seismic event location techniques