1949 Ambato earthquake
Encyclopedia
The 1949 Ambato earthquake was the largest earthquake
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...

 in the Western Hemisphere
Western Hemisphere
The Western Hemisphere or western hemisphere is mainly used as a geographical term for the half of the Earth that lies west of the Prime Meridian and east of the Antimeridian , the other half being called the Eastern Hemisphere.In this sense, the western hemisphere consists of the western portions...

 in more than five years. On August 5, 1949, it struck Ecuador's Tungurahua Province
Tungurahua Province
Tungurahua is one of the twenty-four provinces of Ecuador. Its capital is Ambato. The province takes its name from the Tungurahua volcano, which is located within the boundaries of the provinces.-Population:...

 southeast of its capital, Ambato, and killed 5,050 people. Measuring 6.8 on the Richter scale
Richter magnitude scale
The expression Richter magnitude scale refers to a number of ways to assign a single number to quantify the energy contained in an earthquake....

, it originated from a hypocenter
Hypocenter
The hypocenter refers to the site of an earthquake or a nuclear explosion...

 40 km (25 mi) beneath the surface. The nearby villages of Guano
Guano, Ecuador
Guano is a location in the Chimborazo Province, Ecuador. It is the seat of the Guano Canton.- References :* * - External links :*...

, Patate
Patate
Patate is a town in Ecuador in the Tungurahua Province in northwestern South America between San Juan de Ambato and Baños. It is close to the foothills of the still active Tungurahua volcano.- References :* * - External links :*...

, Pelileo
Pelileo
Pelileo is a city located at the center of the Andean region of Ecuador called La Sierra...

, and Pillaro
Pillaro
Píllaro is a city in Ecuador, located in the province of Tungurahua. It is the capital of the Píllaro Canton and stands about 19 km northeast of Ambato, the provincial capital ....

 were destroyed, and the city of Ambato suffered heavy damage. The earthquake flattened entire buildings, and subsequent landslide
Landslide
A landslide or landslip is a geological phenomenon which includes a wide range of ground movement, such as rockfalls, deep failure of slopes and shallow debris flows, which can occur in offshore, coastal and onshore environments...

s caused damage throughout the Tungurahua
Tungurahua Province
Tungurahua is one of the twenty-four provinces of Ecuador. Its capital is Ambato. The province takes its name from the Tungurahua volcano, which is located within the boundaries of the provinces.-Population:...

, Chimborazo
Chimborazo Province
Chimborazo is a province in Ecuador, located in the central Ecuadorian Andes, containing a section of Sangay National Park. The capital is Riobamba. The province contains Chimborazo , Ecuador's highest mountain.- Cantons :...

, and Cotopaxi Province
Cotopaxi Province
Cotopaxi is one of the provinces of Ecuador. The capital is Latacunga. The province contains the Cotopaxi Volcano, an intermittent volcano with a height of 19,388 feet.- Cantons :The province is divided into 7 cantons...

s. It disrupted water mains and communication lines and opened a fissure into which the small town of Libertad sank. Moderate shaking from the event extended as far away as Quito
Quito
San Francisco de Quito, most often called Quito , is the capital city of Ecuador in northwestern South America. It is located in north-central Ecuador in the Guayllabamba river basin, on the eastern slopes of Pichincha, an active stratovolcano in the Andes mountains...

 and Guayaquil
Guayaquil
Guayaquil , officially Santiago de Guayaquil , is the largest and the most populous city in Ecuador,with about 2.3 million inhabitants in the city and nearly 3.1 million in the metropolitan area, as well as that nation's main port...

.

Earthquakes in Ecuador stem from two major interrelated tectonic areas: the subduction
Subduction
In geology, subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate, sinking into the Earth's mantle, as the plates converge. These 3D regions of mantle downwellings are known as "Subduction Zones"...

 of the Nazca Plate
Nazca Plate
]The Nazca Plate, named after the Nazca region of southern Peru, is an oceanic tectonic plate in the eastern Pacific Ocean basin off the west coast of South America. The ongoing subduction along the Peru-Chile Trench of the Nazca Plate under the South American Plate is largely responsible for the...

 under the South American Plate
South American Plate
The South American Plate is a continental tectonic plate which includes the continent of South America and also a sizeable region of the Atlantic Ocean seabed extending eastward to the Mid-Atlantic Ridge....

, and the Andean Volcanic Belt
Andean Volcanic Belt
The Andean Volcanic Belt is a major volcanic belt along the Andean cordillera in Colombia, Bolivia, Peru, Ecuador, Chile and Argentina. It formed as a result of subduction of the Nazca Plate and Antarctic Plate underneath the South American Plate. The belt is subdivided into four main volcanic...

. The 1949 Ambato earthquake initially followed an intersection of several northwest-southeast-trending faults in the Inter-Andean Valley, which were created by the subduction of the Carnegie Ridge
Carnegie Ridge
The Carnegie Ridge is an aseismic ridge on the Nazca Plate that is currently 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...

. Strata of rock cracked as the earthquake ruptured the faults, sending out powerful shockwaves. Today, threats exist throughout the country from both interplate
Interplate earthquake
An interplate earthquake is an earthquake that occurs at the boundary between two tectonic plates. If one plate is trying to move past the other, they will be locked until sufficient stress builds up to cause the plates to slip relative to each other...

 and intraplate
Intraplate earthquake
An intraplate earthquake is an earthquake that occurs in the interior of a tectonic plate, whereas an interplate earthquake is one that occurs at a plate boundary....

 seismicity.

Background

Earthquakes are common in Ecuador. Near the Nazca
Nazca Plate
]The Nazca Plate, named after the Nazca region of southern Peru, is an oceanic tectonic plate in the eastern Pacific Ocean basin off the west coast of South America. The ongoing subduction along the Peru-Chile Trench of the Nazca Plate under the South American Plate is largely responsible for the...

 subduction
Subduction
In geology, subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate, sinking into the Earth's mantle, as the plates converge. These 3D regions of mantle downwellings are known as "Subduction Zones"...

 zone, the recorded history of interplate earthquake
Interplate earthquake
An interplate earthquake is an earthquake that occurs at the boundary between two tectonic plates. If one plate is trying to move past the other, they will be locked until sufficient stress builds up to cause the plates to slip relative to each other...

s spans 80 years. At the time it struck, the 1949 Ambato earthquake was the second-worst earthquake in Ecuador's modern history, topped only by the 1797 Riobamba earthquake
1797 Riobamba earthquake
The 1797 Riobamba earthquake occurred at 12:30 UTC on 4 February. It devastated the city of Riobamba and many other cities in the Interandean valley, causing up to 40,000 casualties. It is estimated that seismic intensities in the epicentral area reached at least XI on the Mercalli scale, and that...

, and the most devastating earthquake in the Western Hemisphere since the 1944 San Juan earthquake
1944 San Juan earthquake
The 1944 San Juan earthquake took place in the province of San Juan, in the center-west area of Argentina, a region highly prone to seismic events. This moderate to strong earthquake destroyed a large part of San Juan, the provincial capital, and killed 10,000 of its inhabitants, 10% of its...

. Several major earthquakes have occurred throughout the country since 1949, including the 1987 Ecuador earthquakes
1987 Ecuador earthquakes
The 1987 Ecuador earthquakes occurred at 1:54 GMT and 4:10 GMT on March 6, 1987 with magnitudes of 6.1 and 6.9 on the surface wave magnitude scale, respectively. The earthquakes were centered in Napo Province in northeast Ecuador; the epicenters were on the eastern slopes of the Andes, about...

 and the 1997 Ecuador earthquake. The 2007 Peru earthquake
2007 Peru earthquake
The 2007 Peru earthquake was an earthquake measuring 8.0 on the moment magnitude scale that hit the central coast of Peru on Wednesday, August 15, 2007; it occurred at 23:40:57 UTC and lasted for about three minutes...

 also affected the country.

Geology

Much of South American seismic activity and volcanism originates from subduction
Subduction
In geology, subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate, sinking into the Earth's mantle, as the plates converge. These 3D regions of mantle downwellings are known as "Subduction Zones"...

 of the oceanic
Oceanic crust
Oceanic crust is the part of Earth's lithosphere that surfaces in the ocean basins. Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium...

 Nazca Plate
Nazca Plate
]The Nazca Plate, named after the Nazca region of southern Peru, is an oceanic tectonic plate in the eastern Pacific Ocean basin off the west coast of South America. The ongoing subduction along the Peru-Chile Trench of the Nazca Plate under the South American Plate is largely responsible for the...

 under the continental South American Plate
South American Plate
The South American Plate is a continental tectonic plate which includes the continent of South America and also a sizeable region of the Atlantic Ocean seabed extending eastward to the Mid-Atlantic Ridge....

 and subduction of the Pacific's lithosphere
Lithosphere
The lithosphere is the rigid outermost shell of a rocky planet. On Earth, it comprises the crust and the portion of the upper mantle that behaves elastically on time scales of thousands of years or greater.- Earth's lithosphere :...

 under the South American continent. This seismicity extends for 6000 km (3,728 mi) along the continent's western edge, and probably stems from a region of northeast-trending faulting near the Ecuadorian Trench. The region of faulting may actually function as its own microplate.

The Carnegie Ridge
Carnegie Ridge
The Carnegie Ridge is an aseismic ridge on the Nazca Plate that is currently 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...

 is sliding under Ecuadorian land, causing coastal uplift and volcanism. The ridge's movement may also have changed the type of faulting along the coast, causing strike-slip faults (faults that move horizontally past each other). Evidence of this subduction altering the course of faulting is found at the Yaquina fault, which, unlike the rest of the Panama Basin faults, trends to the west instead of north-south, indicating that the Carnegie Ridge may be colliding with the continental mass of Ecuador. This collision created northwest-southeast and northeast-southwest-trending faults in the region, and with that, caused strong earthquakes in Riobamba in 1797 and Alausi in 1961. Several of the northwest-southeast-trending faults converge in the Inter-Andean Valley, where the 1949 Ambato earthquake took place.

The hypocenter
Hypocenter
The hypocenter refers to the site of an earthquake or a nuclear explosion...

 of the earthquake occurred 40 km (25 mi) beneath the surface, under a mountain 72 km (45 mi) from Ambato. Nearby fault lines ruptured, breaking rock strata and sending shock waves to the surface capable of bringing down entire buildings. Life
Life (magazine)
Life generally refers to three American magazines:*A humor and general interest magazine published from 1883 to 1936. Time founder Henry Luce bought the magazine in 1936 solely so that he could acquire the rights to its name....

reported that local seismologists first placed the earthquake's magnitude at 7.5, but the official measurement was later revised to 6.8.

Damage and casualties

The earthquake was preceded by a foreshock
Foreshock
A foreshock is an earthquake that occurs before a larger seismic event and is related to it in both time and space. The designation of an earthquake as foreshock, mainshock or aftershock is only possible after the event....

, which although modest, was strong enough to cause chaos and force people to flee from their homes into the streets. The main shock originated
Epicenter
The epicenter or epicentre is the point on the Earth's surface that is directly above the hypocenter or focus, the point where an earthquake or underground explosion originates...

 southeast of Ambato. When the primary shock hit, Ambato's main cathedral and military barracks collapsed, as did most of the city's buildings. Scores of young girls preparing for their first communion
First Communion
The First Communion, or First Holy Communion, is a Catholic Church ceremony. It is the colloquial name for a person's first reception of the Sacrament of the Holy Eucharist. Catholics believe this event to be very important, as the Eucharist is one of the central focuses of the Catholic Church...

s perished in the cathedral. The shaking ruptured water mains
Water supply network
A water supply system or water supply network is a system of engineered hydrologic and hydraulic components which provide water supply. A water supply system typically includes:# A drainage basin ;...

, disabled communication lines, opened cracks in the earth, reduced bridges to rubble, and derailed a train. The earthquake demolished buildings in rural hamlets
Hamlet (place)
A hamlet is usually a rural settlement which is too small to be considered a village, though sometimes the word is used for a different sort of community. Historically, when a hamlet became large enough to justify building a church, it was then classified as a village...

; closer to the nearest mountains of the Andes, landslide
Landslide
A landslide or landslip is a geological phenomenon which includes a wide range of ground movement, such as rockfalls, deep failure of slopes and shallow debris flows, which can occur in offshore, coastal and onshore environments...

s destroyed roads and blocked rivers. The village of Libertad, near Pelileo, sank 460 m (1,509 ft) into a huge hole about 800 m (2,625 ft) in diameter with all of its 100 inhabitants. Shaking up to intensity
Mercalli intensity scale
The Mercalli intensity scale is a seismic scale used for measuring the intensity of an earthquake. It measures the effects of an earthquake, and is distinct from the moment magnitude M_w usually reported for an earthquake , which is a measure of the energy released...

 IV extended as far away as Quito
Quito
San Francisco de Quito, most often called Quito , is the capital city of Ecuador in northwestern South America. It is located in north-central Ecuador in the Guayllabamba river basin, on the eastern slopes of Pichincha, an active stratovolcano in the Andes mountains...

 and Guayaquil
Guayaquil
Guayaquil , officially Santiago de Guayaquil , is the largest and the most populous city in Ecuador,with about 2.3 million inhabitants in the city and nearly 3.1 million in the metropolitan area, as well as that nation's main port...

.

Initial reports (around August 7) estimated the death toll at 2,700 people. The cities of Patate
Patate
Patate is a town in Ecuador in the Tungurahua Province in northwestern South America between San Juan de Ambato and Baños. It is close to the foothills of the still active Tungurahua volcano.- References :* * - External links :*...

 and Pelileo
Pelileo
Pelileo is a city located at the center of the Andean region of Ecuador called La Sierra...

 suffered the most, with 1,000 and 1,300 dead respectively. In Ambato, reports of the death toll ranged from 400 to 500, and the Ecuadorean Embassy in Washington, D.C., estimated that 1,000 to more than 2,000 people were injured. The town of Pillaro
Pillaro
Píllaro is a city in Ecuador, located in the province of Tungurahua. It is the capital of the Píllaro Canton and stands about 19 km northeast of Ambato, the provincial capital ....

, destroyed by the quake, had more than 20 dead, and in Latacunga
Latacunga
Latacunga is a plateau town of Ecuador, capital of the Cotopaxi Province, south of Quito, near the confluence of the Alaques and Cutuchi rivers to form the Patate, the headstream of the Pastaza. At the time of census 2001 Latacunga had 51,689 inhabitants, largely mestizo and indigenous.Latacunga...

, 11 were killed and 30 injured; 50 homes, two churches, and the local government building were also ruined. Fifteen other towns and cities were also badly affected, including Guano
Guano, Ecuador
Guano is a location in the Chimborazo Province, Ecuador. It is the seat of the Guano Canton.- References :* * - External links :*...

, which was devastated.

Later counts assumed around 3,200 casualties in Pelileo; the total death toll estimates were adjusted to around 4,000 people. Officials reported that many of the dead had been inside buildings as they buckled, or were killed by flooding brought about by the blockage of a drainage canal
Ditch
A ditch is usually defined as a small to moderate depression created to channel water.In Anglo-Saxon, the word dïc already existed and was pronounced 'deek' in northern England and 'deetch' in the south. The origins of the word lie in digging a trench and forming the upcast soil into a bank...

. Others were crushed by landslides from nearby mountains. No homes in the city of Pelileo were left standing, many buildings were flattened, and large cracks formed in the ground. In Ambato alone, 75 percent of the homes still standing had to be demolished. On August 8, an aftershock
Aftershock
An aftershock is a smaller earthquake that occurs after a previous large earthquake, in the same area of the main shock. If an aftershock is larger than the main shock, the aftershock is redesignated as the main shock and the original main shock is redesignated as a foreshock...

 with "considerable strength" struck near Ambato.

The final death toll, according to the United States Geological Survey
United States Geological Survey
The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...

, was 5,050. The earthquake severely affected some 30 communities and left approximately 100,000 people homeless.

Relief efforts

Ecuador's President, Galo Plaza Lasso
Galo Plaza
Galo Plaza Lasso was an Ecuadorian politician and statesman who served as the Ecuadorian Ambassador to the U.S, President of Ecuador from 1948 to 1952, and Secretary General of the Organization of American States from 1968 to 1975...

, flew to Ambato to take personal charge of the primary relief efforts. Plaza directed rescue efforts for two days as airlifts from Quito dropped supplies. A group of Red Cross volunteers and medical supplies were sent on American aircraft. The United States Army sent two relief teams equipped with serum and blood plasma. The mayor of Miami along with seven other politicians began a fund-raising campaign for medical needs and clothing, and coordinated the distribution of 69 kg (152 lb) of Rexall
Rexall
Rexall was a chain of North American drugstores, and the name of their store-branded products. The stores, having roots in the federation of United Drug Stores starting in 1902, licensed the Rexall brand name to as many as 12,000 drug stores across the United States from 1920 to 1977...

 drugs. Several nearby countries sent airplanes carrying medicine and food. A local fund-raising effort collected 250,000 Ecuadorian sucre
Ecuadorian sucre
The sucre was the currency of Ecuador between 1884 and 2000. Its ISO code was ECS and it was subdivided into 10 decimos or 100 centavos. The sucre was named after Antonio José de Sucre.-History:...

s (approximately $14,815 1949 USD) within two hours of its launch. Plaza said "We have not lost our courage. Neither Ambato nor Ecuador shall cry any more, but begin to work."

On August 7, a plane carrying 34 rescue workers from the Shell Oil Company
Shell Oil Company
Shell Oil Company is the United States-based subsidiary of Royal Dutch Shell, a multinational oil company of Anglo Dutch origins, which is amongst the largest oil companies in the world. Approximately 22,000 Shell employees are based in the U.S. The head office in the U.S. is in Houston, Texas...

 crashed 32 km (20 mi) from Ambato leaving no survivors. Disease began to spread in Pelileo within days of the earthquake, which prompted a team of American soldiers – who were acting as relief workers – to order water purification devices and DDT
DDT
DDT is one of the most well-known synthetic insecticides. It is a chemical with a long, unique, and controversial history....

 airdrops to cleanse the area of airborne agents. Sick victims were quarantined and prevented from leaving the city.

Aftermath

The earthquake considerably impacted a number of cities: it destroyed Guano, Patate, Pelileo, Pillaro, and one-third of Ambato. The city of Ambato was a "scene of anguish and pain" described by "scores of little funerals winding their way through the debris". The brand-new hospital had been reduced to four walls, and most of the buildings in town were demolished. In Pelileo, relief workers found victims feeding buried people through holes in the ground. In the days following the earthquakes, aftershocks occurred and torrential rains ensued.

In an effort to help the inhabitants, a festival of fruit and flowers was held on 29 June 1950. The festival was a success and became an annual event that is celebrated each year during Carnaval
Carnival
Carnaval is a festive season which occurs immediately before Lent; the main events are usually during February. Carnaval typically involves a public celebration or parade combining some elements of a circus, mask and public street party...

 and is now an important tourist attraction. Ambato was completely rebuilt after the earthquake. The city's main church, the Iglesia Matriz de Ambato, was replaced by a new cathedral, known as Iglesia La Catedral, in 1954. Pelileo was rebuilt on a new site about 2 km (1.2 mi) from its previous location.

Current situation

Ambato is frequently visited by tourists traveling on the Pan-American Highway
Pan-American Highway
The Pan-American Highway is a network of roads measuring about in total length. Except for an rainforest break, called the Darién Gap, the road links the mainland nations of the Americas in a connected highway system. According to Guinness World Records, the Pan-American Highway is the world's...

. The city is well-known for its extensive market, which sells a wide array of items including local delicacies and flowers, and for its quintas – old estates that serve as historic parks – some of which pre-date the earthquake.

Ecuador is still at risk from earthquakes: both intraplate
Intraplate earthquake
An intraplate earthquake is an earthquake that occurs in the interior of a tectonic plate, whereas an interplate earthquake is one that occurs at a plate boundary....

 (such as those in March 1987) and interplate earthquake
Interplate earthquake
An interplate earthquake is an earthquake that occurs at the boundary between two tectonic plates. If one plate is trying to move past the other, they will be locked until sufficient stress builds up to cause the plates to slip relative to each other...

s are possible. Intraplate seismicity poses a more formidable threat, as it can be much more powerful than interplate seismicity and is usually associated with landslides, subsidence
Subsidence
Subsidence is the motion of a surface as it shifts downward relative to a datum such as sea-level. The opposite of subsidence is uplift, which results in an increase in elevation...

, and even soil liquefaction
Soil liquefaction
Soil liquefaction describes a phenomenon whereby a saturated soil substantially loses strength and stiffness in response to an applied stress, usually earthquake shaking or other sudden change in stress condition, causing it to behave like a liquid....

.
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