Amasya's narrow valleys, broad plains and steep limestone ridges give, at first sight, the impression of a still and settled landscape. Yet almost every line of that landscape is the product of a tension that persists deep beneath the ground. The city and most of the province lie within the reach of the North Anatolian Fault, one of the fastest-moving and most active right-lateral strike-slip faults in the world, and of the branch faults that split away from it. To understand why the plains opened where they did, why the Yeşilırmak passes through those particular gorges and why hot springs rise to the surface along certain lines, one has to know this fault system. The same knowledge underlies the question of how and where to build in Amasya.

What Is the North Anatolian Fault

The North Anatolian Fault is a fracture system that marks the boundary between the Anatolian Plate and the Eurasian Plate, starting at Karlıova in the east and tracing a broad arc almost parallel to the Black Sea coast as far as the Gulf of Saros and from there into the Aegean Sea. Its length is given in the sources as anywhere between 1,100 and 1,500 kilometres; the difference depends on where the western end of the fault is taken to stop in the Marmara and the Aegean, and on whether its branches are counted. The fault is right-lateral strike-slip in character. This means that its two sides slide horizontally past each other, and an observer standing on one side would see the opposite side moving off to his right. Measurements taken during earthquakes have shown that the northern block always moves to the right, and somewhat downward, relative to the southern block.

The driving force behind this movement is the northward advance of the Arabian Plate. Squeezed from the south, Anatolia presses against the almost motionless Eurasian Plate to the north and escapes westward to free itself from the compression. This escape is accompanied by a slight anticlockwise rotation. The North Anatolian Fault forms the northern boundary of that rotation. The annual slip rate along the fault is calculated at roughly 17 to 25 millimetres, about 2 centimetres on average. Small as this figure seems on the scale of a human life, when it accumulates over centuries and is released as a sudden slip of several metres it gives rise to great earthquakes.

The fault is not a single sharp line. İhsan Ketin of Istanbul Technical University, in a study published in 1969 and regarded as one of the foundational texts on the fault written in Turkish, defined the North Anatolian Fault as a fault zone reaching 500 to 1,000 metres in width in places. Within this zone the rocks are crushed and shattered, hot and cold springs have emerged, travertines have formed around old springs, small lakes have appeared and, in some sections, young volcanic cones have risen. Its great counterpart is usually said to be the San Andreas Fault in California. Both are continental transform faults of similar length with similar slip rates.

The Course of the Fault Through Amasya

The main strand of the North Anatolian Fault passes through the north of Amasya province, broadly following the line of Niksar, Taşova, Ladik and Havza. According to the route Ketin drew in the 1960s on the basis of field observations and earlier reports, the fault comes from the direction of Kargı in the west, follows the Soruk valley, passes south of Vezirköprü and just north of Havza, and crosses the Samsun–Amasya railway. From there it runs along the northern edge of the Ladik plain, enters the Destek gorge, passes through the Destek subdistrict and north of Taşova and Erbaa, and reaches Niksar. About 12 kilometres south of Niksar it enters the Kelkit valley and continues eastward through Reşadiye, Koyulhisar, Suşehri and Refahiye to the Erzincan plain. A branch leaving the Kelkit valley carries on westward towards Ezinepazar.

This route shows that Amasya's northern districts lie directly on the main fault zone or very close to it. The Yeşilırmak valley at Taşova, the area around Destek and the flats bordering Ladik are depressions opened and shaped by the fault. In these areas close to the main strand, the Yeşilırmak valley has the character of what some researchers call a graben broken by the fault, that is, a trough that has subsided between two fractures. The Taşova–Erbaa, Havza–Ladik and Niksar basins are described as depressions that developed on the North Anatolian Fault Zone.

Branch Faults and the Amasya Shear Zone

What makes Amasya distinctive on the fault map is not only its proximity to the main strand. In the middle section of its arc parallel to the Black Sea coast, roughly between longitudes 34 and 37 degrees east, the North Anatolian Fault turns from a northwest–southeast trend towards an east–west one. As a result of this convex bend, numerous branch faults have developed, opening southwestward from the main fracture. In the Amasya region these branches are traced as the Ezinepazarı–Sungurlu, Taşova–Çorum, Laçin and Merzifon faults. Their movement dies away as they advance into the interior of Anatolia. Close to the main line, however, they have the potential, though with a lower probability, to produce destructive earthquakes.

The broad area formed by the main fault and these branches was studied under the name Amasya Shear Zone in a doctoral thesis prepared by Mehmet Korhan Erturaç at Istanbul Technical University in 2009. Bounded to the north by the main strand of the North Anatolian Fault and to the south by the Ezinepazar–Sungurlu Fault System, this zone begins at Niksar in the east with a width of about 10 kilometres and widens steadily westward into a wedge-shaped deformation area more than 100 kilometres across. In the middle of the zone lie the Esençay Fault and the Suluova Fault System. Erturaç compares the geometry of the fault system, using an image common in the geological literature, to a half fishbone or a horsetail: the main strand forms the spine, while the branches that split off and fan out westward form the bones. These systems consist in general of east–west trending right-lateral main faults and northeast–southwest trending left-lateral faults that connect them.

One of the thesis's important findings is that the activity and displacement of the fault zones decrease with distance from the main strand, that is, towards the west. Microearthquake activity likewise forms distinct clusters in the eastern and central parts of the zone but thins out and scatters towards the west. Developing cities of the region such as Amasya, Çorum and Tokat lie within this shear zone. Erturaç concluded that the active faults within the zone have the potential to produce destructive earthquakes, and by constructing earthquake scenarios for fault segments that have not ruptured in the recent past he produced an integrated hazard map for the region.

A more detailed inventory at the local scale is provided by a study of Amasya's natural resources by the General Directorate of Mineral Research and Exploration (MTA), made public in the second half of the 2000s. According to this study, Amasya lies amid active faults capable of producing earthquakes, such as the North Anatolian Fault, the Esençay–Merzifon Fault, the Ezinepazar–Sungurlu Fault, the Almus Fault, the Turhal Fault and the Çorum–Sulhançayı Fault; with the exception of the Almus Fault, parts of these pass through areas close to the provincial centre. The same study stresses that the section of the Esençay–Merzifon Fault between the Niksar plain and the town of Tekke, and its segments in the Yeşilırmak valley and the Merzifon plain, have not ruptured in the recent historical period or in the last century, and therefore carry the possibility of producing a destructive earthquake.

The Taşova–Çorum and Laçin Faults

The Taşova–Laçin–Çorum fault branches off the North Anatolian Fault under the name of the Esençay segment. Traced as a straight, single strand between Taşova and Eraslan, the fault divides in two west of Sarıbuğday: one branch continues westward as the Laçin Fault, while the other curves southward to form the Sarıbuğday Fault. Both branches are seismically active and have produced earthquakes of considerable size in the last century. The Laçin Fault is reported to have ruptured on 2 December 1942, producing an earthquake of magnitude 5.9, while the Sarıbuğday Fault was the source of a magnitude 5.6 shock on 14 August 1996. In some studies the 1996 earthquake is referred to as the Salhan valley earthquake, with a magnitude of 5.7; local sources associate the same event with the Çorum–Sulhançayı Fault.

The Merzifon–Gümüşhacıköy Fault and the Suluova Basin

The Merzifon–Gümüşhacıköy fault, which bounds the Suluova basin on the north and runs westward via Gümüşhacıköy towards Osmancık, is a very conspicuous structure in the field. Of the earthquakes that followed one another around Osmancık in 1942, the one of 2 December is accepted as having occurred on this line. Erturaç refers to these shocks as the Kızılırmak valley earthquakes, with magnitudes between 5.6 and 6.0. The shares of the Laçin branch and the Merzifon branch in the 1942 earthquake are not always distinguished in the same way in the sources.

The Suluova basin is the widest depression created by this fault network. According to the evolution reconstructed by Erturaç, the basin, which takes in the Suluova, Merzifon, Gümüşhacıköy and Alıcık plains, began to form in the Middle Pliocene as a half-graben controlled by the Bayırlı Fault Zone in its northeast. Initially a closed bowl with no outflow, the basin widened considerably from the Late Pleistocene onward with the development of the Eraslan Fault Zone to the south and became a large lake, which the researcher calls Lake Suluova. After the Middle Pleistocene the east–west trending, right-lateral strike-slip Suluova Fault formed in the central part of the basin, and today's Suluova plain took shape as a pull-apart basin opened by the stepped structure of this fault. The Gümüşhacıköy and Alıcık plains are likewise young depressions opened in the same period.

MTA's geothermal investigations describe the basin as a pull-apart basin bounded by the Merzifon, Sarıbuğday, Büyükçay, Eraslan and Suluova faults and further shaped by the Uzunyazı and Çetmi faults. In three geothermal wells drilled as part of this research, bottom-hole temperatures of 95.5, 87.65 and 94.05 degrees were measured, and the average geothermal gradient was calculated at 0.036 degrees per metre. Chemical geothermometers point to a reservoir temperature at depth of between 100 and 170 degrees. Because the faults provide the fracture systems that allow groundwater to sink to depth, warm up and rise again, these hot waters are the other face of the structures that create the earthquake risk.

The Ezinepazar–Sungurlu Fault System and the Amasya Basin

The Ezinepazar–Sungurlu Fault System, which marks the southern boundary of the shear zone, starts from the Aydınca basin and extends westward to Sungurlu. On this system lies the depression Erturaç named the Amasya Basin, made up of the Aydınca, Geldingen and Mecitözü plains, which are linked to one another by streams. In the east the narrow, wedge-shaped Aydınca plain developed under the control of the Deliçay Fault, while the Geldingen plain, the broad flat in the middle of the basin, became the meeting place of five important rivers that make up the Yeşilırmak basin. Present-day sedimentation in the Geldingen plain is thought to continue around a young pull-apart basin opened by the geometric difference between the Deliçay and Geldingen faults. River terraces at two levels, reaching a total thickness of 40 metres on the slopes of the gorges at the edge of the plain, bear the traces of tectonic movement as well as of the climatic changes of the last glacial period. The roughly 25-metre difference in elevation between the base of the terraces and today's floodplain has been explained by uplift of the plain's southern boundary or by steady subsidence of the plain, and the rate of this movement has been calculated at between 0.16 and 0.4 millimetres a year.

A Fault That Cuts a Continental Collision

The North Anatolian Fault runs along, and in places cuts across, a geological structure much older than itself. Between Erzincan and Amasya the fault has cut and offset an ancient suture belt formed by the collision of the Pontide and Anatolide blocks. A suture belt is the seam left behind when an ocean that once separated two landmasses closed. The fault's arc parallel to the Black Sea coast also broadly follows this old seam. The block on which Amasya stands belongs to the Tokat Massif, the eastern extension of the Sakarya Continent. The massif consists of four different rock assemblages separated by regional unconformities: a Triassic metamorphic basement belonging to the Karakaya complex; Liassic to Lower Cretaceous clastic, volcanic and carbonate rocks covering that basement; Upper Cretaceous blocky limestones, ophiolites and volcanics; and Eocene sedimentary and volcanic rocks.

Amasya's rocks also played a part in a famous scientific debate over how far the fault has moved in total. In 1961 the Swiss geologist N. Pavoni argued that a right-lateral slip of 350 to 400 kilometres had taken place along the North Anatolian Fault since the beginning of the Tertiary. One of his proofs was the similarity between the Liassic and Lower Cretaceous formations exposed north of the fault around Şiran, Kelkit and Bayburt and rocks of the same age in the Havza, Ladik and Amasya region south of the fault. Pavoni estimated that these two areas had moved some 250 kilometres apart along the fault.

Ketin opposed this view. He pointed out that the Lias at Bayburt was nearly 2,000 metres thick with volcanic interlayers, whereas the Lias at Amasya presented a very different picture. In the Amasya region, on the high plateaus of Taşlıdağ, that is, Akdağ, the Lias developed in limestone facies lies in close contact with Permo-Carboniferous limestones and is no more than a few metres thick. The richly fossiliferous beds that develop here as nodular clayey limestones and marls represent the Domerian stage. The red Liassic beds exposed at Kayabaşı, south of Amasya, belong to the younger Toarcian and Aalenian levels. Above these fossiliferous limestones comes a very thick series in flysch facies, which covers the northern slopes of Akdağ and continues as far as the vicinity of Ladik. In Ketin's view these differences made it hard to regard the Lias around Bayburt, Amasya and Ankara as fragments of a single mass split by the fault and carried hundreds of kilometres apart. He himself believed the fault to be very young, set in motion most probably after the Miocene, during the Pliocene–Quaternary, and to have produced perhaps a few tens of kilometres of offset. Young valley floors cut and offset by the fault pointed to horizontal slip since the late Quaternary of 750 to 800 metres around Reşadiye and 800 to 1,000 metres east of Gerede.

In the following decades the debate largely settled close to Ketin's cautious position. More recent assessments give the fault's total offset as between 25 and 85 kilometres. For the age of the fault, a range between the Upper Miocene and the Late Pliocene, reaching back roughly 12 to 2 million years, has been proposed. The few metres of fossiliferous limestone on Amasya's Akdağ thus entered the record of an international debate over Anatolia's great fracture.

The Rupturing of the Fault in the Twentieth Century

The map of the North Anatolian Fault as it is known today was drawn largely by tracing the ruptures left at the surface by the great earthquakes that followed one another in the twentieth century. During the Erzincan earthquake of 27 December 1939 the first section of the fault, some 340 kilometres long, ruptured at the surface. The rupture extended from the Sansa gorge east of Erzincan along the northern edge of the Erzincan plain, through Refahiye, Suşehri, Koyulhisar and Reşadiye to a point 12 kilometres south of Niksar, and from there along the Deliçay valley as far as Ezinepazar. At Reşadiye the fault had offset a tree-lined north–south road horizontally by 3.70 metres. One local source gives the length of the surface faulting as 360 kilometres, from Erzincan to Erbaa and on to Amasya. Erturaç reports that the western extension of this rupture caused an offset of 1.5 to 2 metres on the Ezinepazar Fault.

Three years later, on 20 December 1942, the Erbaa–Niksar earthquake produced a new fault segment 40 kilometres long, starting near Niksar, about 12 kilometres north of the 1939 rupture, and running towards Erbaa. This rupture was traced as far as the point where the Kelkit Çayı joins the Yeşilırmak. Around Bozköy, water pipes had been displaced horizontally by 1 to 1.75 metres. The magnitude of the earthquake is given as 7.0 in some sources and 7.3 in others. A year later, on 27 November 1943, the Tosya–Ladik earthquake ruptured a fault zone of about 280 kilometres, starting near Erbaa and extending westward to the village of Bayramören. The Swiss geologist Moritz Blumenthal, who studied the 65-kilometre section of this zone running from the Erbaa plain to the hills southwest of Vezirköprü, described it as the Ladik earthquake line. According to Blumenthal, the line began near Zilhor north of Erbaa and, passing through the Destek gorge and along the shore of Lake Ladik, cut across the Tersakan Çayı and the Samsun–Ankara road. A vertical offset of 50 centimetres was measured in the alluvium of the Tersakan Çayı. For the magnitude of this earthquake, too, different values between 7.2 and 7.7 are found.

According to Erturaç, the 1942 Erbaa and 1943 Tosya–Ladik earthquakes ruptured the section of the North Anatolian Fault passing near Amasya from end to end and released most of the stress that had accumulated on it. These ruptures were part of the well-known earthquake sequence that advanced from east to west from 1939 onward. Seismologists believe that each large earthquake triggered the next by raising the stress on the neighbouring fault segment. This migrating earthquake pattern is also one of the main grounds for concern about Istanbul at the western end of the fault. For Amasya the important consequence is this: while the section of the main strand crossing the province ruptured in the recent past, some segments of the branch faults have not ruptured for a long time, and it is on these segments that attention in hazard assessments is chiefly focused.

Instrumental records alone are not enough to understand the long-term behaviour of the fault. Erturaç notes that, of eleven large earthquakes recorded in the sources for their destructive effects in and around the study area from the second century AD to the instrumental period, five have been shown by trench studies to have occurred on the North Anatolian Fault. The others, in particular the earthquakes of 1579 and 1794 for which the sources give a detailed distribution of damage, are thought to have occurred on the branch faults within the shear zone. According to scenarios built with geographic information systems, a magnitude 6.9 earthquake caused by the rupture of a 35-kilometre section of the Ezinepazar Fault can account for the intensity distribution of the 1579 earthquake, and a magnitude 6.7–6.8 earthquake caused by a 26- to 30-kilometre rupture of the Alıcık–Laçin or Hamamözü fault can account for the intensity distribution of the 1794 earthquake.

Earthquake Hazard and Risk Areas

Amasya is among Turkey's provinces with a high earthquake hazard, and on the old map that remained in force for a long time it was shown in a first-degree earthquake zone. The new Turkey Earthquake Hazard Map, published in the Official Gazette of 18 March 2018 and in force since 1 January 2019, gives the expected peak ground acceleration values for each point instead of dividing provinces into degrees. The Turkish Building Earthquake Code, published on the same date, requires these values to be used in structural design. It has thus become possible to assess every settlement, from the city centre to the districts and from the plain to the hillside, by its own hazard value rather than to refer to Amasya by a single risk degree. It should also be remembered that the hazard map is not a risk map. Hazard describes the expected severity of ground shaking. Risk concerns the losses that shaking would cause when combined with the building stock, the population and ground conditions.

The renewed Active Fault Map of Turkey prepared by MTA shows 485 active faults, each defined as a source zone capable of producing earthquakes of magnitude 5.5 and above. Amasya is among the provinces crossed by active faults on this map. Within the province, the areas most prominent in terms of risk are Merzifon and Suluova, because of their settlement density and ground characteristics. Recent assessments add the Central, Taşova and Gümüşhacıköy districts to these. When faults run beneath or along the edges of the plains, combined with the tendency of alluvial ground to amplify seismic waves, building safety on these flats takes on particular importance. Loose, water-saturated plain sediments make shaking felt longer and more strongly than in a building founded on solid rock.

Young fractures of the branch faults in alluvial ground and, in particular, the thermal springs along the Mecitözü–Doğantepe line are regarded as surface signs that these faults remain active. The restlessness of the region still makes itself felt today in small and moderate earthquakes. On 12 May 2025 two earthquakes of magnitude 4.4 and 4.2 were recorded a few minutes apart in Gümüşhacıköy, and these tremors brought Amasya's fault lines back onto the public agenda.

The Force That Shapes the Landscape

The tension of the faults should not be seen only as a source of danger, for the same force also created many elements of the Amasya landscape. The arrangement of the plains, the direction of the valleys of the Yeşilırmak and its tributaries, narrow uplands approaching 2,000 metres such as the Akdağ, Sakarat and Tavşan mountains, and the broad depressions opened between them are the direct result of fault activity within the shear zone. The fertile flats of Suluova and Merzifon were built over thousands of years on lake and river sediments that filled the basins opened by the faults.

One of the most striking examples of this relationship is Lake Borabay at Taşova. Also found in the sources under the name Boraboy, the lake is a typical landslide-dammed lake lying northeast of Amasya, south of the North Anatolian Fault and west of the village of Borabay. The valley of the Çatağın Deresi, which flows between Kaleboynu Tepe and Ortaçal Tepe, 1,324 metres high, was blocked by a mass that broke away from the stream's northern slope, and the lake formed as water collected behind this natural dam. The Çatağın Deresi then joins the Borabay Deresi and reaches the Destek Çayı and, through it, the Yeşilırmak. The lake is about 750 metres long, 200 metres wide and 11 metres deep.

The landslide that created the lake took place on ground prepared by the fault system. Permian crystallised limestones and Jurassic tuffs, agglomerates, clays and sandstones are exposed around the lake. The landslide is related in particular to a fault line between the Jurassic units and the Permian limestones. Water seeping to depth along the contact zone and cracks formed by this line facilitated the mass movement over the tuffs and agglomerates. According to a geomorphometric study published in 2024, the difference in elevation between the head of the landslide mass that blocked the valley and its toe is 217 metres, and by the three separate indices used the lake falls into the class of stable landslide-dammed lakes. The same study establishes that aerial photographs of 1953 show two separate lakes behind and on top of the landslide dam, while the 1966 images show that an embankment had been built in front of the lake and that the second lake on the dam had disappeared. This intervention is thought to have been made out of concern that the lake might drain and threaten the village of Borabay below with floods and torrents. In the 2000s, sediment-trapping check dams were also built at different elevations in the valley feeding the lake. The researchers stress that the pressure of the lake's water mass on the landslide dam, lying right beside a powerful active fault such as the North Anatolian Fault, should be monitored regularly together with the seismic conditions of the area.

Living with the Fault

Amasya is a land that has experienced many earthquakes over the course of history, and this experience has helped to form an awareness in the region in many areas, from building culture to the choice of sites. One of the oldest places of settlement in Anatolia, Amasya has witnessed many earthquakes throughout history because of its geographical position and its place within a young tectonic structure. Today that awareness finds expression in ground surveys, zoning plans and building practice that conforms to the earthquake code. Detailed investigation of ground conditions for structures to be built near a fault line or on alluvial plain floors, assessment of the resilience of the old building stock, and correct incorporation into design of the ground acceleration values given by the hazard map are the basic steps towards a pattern of settlement in keeping with the reality of the fault.

To know the fault rather than ignore its existence is the condition, in Amasya, both of a safe life and of settlement in balance with nature. The force that created the fertility of the plains, the healing of the hot springs and natural beauties such as Borabay is the same force that produces destructive earthquakes. This double face also explains why Amasya is of such interest from the standpoint of the earth sciences.

Chronology

1939: The Erzincan earthquake of 27 December. A section of the North Anatolian Fault some 340 kilometres long ruptured at the surface from the Sansa gorge to south of Niksar and on to Ezinepazar.

1942: On 2 December, a magnitude 5.9 earthquake associated with the Laçin and Merzifon–Gümüşhacıköy faults. On 20 December, the Erbaa–Niksar earthquake created a new fault segment 40 kilometres long.

1943: The Tosya–Ladik earthquake of 27 November. A fault zone of about 280 kilometres between Erbaa and Bayramören ruptured.

1945: Moritz Blumenthal published the 65-kilometre rupture between Erbaa and Vezirköprü under the name of the Ladik earthquake line.

1953: Aerial photographs show two separate lakes behind and on top of the Borabay landslide dam.

1961: N. Pavoni put forward his thesis of 350–400 kilometres of slip along the fault. Among his proofs were the Liassic rocks of the Amasya region.

1966: Aerial photographs show that an embankment had been built in front of Lake Borabay and that the second lake had disappeared.

1969: İhsan Ketin's article Kuzey Anadolu Fayı Hakkında was published. Discussing the Amasya Lias among other evidence, Ketin rejected Pavoni's thesis.

1996: On 14 August, the Sarıbuğday (Salhan valley) earthquake, magnitude 5.6–5.7.

2009: Mehmet Korhan Erturaç's doctoral thesis defining the Amasya Shear Zone was completed at Istanbul Technical University.

2018: The new Turkey Earthquake Hazard Map and the Turkish Building Earthquake Code were published on 18 March. Both came into force on 1 January 2019.

2025: On 12 May, two earthquakes of magnitude 4.4 and 4.2 were recorded in Gümüşhacıköy.

Bibliography

Academic studies

  • Ketin, İhsan. Kuzey Anadolu Fayı Hakkında. Bulletin of the Mineral Research and Exploration (MTA Dergisi), 1969.
  • Erturaç, Mehmet Korhan. Amasya ve Çevresinin Morfotektonik Evrimi. Doctoral thesis, Istanbul Technical University, Eurasia Institute of Earth Sciences, 2009.
  • Merzifon-Suluova çek-ayır havzası jeotermal özelliklerinin araştırılması ve havzanın kavramsal modeli. MTA Journal of Earth Sciences and Mining (MTA Yerbilimleri ve Madencilik Dergisi).
  • Yayla, Onur and Atayeter, Yıldırım. Boraboy Heyelanında (Amasya) Jeomorfometrik Değerlendirmeler. Ahi Evran University Journal of the Institute of Social Sciences, 10(1), 2024, pp. 169-187.

Other sources

  • Blumenthal, M. Lâdik deprem hattı (Samsun ili). MTA Mecmuası, 1945.
  • Pavoni, N. Die Nordanatolische Horizontalverschiebung. Geologische Rundschau, 51, 1961.
  • AFAD (Disaster and Emergency Management Authority). Turkey Earthquake Hazard Map (2018) and information leaflet on the North Anatolian Fault Zone.
  • MTA Central Anatolia 1st Regional Directorate and the Governorship of Amasya, study of Amasya's natural resources (Anayurt Gazetesi, "Amasya'nın altı fay hattı dolu", 2008). anayurtgazetesi.com
  • Cumhuriyet, "Amasya fay hattı üzerinde mi? Amasya'da deprem tehlikesi var mı?", 12 May 2025. cumhuriyet.com.tr
  • MTA Active Fault Map of Turkey data (Sabah, "MTA Diri Fay Haritası").
  • Wikipedia articles Kuzey Anadolu Fay Hattı, North Anatolian Fault and 1943 Tosya–Ladik earthquake (auxiliary source).

Online sources