1986 Vrancea earthquake

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1986 Vrancea Earthquake
Date 30 August 1986 (1986-08-30)
Magnitude Mw 7.1
Depth 132 km
Epicenter 45°32′49″N 26°18′58″E / 45.547°N 26.316°E / 45.547; 26.316Coordinates: 45°32′49″N 26°18′58″E / 45.547°N 26.316°E / 45.547; 26.316
Countries or regions  Romania
 Bulgaria
 Yugoslavia
 Moldova
 Ukraine
Total damage 55,000 households damaged or destroyed
Landslides Yes
Aftershocks 77[1]
Casualties 150+ deaths[2]
558 injuries

Striking central Romania on August 30 at 21:28 UTC, the 1986 Vrancea earthquake killed more than 150 people, injured over 500, and damaged over 50,000 homes. The second largest earthquake in the area since the modernization of earthquake monitoring devices,[3] it was felt north to Poland and south to Italy and Greece.

One local news facility listed that the earthquake measured 6.5 on the Richter scale,[4] and USGS listed its seismic moments as 5.6 and 7.9.[5] A research paper of V. I. Ulomov cited this earthquake with magnitude Mw 7.1.[6] Its epicenter was somewhere in the Vrancea Mountains.

The focal mechanism of the earthquake was described as "moderately well controlled" suggesting reverse faulting with some strike-slip motion.

Geography

The epicenter was pinpointed to Vrancea County, specifically to the Vrancea Mountains, about 110 miles (177 km) north of Bucharest.[4] In 1977, another strong quake ruptured oil fields in the area.[4]

Aftershocks

The rupture was located between 131–148 km depth, as shown the relocation of aftershocks hypocenters. The strongest aftershock occurred in the morning of September 2, 1986, at 5:00 a.m. (EET), at 143 km depth, with magnitude 5.0 Ms and felt in Bucharest with an intensity of about III-IV degrees on Mercalli scale. In total, 77 aftershocks were recorded with a magnitude over 3.2 on the Richter scale, of which 19 exceeded the value of 4.0 magnitude on the Richter scale.[7]

Damage and casualties

The earthquake was felt in at least eight geographically diverse countries, affecting most of southeast Europe.[5] The worst affected area was in the Focşani–Bârlad region, where intensity VIII (destructive) damage was recorded, causing a church to collapse.[5] In Bessarabia, earthquake has, in patches, quite severe effects. In Chișinău 4 apartment buildings collapsed, causing at least 100 casualties. In the south-west of Bessarabia, near Prut floodplain, were observed subsidence of land, sand spirts and formation of craters near the Prut river bed. In Bucharest, 50 laborers who worked in the basement of a building died crushed by piles of rubble.[8]

Causing 150 deaths, the earthquake also injured 558 people and fractured at least 55,000 households.[5] Intensity of VII was reported in Bucharest (very strong), and in northern Bulgaria. In addition, intensities of V (rather strong) were recorded in Skopje (now the capital of the Republic of Macedonia, suggesting the earthquake was widespread.[5] This is confirmed by reports of the earthquake as far north as Hungary and east Poland, and as south as Greece and Italy.[5] Lesser intensities of IV (moderate) in Simferopol and Kiev in the Soviet Union and in Belgrade, Yugloslavia and intensity III (slight) in Moscow and Titograd, Yugoslavia were recorded.[5]

See also

References

  1. ↑ "1986 Vrancea earthquake", Cutremur.net
  2. ↑ http://earthquake.usgs.gov/earthquakes/eqarchives/significant/sig_1986.php
  3. ↑ Monfret, Tony; Deschamps, Anne, and Romanowicz, Barbara (April 1990). "The Romanian earthquake of August 30, 1986: A study based on GEOSCOPE very long-period and broadband data". Pure and Applied Geophysics 133 (2): 367–379. Bibcode:1990PApGe.133..367M. doi:10.1007/BF00877169. Retrieved 2009-08-30. 
  4. ↑ 4.0 4.1 4.2 "Major Earthquake Rocks Eastern Europe". AGERPRES. September 1, 1986. Retrieved August 31, 2009. 
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 "Significant Earthquakes of the World: 1986". United States Geological Survey. July 16, 2008. Retrieved August 30, 2009. 
  6. ↑ http://www.springerlink.com/content/n3n160453030h443/fulltext.pdf
  7. ↑ "Seismicity of Romania", National Institute for Earth Physics, section Vrancea subcrustal zone
  8. ↑ "A magnitude 3.6 earthquake occurred near Bucharest", Realitatea.net
Very large
(7.0 or greater)
Large
(6.0–6.9)
  • 1545 Vrancea (6.8)
  • 1790 Vrancea (6.8)
  • 1812 Vrancea (6.5)
  • 1945 Vrancea (6.8)
  • 1990 Vrancea (6.9, 6.2, 6.1)
  • 2004 Vrancea (6.0)
Moderate
(less than 6.0)
  • 1974 Timiș (5.6)
  • 1991 Caraș-Severin (5.6)
  • 2004 Tulcea (5.0)
  • 2005 Buzău (5.1)
  • June 2005 Vrancea (5.0)
  • December 2005 Vrancea (5.0)
  • 2009 Vrancea (5.3)
  • 2013 Vrancea (5.3)
1 the most powerful earthquake ever recorded in Romania
2 the deadliest earthquake ever recorded in Romania
← Earthquakes in 1986 →
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