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1840 Ahora earthquake

Coordinates: 39°36′N 44°06′E / 39.6°N 44.1°E / 39.6; 44.1
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1840 Ahora earthquake
1840 Ahora earthquake is located in Turkey
1840 Ahora earthquake
Local date2 July 1840 (1840-07-02)
Local time16:00
Magnitude7.4 Ms
Epicenter39°36′N 44°06′E / 39.6°N 44.1°E / 39.6; 44.1
Areas affectedOttoman Empire
Max. intensityMMI IX (Violent)
Casualties10,000 dead

The 1840 Ahora earthquake occurred on 2 July at 16:00 local time, affecting Ağrı Province in the Eastern Anatolia Region of present-day Turkey. The earthquake had an epicenter near Mount Ararat, where it triggered an eruption and caused a landslide that destroyed villages. An estimated 10,000 people were killed by the earthquake and its damaging aftershocks. Earthquake catalogs place the surface-wave magnitude at Ms  7.4 and maximum Modified Mercalli intensity scale assigned IX (Violent).[1]

Geology

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Ağrı Province in Anatolia lies near the triple junction where the North Anatolian Fault meets the East Anatolian Fault and Zagros fold and thrust belt. These three features mark the plate boundaries of the Anatolian sub-plate, Arabian plate and Eurasian plate. Being at the junction of three tectonic plates, the region is prone to large shallow earthquakes, mainly of the strike-slip and thrust mechanism.[2] [3]

The magnitude 7.4 Ms  earthquake occurred along the flanks of Mount Ararat.[4] A 72 km (45 mi) surface rupture was associated with the shock.[5] Rupture occurred along the Gailatu–Siah Cheshmeh–Khoy Fault—large earthquakes along the fault also occurred in 139 (M 7.0) and 1319 (M 7.4).[3]

Impact

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Saint Hakob of Akori monastery was destroyed by the earthquake

As many as 10,000 people died in the earthquake and the associated effects, including 1,900 inhabitants from Akory.[6] An estimated 4,000 people died from the secondary effects. The earthquake and lahar killed all 1,000 residents and monks of Akory (Yenidoğan) and the Saint Hakob of Akori monastery. A massive air blast caused severe damage. The regions of Avajiq, Pambukh, and Gailatu were devastated; nearly every single village was wiped out. Many homes collapsed and a castle was left in ruins at Doğubayazıt. Few homes remained intact. Liquefaction and landslides occurred in the areas further away from Mount Ararat. Liquefaction destroyed many villages including Karakhasanlou, Alesher and Karachalou. Sand erupted from fissures in the ground. Some fissures extended up to 1 km (0.62 mi) along the Aras, Karasu, Akhourian and Arpa rivers.[3]

In Nakhichevan and Sharur districts, at least 7,821 homes and 24 places of worship were destroyed. Approximately 49 people died and 30 were injured in Russia.[1] The slide also temporarily dammed the Metsamor River.[7] Cities including Etchmiadzin, Yerevan, Garni, Van, Tbilisi, Tabriz and Gyumri were damaged.[5]

Volcanic eruption

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A Bandai-style phreatic eruption was triggered, melting the glacier on the summit, resulting in a lahar that buried villages. The lahar and landslide deposited near the base of the volcano creating a large alluvial fan.[8] A phreatic eruption occurred on Mount Ararat on the day the earthquake struck. It generated a pyroclastic flow from fissure vents along the upper northern flank of the volcano.[9]

Historical archive from the Ararat Diocese of the Armenian Apostolic Church said immediately after the earthquake, a large cloud reminiscent of a smoke column appeared over the canyon at Mount Ararat's northern slope. The village of Akori and Saint Hakob monastery were located at the canyon. A bright-red and blue light illuminated inside the cloud. There was an intense sulfur smell. Boulders measuring 300–500 kg (660–1,100 lb) were thrown from a fissure uphill from the monastery and village. The cloud rose above Mount Ararat's summit while another dark red-luminous dust cloud raced down the slope at high speed, destroying the village and killing many people. Trees in the village garden were burnt and uprooted. These descriptions were interpreted as the eruption of Mount Ararat and a pyroclastic flow.[3]

Landslide

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The gorge on Mount Ararat where the landslide occurred

A large landslide occurred on the northeastern flank of the volcano, forming the Ahora Gorge. It destroyed the Saint Hakob of Akori monastery and Akory. Movement ceased at an elevation of 900 m (3,000 ft) where a natural dam formed. The dam was breached several days later, flooding and destroying the nearby villages. Additional landslides also caused flooding.[5]

The earthquake and explosive eruption destabilized and damaged the upper slopes of the mountain. It detached and collapsed down the slope, through the canyon, disintegrating and moving at great velocity.[3] In 2006, an academic study estimated 3 × 108 m3 of volcanic material and glacial melt flowed down the gorge at 175 m (574 ft) per second.[10]

The landslide consisted of blue liquid mud and large stones which traveled at high speed. An intense smell accompanied the landslide. The flow traveled more than 7 km (4.3 mi), creating a dam at the canyon. Large volumes of partially-melted ice, mud, rocks and water collected behind the dam. Bright blue-colored rain fell from the eruption cloud. At Etchmiadzin Cathedral, 55 km (34 mi) from Mount Ararat, the smell of sulfur was intense. Fractures that formed in the canyon ejected murky water with a strong sulfur smell.[3]

An aftershock on 6 July caused a dam breach, releasing accumulated debris up to 21 km (13 mi) away. It reached the Aras River valley, spreading 12 km (7.5 mi) across before drying up. The landslide deposits contained boulders and a thick band of blue clay. Several villages including Aralık were destroyed, along with some Russian military installations. The landslide also dammed the Karasu River.[3] The debris flowed into fields, destroying the grain and fruit supply.[11]

See also

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References

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  1. ^ a b National Geophysical Data Center (1972). "National Geophysical Data Center / World Data Service (NGDC/WDS)". Global Significant Earthquake Database. NOAA National Centers for Environmental Information. doi:10.7289/V5TD9V7K. Retrieved 12 March 2023.
  2. ^ Bayrak, Yusuf; Öztürk, Serkan; Çınar, Hakan; Kalafat, Doğan; Tsapanos, Theodoros M.; Koravos, G. Ch.; Leventakis, G.-A. (2009). "Estimating earthquake hazard parameters from instrumental data for different regions in and around Turkey". Engineering Geology. 105 (3–4). Elsevier: 200–210. Bibcode:2009EngGe.105..200B. doi:10.1016/j.enggeo.2009.02.004.
  3. ^ a b c d e f g Karakhanian, A.S.; Trifonov, V.G.; Philip, H.; Avagyan, A.; Hessami, K.; Jamali, F.; Bayraktutan, M. S.; Bagdassarian, H.; Arakelian, S.; Davtian, V.; Adilkhanyan, A. (2004). "Active faulting and natural hazards in Armenia, Eastern Turkey and North-Western Iran". Tectonophysics. 380 (3–4): 189–219. Bibcode:2004Tectp.380..189K. doi:10.1016/j.tecto.2003.09.020.
  4. ^ Nikolai V. Shebalin; Günter Leydecker (1997). Earthquake catalogue for the former Soviet Union and borders up to 1988. Nuclear Science and Technology Series. Luxembourg: Office for Official Publications of the European Communities. ISBN 92-828-1509-9. ISSN 1018-5593.
  5. ^ a b c Havenith, H.B. (2022). "Recent Earthquake-Triggered Landslide Events in Central Asia, Evidence of Seismic Landslides in the Lesser Caucasus and the Carpathians. In: Towhata, I., Wang, G., Xu, Q., Massey, C. (eds) Coseismic Landslides" (PDF). Coseismic Landslides. Springer Natural Hazards. Springer: 115–141. doi:10.1007/978-981-19-6597-5_5.
  6. ^ Siebert, L., T. Simkin, and P. Kimberly (2010) Volcanoes of the world, 3rd ed. University of California Press, Berkeley, California. 551 pp. ISBN 978-0-520-26877-7.
  7. ^ Karakhanian, A.; Djrbashian, R.; Trifonov, V.; Philip, H.; Arakelian, S.; Avagian, A. (2002). "Holocene–Historical Volcanism and Active Faults as Natural Risk Factor for Armenia and Adjacent Countries". Journal of Volcanology and Geothermal Research. 113 (1): 319–344. Bibcode:2002JVGR..113..319K. doi:10.1016/s0377-0273(01)00264-5.
  8. ^ Roberto Sergio Azzoni; Davide Fugazza; Carlo Alberto Garzonio; Kathleen Nicoll; Guglielmina Adele Diolaiuti; Manuela Pelfini; Andrea Zerboni (2019). "Geomorphological effects of the 1840 Ahora Gorge catastrophe on Mount Ararat (Eastern Turkey)". Geomorphology. 332. Elsevier: 10–21. Bibcode:2019Geomo.332...10A. doi:10.1016/j.geomorph.2019.02.001. S2CID 133968021.
  9. ^ Haroutiunian, R. A. (2005). "Катастрофическое извержение вулкана Арарат 2 июля 1840 года" [Catastrophic eruption of volcano Ararat on 2 july 1840]]. Proceedings of the National Academy of Sciences of the Republic of Armenia: Earth Sciences (in Russian). 58 (1): 27–35. ISSN 0515-961X. Archived from the original on 7 December 2015. Retrieved 26 November 2015.
  10. ^ A. Karakhanian; R. Jrbashyan; V. Trifonov; H. Philip; S. Arakelian; A. Avagyan; H. Baghdassaryan; V. Davtian (2006). "Historical volcanoes of Armenia and adjacent areas: What is revisited?". Journal of Volcanology and Geothermal Research. 155 (3–4). Elsevier: 338–345. Bibcode:2006JVGR..155..338K. doi:10.1016/j.jvolgeores.2006.04.008.
  11. ^ "The earthquake at Mount Ararat". The South Australian. 25 June 1841. p. 3. Retrieved 19 March 2023.
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