After the 6.6 magnitude İzmir earthquake in the region between Samos Island and Kuşadası Bay on 30 October 2020, TÜBİTAK MARMARA Research Vessel, which departed for an expedition on 31 May 2021 within the scope of the Project on the “Determination of Seismicity and Active Tectonic Characteristics of Faults in Kuşadası Bay with High Resolution Seafloor Measurements” conducted by the Turkish Earthquake Platform under the coordination of TÜBİTAK with a view to examine the earthquake risk of the region and to investigate the fault lines, completed its first expedition on 13 June 2021 and returned to İzmir Alsancak Port.
TÜBİTAK President Prof. Hasan Mandal welcomed the crew and scientific team of the TÜBİTAK MARMARA Research Vessel. Sharing information about the expedition together with the Project Coordinators Dr. Gülsen UÇARKUŞ from ITU Applied Research Center of Eastern Mediterranean Oceanography and Limnology, Prof. Derman DONDURUR from Dokuz Eylül University Marine Sciences and Technologies Institute and Assoc. Prof. Denizhan VARDAR from İstanbul University Marine Sciences and Management Institute; Prof. Hasan MANDAL stated that we know the faults on land, however, we need to examine the faults in the sea. Reminding that Turkish Earthquake Platform was formed bringing together all relevant stakeholders including TÜBİTAK MAM, İstanbul Technical University, Dokuz Eylül University, İstanbul University, Middle East Technical University, AFAD (Disaster and Emergency Management Presidency), Turkish Naval Forces Command Office of Navigation Hydrography and Oceanography under the coordination of TÜBİTAK, Prof. MANDAL stated that, as part of a project under this platform, TÜBİTAK MARMARA Research Vessel conducted studies for two weeks in order to reveal the seismicity and active tectonic characteristics of the region. He added that bathymetric analyses were conducted during the expedition, the measurements were made with acoustic data, all preliminary information for making a map of the region was collected, and all this information obtained for the first time is quite precious.
Roadmap will be made in the second expedition
Prof. MANDAL stated that the obtained information was shared with the rectors and administrators of the relevant universities and added: “The studies in this expedition were the first ones both in the national and international waters. With the information obtained, we now know the region much more closely. A quick study will be made, and after mapmaking studies, a second expedition will be made in which core samples will be collected. With the aging method, we will figure out at what intervals the earthquakes occurred in the past in this region and what kind of roadmap we will have in the future. We will share all this information with the public.”
1300 km scanned in two weeks
Stating that an area of 1300 km was scanned in the two week period of the expedition, Prof. MANDAL said: “This is a quite important area. Operation time is 7/24. The working method is collaborative work, that is, each researcher brought whatever he or she had in his/her own laboratory. We managed to collect data so efficiently in such a short period of time. The data our scientists will collect will be necessary not only for Turkey but also for Greece and the world. Such a working method is an important tool for a much more effective and efficient solution to the earthquake problem of our country.”
Earthquakes under the sea are more difficult to respond
Project Coordinator Dr. Gülsen Uçarkuş, a faculty member from ITU Applied Research Center of Eastern Mediterranean Oceanography and Limnology, pointed out that Turkey is located in an earthquake zone and stated that there are active faults in different regions of the country. Reminding our earthquake experiences in Elazığ and in İzmit (1999), Dr. UÇARKUŞ emphasized the difference between earthquakes that occur on land and those that occur in the sea. She said “The difference is as follows: When a fault breaks on land, as geoscientists, we can immediately reach the site, however, in earthquakes that occur under the sea, as in the earthquake that occurred in the Kuşadası Bay, in the north of Samos Island, we have only one method to reach there: a research vessel equipped with technological infrastructure. Therefore, earthquake research in seas is a bit more laborious and requires high technology compared to land studies. Under this platform created by TÜBİTAK bringing together four universities and putting the expertise and devices to collect acoustic data in the possession of our universities in the same pot - we call them high-tech devices that can collect hydrographic and oceanographic data sets - as Turkey, we now have these infrastructures. We designed this project by means of the MARMARA Research Vessel of TÜBİTAK MAM”.
We worked devotedly for 12 days.
Dr. UÇARKUŞ stated that the fault causing the earthquake in the north of Samos Island does not pass through Turkish waters or international waters, therefore that part is studied by Greek scientists, and explained the aim of the work under the Turkish Earthquake Platform with the following words: “Since this zone is intersected by many fault systems, we have made a setup to study other active fault systems under the sea such as Tuzla Fault, Gülbahçe Fault or other active fault systems extending from Küçük Menderes (Little Meander) graben to the sea. What we're trying to do this way is to come up first with a map of the seafloor and to figure out the morphology. Using the data obtained by the Turkish Naval Forces Office of Navigation, Hydrography and Oceanography, we added new data sets to our expedition. Most importantly, we used a device called Sub Bottom Profiler, owned by Istanbul University, to analyze and display the faults extending from land to the bay and the faults that intersect the layers in the sea. We collected acoustic data in an area of 1300 km. These data were collected in as little as 12 days thanks to the great effort of the ship's crew and science team working in 24-hour shifts. It was a selfless job.”
Earthquake research at sea requires multidisciplinary work
Stating that, during the expedition, they expected to witness normal faults in the Aegean Stress Regime, which tectonically affects this zone, and strike-slip fault systems on land, Dr. UÇARKUŞ added: “As the first findings, we observed with our acoustic data how our vertical component faults intersect the layers. This will enable us to make a successful map, that is, to create an active fault map. This alone will not be enough, because the investigation of earthquakes in seas requires multidisciplinary studies, so we are together with professors from different specialties such as geological engineering and geophysical engineering. Professors from other disciplines will also participate.”
What is next in the second expedition?
Uçarkuş stated that, in the second earthquake expedition of TÜBİTAK MARMARA Research Vessel, the deformations of the past earthquakes on the previously mentioned layers will be determined by getting geological core samples from the vicinity of active faults. Dr. UÇARKUŞ stated that specific precipitations will be detected in the core samples and they will be aged by radiometric methods and said: Therefore, we all aim to get important epistemic findings about the earthquakes created by these faults and the seismic cycles. This will create a new data set for the determination of the seismicity of İzmir and its vicinity. We are really excited about that.”
The scientific results obtained are invaluable
Dokuz Eylül University (DEÜ) Marine Sciences and Technology Institute Faculty Member Prof. Derman DONDURUR stated that the research continues day and night and that the scientific results obtained are very valuable. He said they observed in the studies that the activity of the Tuzla Fault on the seafloor is much more intense, revealing that the fault is longer than expected. He noted that there was a basin especially in the southwestern part of the study area, and that they obtained data that would enable them to make inferences about how this structure extending to a depth of 1200 meters was formed. Noting that there is no clear date yet for the second research expedition, Dondurur added that plans are being made for the autumn months.