2012 Costa Rica earthquake

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2012 Costa Rica earthquake
2012 Costa Rica earthquake is located in Costa Rica
2012 Costa Rica earthquake
Date September 5, 2012 (2012-09-05)
Magnitude 7.6 Mw
Depth 40.2 km (25.0 mi)[1]
Epicenter 9°59′46″N 85°19′05″W / 9.996°N 85.318°W / 9.996; -85.318
Countries or regions Costa Rica
Max. intensity MM X+[2]
Peak acceleration 1.61 g (1580.0 cm/s2)[3]
Aftershocks 1,650[4]
Casualties 2

The 2012 Costa Rica earthquake occurred at 08:42 local time (14:42 UTC) on September 5, 2012. The epicenter of the 7.6 Mw earthquake was in the Nicoya Peninsula, 11 kilometers east-southeast of Nicoya.[5] A tsunami warning was issued shortly afterwards, but later cancelled. Two people are known to have died, one from a heart attack and another, a construction worker, crushed by a collapsing wall.[6] It was the second strongest earthquake recorded in Costa Rica's history, following the 1991_Limon_earthquake.[7]

Geology[edit]

Costa Rica lies above the convergent plate boundary where the Cocos Plate is subducting beneath the Caribbean Plate at a rate of 9 cm per year. Off the Nicoya Peninsula, the Cocos Plate is subducting along the Middle America Trench, and the Nicoya Peninsula is unique in being one of the few landmasses along the Pacific Rim located directly above the seismogenic zone of a subduction megathrust fault.[8] The earthquake is thought to have occurred as a result of thrust faulting on the plate interface.[9][10] The earthquake has a maximum slip of about 2.5 m.[11] The 1950 earthquake essentially the same part of the plate boundary as the 2012 earthquake.[10]

The same area was struck by a M7.7 earthquake in 1950 but had been quiet before the recent earthquake, and the segment of the plate boundary was known as the Nicoya Peninsula seismic gap. In the intervening period, up to 2010, there was an estimated 5 m of missing displacement. Studies determined that the earthquake recurrence interval for the Nicoya Peninsula was about 50 years.[12] The Volcanological and Seismological Observatory of Costa Rica (OVSICORI) stated that the earthquake had released 40% of the energy accumulated during the 8 years before it and did not exclude the possibility of an earthquake of equal or larger magnitude.[13]

The earthquake[edit]

A USGS ShakeMap for the event

The earthquake was felt all over Costa Rica as well as in Nicaragua, El Salvador, and Panama.[6][14] The maximum intensity reached MM X or higher in Nosara near the epicenter. The shaking has intensities of MM VIII in Santa Cruz and MM V in San José.[2][11] The recorded acceleration in Fraijanes, Alajuela was larger than that of Nicoya, Guanacaste.[15] A tsunami warning was issued for neighbouring countries along the Pacific Coast shortly afterwards, but later cancelled.[16]

In neighbouring Nicaragua, the Nicaraguan Institute of Territorial Studies began monitoring the seven active volcanoes in the country, expecting that the strong earthquake could activate them. The country's highest volcano, San Cristóbal Volcano (1,745 metres), erupted on September 8, sending an ash cloud to 5,000 metres and forcing the evacuation of 3,000 people from five communities in the area.[17]

Aftershocks[edit]

Some 1,650 aftershocks occurred in the following five days, including one of 5.4 magnitude, or Mw 5.7 by USGS,[18] about 13 km southeast of Playa Sámara on September 8 at 20:29 UTC (14:29 local time), according to OVSICORI, with no further damages or casualties reported.[4][19]

The most powerful aftershock since the September earthquake, lasting at least 30 seconds and measuring magnitude 6.6, struck at 00:45 UTC on 24 October 2012 (18:45 on 23 October, locally) near the town of Hojancha in the Nicoya Peninsula.[20][21][22][23] In San José, people rushed to the streets out of fear. A thunderous sound accompanying the aftershock was reported by residents in Matapalo.[24]

Damage[edit]

There were reports of destroyed houses in the cantons of Hojancha, Nicoya, Nandayure, and Santa Cruz of the province of Guanacaste.[25] Building damage was reported in San José, including broken windows, cracks on walls, and materials detached from the buildings. In the city center of San José, many people stopped working and grouped on the streets waiting for safety checks for the buildings.[26] In total, at least 169 houses were damaged.[27] Cracks were found at the dyke protecting Filadelfia from the Tempisque River.[27] The Hospital Monseñor Sanabria in Puntarenas suffered damage, and the building was partially closed.[28]

School classes were cancelled for one day in stricken areas and students were evacuated.[29] Fifty-five thousand people were deprived of running water in the provinces of Puntarenas and Guanacaste.[30] Water tank in Filadelfia collapsed.[31] Power losses were reported in some areas in and around the capital city San José and in the Nicoya Peninsula and the Chira Island.[27][30][32][33] GSM and 3G services were interrupted in some places near the epicentre.[34]

Relief and reconstruction[edit]

Following the earthquake, the Ministry of Public Education announced that 56 schools in the country would have to be demolished and rebuilt at a preliminary cost of 3 billion. The final bill will be higher, however, because many other schools suffered lesser damage which also requires repair.[35] The Costa Rican Red Cross deployed emergency teams with about 205 members and 66 vehicles.[31] According to a preliminary estimation from the Costa Rican government, the earthquake caused a loss of about ₡ 22.36 billion.[36] Facing the damage, the president of Costa Rica expressed the need of a loan from the World Bank.[37]

References[edit]

  1. ^ "Magnitude 7.6 - COSTA RICA: Technical". United States Geological Survey. 2012-09-05. Retrieved 2012-09-05. 
  2. ^ a b "Reporte". Lis.ucr.ac.cr. Retrieved 2012-11-09. 
  3. ^ "Laboratorio de Ingeniería Sísmica". Lis.ucr.ac.cr. Retrieved 2012-11-09. 
  4. ^ a b Latest report from Ovsicori: 1,650 aftershocks registered The Tico Times, 2012-09-10.
  5. ^ M7.6 - 12km ESE of Hojancha, Costa Rica United States Geological Survey, 5 September 2012.
  6. ^ a b BBC, 2012-09-05 (2012-09-05). "Powerful earthquake rocks Costa Rica's north-west". BBC News. Retrieved 2012-09-05. 
  7. ^ Marino Protti: ‘Podíamos decir dónde y qué tan grande sería el terremoto 2012’ La Nación, 2014-02-05. (Spanish)
  8. ^ "Megathrust earthquakes, coastal uplift, and emergent marine terraces of Costa Rica’s Nicoya Peninsula". Serc.carleton.edu. Retrieved 2012-11-09. 
  9. ^ "Magnitude 7.6 - COSTA RICA: Summary". United States Geological Survey. 2012-09-05. Retrieved 2012-09-05. 
  10. ^ a b "Earthquakes". Labs.cas.usf.edu. doi:10.1029/2001TC001304. Retrieved 2012-11-09. 
  11. ^ a b "Terremoto del 05 de setiembre del 2012". Lis.ucr.ac.cr. Retrieved 2012-11-09. 
  12. ^ Morrish, S.C.; Butcher A.J., Ritzinger B.T., Wellington K.L. & Marshall J.S. (2010). "Tectonic geomorphology and earthquake hazards of the Nicoya Peninsula Seismic Gap, Costa Rica, Central America". Retrieved 5 September 2012. 
  13. ^ "Terremoto de Nicoya solo liberó el 40% de la energía acumulada - SUCESOS - La Nación". Nacion.com. 2012-09-12. Retrieved 2012-11-09. 
  14. ^ Cota, Isabella (2012-09-05). "Powerful quake hits Costa Rica, two dead". Reuters. Retrieved 2012-11-09. 
  15. ^ "En zonas de Alajuela el suelo se movió más que en Nicoya - EL PAÍS - La Nación". Nacion.com. Retrieved 2012-11-09. 
  16. ^ "''USGS: Major earthquake hits Costa Rica, tsunami warning issued; c.2012 World News on NBCNEWS.com". Worldnews.nbcnews.com. 2012-10-24. Retrieved 2012-11-09. 
  17. ^ Nicaragua’s San Cristóbal volcano erupts The Tico Times, 2012-09-08.
  18. ^ "M5.7 - 8km ENE of Hojancha, Costa Rica 2012-09-08 20:29:31 UTC". Comcat.cr.usgs.gov. Retrieved 2012-11-09. 
  19. ^ "Sismicidad Mensual". Ovsicori.una.ac.cr. Retrieved 2012-11-09. 
  20. ^ Réplica de terremoto de Nicoya causó gran alarma en el país La Nación, 2012-10-24. (Spanish)
  21. ^ Temblor fuerte de 6.6 grados en Nicoya La Nación, 2012-10-23. (Spanish)
  22. ^ Magnitude-6.6 earthquake rocks Costa Rica on Tuesday night The Tico Times, 2012-10-23.
  23. ^ M6.5 - 13km ENE of Hojancha, Costa Rica United States Geological Survey, 2012-10-23.
  24. ^ "Temblor de 6.5 sacude Costa Rica". Milenio.com. Retrieved 2012-11-09. 
  25. ^ "Sismo destruyó viviendas en varios cantones de Guanacaste y Alajuela - EL PAÍS - La Nación". Nacion.com. 2012-09-06. Retrieved 2012-11-09. 
  26. ^ "Temblor causó daños en algunos edificios de San José - SUCESOS - La Nación". Nacion.com. 2012-09-05. Retrieved 2012-11-09. 
  27. ^ a b c "Recuento: 169 casas dañadas y 260 personas en albergues - SUCESOS - La Nación". Nacion.com. Retrieved 2012-11-09. 
  28. ^ "Telenoticias7/Nacionales". Telenoticias7.com. Retrieved 2012-11-09. 
  29. ^ "MEP suspende clases en la zona de influencia del temblor - SUCESOS - La Nación". Nacion.com. 2012-09-05. Retrieved 2012-11-09. [dead link]
  30. ^ a b "55 MIL SIN AGUA Y 21 MIL SIN LUZ". DiarioExtra.com. Retrieved 2012-11-09. 
  31. ^ a b http://adore.ifrc.org/Download.aspx?FileId=30754
  32. ^ "Fuerza y Luz ya restableció fluido eléctrico en zonas afectadas luego de temblor - SUCESOS - La Nación". Nacion.com. Retrieved 2012-11-09. 
  33. ^ 4:08PM BST 05 Sep 2012 (2012-09-05). "Tsunami warning issued after Costa Rica earthquake". London: Telegraph. Retrieved 2012-11-09. 
  34. ^ "ICE reporta afectación en telefonía GSM y 3G y zonas cerca del sismo sin luz - SUCESOS - La Nación". Nacion.com. Retrieved 2012-11-09. 
  35. ^ MEP deberá reconstruir 56 escuelas a raíz del terremoto La Nación, 2012-09-10.
  36. ^ "Gobierno estima daños por terremoto en ¢22.000 millones - EL PAÍS - La Nación". Nacion.com. 2012-09-19. Retrieved 2012-11-30. 
  37. ^ "Informes Determinarán Monto De Préstamo Para Afrontar Daños De Terremoto". Prensalibre.cr. Retrieved 2012-11-30.