1901 Black Sea earthquake

{{Short description|Earthquake struck Dobrich Province, Bulgaria on March 31, 1901}}

{{Infobox earthquake

|title = 1901 Black Sea earthquake

|timestamp = 1901-03-31 07:12:24

|isc-event = n/a

|anss-url = n/a

|image =

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|map2 ={{Location map |Bulgaria|relief=1

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| lat = 43.4

| long = 28.7

| mark = Bullseye1.png

| marksize = 50

| position = top

| width = 250

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|local-date = {{Start date|1901|3|31}}{{cite web |url=http://www.astrele.ro/2014/01/21/cutremurele-din-romania-partea-i/ |title=Cutremurele din România (partea I) |work=Astrele |author=Mihaela Dicu |date=January 21, 2014 |language=ro}}{{cite web |url=http://esnet.infp.ro/content/Romania_CAR.pdf |title=Romania CAR |work=ESnet}}

|local-time = 09:12:24

|duration =

|magnitude = 7.2 {{M|w|link=y}}

|depth = {{convert|14|km|mi|0|abbr=on}}

|location =

|type =

|countries affected = Romania
Bulgaria

|damage =1,200 houses destroyed{{cite web |url=http://www.mgu.bg/sessions/11/01/brrrsdgordmdapodssnd.pdf |title=Marinegeohazard project – Key core elements of the early warning system in the Black Sea |publisher=University of Mining and Geology "St. Ivan Rilski" |date=2011}}

|intensity = {{MMI|X}}{{cite book |last=Karnik |first=V. |title=Seismicity of the European Area |publisher=D. Riedel Publishing Co. |location=Dordrecht |year=1969 |page=364}}

|PGA =

|tsunami = 4–5 m

|landslide = Yes

|foreshocks =

|aftershocks = 5 {{M|w|link=y}} (at 11:30 local time)

|casualties = uncertain

}}

The 1901 Black Sea earthquake (also known in Bulgaria as the Balchik earthquake){{Cite web|url = https://gq.pgi.gov.pl/article/viewFile/8109/pdf_215|title = Recent geological activity along the northeastern Bnlgarian Black Sea coast|date = July 20, 2000|website = Geological Quarterly|last = Matova|first = Margarita}} was a 7.2 magnitude earthquake,{{Cite journal |last=Matova |first=M. |date=1999 |title=Some geoindications of recent geological activity along the northern Bulgarian coast |url=http://www.lgt.lt/geoin/files/vilnius_13.pdf |journal=Geoindicators|archive-url=https://web.archive.org/web/20160303224817/http://www.lgt.lt/geoin/files/vilnius_13.pdf |archive-date=March 3, 2016 }}' the most powerful earthquake ever recorded in the Black Sea.[http://jurnalul.ro/stiri/observator/s-a-cutremurat-marea-neagra-516870.html "S-a cutremurat Marea Neagră"] {{Webarchive|url=https://web.archive.org/web/20140529182737/http://jurnalul.ro/stiri/observator/s-a-cutremurat-marea-neagra-516870.html |date=May 29, 2014 }}, Jurnalul.ro, August 5, 2009 The earthquake epicenter was located in the east of Cape Kaliakra, {{convert|30|km}} off northeast coast of Bulgaria.{{cite news |url=http://www.ziare.com/international/stiri-externe/cutremure-in-marea-neagra-pericol-de-tsunami-843270 |title=Cutremure în Marea Neagră: pericol de tsunami? |newspaper=Ziare.com |date=August 5, 2009 |language=ro |author=Valentin Dimitriu}} The mainshock occurred at a depth of {{convert|15|km|abbr=on}} and generated a {{convert|4|–|5|m|adj=on}} high tsunami{{Cite book|title = Tsunamis along the coasts of the Black Sea|last = Altinok|first = Yildiz|publisher = Second Balkan Geophysical Congress and Exhibition|year = 1999|location = Istanbul|pages = 46–47|url = http://www.balkangeophysoc.gr/menu/congresses/oral/46-47-O8-1-Yildiz_Altinok.PDF}} that devastated the coastal areas of Romania and Bulgaria.{{cite web |url=http://www.romanialibera.ro/actualitate/eveniment/tsunami-in-marea-neagra-140318 |title=Tsunami în Marea Neagră |work=România Liberă |author=Darius Martinescu |date=November 27, 2008 |language=ro}}{{Cite book|title = Seismic activity after the earthquake of 31 March, 1901 in the Shabla-Kaliakra zone|last1 = Ranguelov|first1 = B.|publisher = Bulgarian Geophysical Journal|year = 1994|pages = 44–49|last2 = Gospodinov|first2 = D.}} In Romania, the earthquake was felt not only throughout Northern Dobruja, but also in Oltenia and Muntenia, and even in southern Moldova.

The earthquake was followed by a large number of aftershocks, which continued until 1905; the strongest reached magnitudes of 5.5–6.0 on the Richter scale and were also felt in southern Romania, including Bucharest. After 1905, Pontic seismic activity began to subside, although weak and moderate earthquakes were also reported in subsequent years.

Such events are rare in the Black Sea. In the last 200 years, in the Black Sea region 24 tsunamis occurred, of which two were in the territory of Dobruja. The earliest recorded tsunami in Romania dates from 104, when the city of Callatis, current Mangalia, was badly affected.{{cite news |url=http://www.9am.ro/stiri-revista-presei/Social/18032/Tsunami-de-Marea-Neagra.html |title=Tsunami de Marea Neagră |newspaper=9AM |author=Antoaneta Etves |date=September 8, 2005 |language=ro}}

Tectonic setting

The northernmost part of Bulgaria lies to the north of the main part of the fold and thrust belt that forms the frontal part of the Alpine orogenic belt, known as the Balkan orogen. The foreland to the Alpine belt is known as the Moesian Platform that remained almost undeformed during the three main separate phases of thrust tectonics from the Cretaceous to the Neogene.{{Cite journal |last1=Burchfiel |first1=B.C. |last2=Narkov |first2=R. |date=2015 |title=The multiply deformed foreland fold-thrust belt of the Balkan orogen, northern Bulgaria |journal=Geosphere |volume=11 |issue=2 |pages=463–490 |doi=10.1130/GES01020.1|bibcode=2015Geosp..11..463B |doi-access=free }} The Balkan orogen links to the southeast with the Pontide belt, which runs along the northern coast of Turkey. The Black Sea opened as a back arc basin during the Cretaceous to Paleocene. The basin was then inverted during the last phase of the Alpine orogeny during the Late Eocene to Miocene.{{Cite journal |last1=Munteanu |first1=I. |last2=Matenco |first2=L. |last3=Dinu |first3=C. |last4=Cloetingh |first4=S. |date=2011 |title=Kinematics of back-arc inversion of the Western Black Sea Basin |journal=Tectonics |volume=30 |issue=5 |doi=10.1029/2011TC002865|bibcode=2011Tecto..30.5004M }}

Offshore, the main west–east trending structures are cut by several fault zones of SSW-NNE to SW-NE trend. Geophysical investigations close to Shabla have identified a major fault zone of this trend, known as the Kaliakra Fault Zone,{{Cite journal |last1=Korzhenkov |first1=A.M. |last2=Ovsyuchenko |first2=A.N. |last3=Dimitrov |first3=O.V. |last4=Dimov |first4=T. |last5=La'rkov |first5=A.S. |last6=Ranguelov |first6=B. |last7=Rogozhin |first7=E.A. |last8=Rodina |first8=S.N. |date=2020 |title=Traces of Strong Eneolithic and Medieval Earthquakes Hitting The Durankulak Archaeological Settlement in Northeastern Bulgaria |journal=Journal of Volcanology and Seismology |volume=14 |issue=4 |pages=262–282 |doi=10.1134/S0742046320040028|bibcode=2020JVolS..14..262K }} that continues southwards until it links with the north–south trending part of the Balkan-Pontide belt in the southwestern Black Sea.{{Cite journal |last=Georgiev |first=G. |date=2011 |title=Geology and Hydrocarbon Systems in the Western Black Sea |journal=Turkish Journal of Earth Sciences |volume=21 |pages=723–754 |doi=10.3906/yer-1102-4 }}

Seismicity

The off-shore region of Southern Dobruja, especially the epicentral area located to the south of Mangalia, including the Bulgarian shelf of the Black Sea, has been affected over the years by earthquakes that, in certain cases, have been very strong, reaching magnitudes of 7–7.5 on the Richter scale. These are also shallow ({{convert|5|–|30|km}}) crustal earthquakes, with severe effects in the epicentral areas. Sometimes, in case of earthquakes with underwater focus (as those located to the east of Shabla Cape), tsunami waves were generated, like in 1901.

The analysis of historical records has shown that Pontic earthquakes with destructive behaviour, comparable to that in 1901, repeat at mean periods of 300–500 years. One of the earliest occurred in the 1st century BC at Kavarna.{{Cite book|title = Tsunami: The Underrated Hazard|last = Bryant|first = Edward|publisher = Springer|date = December 12, 2007|isbn = 978-3540742739|pages = 15|url = https://books.google.com/books?id=tOkpBAAAQBAJ&pg=PA15|edition = 2nd}} In AD 853, a tsunami at Varna swept {{convert|6.5|km}} inland over flat coastal plain and travelled {{convert|30|km}} up a river.[http://www.uni-weimar.de/cms/uploads/media/Lazarescu_Borovetz_ARW.pdf "Seismic risk in Romania"]{{Dead link|date=August 2019 |bot=InternetArchiveBot |fix-attempted=yes }}, Bauhaus-University Weimar

Earthquake

The earthquake had an estimated magnitude of about 7.2 {{M|w}},{{Cite journal |last1=Stanciu |last2=Ioane |first2=D. |date=2019–2020 |title=Active fault systems in the Shabla Region (Bulgaria) as interpreted on geophysical and seismicity data |journal=Rev. Roum. Géophysique |volume=63–64 |pages=3–21}} with magnitudes of 7.1, 6.5 and 6.4 also being reported.{{Cite web |last=Utsu |first=T. |date=2004 |title=Catalog of Damaging Earthquakes in the World (Through 2019) |url=https://iisee.kenken.go.jp/utsu/utsuweq_bak_eng.html |access-date=May 23, 2024}} The maximum observed intensity was X (Devastating) on the Medvedev–Sponheuer–Karnik scale at Cape Shabla with much of northeastern Bulgaria reaching at least VII (Very Strong).{{Cite journal |last1=Ranguelov |first1=B. |last2=Radichev |first2=R. |last3=Dimovsky |first3=S. |last4=Oaie |first4=G. |last5=Dimitriu |first5=R. |last6=Diaconescu |first6=M. |last7=Palazov |first7=A. |last8=Dimitrov |first8=O. |last9=Shanov |first9=S. |last10=Dobrev |first10=N. |date=2011 |title=MARINEGEOHAZARDS Project – Key core elements of theEarly Warning System in the Black Sea |journal=Annual of the University of Mining and Geology "St. Ivan Rilski" |volume=54 |issue=1 Geology and Geophysics}}

Impact

= Felt area =

The shock was felt throughout Bulgaria, southeast Romania, eastern Serbia and northwest Anatolia, causing great panic in Istanbul and on the Asiatic coast of the Bosphorus and the Marmara. Long period effects lasting about a minute were reported from the Danube valley, from Szeged in Hungary, and from Odessa. The shock was perceptible in Thessaloniki in Macedonia, in Dorohoi in Romania, and throughout the province of Sivas.{{cite book |title=Seismicity of Turkey and neighbouring regions, 1899–1915 |last1=Ambraseys |first1=N. N. |last2=Adams |first2=R. D. |publisher=Annales Geophysicae |location=Paris |date=1987 |pages=701–726}}

= Damage =

The earthquake had devastating consequences in the coastal area of southern Mangalia, many villages being ruined (maximum intensity of X on the Mercalli intensity scale); likewise, the earthquake generated a {{convert|4|–|5|m}} high tsunami wave and there occurred bank dislocations and other local geomorphological phenomena.[http://www.ziuaconstanta.ro/rubrici/eveniment/cutremure-si-tsunami-in-dobrogea.html "Cutremure și tsunami în Constanța"], Ziua de Constanța, May 1, 2009 Maximum damage was sustained by a small number of villages situated on the alluvial lowlands along the coast between Balchik, Kavarna, Durankulak and Limanu. Slumping of the coast destroyed many landing-places and coastal settlements including the lighthouse at Kaliakra. Large scale landslides along the coast continued to develop for almost two weeks after the earthquake, disrupting communications and causing additional damage.{{Cite web|url = https://www.ngdc.noaa.gov/hazel/view/hazards/earthquake/event-more-info/9778|title = Significant Earthquake Information|last=National Geophysical Data Center / World Data Service (NGDC/WDS): NCEI/WDS Global Significant Earthquake Database. NOAA National Centers for Environmental Information. | date=1972 | publisher=NOAA National Centers for Environmental Information |doi=10.7289/V5TD9V7K}} In Bucharest, the seismic intensity was V–VI degrees on the Mercalli intensity scale, causing panic among the population and light damage to buildings.

The Bulgarian province of Dobrich was also severely hit by the tsunami. In several localities, including Balchik, homes were inundated by water.{{Cite journal |last1=Papadopoulos |first1=G.A. |last2=Diakogianni |first2=G. |last3=Fokaefs |first3=A. |last4=Ranguelov |first4=B. |date=2011 |title=Tsunami hazard in the Black Sea and the Azov Sea: a new tsunami catalogue |journal=Natural Hazards and Earth System Science |volume=11 |issue=3 |pages=945–963 |doi=10.5194/nhess-11-945-2011|doi-access=free |bibcode=2011NHESS..11..945P }} In the village of Momchil, a large landslide buried people's homes over an area of about {{convert|30|ha}}.{{Cite book|title = Landslide Science and Practice – Volume 7: Social and Economic Impact and Policies|last1 = Margottini|first1 = Claudio|publisher = Springer|year = 2013|isbn = 978-3-642-31313-4|pages = 188|last2 = Canuti|first2 = Paolo|last3 = Gassa|first3 = Kyoji|url = https://books.google.com/books?id=Yea9BAAAQBAJ&pg=PA188}}