Izmir Metropolitan Municipality continues its studies to determine the soil characteristics of the Bornova Plain and its surroundings and their behavior during the earthquake. In the study, three-dimensional modeling of the plain will be extracted and how it will be affected by a possible earthquake will be determined. Then, the settlement suitability assessment will be reconstructed by integrating it with other results from the microzonation study.
The seismicity research initiated by the Izmir Metropolitan Municipality on land and sea in order to make the city resistant to disasters continues. Drilling work was also started in the Bornova Ege University Campus area in order to determine healthy grounds for constructions. When the studies to determine the soil characteristics of the Bornova Plain and its surroundings as well as their behavior during earthquakes are completed, areas that are suitable and unsuitable for construction, known as microzonation, will be determined. In addition, it will become clear after the study how the existing settlements will be affected by possible earthquakes.
Samples taken from the region
The depth of the well in Ege University Campus, which is one of the 49 meters of geological, geotechnical and hydrogeological drilling wells in the district, is 900 meters. Nihat Sinan Işık, a faculty member in the Department of Civil Engineering, Faculty of Technology, Gazi University, who was part of the team that carried out the study, said that they carried out studies to determine the soil characteristics of the Bornova Plain and its surroundings, their behavior during the earthquake, and that samples were taken from the region. Nihat Sinan Işık, who stated that experiments will be carried out in laboratories on the samples, said, "After these, the mechanical properties and dynamic properties of the soil will be determined, and the response of this region during the earthquake will be measured by applying earthquake motion in the computer environment at the end of the project."
17 deep wells will be drilled for geotechnical purposes
Explaining that wells were drilled for the purpose of both monitoring landslides and determining soil characteristics, Işık said: “There will be 17 deep well drilling works in total. Their depth will change, it will be determined on the spot. It is the first study conducted in such depth in Turkey. Other geotechnical boreholes ranged from 30 meters to 15 meters. They are intended for shallower structures. But since this is a deep drilling, we will determine the structure of the whole plain, the whole basin.”
Bornova Plain will be modeled in three dimensions
Çanakkale Onsekiz Mart University Faculty Member Geophysics Engineer Prof. Dr. Aydın Büyüksaraç stated that they used the PS logging application, which is a method for detecting the dynamic modules of the soil. Emphasizing that such an intensive measurement was applied for the first time, Büyüksaraç said, “We take 200 geophysical measurements in cells of 560 square meters in the Bornova Plain. These 9 different measurements are performed simultaneously and at regular intervals. We also do acceleration records. Acceleration records are also made where the Bornova Plain may be the deepest. We plan to model the Bornova Plain in three dimensions by evaluating all of these together. There are studies that have been done before, but this is the first time that such an intensive and comprehensive study has been carried out”.
The basin model will emerge
Explaining that seismic measurements are normally made from the surface, Aydın Büyüksaraç said, “Here, the drilling depth is 300 meters and the PS logging work at a depth of 300 meters is made for the first time in Turkey. In that respect, it is a very important work. This device is 7 meters long. It is lowered into the well with a steel crane. We obtain seismic velocity values from the deepest points of the basin. With the acquisition of information from the first 30 meters of depth, settlement suitability maps were created. However, today, it has been understood that the first 30 meters of information is not enough, especially in places with deep basins such as the Bornova Plain. PS logging will be integrated with other geophysical studies from the surface, resulting in a more accurate and higher precision basin model. We will be able to better define the character of the basin,” he said.
Safe cities will be built
Stating that at the end of the studies, weak soils and qualified soils will be clarified, Prof. Dr. Büyüksaraç gave the following information: “As a result, microzonation will take place. In other words, suitable or unsuitable places for settlement will be distinguished. This will be included in the zoning plans. When issuing the zoning permit, clear information will emerge about which floor height can be dangerous. We will obtain information that will directly affect the construction. The main condition for the sustainability of cities in Turkey is to prioritize earthquake safety. While creating earthquake-safe cities, we must first know what characteristics of the ground and soil we live on. When you model the basin, we will have to lower the depth and how many meters of foundation for construction, or we will provide information about the earthquake resistance of existing buildings.”
20 thousand meters of boreholes were drilled
Of the 49 meters of drilling planned to be opened, a total of 900 thousand meters of drilling wells have been drilled so far, approximately 17 thousand meters for geotechnical, 3 thousand meters for landslide and hydrogeological purposes. When the works are completed, all kinds of disaster hazards and risks, from landslide to liquefaction, from medical geology to flood, and the suitability of the region for settlement will be evaluated. In project scope BayraklıWork will be carried out on a total area of 12 thousand hectares within the borders of , Bornova and Konak.