2001 El Salvador earthquakes

earthquake
title= 2001 El Salvador earthquake (First)
date= January 13 2001

---

magnitude = 7.6 M_wLater estimates were revised to 7.7 or 7.9; see [http://neic.usgs.gov/neis/eq_depot/2001/eq_010113/ USGS Preliminary Earthquake Report] and [http://www.redcross.org/general/0,1082,0_180_,00.html American Red Cross] , for example.]
depth = 39 kmNational Aeronautics and Space Administration. [http://www.gsfc.nasa.gov/gsfc/educ/science/2000/02-08-01.htm "Science Question of the Week"] (comparing January 2001 quakes in India and El Salvador), NASA.gov, February 8, 2001.]
countries affected = El Salvador, Guatemala
casualties = El Salvador: 844 fatalities, 4,723 injured
Guatemala: 8 fatalities [http://neic.usgs.gov/neis/eq_depot/2001/eq_010113/] |The 2001 El Salvador earthquakes were two earthquakes which hit El Salvador within exactly one month of each other, on January 13 and February 13 2001.

The January 13 earthquake

At 17:33:34 UTC the 7.6 (later estimated to be 7.7 or 7.9)Later estimates were revised to 7.7 or 7.9; see [http://neic.usgs.gov/neis/eq_depot/2001/eq_010113/ USGS Preliminary Earthquake Report] and [http://www.redcross.org/general/0,1082,0_180_,00.html American Red Cross] , for example.] quake struck with the epicentre at 60 miles (100 km) SW of San Miguel, El Salvador (13.04N 88.66W) at the depth of 60 km. At least 844 people were killed, 4,723 injured, 108,226 houses destroyed — with another 113,416 houses damaged — and more than 150,000 buildings were damaged in El Salvador.Christian Aid. [http://www.reliefweb.int/rw/rwb.nsf/db900SID/OCHA-64DFMC?OpenDocument "El Salvador Earthquake: Emergency Update 02 Feb 2001"] (press release), on ReliefWeb.int, February 2, 2001.] About 585 of the deaths were caused by large landslides in Santa Tecla (also known as Nueva San Salvador) and Comasagua. Utilities and roads were damaged by more than 16,000 landslides. Damage and injuries occurred in every department of El Salvador, particularly the departments of La Libertad and Usulután. Eight people were killed in Guatemala. The tremor was felt from Mexico City to Colombia. [http://neic.usgs.gov/neis/eq_depot/2001/eq_010113/ http://neic.usgs.gov/neis/eq_depot/2001/eq_010113/] ] An aftershock measuring 5.7 magnitude was felt on January 15, an event not widely reported outside the country until after the February quake, which initially was assessed by the USGS at 5.7 magnitude as well.CNN. [http://archives.cnn.com/2001/WORLD/americas/02/13/salvador.quake/index.html "Quake aftershock frightens Salvadorans,"] CNN.com, February 13, 2001.]

As of February 2, 2001, more than 2,500 aftershocks had hit El Salvador, leading to additional damage and terrorizing the inhabitants. Clean water and sanitation became a matter of grave concern in many areas due to the earthquake's destruction of some $7 million to municipal drinking water systems, and tens of thousands of people were living outdoors in spite of the approaching rainy season ("invierno").Christian Aid press release, op. cit.] Government and public health organizations warned of the possible spread of disease as desperate people began to scavenge debris piles — some containing severed human limbs — looking for items they could pawn to purchase needed food and other commodities.CNN. [http://archives.cnn.com/2001/WORLD/americas/01/20/el.salvador.quake/index.html "Poor sanitation fuels disease fears in aftermath of Salvador quake,"] CNN.com, January 20, 2001.]

earthquake
title= 2001 El Salvador earthquake (Second)
date= February 13 2001


magnitude = 6.6 M_w
countries affected = El Salvador, Guatemala, Honduras
casualties = El Salvador: 315 fatalities|

The February 13 earthquake

At 14:22:05 UTC, the 6.6 quake struck with the epicentre at 15 miles (30 km) E of San Salvador, El Salvador (13.67N 88.93W) at the depth of 10 km. At least 315 people were killed, 3,399 injured and extensive damage. The most severe damage occurred in the San Juan Tepezontes-San Vicente-Cojutepeque area, though the quake was felt throughout the country and in neighboring Guatemala and Honduras. Landslides occurred in many areas of El Salvador.

Quakes mechanism

The earthquakes occurred within the Cocos-Caribbean subduction zone. El Salvador sits atop the western part of the Caribbean plate, where it is overriding (subducting) the Cocos plate. Subduction zones such as this are geologically very complex and produce numerous earthquakes from multiple sources. Shallow intraplate (crustal) earthquakes occur within the crust of the overriding Caribbean plate. Deeper intraplate earthquakes occur within the subducting Cocos plate. The earthquake sequence in the El Salvador region has involved intraplate faulting in both the Cocos and Caribbean plates, with the largest earthquake in the sequence (January 13) occurring in the lower (Cocos) plate. The February 13 earthquake was a strong, shallow intraplate earthquake, occurring within the crust of the overlying Caribbean plate. This earthquake was a strike-slip faulting earthquake, which likely occurred in response to the complicated stresses in the Caribbean plate as it overrides the Cocos plate. It was about 85 km away from the 13 January earthquake and about 30 km shallower.

These two earthquakes occurred in two different plates. The occurrence of any large earthquake changes the stresses throughout the surrounding region. Aftershocks occur in response to these changes. Occasionally, other earthquakes will occur in response to the altered regional stresses. While not technically aftershocks, these earthquakes are related, becoming part of a regional earthquake sequence.

Another example of a regional earthquake sequence is the 1992 Landers-Big Bear sequence in southern California. The magnitude 7.3 Landers earthquake was followed by the magnitude 6.4 Big Bear earthquake, which occurred on a different fault approximately 36 km away. [http://neic.usgs.gov/neis/eq_depot/2001/eq_010213/ http://neic.usgs.gov/neis/eq_depot/2001/eq_010213/] ]

Post-quake analyses

In the days and weeks following the earthquakes, Salvadoran and foreign agencies analyzed the factors that had facilitated the destruction the disasters had caused. While Salvadoran government representatives were quick to point out that the destruction had been far less than that of the 1986 earthquakes,Ambassador Rene Leon, interviewed by Ray Suarez. [http://www.pbs.org/newshour/bb/latin_america/jan-june01/quake_1-15.html "Salvadoran Earthquake,"] "OnlineNewsHour", January 15, 2001.] outside researchers critiqued shortcomings in preparedness and in policies toward land development that had permitted massive deforestation in the Santa Tecla area. Mexican seismologists invited by the Salvadoran government summarized their observations this way: Cquote|The construction equipment of the Ministry of Public Works was thinly stretched over hundreds of earth slumps and seemed inadequate to the task. ... The many homeless were not much in evidence; in the countryside they had been housed in temporary huts under the supervision of the armed forces, or with relatives. No homeless people were seen in the streets of San Salvador, presumably because the middle class had sustained the brunt of the damage. There was a palpable desire in the capital to forget the earthquake drama as quickly as possible.

This may be the wrong time to forget.

...According to some press reports, the developers at Las Colinas had been authorized to proceed in spite of existing zoning regulations designed to prevent residential developments on the slopes. The location was a desirable one because the Santa Tecla area was relatively safe from guerrilla operations. After pacification the pressure from developers subsided as there seems to be plenty of available land in the valley; but there is a definite need for setting up enforceable zoning regulations in order to protect the hillsides from future deforestation and encroachment by developers. ...

The 2001 earthquake did not approach the level of severity of some previous earthquakes, yet it wiped out the equivalent of half the annual gross national income. A small investment in preparedness would pay off handsomely.|30px|Cinna Lomnitz and Sergio Rodríguez ElizararrásCinna Lomnitz and Sergio Rodríguez Elizararrás, Universidad Nacional Autónoma de México. [http://www.radixonline.org/resources/lomnitz-salvador-rept.doc "El Salvador 2001: Earthquake disaster and disaster preparedness in a tropical volcanic environment,"] paper submitted to "Seismological Research Letters".]

The government's response to the earthquakes was critiqued from different sides, with some criticizing the legislature for not approving the full amount of emergency funding urged by President Flores,CNN. [http://archives.cnn.com/2001/WORLD/americas/01/20/el.salvador.quake/index.html "Poor sanitation fuels disease fears in aftermath of Salvador quake,"] CNN.com, January 20, 2001.] and others condemning what they saw as the ARENA government's contributions to the devastation. The Nicaragua-based magazine "Envío" argued that the conservative government's pro-business stance had fostered aggressive levels of land development, coupled with high poverty rates that forced poor rural residents to make do with inadequate but cheap building materials, asserting: "Totaling up these factors makes it clear that the consequences of a natural phenomenon like an earthquake cannot be described as 'natural' ... Describing the January 13 earthquake as a 'natural disaster' is not only irresponsible, but also a declaration of future impotence. It assumes fatalistic acceptance that no natural phenomena can be prevented and that all one can do is respond to emergencies as they arise and try to rehabilitate and reconstruct what has been destroyed." The magazine further critiqued the government's optimism about economic recovery in the aftermath of the first quake as an "insulting" minimization of the tragedy caused across the country and as an attempt to shore up the dollarization campaign that had been the focus of political attention up until the quakes.Ismael Moreno. [http://www.envio.org.ni/articulo/1473 "Dollarization and the Earthquake: Two Manmade Disasters,"] "Revista Envío", January 2001.]

Notes

External links

* [http://neic.usgs.gov/neis/eq_depot/2001/eq_010113/ First quake (USGS)]
* [http://neic.usgs.gov/neis/eq_depot/2001/eq_010213/ Second quake (USGS)]
* [http://www.redcross.org/general/0,1082,0_180_,00.html Images - International Services - El Salvador Earthquake, 2001] , photos and information by the American Red Cross