It is the stuff of legend. Known as "Lesser Judgment Day", the old city walls crumbled, mosques were levelled, and Marmara sea levels rose to unprecedented heights. Over 500 years ago, in 1509, the approximately 7.0-magnitude earthquake almost ruined Constantinople (modern-day Istanbul). It destroyed about 1,000 buildings and killed between 4,000 and 12,000 people; aftershocks were felt for more than a month after the ground first shook.
Located on the North Anatolian fault line, Istanbul and its surrounding areas have been hit by an estimated 120 earthquakes over the last 2,000 years, according to the Istanbul municipality's Disaster Coordination Center. More than 110,000 deaths, 250,000 hospitalisations and 600,000 destroyed housing units were recorded across Turkey as a result of earthquakes in the 20th century.
Experts estimate that there is a 65 percent probability that another major earthquake (7.0-magnitude or higher) will strike Istanbul's approximately 14 million residents in the next 30 years.
"The knowledge of people [in Istanbul] is very high. The understanding of the threat and the awareness of the threat is very high," explained Mustafa Erdik, chairman of the Department of Earthquake Engineering at Istanbul's Bogazici University, and a researcher at the Kandilli Observatory and Earthquake Research Institute.
Erdik told Al Jazeera that the probability of a major earthquake hitting Istanbul is two percent annually, a rate about 10 times higher than other parts of Turkey, putting the city on par with San Francisco and Tokyo.
He explained that of the approximately one million buildings in Istanbul, two percent would be damaged beyond repair (either collapse fully or be on the verge of collapse), five percent would suffer extensive damage, 20 percent would be moderately damaged, and 30 percent would be lightly damaged in an earthquake.
"The important thing here is to appease the people… The psychological and social issues, and satisfying people, will take a long time," Erdik said.
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Most of Turkey sits on top of the Anatolian tectonic plate, a micro-plate squished between the massive Eurasian, Arabian, and African plates. The Anatolia plate moves counter-clockwise, as the Arabian plate pushes Turkey westward, but it is impeded from moving north due to the Eurasian plate. This causes seismic friction and mountain building, and leads to earthquakes.
|The Anatolian plate is wedged between the Eurasian, Arabian, and African plates [Creative Commons]
"While mountain building can take up to millions of years, the formation is prone to breaking, especially around the faults," explained Justin Wilkinson, an Earth Observatory scientist at NASA, the US space agency.
The faults are where most of the tectonic activity happens, and where the most severe earthquakes take place. Istanbul is located near the North Anatolian fault, which buttresses up against the Eurasia plate to the north. While there have only been three major earthquakes along the fault over the past 30 years, these earthquakes are often severe – above a 6-magnitude rating, on average – and they take place closer to the surface, which causes more widespread destruction.
The Centre for International Earth Science Information Network (CIESN) at Columbia University categorises Istanbul as a "very high" seismic hazard location – the highest category. In addition, CIESN places Istanbul in the highest levels of economic loss and mortality, as a result of an earthquake.
But while Istanbul's location is highly susceptible to major disasters, the coastal town of Izmit is far worse off.
Located directly on top of the North Anatolian fault, a 7.6-magnitude earthquake – known as the Golcuk-Kocaeli earthquake – directly struck Izmit in 1999, killing over 17,100 people, and displacing 250,000 others. About 214,000 residential units, 30,500 business units and 820 schools were also damaged. Istanbul, approximately 110 kilometres from the epicentre of the earthquake, also sustained heavy damage.
"Izmit is extremely prone to earthquakes and as a result of its location, tsunamis also ought to be a problem," Wilkinson told Al Jazeera.
The World Bank loaned Turkey $757m after the 1999 earthquake. Of this, $252m was put towards an Emergency Earthquake Recovery Loan. The remaining sum was earmarked for a Marmara Earthquake Emergency Reconstruction Project, to build a national emergency response system for the future.
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The Turkish government points to waves of domestic migration to urban centres, beginning in large numbers in the 1950s, as a major factor in Istanbul's high earthquake risk. "Poorly supervised urban development [has] combined with an equally rapid industrialisation process to deliver cities that are critically vulnerable to all natural, technologic, environmental and human-induced hazards," the Prime Minister's office found.
Passed in 2005, Municipal Law 5393 granted the Istanbul municipality the right to "adopt urbanisation and development projects in order to... take measures against the earthquake risk or to protect the historical and cultural structure of the city". Under Law 5393, only neighbourhoods designated as historical areas could be renovated.
The Law for the Regeneration of Areas Under Disaster Risk (Law 6306, known as the "disaster law") was passed in 2012, however, and extended the areas where regeneration projects can be carried out for the sake of protecting residents against natural disasters to everywhere in Turkey.
Tolga Islam is an urban planning professor at Yildiz Technical University in Istanbul, and an expert on gentrification in the city. He told Al Jazeera that while the earthquake risk in Istanbul is real, it is used as a pretext to justify urban regeneration projects.
"The [authorities’] concern is mainly on the physical fabric, which is very archaic thinking in terms of regeneration," Islam said. "If you are going to plan and implement a project, you have to consider the people. You have to focus on the social fabric, even more than the physical fabric."
We have to rebuild new houses, new buildings, [and] in some parts, new infrastructure also. But it takes time.
The neighbourhood of Zeytinburnu, along the coast near Istanbul's historic peninsula, was one of the first areas to undergo earthquake-related redevelopment as part of the government's programme. Other Istanbul neighbourhoods, such as Kadikoy, Uskudar and Fatih, are also considered high-risk earthquake zones.
According to the World Bank, the government retrofitted 700 public buildings, rebuilt 21 others, and provided more than 450,000 people with disaster training by October 2013, making Istanbul "one of the most proactive cities in the world in terms of safeguarding against seismic risks" and "a model for disaster risk management".
But local groups have complained about a lack of input from residents, and accuse the government of intimidating people to move out of neighbourhoods slated for renovation. "Individual families have to negotiate with officials and such negotiations are in most cases intimidating for the poor," researchers found in a 2009 report on the right to housing in Turkey, presented to the UN Habitat Programme director.
Law 5366, the "Law on the Protection of Deteriorated Historic and Cultural Heritage through Renewal and Re-use", has been used "as a threat at beginning of the negotiations to convince the owners to come to terms with the municipality", the report found. "The owners are informed at the beginning that they can either agree with the municipality or their properties will be expropriated."
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|An earthquake in the eastern city of Van killed 644 people and injured over 2,600 others in 2011 [EPA]
Earthquake experts insist that housing renovations are necessary to protect residents from an impending disaster.
In 2011, a 7.2-magnitude earthquake near the city of Van, in eastern Anatolia, killed 644 people and injured more than 2,600. According to an earthquake symposium held in the city in 2013, it took approximately 14 months for permanent housing to be rebuilt, and for displaced residents to return home.
"We have to rebuild new houses, new buildings, [and] in some parts, new infrastructure also," O. Metin Ilkisik, an earthquake specialist who helped draft Istanbul's first earthquake master plan, told Al Jazeera.
Ilkisik explained that earthquake preparedness is largely a social issue, and needs to be a joint effort between the central government in Ankara and local municipalities. "If you're trying to overcome the effects of a disaster, you must tie your connections to the local governments, especially with the municipalities," he said.
According to urban planner Tolga Islam, the negative impact past urban renewal projects had on residents of Istanbul neighbourhoods, like Sulukule and Tarlabasi, does not leave much hope that future development will be carried out effectively. "The social fabric is devastated [and was] affected dramatically by these projects," he said.
"All these regeneration projects serve one single purpose: the gentrification of the city, the invasion of the central locations in the city by high-income groups, displacing the low-income people, forcing them to abandon the central areas and move to the peripheries."
Follow Jillian Kestler-D'Amours on Twitter: @jkdamours
Additional reporting was done by Jacob Powell