Seismic Activity in the Balkans
Europe isn’t well known for intense seismic activity, but large earthquakes do occur there. Although we’ve already discussed seismic activity in Europe here today we are going to focus on the seismic activity in the Balkan region located in the southeastern part of Europe.
The Balkan countries include Slovenia, Croatia, Bosnia and Herzegovina, Serbia, Montenegro, Albania, North Macedonia, Bulgaria, Romania, Greece, and Turkey. Greece and Turkey are seismically very active and deserve their own blog post. So, here we will describe the seismic activity of the following countries: Bosnia and Herzegovina, Croatia, Kosovo, Montenegro, North Macedonia, Serbia, Slovenia, Albania, Romania, and Bulgaria.
Picture 1: The Balkan countries.
Seismic Activity in the Balkans
The Balkans is a tectonically active area due to collision, compression, and rotation of the Adria microplate in the north and due to rotation in the large transform Northern Anatolian fault in the south. These processes generate frequent, though usually small, earthquakes1.
The Balkan region falls within the zone of collision between three large plates: Eurasian, African, and Anatolian, which are further divided into smaller plates.
The present-day geodynamics of the Balkan region is controlled by the active tectonic processes in the Eastern Mediterranean: the collision of the Adriatic (Apulian) microplate with the Dinarides, the subduction of Ionian and Levantine oceanic lithosphere under the Hellenic arc-and-trench system, and the collision between Eurasia and Arabia with the related westward escape of Anatolia along the North Anatolian dextral strike-slip fault2.
Simply put, the geographic region that makes up the Balkans is located in a very complex geological setting where many tectonic plates meet.
Picture 2: Tectonic plates worldwide.
The most devastating earthquake in the last 100 years in the Balkan region happened in North Macedonia's capital Skopje in July 1963, killing more than a thousand people, injuring more than 4,000, and destroying some 80 % of the city3.
Picture 3: Symbol of the earthquake: The Old Railway Station in Skopje. The clock stopped at 5:17 on July 26, 1963.
In recent years, it was the magnitude 6.4 Petrinja earthquake in Croatia on December 29, 2020 that caught the eyes of many seismologists. Seven people were confirmed dead and many buildings were destroyed4.
An analysis titled “Losses due to historical earthquakes in the Balkan region: Overview of publicly available data” was conducted for the Balkan region4. It has shown that a significant number of people died or were affected by earthquakes in the Balkan region and that the region suffered significant material losses. More specific details are presented in the following table:
Let’s now take a closer look at the seismic activities in the above-mentioned Balkan countries.
Picture 4: Flag of Bosnia and Herzegovina.
In Bosnia and Herzegovina, earthquakes may cause heavy damage near the epicenter. Due to the special tectonic situation of the country, there are more earthquakes than in other Balkan countries. They mostly occur because of the northward movement of the African plate and its collision with Eurasia while sliding beneath the European continent6.
As a result of its tectonics, Bosnia can see episodic earthquakes of magnitude 5.0 and above, which are potentially threatening to human life and habitats. Earthquakes causing fatalities and vast urban destruction have been recorded recently as well, such as the magnitude 6.4 Banja Luka earthquake on October 27, 1969, which was preceded by a magnitude 4.0 foreshock on October 26, 1969. Newspapers were full of titles like Earthquake Destroys Banja Luka, reporting that 15 people were confirmed dead, 1,117 people were injured, 86,000 apartments were completely destroyed, and a great deal of damage was inflicted on schools (266), health facilities (133), and social and public administration facilities (152)7. The country’s economy suffered significant losses: over US$ 300 million in damages. Based on current exposure, the same earthquake occurring today is estimated to cause over 400 deaths and more than US$ 4 billion in damages8.
Picture 5: The clock on Banja Luka Square stopped working at the time of the devastating earthquake in Banja Luka, Bosnia and Herzegovina.
The World Bank also states that the annual average population affected by earthquakes in the country is about 40,000 and the annual average affected GDP is about $200 million. The annual average of capital losses caused by earthquakes are around $50 million. However, the fatalities and economic losses caused by more intense, less frequent events can be larger than the annual averages. For example, an earthquake with a 0.4 % annual probability of occurrence (a 250-year return period event) could cause nearly $1 billion in capital loss (about 7 % of GDP)8.
The latest significant earthquake in Bosnia and Herzegovina occurred on April 22, 2022. A magnitude 5.6 earthquake occurred 42 kilometers southeast of the city of Mostar causing one fatality and significant damage to property. It was also felt along the coast of neighboring Croatia, Montenegro, and further southeast in Albania9.
According to the World Data, 29 people died since 1950 in Bosnia and Herzegovina of direct consequences of earthquakes10.
Picture 6: Flag of Croatia.
Let’s move further to Croatia, which suffered a few damaging earthquakes in the last few years that caused great damage.
The Croatian coast lies on a major tectonic structure that extends from Split in the south to Karlovac in the north. Along this structure, the Adria microplate is colliding with the European plate, forming the Dinarides mountain chain. As a result, it experiences multiple small to large earthquakes, some of which are devastating. The year 2020 was a very prolific year for earthquakes in Croatia especially in the northern part of the country in the area surrounding Zagreb.
In March 2020, Zagreb was hit by a 5.3 earthquake that caused extensive damage, but luckily no fatalities. On December 29, 2020, a 6.4-magnitude earthquake hit the town of Petrinja south of the capital, killing seven people and destroying hundreds of buildings and houses11.
Picture 7: Zagreb earthquake.
Its most damaging earthquake took place in 1667 in Dubrovnik, with an estimated magnitude of 7.2. More than 3,000 people got killed and Dubrovnik was completely destroyed. If the same earthquake were to occur today, its estimated death toll would be more than 1,500, and its damage over $7 billion11.
Croatia started focusing on earthquake-proofing buildings in the 1960s after a magnitude 6.1 earthquake rocked North Macedonia, killing 1,070 people. However, after the war broke up in Yugoslavia in the 1990s, not as much attention has been paid to the damage and consequences that a larger earthquake could bring in the future12.
According to the World Data, 17 people died in Croatia since 1950 by direct consequences of earthquakes 13.
The World Bank also states that the annual average population affected by earthquakes in the country is about 100,000 and the annual average affected GDP is around $1 billion. The annual averages of fatalities and capital losses caused by earthquakes are about 20 and about $300 million. However, the fatalities and economic losses caused by more intense earthquakes can be much larger than the annual average. For example, an earthquake with a 0.4 % annual probability of occurrence (a 250-year return period event) could cause nearly 1,000 fatalities and $5 billion in economic loss (about 10 % of GDP)11.
Picture 8: Flag of North Macedonia.
Let’s continue on to North Macedonia. When talking about the seismic activity in North Macedonia, most of the Balkans will still remember the destructive Skopje earthquake that occurred on July 26, 1963, at 05:00 am. The capital of North Macedonia – Skopje – home to more than 200,000 people, got hit by a magnitude 6.1 earthquake, killing more than 1,000 people, injuring around 4,000, leaving more than 200,000 people homeless, and destroying about 80% of the city itself. The economic losses were close to $8 billion in damage14.
Picture 9: Skopje clock.
According to the U.S. Geological Survey, the latest largest earthquake in North Macedonia was a magnitude 5.4 earthquake which occurred on September 10, 2016 at a depth of 10 km, 2 km northeast of Skopje. Authorities reported that no one got killed, but there were more than 50 people injured and many buildings damaged15.
According to the World Data, more than 1000 people died in FYR Macedonia since 1950 by direct consequences of earthquakes 16.
The annual average population affected by earthquakes in North Macedonia is around 40,000 and the annual average affected GDP is around $200 million. The annual averages of fatalities and capital losses caused by earthquakes are around 10 and around $100 million. However, the fatalities and economic losses caused by more intense, less frequent earthquakes can be larger than the annual average. For example, an earthquake with a 0.4 % annual probability of occurrence (a 250-year return period event) could cause around 400 fatalities and $2 billion in economic loss (about 20 % of GDP)14.
Picture 10: Flag of Serbia.
Moving on to Serbia, which lies in a seismically active zone, and although earthquakes are common, serious earthquakes are less frequent but still do occur and cause slight damage to robust houses. According to World Data, 3 people died since 1950 by direct consequences of earthquakes in Serbia17.
One of the last major earthquakes was a magnitude 5.5 earthquake that occurred on November 3, 2010, in central Serbia not far from Kraljevo. The shock was felt across the country including the capital Belgrade as well as in neighboring countries. Two people were killed and over 100 suffered light injuries. There were also many structures that sustained damage, with more than 1,500 declared unsafe for use. It caused more than $100 million in damage18.
The annual average population affected by earthquakes in the country is around 60,000 and the annual average affected GDP is around $399 million. The annual averages of fatalities and economic losses caused by earthquakes are around 10 and around $40 million. However, the fatalities and economic losses caused by more intense, less frequent events can be substantially larger than the annual averages. For example, an earthquake with a 0.4 % annual probability of occurrence (a 250-year return period event) could cause around 500 fatalities and $1 billion in economic loss (around 4 % of GDP)18.
Picture 11: Flag of Slovenia.
Moving further to the north in the Balkans, we find the small country of Slovenia, which represents the meeting point of three different geological units: Alpine, Dinaric, and Pannonian.
Strong earthquakes are rather rare in Slovenia, but they nevertheless have proved in its history to be very dangerous. The largest earthquake in the territory of Slovenia was the magnitude 6.8 Idrija earthquake in 1511. An estimated twelve to fifteen thousand people were killed and there was severe damage. The second-largest was the magnitude 6.1 Ljubljana Earthquake in 1895, which was then the capital of the Austro-Hungarian crown land Carniola. You can see pictures of Ljubljana after the earthquake here. However, its worst earthquake since it gained independence in 1991 occurred in 1998. A magnitude 5.6 earthquake caused over $10 million in damage19.
Volcano Discovery states that since the year 1900, Slovenia witnessed 4 earthquakes above magnitude 5.0, 33 earthquakes between magnitude 4.0 and 4.9, and 242 quakes between magnitude 3.0 and 4.920.
The annual average population affected by earthquakes in Slovenia is about 80,000 and the annual average affected GDP is around $2 billion. The annual averages of fatalities and economic losses caused by earthquakes are around 50 and around $200 million. However, the fatalities and economic losses caused by more intense, less frequent events can be larger than the annual averages. For example, an earthquake with a 0.4 % annual probability of occurrence (a 250-year return period event) could cause around 1,000 fatalities and $5 billion in economic loss (about 8 % of GDP)19.
Picture 12: Flag of Montenegro.
Let’s look next at the seismic activity in Montenegro, which lies in a seismically active zone where small earthquakes are recorded throughout the year. Although serious earthquakes are less frequent, they still do occur. According to the World Data, since 1950 more than 130 people have been killed by direct consequences of earthquakes in Montenegro, while 2 earthquakes also caused a subsequent tsunami, which claimed further lives and damages21.
The last serious earthquake, in 1979, resulted in 94 deaths and approximately 1,000 injuries and caused major structural damage along the Montenegrin coast, and close to $13 billion in damage. The earthquake, which lasted only 10 seconds, left more than 100,000 people without a place to live and destroyed 53 health facilities, 570 social and child protection facilities, etc.21
The annual average population affected by earthquakes in Montenegro is about 9,000 and the annual average affected GDP is about $70 million. The annual averages of fatalities and capital losses caused by earthquakes are about eight and about $10 million, respectively. An earthquake with a 0.4 % annual probability of occurrence (a 250-year return period event) could cause $400 million in capital loss (about 10 % of GDP)21.
According to the World Data, more than 150 people died since 1950 by the direct consequences of earthquakes in Montenegro21.
Picture 13: Flag of Albania.
The next stop is Albania, which is located in the Alpine fold belt extending to the central part of the Dinarides–Hellenides arc. This is an area famous for the intense tectonic-seismic activity that has a considerable influence on shaping the area.
Historically, strong earthquakes have occurred in Albania triggering mass movements causing considerable damages such as loss of lives, destruction of properties, and disruption of the geo-environment. According to the World Data, 87 people died since 1950 by the direct consequences of earthquakes in Montenegro22.
The most devastating earthquake in recent years struck the northwest region of Albania on November 26, 2019. A magnitude 6.4 earthquake occurred due to the thrust faulting near the convergent boundary of the Africa and Eurasia plates. Based on official data from the national authorities, the earthquake caused 51 casualties, with about 3,000 injured and €985 million in losses, corresponding to 7.5% of the 2018 gross domestic product23. It was the strongest earthquake to hit Albania in more than 40 years, its deadliest earthquake in 99 years, and the world's deadliest earthquake in 2019.
The strongest earthquake in Albania happened on November 30, 1967, with a magnitude of 6.5, causing 18 fatalities.
The annual average population affected by earthquakes in Albania is around 200,000 and the annual average affected GDP is around $700 million. The annual averages of fatalities and economic losses caused by earthquakes are around 50 and around $100 million. However, the fatalities and economic losses caused by more intense, less frequent events can be larger than the annual averages. For example, an earthquake with a 0.4% annual probability of occurrence (a 250-year return period event) could cause nearly 3,000 fatalities and $2 billion in economic loss (around 20% of GDP)24.
Finally, let’s have a look at the seismic activity in Bulgaria and Romania.
Picture 14: Flag of Bulgaria.
In Bulgaria, earthquakes are moderate but cause even slight damage to robust houses. According to the World Data, 3 people died since 1950 of direct consequences of earthquakes in Bulgaria25.
Its largest earthquake since 1900 was a magnitude 7.0 earthquake in 1928 in Plovdiv. It caused over 120 fatalities and left more than 260,000 people homeless.
The annual average population affected by earthquakes in Bulgaria is about 100,000 and the annual average affected GDB is about $1 billion. The annual averages of fatalities and capital losses caused by earthquakes are about 100 and about $100 million, respectively. The fatalities and capital losses caused by stronger earthquakes can be larger than the annual averages. For example, an earthquake with a 0.4 % annual probability of occurrence (a 250-year return period event) could cause nearly 5,000 fatalities and $4 billion in capital loss (about 8 % of GDP)26.
The World Bank also stated that Bulgaria, with fewer than 8 million habitants, is Europe's most earthquake-prone Balkan region and should thus act quickly to prepare financially for any major disasters. The Bank, which is working to set up a catastrophe insurance pool for south-east Europe, has estimated that if a major earthquake were to hit Bulgaria’s capital Sofia, losses could reach $5 billion (€3.2 billion), or about 11 % of GDP. The country was hit by a series of over 7.0 magnitude quakes at the start of the 20th century. The last major earthquake in 1986 destroyed 80 % of buildings in the region it struck27.
Picture 15: Flag of Romania.
Lastly, let us have a look at seismic activity in Romania. Romania’s National Institute for Earth Physics Earthquake Catalogue states that Romania is one of the countries most at risk from earthquakes in the EU, with hundreds of lives lost and tens of thousands of buildings damaged in earthquakes in the last 200 years. According to the World Data, more than 1600 people died since 1950 by direct consequences of earthquakes in Romania28.
In the last five centuries, there have been, on average, two earthquakes above magnitude 7.0 each century, with five earthquakes since 1802 with magnitudes above 7.531. Moreover, they report that Bucharest is the most earthquake-prone capital city in the EU because of its proximity to the Vrancea earthquake zone, which is capable of producing earthquakes as high as magnitude 8.1.
One of Romania’s largest earthquakes was an earthquake of magnitude 7.2 that occurred in 1977. It caused more than 1,500 fatalities, more than 11,000 injuries, and more than 150,000 collapsed buildings or severely damaged infrastructure. In 1978, the World Bank estimated a total damage of US$ 2 billion, with Bucharest accounting for 70 % of the total damage (about US$ 1.4 billion). The earthquake contributed greatly to the serious economic crisis that began in Romania in 1979 and lasted even after 198928.
Scientists and engineers calculated that a similar event today would have direct damage costs of €7-11 billion (out of which €5 billion would be uninsured losses), with economic losses exceeding €25 billion. Estimates of lives lost range from 700 to 4,500, with 250,000 people estimated to be homeless for months and years. According to UNSAR, the Romanian insurer’s professional body, more than 80 % of affected families will not have the necessary resources to repair or rebuild after an earthquake similar to the 1977 event28.
Sources:
1) The Conversation. 2019. Can one earthquake cause a cascade of more? Accessed on 06-Jul-2022. Available at: https://theconversation.com/can-one-earthquake-cause-a-cascade-of-more-127946
2) Milev, Georgi. Vassileva, Keranka. 2007. Geodynamics of the Balkan Peninsula and Bulgaria. Accessed on 06-Jul-2022. Available at: https://digbib.ubka.uni-karlsruhe.de/volltexte/beilagen/1/proceedings/pdf/10_Symposium_Bucharest_07_040_Milev.pdf
3) BBC. 1963: Thousands Killed in Yugoslav Earthquake. Accessed on 06-Jul-2022. Available at: news.bbc.co.uk/onthisday/hi/dates/stories/july/26/newsid_2721000/2721635.stm
4) Expat in Croatia. How to Prepare For and Handle an Earthquake in Croatia. Accessed on 06-Jul-2022. Available at: https://www.expatincroatia.com/earthquake-croatia/
5) Abolmasov, Biljana. Jovanovski, Milorad. Ferić, Pavle. Mihalić, Snježana. 2011. Losses Due to Historical Earthquakes in the Balkan Region: Overview of Publicly Available Data. Geofizika, Vol. 28. Accessed on 06-Jul-2022. Available at: https://hrcak.srce.hr/file/105434
6) Omerbashich, Mensur. Sijarić, Galiba. 2006. Seismotectonics of Bosnia - Overview. Acta Geodyn. Geomater. Vol.3, No.2 (142), 17-29. Accessed on 06-Jul-2022. Available at: https://arxiv.org/ftp/physics/papers/0611/0611279.pdf
7) Agencija Anadolija. 2012. Najjači zemljotres u BiH desio se u Banjoj Luci 1969. godine. Accessed on 06-Jul-2022. Available at: https://www.klix.ba/vijesti/bih/najjaci-zemljotres-u-bih-desio-se-u-banjoj-luci-1969-godine/120729075?__cf_chl_jschl_tk__=pmd_h0jSaYtCOvt_iU5BRdlfa506RPqexA4X8z_raJ6MguI-1635739169-0-gqNtZGzNArujcnBszQel
8) World Bank. Bosnia and Herzegovina. Accessed on 06-Jul-2022. Available at: https://www.gfdrr.org/sites/default/files/Bosnia%20and%20Herzegovina.pdf
9) Euronews. 2022. Earthquake in Bosnia Kills One, Causes Significant Damage Across Several Cities. Accessed on 06-Jul-2022. Available at: https://www.euronews.com/2022/04/23/earthquake-in-bosnia-kills-one-causes-significant-damage-across-several-cities
10) World Data. Earthquakes in Bosnia and Herzegovina. Accessed on 06-Jul-2022. Available at: https://www.worlddata.info/europe/bosnia-and-herzegovina/earthquakes.php
11) World Bank. Croatia. Accessed on 06-Jul-2022. Available at: https://www.gfdrr.org/sites/default/files/Croatia.pdf
12) Expat in Croatia. How to Prepare for and Handle an Earthquake in Croatia. Accessed on 06-Jul-2022. Available at: https://www.expatincroatia.com/earthquake-croatia/
13) World Data. Earthquakes in Croatia. Accessed on 06-Jul-2022. Available at: https://www.worlddata.info/europe/croatia/earthquakes.php
14) World Bank. Macedonia, FYR. Accessed on 06-Jul-2022. Available at: https://www.gfdrr.org/sites/default/files/Macedonia.pdf
15) Balkan Insight. 2016. Magnitude-5.3 Earthquake Hits Macedonian Capital Skopje. Accessed on 06-Jul-2022. Available at: https://balkaninsight.com/2016/09/12/magnitude-5-3-earthquake-hits-macedonian-capital-skopje-09-12-2016/
16) World Data. Earthquakes in North Macedonia. Accessed on 06-Jul-2022. Available at: https://www.worlddata.info/europe/northmacedonia/earthquakes.php
17) World Data. Earthquakes in Serbia. Accessed on 06-Jul-2022. Available at: https://www.worlddata.info/europe/serbia/earthquakes.php
18) World Bank. Serbia. Accessed on 06-Jul-2022. Available at: https://documents1.worldbank.org/curated/en/302841494486082323/pdf/114861-WP-PUBLIC-drp-serbia.pdf
19) World Bank. Slovenia. Accessed on 06-Jul-2022. Available at: https://www.gfdrr.org/sites/default/files/Slovenia.pdf
20) Volcano Discovery. Largest Earthquakes in or Near Slovenia on Record Since 1900. Accessed on 06-Jul-2022. Available at: https://www.volcanodiscovery.com/earthquakes/slovenia/largest.html
21) World Data. Earthquakes in Montenegro. Accessed on 06-Jul-2022. Available at: https://www.worlddata.info/europe/montenegro/earthquakes.php
22) World Data. Earthquakes in Albania. Accessed on 06-Jul-2022. Available at: https://www.worlddata.info/europe/albania/earthquakes.php
23) Freddi, Fabio, et al. 2021. Observations from the 26th November 2019 Albania earthquake: the earthquake engineering field investigation team (EEFIT) mission. Accessed on 06-Jul-2022. Available at: https://link.springer.com/article/10.1007/s10518-021-01062-8#:~:text=On%20the%2026th%20of%20November,Durrës%20and%20the%20surrounding%20areas
24) World Bank. Albania. Accessed on 06-07-2022. Available at: https://documents1.worldbank.org/curated/en/839891493703488438/pdf/114694-WP-PUBLIC-drp-albania.pdf
25) World Data. Earthquakes in Bulgaria. Accessed on 06-Jul-2022. Available at: https://www.worlddata.info/europe/bulgaria/earthquakes.php
26) World Bank. Bulgaria. Accessed on 06-07-2022. Available at: https://documents1.worldbank.org/curated/en/688381493716849492/pdf/114725-WP-PUBLIC-drp-bulgaria.pdf
27) Balkan Insight. 2008. Bulgaria ‘Must be Prepared’ for Earthquakes. Accessed on 06-Jul-2022. Available at: https://balkaninsight.com/2008/06/25/bulgaria-must-be-prepared-for-earthquakes/
28) World Data. Romania. Accessed on 06-Jul-2022. Available at: https://www.worlddata.info/europe/romania/earthquakes.php
29) World Bank. 2018. Romania - Systematic Country Diagnostic Climate and Disaster Management. Accessed on 06-Jul-2022. Available at: https://documents1.worldbank.org/curated/en/785381530899707521/pdf/128046-SCD-PUBLIC-P160439-RomaniaSCDBackgroundNoteClimateandDisasterRiskManagement.pdf
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Among natural hazards, geophysical hazards are one of the most common as well as one of the most life-endangering ones.
Earthquakes and tsunamis are natural disasters that are sometimes closely connected through a cause-and-effect relationship.
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