1992 Nicaragua earthquake
Encyclopedia
The 1992 Nicaragua earthquake occurred off the coast of Nicaragua
on September 2, 1992. Some damage was also reported in Costa Rica
. At least 116 people were killed and several more were injured. The quake was located in an active zone of stress and deformation. It created tsunami
s disproportionately large for its surface-wave magnitude, or Ms.
to be captured on modern broadband seismic networks. The initial surface wave magnitude was estimated at 7.2. It was a slow blind thrust earthquake
which occurred on the subduction interface between the Cocos
and Caribbean Plate
s, an active zone of stress and deformation, and due to the absence of sediment on the ocean floor off Nicaragua, the slip propagated up-dip all the way to the trench bottom, a creator of large tsunamis. This occurrence of slip of a plate interface filled with soft subducted sediments caused the rupturing process to be slower than the average subduction-zone thrust earthquakes while the focus
of the earthquake was much shallower than the typical subduction-zone earthquake.
departments of Nicaragua
, though it was also felt elsewhere in Nicaragua at Crucero, Managua
and San Marcos
and at San José
in Costa Rica. It was the strongest seismic event to hit Nicaragua since the earthquake of 1972
.
At least 116 people were killed, most being children sleeping in their beds, with more than 68 missing and over 13,500 left homeless in Nicaragua. At least 1,300 houses and 185 fishing boats were destroyed along the west coast of Nicaragua. Total damage in Nicaragua was estimated at between 20 and 30 million U.S. dollars.
According to the Augusto César Sandino Foundation, the most affected were "inhabitants of small poor communities who live from diverse subsistence activities. Their houses, located beside the sea, were almost entirely destroyed. These people have lost their livelihoods, poor peasants who grow basic grains for their own consumption in marginal areas, and fisherpeople who have lost their fishing equipment, boats, storage sheds and warehouses. Their already extreme poverty has been exacerbated."
was disproportionately large for its surface-wave magnitude, or Ms, and the duration of the rupture process was 100 s, unusually long for its size. The moment magnitude
, or Mw, was 7.6, larger than the 20-s Ms of 7; this Ms–Mw difference is a characteristic of so called tsunami earthquakes. Tide gages were set up at Corinto and Puerto Sandino
, which showed an impulsive tsunami originating 61 minutes after the earthquake. It ran inland 1,000 meters to Masachapa, the hardest hit major town of all, with 9 fatalities.
Violeta Chamorro
stated in her speech to her nation on September 2, 1992 that no international assistance was needed. However, the Red Cross did assist in some operations while the National Civil Defence carried out much of the relief operations, with wounded people being transported to the Hospital Leon and Lenin-Fonseca Hospital.
Nicaragua
Nicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean...
on September 2, 1992. Some damage was also reported in Costa Rica
Costa Rica
Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....
. At least 116 people were killed and several more were injured. The quake was located in an active zone of stress and deformation. It created tsunami
Tsunami
A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake...
s disproportionately large for its surface-wave magnitude, or Ms.
Tectonics
The 1992 Nicaragua earthquake was the first tsunami earthquakeTsunami earthquake
A tsunami earthquake is an earthquake that triggers a tsunami of a magnitude that is very much larger than the magnitude of the earthquake as measured by shorter-period seismic waves. The term was introduced by Hiroo Kanamori in 1972. Such events are a result of relatively slow rupture velocities...
to be captured on modern broadband seismic networks. The initial surface wave magnitude was estimated at 7.2. It was a slow blind thrust earthquake
Blind thrust earthquake
A blind thrust earthquake is an earthquake along a thrust fault that does not show signs on the Earth's surface, hence the designation "blind" . Such faults, being invisible at the surface, have not been mapped by standard surface geological mapping...
which occurred on the subduction interface between the Cocos
Cocos Plate
The Cocos Plate is an oceanic tectonic plate beneath the Pacific Ocean off the west coast of Central America, named for Cocos Island, which rides upon it.-Geology:...
and Caribbean Plate
Caribbean Plate
The Caribbean Plate is a mostly oceanic tectonic plate underlying Central America and the Caribbean Sea off the north coast of South America....
s, an active zone of stress and deformation, and due to the absence of sediment on the ocean floor off Nicaragua, the slip propagated up-dip all the way to the trench bottom, a creator of large tsunamis. This occurrence of slip of a plate interface filled with soft subducted sediments caused the rupturing process to be slower than the average subduction-zone thrust earthquakes while the focus
Hypocenter
The hypocenter refers to the site of an earthquake or a nuclear explosion...
of the earthquake was much shallower than the typical subduction-zone earthquake.
Damage and casualties
The first shock of the earthquake occurred at 0:16 GMT and was followed by several strong aftershocks. The quake was most widely felt in the Chinandega and LeónLeón (department)
León is a department in Nicaragua. It covers an area of 5,107 km² and has a population of 389,600 . The capital is the city of León.- Municipalities :# El Jicaral# El Sauce# La Paz Centro# Larreynaga# León# Nagarote# Quezalguaque...
departments of Nicaragua
Departments of Nicaragua
Nicaragua is a unitary republic, and for administrative purposes, it is divided into 15 departments and two self-governing regions based on the Spanish model:-Zelaya Department:...
, though it was also felt elsewhere in Nicaragua at Crucero, Managua
Managua
Managua is the capital city of Nicaragua as well as the department and municipality by the same name. It is the largest city in Nicaragua in terms of population and geographic size. Located on the southwestern shore of Lake Xolotlán or Lake Managua, the city was declared the national capital in...
and San Marcos
San Marcos, Carazo
San Marcos is a municipality in the Carazo Department of Nicaragua. It is located at south from the capital, Managua, and has a population of around 30,600 inhabitants....
and at San José
San José, Costa Rica
San José is the capital and largest city of Costa Rica. Located in the Central Valley, San José is the seat of national government, the focal point of political and economic activity, and the major transportation hub of this Central American nation.Founded in 1738 by order of Cabildo de León, San...
in Costa Rica. It was the strongest seismic event to hit Nicaragua since the earthquake of 1972
1972 Nicaragua earthquake
The 1972 Nicaragua earthquake was an earthquake that occurred at 12:29 a.m. local time on Saturday, December 23, 1972 near Managua, the capital of Nicaragua. It had a magnitude of 6.2 and occurred at a depth of about 5 kilometers beneath the centre of the city. Within an hour after the main...
.
At least 116 people were killed, most being children sleeping in their beds, with more than 68 missing and over 13,500 left homeless in Nicaragua. At least 1,300 houses and 185 fishing boats were destroyed along the west coast of Nicaragua. Total damage in Nicaragua was estimated at between 20 and 30 million U.S. dollars.
According to the Augusto César Sandino Foundation, the most affected were "inhabitants of small poor communities who live from diverse subsistence activities. Their houses, located beside the sea, were almost entirely destroyed. These people have lost their livelihoods, poor peasants who grow basic grains for their own consumption in marginal areas, and fisherpeople who have lost their fishing equipment, boats, storage sheds and warehouses. Their already extreme poverty has been exacerbated."
Tsunami
Most of the casualties and damage were caused by a tsunami affecting the west coasts of Nicaragua and Costa Rica, and it was one of three tsunamis to occur within a span of six months. Runup heights were measured shortly after the earthquake and reached heights of up to 9.9 meters, though the average height was 3 to 8 meters. The tsunamiTsunami
A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake...
was disproportionately large for its surface-wave magnitude, or Ms, and the duration of the rupture process was 100 s, unusually long for its size. The moment magnitude
Moment magnitude scale
The moment magnitude scale is used by seismologists to measure the size of earthquakes in terms of the energy released. The magnitude is based on the seismic moment of the earthquake, which is equal to the rigidity of the Earth multiplied by the average amount of slip on the fault and the size of...
, or Mw, was 7.6, larger than the 20-s Ms of 7; this Ms–Mw difference is a characteristic of so called tsunami earthquakes. Tide gages were set up at Corinto and Puerto Sandino
Puerto Sandino
Puerto Sandino is a coastal town in western Nicaragua. It is located at around .- U.S. Attacks :While supporting the Contras in the 1980s, U.S. forces attacked Puerto Sandino on September 13 and October 14, 1983. On March 28 and March 30, 1984 U.S. forces attacked patrol boats at Puerto Sandino....
, which showed an impulsive tsunami originating 61 minutes after the earthquake. It ran inland 1,000 meters to Masachapa, the hardest hit major town of all, with 9 fatalities.
Relief efforts
From the onset of the disaster authorities provided initial assistance. PresidentPresident of Nicaragua
The position of President of Nicaragua was created in the Constitution of 1854. From 1825 until the Constitution of 1838 the title of the position was known as Head of State and from 1838 to 1854 as Supreme Director .-Heads of State of Nicaragua within the Federal Republic of Central America...
Violeta Chamorro
Violeta Chamorro
Violeta Barrios Torres de Chamorro is a Nicaraguan political leader, former president and publisher. She became president of Nicaragua on April 25, 1990, when she unseated Daniel Ortega...
stated in her speech to her nation on September 2, 1992 that no international assistance was needed. However, the Red Cross did assist in some operations while the National Civil Defence carried out much of the relief operations, with wounded people being transported to the Hospital Leon and Lenin-Fonseca Hospital.
See also
- List of earthquakes in Nicaragua
- http://www.reliefweb.int/rw/rwb.nsf/db900SID/ACOS-64BHCW?OpenDocument- Nicaragua Earthquake/Tsunami Sep 1992 UNDHA Situation Reports 1 – 7
- [Fernandez, M., E. Molina, J. Havskov, and K. Atakan. 2000. Tsunamis and Tsunami Hazards in Central America. Natural Hazards, 22:91-116.]