The seismic hazard for the mega-city Istanbul is extremely high.
Destructive earthquakes over the past 2000 years have hit Istanbul about once every century. Observations of past earthquakes in the 20th century show a westwards migration of epicentres along the North Anatolian Fault Zone which had reached an area only some hundred kilometres east of the Istanbul where two strong earthquakes in 1999 in Kocaeli (Mw=7.4) and Duzce (Mw=7.1) occurred. Approximately 1000 people in the Istanbul suburb of Avcilar were killed and the damage to buildings and structures was rather serious, though the epicentre of the Kocaeli earthquake was more than 110 km away.

Westward Migration of Strong Earthquake along the North Anatolian Fault

An extension of the North Anatolian Fault passes just 25 km south of Istanbul. This region to the immediate south has been identified as a seismic gap where the probability of a large earthquake occurring in the near future is high. A large earthquake in this area would affect between third to a half of the total Turkish industrial activity that is concentrated in the Marmara provinces near Istanbul.

Moreover, the drastic increase of the city's population from 1 to more than 10 million people since 1950 runs parallel with an even more drastic increase in its vulnerability. In addition to overcrowding, faulty land use planning and construction, inadequate infrastructure, as well as environmental degradation, loss of vegetation, and a high percentage of informal settlements are some major reasons for this increased vulnerability.

The catastrophic events in 1999 have raised public awareness of seismic risk within the Marmara region, and Istanbul in particular. In cooperation with governmental institutions, the Kandilli Observatory of the Bogazici University in Istanbul (KOERI), which is our Turkish partner in the SAFER project, has therefore designed and installed the earthquake information system IERREWS (Istanbul Earthquake Rapid Response and Early Warning System). Besides the earthquake early warning component, IERREWS comprises a rapid response system, whose purpose is the rapid processing and broadcasting of information about the distribution of ground-motion parameters relevant to structural damage.
The earthquake early warning system is in a test stage. It consists of 10 tri-axial accelerometers that are installed along the coast of the Marmara Sea, close to the main Marmara Fault. A radio link guarantees continuous real-time communication between the accelerometers and a central processing facility at the Kandilli Observatory in Istanbul.

The main deliverables of the project for this test site will be the operation of a spare Early Warning network in the Istanbul area to provide data for Early Warning optimization, and the production of real-time damage estimates including site effects.