Do you know why Chile is a seismic country ? This South American country is known worldwide for the large number of tremors and earthquakes that are reported every year. Chile's location on the planet, next to the Andes Mountains and great volcanic activity make it one of the most seismic places in the world.
Chile was formed by the process of orogenesis on the west coast of South America, which corresponds to the border at which two tectonic plates converge: the Nazca plate (oceanic plate) and the South American plate (continental plate).
This border was formed during the Paleozoic and Precambrian periods, where a pure zone of subduction created by microcontinents and ancient lands developed.
This subduction shaped four important geological features of the area: the Andes Mountains, the Intermediate Depression, the Coastal Range, and the coastal ditch of Peru and Chile. Chile is on the most active margin of these geological features, so volcanic activity is significant.
This together with the constant collisions of the Nazca, South American and Antarctic plates, make it susceptible to a large number of earthquakes that affect the entire country.
Chile's location is known as the Pacific Ocean's Ring of Fire.
One of the most seismic countries in the world
Earthquakes are unpredictable, especially in a country located in the middle of important tectonic plates such as Chile. The plates that come together on its coast, Nazca and South America, are wide slabs of terrestrial soil and approach each other at a rate of 80 millimeters per year.
Studies indicate that in Chile approximately every 10 years an earthquake occurs with a magnitude greater than 7 degrees on the Richter Scale. This is why more than 100 earthquakes have been reported since 1570 to date.
The Nazca plate is the floor of the Pacific Ocean in front of Chile and is permanently absorbed under the South American plate. This is why the country is the second most seismic in the world - after Japan - with events that not only affect its territory, but the entire South Pacific area in the world.
The fault that the Chilean coasts have is known as a subduction fault and is the same that is found on the coasts of Japan, Alaska and Indonesia, producing some of the most intense earthquakes in the history of the world.
Since the first measurements of earthquakes in Chile, dating back to 1522, dozens of violent earthquakes have been recorded, the one that affected the town of Valdivia, in the south of the country in 1960, the most powerful that has been recorded with instruments. in the world, with a magnitude on the Richter scale of 9.5.
Thousands of people died and several places were completely destroyed, devastated by the earthquake or by the waters of the tsunami that occurred minutes later, with waves that reached 10 meters in height.
Another of the largest earthquakes that Chile has experienced was the one that occurred in 2010, on February 27, with its epicenter in the city of Concepción, also in the south of the country. The magnitude of this event was 8, 8 degrees on the Richter scale and the violent movement destroyed buildings and houses.
For its part, the subsequent tsunami devastated several coastal towns such as Iloca and Duao in the south and the Juan Fernández archipelago, especially the town of San Juan Bautista, which was completely damaged.
This earthquake, known as 27-F, was so intense that it even modified the geography of the coast, raising the ground more than 4 meters, which was discovered by finding algae and seashells on the water.
Due to the geographical location of Chile on two subducting tectonic plates, which in geology is known as an immersion fault, all its territory - including its archipelagos of Easter Island, Juan Fernández and Chiloé - are in permanent movement, since the Nazca plate day after day is introduced under the South American plate.
This is why, according to experts, Chile has permanently experienced a series of earthquakes throughout history, which has caused both the Chilean authorities and the Chilean population to be highly prepared to face this type of disaster.
A country prepared
Chile's infrastructure is one of the best prepared in the world to deal with the earthquakes that constantly affect its territory.
In addition to this there is a preventive and alert system that circulates in its population. For example, turning on the sirens every time an earthquake is felt in coastal cities, so that the population can ascend to higher areas and prevent damage in the event of a subsequent tsunami.
On the other hand, building construction codes must be prepared to withstand a magnitude 9 earthquake on the Richter scale.
The building may crack and wobble, but it must not collapse. This among other security protocols in earthquakes have been adapted and implemented to the local reality of Chile, being widely managed by all its population.
This seismic culture is found not only in new constructions, but also in old buildings that exist in northern Chile, as is the case of the use of geometry in Andean houses, built only with adobe (a mixture of mud, straw and water) due to the scarcity of wood in the area. These houses are shaped like a trapezoid and with this they achieve greater stability in the center of the building.
On the other hand, in Tarapacá, in the north of Chile, another material known as "quincha" is used, very light and malleable to the movements of the earth, so it does not break or collapse in the case of a major seismic event..
This is why Chile is considered one of the examples in the world regarding the management of seismic events.
References
- Geology of Chile. Recovered from Wikipedia.com.
- Chile's long experience of quakes. Recovered from news.bbc.co.uk.
- What Caused the Chilean Earthquake? Faults Explained. Recovered from news.nationalgeographic.com.
- How did Chile manage to survive its recent earthquake virtually unscathed ?. Recovered from theguardian.com.
- Why do so many powerful earthquakes happen in Chile? Recovered from quora.com.
- Case study: Vernacular seismic culture in Chile. N. Jorquera Department of Architecture, Universidad de Chile, Santiago, Chile H. Pereira PROTERRA Iberian-American Network and Universidad Tecnológica Metropolitana, Santiago, Chile. Recovered from repository.uchile.cl.
- Huge Chilean Earthquake Raised Country's Coast. Recovered from livescience.com.