Turkey Makes Major Investment in Earthquake Research
(Multi-Disciplinary Earthquake Researches in High Risk Regions of Turkey Representing Different Tectonic Regimes – TURDEP Project)
Following the devastating Mw 7.4 İzmit earthquake on 17 August 1999, major state of- the-art earthquake studies were conducted in the Marmara region of northwestern Turkey. However, other faults with the potential to generate big and potentially devastating earthquakes occur in a variety of different tectonic regimes in Turkey, and these faults and regions have not received similar attention.
For example, the East Anatolian Fault (EAF) is influenced by the convergence of the Arabian and Anatolian plates along the Zagros-Bitlis suture zone. Faults in the Aegean Extensional Province (AEP) are purely normal faults. The main faults in the Marmara region occur within both transtensional and transpressional domains (locations are shown in Figure 1). All of these regions pose seismic hazards and also require focused study.
Therefore, different methods for earthquake prediction and hazard estimation are needed in each tectonic regime where the faults are subject to different forces and the earthquakes generated may provide different signals in the preseismic earthquake preparation period.
The Scientific and Technological Research Council of the Turkish Republic (TÜBİTAK) recently granted US$12 million to a consortium for a multidisciplinary and multilateral earthquake research project that started in November 2005 and will be completed by November 2009. A consortium member, the Earth and Marine Sciences Institute of the Marmara Research Center (MRC) of TÜBİTAK, is leading and coordinating the multilateral project, “Multi-Disciplinary Earthquake Researches in High Risk Regions of Turkey Representing Different Tectonic Regimes.” Other consortium members are the Ministry of Construction and Settlement’s General Directorate of Disaster Affairs (GDDA) and 14 universities. Several studies supported by the project include international collaboration with the U.S. Geological Survey; Massachusetts Institute of Technology’s Earth Resources Laboratory; University of California, Berkeley; and the University of Darmstadt, Germany. Additional collaborations will be established as needed.
This new project focuses multidisciplinary studies in the Marmara Sea/Istanbul region, which is believed to be a seismic gap (a region seismically inactive at present but accumulating stress and thus posing great danger) and also in other regions where large earthquakes are expected, including the region encompassing the East Anatolian Fault System (EAFS) and the Aegean Extensional System (EAS). Realistic countrywide estimates of earthquake risk require mapping active faults, determining the strain accumulation and stress buildup as a function of space and time on these faults, determining the temporal and spatial distribution of historic and prehistoric earthquakes, monitoring a variety of phenomena (i.e., the time variation of the emanation of gas and water from faults as well as small earthquakes and the deformation of the crust) that may provide indications of future earthquakes, and better understanding the interaction between adjacent active fault segments.
These efforts require the continuation of ongoing geophysical and geological studies as well as the application of new methods of observations toward understanding earthquake processes. Multidisciplinary approaches being used include seismology, borehole tilt/strain measurements, Global Positioning System (GPS)/interferometric synthetic aperture radar (InSAR), and geochemistry of gas and water emanating from major fracture zones. These observations need to be conducted continuously and for several years and even for several decades until sufficient data are acquired to obtain scientifically reliable and accurate explanations for the earthquake phenomena.
Fig. 1. Locations of the established and continuously run monitoring stations under the scope of the project. Abbreviations are MR, Marmara region; AEP, Aegean Extensional Province; EAFS, East Anatolian Fault System; NAFS, North Anatolian Fault System; ZBSZ, Zagros-Bitlis suture zone. Arrowhead points to the epicenter of the İzmit earthquake of 17 August 1999.
Such observation stations have recently been established for the seismically active areas of Turkey (see Figure 1). Further, the initiative will concentrate on monitoring active faults and earthquake activity in different tectonic regimes in order to provide a physical basis for comparative analyses utilizing the continuously operating monitoring stations shown in Figure 1. The initiative will be among the world’s first examples of a fully integrated earthquake hazards approach that includes a variety of tectonic settings.
Targeted Outputs of the Project
Some anticipated results of the earthquake research initiative include the following:
• Mostly “online” multiparameter (macroseismology and microseismology, radon gas, and spring water monitoring, as well as GPS, tilt, InSAR, and strain) data will be acquired for earthquake behavior in priority and pilot areas representing the different tectonic regimes described above and shown in Figure 1. This will include integrating the data for interpretation as well as for modeling crustal deformation using the continuously acquired data.
• Daily microseismological observations will be collected of the main active fault segments threatening densely populated areas (for example, in the Marmara region, the Istanbul, Bursa, Kocaeli, Balıkesir, Çanakkale, and Tekirdağ city centers; on the EAFS, the Adana, K. Maraş, Malatya, Elazığ, and Bingöl city centers; in the Aegean Extensional Province, the İzmir, Aydın, Manisa, and Denizli city centers). Ocean-bottom seismometers will also be utilized in the Marmara region for this purpose. Thus, anomalies in seismic activity such as swarms will be monitored on a daily basis. Moreover, the active fault map of Turkey will be updated based on the microseismological data that are collected and interpreted. The microseismological stations additionally will strengthen the seismological observation network currently run by the GDDA.
• Seismic ground amplification studies characterizing the basement rock lithology will be conducted in densely populated areas in the regions mentioned above. Thus, the suitability for development in these areas will be determined at the macroscale. Furthermore, the results of these studies will be used to determine the areas where more detailed microscale zonation work is necessary for urban planning and land use.
• There will be continuous collection of the geophysical data utilizing a geographic information system (GIS) database and visualization tools to be updated every 2 months for use by decision-makers.
• Measurement systems for radon gas and data acquisition and techniques will be improved, and a knowledge base for commercial applications will be created.
Mitigating Risks
By the completion of the project, earthquake mechanics and hazards research studies should be under way countrywide, resulting in an improved basis for mitigating earthquake losses. The GDDA and other Turkish national and local authorities will be provided with the data collected and results obtained in a form that will allow this information to guide national policies. Furthermore, the project aims to transfer the accumulated knowledge and experience of TÜBİTAK and GDDA to 14 cooperating universities, which should lead to a nationwide accumulated knowledge base for future projects. Participating universities are Boğaziçi University, Cumhuriyet University, Çukurova University, Dicle University, Dokuz Eylül University, Ege University, Eskişehir Osmangazi University, Fırat University, Hacettepe University, İnönü University, Istanbul Technical University, Süleyman Demirel University, Kahramanmaraş Sütçü İmam University, and Yıldız Technical University.
The project will provide authorities tasked with informing the public about earthquakes with the latest information available, which could improve efforts to ensure public safety during and after seismic disasters. In addition, the initiative could trigger and enhance earthquake research and expertise nationwide as called for by the Supreme Council of Science and Technology of Turkey, a body under the direction of the prime minister.
Data transmitted to the institute by on-line ground survey stations are continuously followed up
High volume data are processed and archived by high capacity servers
A satellite supported online seismology station (Akçakale, Elazığ)
A solar panel supported online soil radon monitoring station (Hersek Delta, Yalova)
An online spring water monitoring station (Pamukkale, Denizli)
A solar panel supported online GPS station (Elazığ)