At The Fault Lines

On February 6, 2023, two consecutive earthquakes with magnitudes of 7.8 and 7.7 struck southern Turkey and northern Syria, resulting in the deaths of more than 60,000 people. Now named as the Kahramanmaraş Earthquakes, largest since the 1939 Erzincan Earthquake of the same magnitude, is the second most powerful ever recorded in the region. Affecting 14 million people and leaving 1.5 million homeless across 11 provinces, it is now recognized as the deadliest natural disaster in the history of Turkey.

The earthquake region, encompassing the 11 southeastern provinces of Kahramanmaraş, Hatay, Osmaniye, Adıyaman, Gaziantep, Şanlıurfa, Diyarbakır, Malatya, Kilis, Adana, and Elazığ, totals up to over 110,000 square kilometers (42,000 square miles) - nearly the same size as the neighboring Bulgaria. This is equivalent to stretching from Washington, D.C. to Boston, MA, encompassing the entire northeastern metropolitan region of the United States.

In Hatay province, the historic center of Antakya is now nearly uninhabitable. The city, which has stood for millennia, has been flattened, leaving it almost unrecognizable. The extent of the destruction has driven nearly all residents away, transforming familiar streets and landmarks into a stark, altered landscape. In Kahramanmaraş, the historic district has been decimated, leaving once-vibrant neighborhoods in ruins. Similarly, Gaziantep, known for its rich history and architectural heritage, has seen extensive damage to its old city center, including the Gaziantep Castle—originally built by the Hittite Empire and later expanded by the Romans—and its traditional markets. Despite more than a year of reconstruction efforts, most of these cities remain unrecognizable to more than 500,000 people who once called them home.

Yet, Turkey is no stranger to such catastrophic earthquakes, as the country geographically sits on top two major fault zones - the North Anatolian fault zone being one of the most seismically active in the World. 20 years ago when a similarly destructive earthquake struck near Istanbul, the country’s economic and population center, it was a wake up call for the country: The government changed shortly after being deemed “incompetent,” much stricter building codes and regulations were put in place, nation-wide first response organizations were founded, and a new “earthquake tax” was introduced to help fund urban renewal and recovery efforts. The recent earthquakes exposed that many of these efforts have been immensely inadequate, mostly due to large-scale corrupt political, regulatory, and construction practices throughout the 20-year AKP rule. Moreover, the country’s most prominent scientists have been incessantly alarming against a long-awaited “Istanbul Earthquake” to strike in the next decade, with consequences exponentially graver.

This study aims to dissect these corrupt practices, identify their traces in the architectural level across an urban scale, and develop an alternative risk assessment mapping method that may offer critical insight for local authorities, municipalities, as well as individuals. Recent developments in interctive mapping techniques, artificial intelligence and machine learning have allowed large urban-scale risk assessment models to be implemented in order to detect possible structural defects before any failure or collapse. In this article, we will explain the structural malpractices that led to such destruction in the area, and will propose an automated, faster, and more scalable alternative “risk assessment method” that could be used to create an earthquake risk map of the bustling metropolis of Istanbul that is home to 16 million people.

In order to better understand this, we first need to zoom out and understand the country’s geological, social, and political relationship with the earthquakes — starting with the East Anatolian Fault, which is where the Feb 6 earthquakes happened.

The North Anatolian Fault (NAF) is a major strike-slip fault zone stretching approximately 1,500 kilometers (900 miles) across northern Turkey, from the junction with the East Anatolian Fault in eastern Turkey to the northern Aegean Sea.

Since the mid-20th century, seismologists have understood that earthquakes along the NAF move in a westward progression, with each quake triggering the next. This phenomenon became evident following the 1939 Erzincan earthquake, which resulted in over 32,000 fatalities and more than 100,000 injuries.

Research indicates that nine out of ten major earthquakes along the NAF between 1939 and 1992 were brought closer to failure by the preceding shocks due to the transfer of stress along the fault line. This progressive failure mechanism suggests that each large earthquake can set up the next one by altering the stress distribution along the fault.

By studying the sequence of past earthquakes, seismologists can identify patterns and potential stress points, enabling them to predict future earthquakes. The most recent major earthquake along the NAF, the 1999 Izmit earthquake, which killed over 17,000 people, has led the scientific community to anticipate the next major earthquake hitting Istanbul.

Due to Istanbul’s proximity to the NAF, the warning time for a major earthquake could be as short as 2-6 seconds, making a rapid response challenging. Combined with its dense population of 20 million and inconsistent infrastructure quality, the city could face an unprecedented level of destruction.

The most recent major tectonic event along the North Anatolian Fault, the 1999 Izmit-Gölcük Earthquake, struck on August 17 at 3:01 AM local time. With a magnitude of 7.6 and an epicenter just 90 kilometers east of Istanbul, this 37-second tremor claimed over 17,000 lives and displaced 500,000 people. As Turkey’s most destructive earthquake until February 6, it exposed critical vulnerabilities in the country’s disaster preparedness, many of which were due to rampant corruption in the construction industry.

The incumbent government’s organizational failure and inability to respond and provide help to the area, combined with a long-standing financial crisis, has left the public with a bitter sentiment that “the state has left them on their own.” As a result, the government received less than 10% of the vote in the 2002 elections.

The Justice and Development Party (AKP), which still is the ruling party in the country, rose to power in the elections with Mr. Recep Tayyip Erdogan, back then the very popular and highly-acclaimed Mayor of Istanbul, promising drastic changes. The newly appointed government codified what was initially planned to be a short-term recovery act, the infamous “Earthquake Tax,” making it permanent. It also launched the country’s first nationwide disaster response organization, AFAD, fore-fronted much stricter construction regulations and building codes, and introduced massive-scale urban renewal programs.

Since 2002, the AKP has been able to consolidate its base largely due to initiatives that many believed had transformed Turkey from a run-down, old country to modern standards, with new highways, residences, and other infrastructure improvements. However, the February 6 earthquakes have led to widespread disillusionment. The devastation revealed that many of the government’s commitments were not fulfilled, exposing significant inadequacies and corruption in regulatory enforcement, infrastructural reconstruction and disaster preparedness efforts.

This, along with the westward pattern of the seismic activity along the North Anatolian Fault suggesting an increased possibility of a tectonic event taking place around Istanbul, directly to the west of the most-recent quake zone Izmit, has left a city of 20 million worried about the safety of their homes and workplaces.

The devastating earthquake in February has heightened anxiety among Istanbul’s residents about the inevitable arrival of “the big one.”

A city of 16 million (20 million, including undocumented residents according to the experts) living in highly dense neighborhoods with apartment buildings of five stories or taller, many of which were built before the 1999 quake thus not up to the latest building codes. These older structures, more than 625,000 of them, are particularly vulnerable, says Mehmet Özhaseki, Minister of Environment and Urbanism citing studies conducted by both the city and Ankara government.

Since then, the Municipality has conducted various studies that tries to simulate the extent of damage (both buildings, people, and infrastructure) and shared it on its Open Data portal as a spreadsheet. The below map is an interactive visualization of this data, showing the number of damaged buildings, injuries, death toll, and shelter availability per neighborhood. This study allows us to have an overall idea by ZIP code, yet it lack the granularity of a high-resolution map at the building level - which is critical, as the extent of damage varies per structure dramatically.

The situation becomes even more dire as the wait time for structural testing can stretch up to 21 years at the current rate of 120 buildings per day. With the North Anatolian Fault indicating an imminent earthquake, local architects, engineers, and students have initiated alternative methods for identifying structural issues. Using makeshift lists of easily identifiable deficiencies, these grassroots movements on social media have become highly popular among the public with posts sparking conversations and sharing of information at the scale of millions in helping people make crucial decisions involving their safety. This and many other initiatives has also shown that the solution to Istanbul's testing problem had to be more agile yet granular, and easily scalable.

After delving into the history of earthquakes in Turkey, examining corrupt construction practices, and exploring how AI can extract information from street view images, we present the culmination of this research: an interactive map.

This interactive map, the product of a year-long effort at the Center for Spatial Research, allows residents to access critical structural information about their buildings through a simple search interface. The map provides risk insights in a transparent, immersive, and easy-to-digest manner, embodying our commitment to accessibility and user-friendliness.

Initially available for Hurriyet Mahallesi, a densely packed pilot neighborhood with buildings constructed mostly before the 1999 Earthquake, the map offers risk insights on “misaligned floor calculations.” This area, with minimal open spaces or greenery, is notably highlighted in the IMM Earthquake Risk Simulation dataset for its high projected damage and death tolls.

Currently, the map covers selected ZIP codes, but it will gradually expand to encompass all boroughs and ZIP codes across Istanbul. This expansion will increase the number of tests performed and the data used to calculate the overall risk score for each building, ensuring more comprehensive coverage over time.

To use the map, residents can search for building names, door numbers, addresses, and more, limited to the available ZIP codes for now. By hovering over each building, users can access an in-depth risk report and a visual representation of the performed tests. This interface allows anyone to look up their address and access “machine-generated” structural insights.

Transparency is vital when dealing with AI-generated data, especially since much of it results from “blackbox” processes beyond our control. In developing this project, we made sure all computations made on the initial images were visible, explainable, and shareable. We clarified our aims with each computation and used language that encouraged users to critically assess every AI-generated result. This approach ensured that these “risk insights” were understood as fallible and provided citizens with our “training methods,” helping them recognize structural cues in their environments.

We hope this tool will serve as an insightful resource, helping residents understand the structural integrity of their buildings and prompting necessary actions to enhance safety. By making critical information accessible and transparent, we aim to empower residents to engage with their built environment and take informed steps toward improving their safety and resilience.