1979 Tumaco earthquake

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1979 Tumaco earthquake
Colombia relief location map.jpg
UTC  time1979-12-12 07:59:05
ISC  event 654039
Local dateDecember 12, 1979 (1979-12-12)
Local time02:59:05 COT
Magnitude8.2 Mw [1]
Depth33 km (21 mi) [2]
Epicenter 1°35′53″N79°21′29″W / 1.598°N 79.358°W / 1.598; -79.358 Coordinates: 1°35′53″N79°21′29″W / 1.598°N 79.358°W / 1.598; -79.358 [2]
Type Megathrust
Areas affected Colombia, Ecuador
Total damage$8 million [3]
Max. intensity IX (Violent)
Tsunami6 m (20 ft) [3]
Casualties300–600 [3]

The 1979 Tumaco earthquake occurred at 02:59 local time on 12 December with a moment magnitude of 8.2 and a maximum Mercalli intensity of IX (Violent). The epicenter was just offshore from the border between Ecuador and Colombia, near the port city of Tumaco. It triggered a major tsunami, which was responsible for most of the estimated 300–600 deaths. The hardest hit area was Colombia's Nariño Department. [2]

The moment magnitude scale is a measure of n earthquake's magnitude based on its seismic moment, expressed in terms of the familiar magnitudes of the original "Richter" magnitude scale.

The epicenter, epicentre or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates.

Tumaco Place in Nariño Department, Colombia

Tumaco is a port city and municipality in the Nariño Department, Colombia, by the Pacific Ocean. It is located on the southwestern corner of Colombia, near the border with Ecuador, and enjoys of hot tropical climate. Tumaco is inhabited mainly by Afro-Colombians and some indigenous people.


Tectonic setting

Coastal parts of Ecuador and southern Colombia lie above the convergent boundary where the Malpelo Plate subducts beneath the South American Plate along the Colombia–Ecuador Trench. At his location the Malpelo Plate, the microplate northeast of the Nazca Plate, is moving to the east relative to South America at a rate of 58 mm per year. [4] North of the Carnegie Ridge, the subduction interface has four recognisable segments, from south to north, the Esmeraldas, Manglares, Tumaco and Patia segments. [5] This plate boundary has been the location of several great historical earthquakes, most associated with damaging tsunamis. In 1906 a 5–600 km long segment of the plate interface ruptured, causing a M 8.8 earthquake (rupturing all four segments) and a trans-Pacific tsunami. [1]

Convergent boundary Region of active deformation between colliding lithospheric plates

Convergent boundaries are areas on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other causing a process known as subduction. The subduction zone can be defined by a plane where many earthquakes occur, called the Benioff Zone. These collisions happen on scales of millions to tens of millions of years and can lead to volcanism, earthquakes, orogenesis, destruction of lithosphere, and deformation. Convergent boundaries occur between oceanic-oceanic lithosphere, oceanic-continental lithosphere, and continental-continental lithosphere. The geologic features related to convergent boundaries vary depending on crust types.

Malpelo Plate A small tectonic plate off the coast west of Ecuador and Colombia

The Malpelo Plate is a small tectonic plate located off the coasts west of Ecuador and Colombia. It is the 57th plate to be identified. It is named after Malpelo Island, the only emerged part of the plate. It is bounded on the west by the Cocos Plate, on the south by the Nazca Plate, on the east by the North Andes Plate, and on the north by the Coiba Plate, separated by the Coiba Transform Fault (CTF). This microplate was previously assumed to be part of the Nazca Plate. The Malpelo Plate borders three major faults of Pacific Colombia, the north to south striking Bahía Solano Fault in the north and the Naya-Micay and Remolino-El Charco Faults in the south.

Subduction A geological process at convergent tectonic plate boundaries where one plate moves under the other

Subduction is a geological process that takes place at convergent boundaries of tectonic plates where one plate moves under another and is forced to sink due to gravity into the mantle. Regions where this process occurs are known as subduction zones. Rates of subduction are typically in centimeters per year, with the average rate of convergence being approximately two to eight centimeters per year along most plate boundaries.


This event was the last of three earthquakes that ruptured adjacent parts of the plate interface, forming a northeastward migrating sequence. The 1942 earthquake ruptured the Esmeraldas segment, the 1958 earthquake ruptured the Manglares segment and the 1979 event ruptured the Tumaco and Patia segments. [5] Together they ruptured the same part of the megathrust as the 1906 earthquake. [4] The rupture area of the 1979 earthquake measured 280 km long by 130 km wide. [6]

1958 Ecuador–Colombia earthquake

The 1958 Ecuador–Colombia earthquake struck the coastal regions of Ecuador and Colombia on January 19 with a surface wave magnitude of 7.6 at 9:07 local time. Approximately 30 percent of Esmeraldas (Ecuador) was destroyed, including the children's department of the hospital, where three children died. In all, 111 persons died and 45 were injured as a result of the earthquake. Water mains were broken and power transmission lines were damaged. The Esmeraldas-Quito highway collapsed at many places. Many other roads of the country were made impassable by cracks and fallen trees. According to press reports, a landslide from the slopes of the Andes at Panado village buried a hundred people. The earthquake was destructive in the cities on the northern coast of the country and was strong from Latacunga to Quito, Ibarra and Tulcán. It was felt at Guayaquil.

The earthquake was widely felt in both Ecuador (including Guayaquil, Esmeraldas and Quito) and Colombia (including Bogotá, Cali, Popayán and Buenaventura). [7] The coast in the epicentral region subsided by up to 1.6 m during the earthquake and the land movement locally disrupted river drainage. [8]

Guayaquil City in Guayas, Ecuador

Guayaquil, officially Santiago de Guayaquil, is the largest and most populous city in Ecuador. with 2,578,201 people in the metropolitan area, as well as the nation's main port. The city is the capital of Guayas Province and the seat of Guayaquil canton.

Esmeraldas, Ecuador Place in Esmeraldas, Ecuador

Esmeraldas is a coastal city in northwestern Ecuador. It is the seat of the Esmeraldas Canton and capital of the Esmeraldas Province. It has an international sea port and a small airport. Esmeraldas is the major seaport of northwestern Ecuador, and it lies on the Pacific coast at the mouth of the Esmeraldas River. It is exactly at the antipodes of Padang, Indonesia. The city is the principal trading hub for the region's agricultural and lumber resources, and is the terminus of the 313-mile (504-km) Trans-Ecuadorian Pipeline from the oil fields in northeastern Ecuador.

Quito Capital city in Pichincha, Ecuador

Quito is the capital and the second largest city of Ecuador, and at an elevation of 2,850 metres (9,350 ft) above sea level, it is the second-highest official capital city in the world, after La Paz, and the one which is closest to the equator. It is located in the Guayllabamba river basin, on the eastern slopes of Pichincha, an active stratovolcano in the Andes Mountains. With a population of 2,671,191 according to statistical projections (2019), Quito is the most populous city in Ecuador. It is also the capital of the Pichincha province and the seat of the Metropolitan District of Quito. The canton recorded a population of 2,239,191 residents in the 2010 national census. In 2008, the city was designated as the headquarters of the Union of South American Nations.


The coast nearest the epicenter was hit by the first wave of the tsunami about three minutes after the earthquake. Three to four waves were observed, with the third being the highest. The third wave coincided with low tide, greatly reducing the extent of the inundation and the likely death toll. [9] The maximum observed water height was 6.0 m at San Juan de la Costa, northeast of Tumaco. The tsunami was observed on the east coast of Japan, in Hawaii, Tahiti and Mexico. [9]


The earthquake caused widespread damage, particularly in Tumaco, where about a tenth of all buildings were destroyed, including 1,280 houses, and 25 people were reported either dead or missing. [2] [7] The fishing village of Charco was almost completely destroyed by the tsunami, the waves washing the houses inland into a nearby lake. 93 of the original population of 4,000 were reported either dead or missing. The tsunami also destroyed all the houses in San Juan de la Costa, with 199 reported either dead or missing. The total death toll was estimated to be 500–600 with another 4,000 injured. [7]


The damage caused by this earthquake and the 1983 Popayán earthquake, near central Colombia, led to the development of a national building code for earthquake-resistant structures for Colombia, [10] which came into law in 1984. [11]

Related Research Articles

Carnegie Ridge An aseismic ridge on the Nazca Plate that is being subducted beneath the South American Plate

The Carnegie Ridge is an aseismic ridge on the Nazca Plate that is being subducted beneath the South American Plate. The ridge is thought to be a result of the passage of the Nazca Plate over the Galapagos hotspot. It is named for the research vessel Carnegie, which discovered it in 1929.

A slow earthquake is a discontinuous, earthquake-like event that releases energy over a period of hours to months, rather than the seconds to minutes characteristic of a typical earthquake. First detected using long term strain measurements, most slow earthquakes now appear to be accompanied by fluid flow and related tremor, which can be detected and approximately located using seismometer data filtered appropriately. That is, they are quiet compared to a regular earthquake, but not "silent" as described in the past.

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Sunda megathrust

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1861 Sumatra earthquake

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1932 Jalisco earthquakes

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1953 Tumbes earthquake

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1942 Peru earthquake

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Romeral Fault System

The Romeral Fault System is a megaregional system of major parallel and anastomosing faults in the Central Ranges of the Colombian Andes and the Cauca, Amagá, and Sinú-San Jacinto Basins. The system spans across ten departments of Colombia, from northeast to south Bolívar, Sucre, Córdoba, Antioquia, Caldas, Risaralda, Quindío, Valle del Cauca, Cauca and Nariño. The fault zone extends into Ecuador where it is known as the Peltetec Fault System. The in detail described part of the Romeral Fault System south of Córdoba has a total length of 697.4 kilometres (433.3 mi) with a cumulative length of 1,787.9 kilometres (1,110.9 mi) and runs along an average north to south strike of 017.6 ± 16, cross-cutting the central-western portion of Colombia.


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