Restoration / Architecture · Design and Construction
Earthquake-Resistant Building · Antakya · Hatay
The ground and faults of Antakya
However correctly you build, the ground is half the equation. Antakya stands on alluvium, active faults run beneath the city centre, and all of this was set out in writing two years before the earthquake. This page describes that picture and what can be done today.
When earthquake damage is discussed the starting point is usually the building: its structural system, materials and workmanship. These are decisive, but they are half the equation. The other half is the ground the building sits on, and in Antakya that half weighs especially heavily.
The information below rests on the February 2021 Hatay report of the Chamber of Geological Engineers of Türkiye (TMMOB JMO) — a publicly issued warning document published two years before the earthquake.
What is Antakya built on?
However correctly you build, the ground is half the equation. In Antakya that half weighs especially heavily, and the reason is written into the city’s geography.
The city was founded at the foot of Habib-i Neccar mountain to its north, on the alluvial plain laid down by the Orontes river. The mountain is limestone — solid rock. The plain consists of loose sediments carried by the river over hundreds of thousands of years. The boundary between mountain and plain is not accidental: a fault draws that line.
The February 2021 Hatay report of the Chamber of Geological Engineers of Türkiye (TMMOB JMO) set this picture out plainly. It recorded that Antakya stands on weak ground and that active faults run beneath buildings in the city centre, and stated that in a possible earthquake greater than magnitude 6.5 the city faced both violent shaking and the hazard of surface faulting.
The Amik plain is a junction where the Dead Sea Fault, the East Anatolian Fault and fault branches reaching in from the Mediterranean meet. This explains why Hatay has been shaken by so many destructive earthquakes throughout its history.
How many times has Antakya been destroyed?
Ground and fault data can feel abstract. In the case of Antakya a second record makes it concrete: a written earthquake history spanning more than two thousand years. After the city was founded in 300 BC, the first destructive earthquake to enter the record came in 148 BC. Others followed in 130 and 69 BC and in AD 35/37 and 115; the earthquake of 115, which struck while the emperor Trajan was in the city, badly damaged both Antakya and the towns around it.
The destruction continued through the Middle Ages. The earthquakes of 458, 526 and 528 are counted among the heaviest disasters in the city’s history; the sources describe 526 with a very great loss of life, and it brought down the walls as well, weakening the city’s defences. The earthquakes of 551, 557, 577 and 588 followed. In the Islamic period the aftershocks of the 713 earthquake spread over two years; part of the population lived in tents and part left the city. The earthquake of 859/860 destroyed some 1,500 houses in Antakya and more than ninety of the towers on its walls, striking Adana, Urfa, Aleppo, Damascus and Latakia at the same time. Then came 971, 1053, 1063, 1075, 1082, 1114, 1157, 1170, 1407 and 1408.
For an architectural practice the list means this: a historic building in Antakya has passed through the hands not of one earthquake but of dozens in succession. The traces of repair you see in a wall still standing are often the marks of separate disasters centuries apart. Writing them off in a survey as “decay” would be wrong; they are the record of the building’s seismic history and they make it possible to read, in the restitution, which layer belongs to which period.
The earthquakes of 6 February 2023 are the latest link in this chain. The similarities between the historical record and the present picture are striking: fire and the risk of epidemic after the destruction, life in tents, migration from the city and a falling population, then rebuilding by the state. People say that Antakya has been destroyed and rebuilt seven times by earthquakes. Each time the city was built again — which is not a counsel of despair but a sign that reconstruction is itself a tradition in Antakya.
Site amplification and liquefaction
Loose soils do not damp a seismic wave; they amplify it. This is called site amplification: a building on rock and a building on alluvium do not experience the same earthquake. The one on alluvium shakes longer and with greater amplitude. Two years in advance, the JMO report stated that Antakya would shake more violently than provinces founded on rock, and that the damage ratio would be higher for that reason.
The second hazard is liquefaction. Saturated, loose sand and silt layers lose the contact between their grains under strong shaking and behave for a time like a liquid. The ground loses its bearing capacity; the building above tilts, sinks or floats. The report noted that liquefaction could occur across a significant part of Antakya in a large earthquake.
The third is surface faulting. If the earthquake is large enough the fault reaches the surface, producing ruptures, subsidence or heave measured in metres. A building inside that zone cannot be saved however well it is built, because the problem is not the structure but the ground beneath it splitting in two. The only remedy is to locate the fault line precisely and forbid building within that band.
If you are building today
This picture is not cause for despair but a reason to ask the right questions. If you are having a building put up in Antakya today, follow three things about the ground.
The soil survey is not a formality. A geological-geotechnical survey specific to your parcel, with boreholes and laboratory testing, must be carried out. The report should give the soil class, bearing capacity, settlement calculation and — critical for Antakya — an assessment of liquefaction. The foundation type is chosen from that report, not from what the neighbours did.
Ask for the microzonation and development-plan data. The municipality can tell you what the geological-geotechnical report says about the area your parcel lies in. Whether you fall inside a fault avoidance band, a flood zone or an area at risk of liquefaction must be known before work begins.
Ground improvement is an option. Where the soil is weak there are things that can be done: deep foundations, raft foundations, ground improvement techniques. All of them cost money, but none costs as much as a building seated on the wrong ground with the wrong foundation.
With a historic building the equation changes: the building is already there and cannot be moved. What can be done is to document the condition of the existing foundation and the ground, to strengthen it with underpinning where necessary, and to frame the intervention together with conservation principles. A separate guide sets out, in figures, the condition of the registered buildings in the Antakya conservation area after the earthquake.
Frequently Asked Questions
Where can I find out about the ground on my parcel?
There are two sources. The first is to ask the relevant municipal department what the geological-geotechnical report says about your area. The second, and the binding one, is to have a borehole soil survey carried out specifically for your parcel. The first is regional, the second is yours, and the foundation type is chosen from the second.
If my ground is weak, can I not build at all?
In most cases you can; the answer lies in the foundation and in ground improvement. Deep foundations, raft foundations or ground improvement techniques make it possible to build safely on weak ground. What cannot be built is different: within a fault avoidance band, buildings are not permitted, because there the problem is not bearing capacity but the ground tearing apart.
What can be done about the ground under my historic building?
The building cannot be moved, so the matter begins with documenting the condition of the existing foundation and the ground beneath it. Underpinning is carried out where necessary. In a registered building this intervention too is framed together with conservation principles and is subject to Regional Conservation Board approval; archaeological findings that may emerge during ground works additionally require museum supervision.
How have historic buildings in Antakya survived so many earthquakes?
Largely they have not — the building stock we see today is one rebuilt each time after successive earthquakes. Those that survived often did so through post-earthquake repair: added buttresses, thickened walls, replaced ties. It is therefore normal to see masonry of more than one period in the wall of an Antakya building. In a survey these different bonds should be mapped separately, and the restitution should argue which belongs to which period.
Sources and scope
The information on ground and faults on this page rests on the publicly issued report “Our Provinces Living on Faults: Hatay Report” (February 2021) of the Chamber of Geological Engineers of Türkiye. Soil surveys and foundation design are carried out for every building by a licensed civil engineer under TBDY 2018. For the historical earthquake record: Çelik, M. Y. (2025). The similarities between medieval Antakya earthquakes and the February 2023 earthquakes in terms of their effects and consequences. SÜREK Journal of Alevism – Bektasism and Cultural Studies, 4, 13–29. The text and diagrams were prepared originally by YOY Mimarlık.