earthquake An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, fr ...

measuring 8.0 struck

Santiago Chile Santiago (, ; ), also known as Santiago de Chile, is the capital and largest city of Chile as well as one of the largest cities in the Americas. It is the center of Chile's most densely populated region, the Santiago Metropolitan Region, whose ...

on 3 March 1985, and ended up killing 177 people and injuring about 2,575 others. This earthquake was being felt between the northern

Antofagasta Antofagasta () is a port city in northern Chile, about north of Santiago. It is the capital of Antofagasta Province and Antofagasta Region. According to the 2015 census, the city has a population of 402,669. After the Spanish American wars ...

Region and the southern

Los Lagos Region Los Lagos Region ( es, Región de Los Lagos , ''Region of the Lakes'') is one of Chile's 16 regions, which are first order administrative divisions, and comprises four provinces: Chiloé, Llanquihue, Osorno and Palena. The region contains ...

. It was felt with a maximum intensity of VIII on the Mercalli intensity scale.

Damage and effects

The quake left 177 people dead, 2,575 injured, 85,358 houses damaged or destroyed and about a million people homeless. Many landslides were registered too, pavement breaks with the destruction of the

Pan-American Highway The Pan-American Highway (french: (Auto)route panaméricaine/transaméricaine; pt, Rodovia/Auto-estrada Pan-americana; es, Autopista/Carretera/Ruta Panamericana) is a network of roads stretching across the Americas and measuring about in to ...

in several points, broken-down

bridge A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually someth ...

s and considerable damage in affected town's infrastructure, with a long interruption on basic services. The damage was valued in more than 1 billion

US dollar The United States dollar ( symbol: $; code: USD; also abbreviated US$ or U.S. Dollar, to distinguish it from other dollar-denominated currencies; referred to as the dollar, U.S. dollar, American dollar, or colloquially buck) is the officia ...

s. Reports by local residents in the coastal area from Matanzas to several kilometers north of Algarrobo indicated unusually low tides for a period of 3 to 5 days following the earthquake. After this, the tides reportedly returned to normal. This suggests that there was earthquake-related uplift along parts of the coast which was recovered in 3 to 5 days after the earthquake. Near Algarrobo, an estimate of the change is about 20 cm uplift.

Tectonic setting

Chile lies on the boundary between the

Nazca Plate The Nazca Plate or Nasca 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 N ...

of the South Pacific continental plate. This results in Chile being one of the most seismically active regions in the world. On average, a magnitude 8

or greater occurs in the region about once every 25 years. Meaning that there is an expectation that a similar earthquake will happen in Chile in the future every 25 years. The main shock was actually made up of at least two shocks, with the initial motion beginning at approximately 11:00 PM followed by a greater event soon after. The magnitudes of the first and second shocks were calculated to be 5.2 and 6.9 respectively. The calculated proportion of energy released as aftershocks vs the main shock was relatively high, most likely due to the 7.2 aftershock on 9 April.

Scientific understanding

The earthquake was seen as particularly powerful, garnering the attention of the United States. They sent a team of

geologist A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althou ...

s to study its effects because the overall information that could be gained from studying the earthquake could give better understandings overall of these powerful earthquakes. This earthquake in particular was considered extremely important in the understanding of earthquakes as "it was very significant as a geophysical event and that the scientific and engineering study of this major shock would be of great value in improving our understanding of plate margin earthquakes, the distribution of strong ground motion, resulting building damage and geologic effects such as soil liquefaction and landsliding". The 1985 Algarrobo earthquake shows a clear example of how these types of

natural phenomenon A natural phenomenon is an observable event which is not man-made. Examples include: sunrise, weather, fog, thunder, tornadoes; biological processes, decomposition, germination; physical processes, wave propagation, erosion; tidal flow, and natura ...

can be studied and be used to better help humanity in the future in order to minimize the damages to both

infrastructure Infrastructure is the set of facilities and systems that serve a country, city, or other area, and encompasses the services and facilities necessary for its economy, households and firms to function. Infrastructure is composed of public and priv ...

and human lives. The precautions that Chile takes now in order to mitigate future risks is to educate its citizens in drills on how to react, having better building codes, and studying seismic data.

References

External links

* {{DEFAULTSORT:Algarrobo Earthquake, 1985 1985 Algarrobo earthquake 1985 in Chile 1985 earthquakes March 1985 events in South America

Damage and effects

Tectonic setting

Scientific understanding

See also

References

Further reading

External links