The 1906 Valparaíso earthquake hit Valparaíso, Chile, on August 16 at 19:55 local time. Its epicenter was offshore from the Valparaíso Region, and its intensity was estimated at magnitude 8.2 . This earthquake occurred thirty minutes after the

1906 Aleutian Islands earthquake The 1906 Aleutian Islands earthquake occurred at 00:11 UTC on August 17. It had an estimated seismic moment of 3.8 x 1028 dyn cm−1, equivalent to a magnitude of 8.35 on the moment magnitude scale. This earthquake was followed thirty minutes late ...

. Much of Valparaíso was destroyed; there was severe damage in

central Chile Central Chile (''Zona central'') is one of the five natural regions into which CORFO divided continental Chile in 1950. It is home to a majority of the Chilean population and includes the three largest metropolitan areas—Santiago, Valparaís ...

from

Illapel Illapel () is a Chilean city, which is the capital of the Choapa Province, Coquimbo Region. It lies along the Illapel River and marks the country's narrowest point along a parallel (94 km). It is located to the east of Los Vilos. Administrat ...

to Talca. The earthquake was felt from Tacna to

Puerto Montt Puerto Montt (Mapuche: Meli Pulli) is a port city and commune in southern Chile, located at the northern end of the Reloncaví Sound in the Llanquihue Province, Los Lagos Region, 1,055 km to the south of the capital, Santiago. The commune spa ...

. Reports said the earthquake lasted four minutes. A tsunami was also generated. The earthquake killed a reported 3,882 people. The record of previous seismic activity includes major earthquakes in 1647, 1730 and 1822. The 1906 disaster was predicted by Captain Arturo Middleton, Chief of the Chilean Army Meteorological Office, in a letter that was published in '' El Mercurio'', one week before it occurred. Admiral Luis Gómez Carreño ordered the shooting of at least 15 people, who were caught looting after the earthquake. A Board for Reconstruction was formed some weeks after the earthquake. The Seismological Service of Chile was also created.

Background

Chile lies above a

convergent plate boundary A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can be defined by a ...

, an area where 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 Na ...

under the Pacific Ocean is

subducted Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...

or moved beneath the

South American Plate The South American Plate is a major tectonic plate which includes the continent of South America as well as a sizable region of the Atlantic Ocean seabed extending eastward to the African Plate, with which it forms the southern part of the Mid-A ...

. In the region around Valparaiso, the rate of convergence is about 70 mm/yr. As these two plates converge, it drives the Nazca plate with massive movements called megathrust earthquakes. The 1906 event was one of many large earthquakes in Chile along this plate boundary. Earthquakes can originate at the plate interface itself or within either the subducting or overriding plates. Citing the conjunction of

Neptune Neptune is the eighth planet from the Sun and the farthest known planet in the Solar System. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times ...

with the moon, Captain Arturo Middleton, Chief of the Chilean Army's Meteorological Office, predicted the earthquake in a letter published in the Valparaíso newspaper '' El Mercurio'' on August 6. Captain Middleton was severely criticized in the following days, and was described as "ignorant and obscurantist."

Earthquake characteristics

On August 16, 1906, at 19:55 local time, while most Chileans were dining, a subterraneous sound was heard, and before it ended, the first tremor occurred, lasting about four minutes. The second tremor occurred at 20:06 and, although it lasted only two minutes, was much more violent. There were numerous aftershocks: at least 56 of them occurred during the first 24 hours after the beginning tremors. The magnitude of the earthquake has been estimated to be 8.4 , 8.2 or 8.2–8.3. The energy release has been re-evaluated with an estimated seismic moment of 2.8 x 10²⁸, equivalent to a magnitude of 8.26 . The rupture length of the earthquake has been estimated at about 200 km with a focal depth of about 40 km. The

focal mechanism The focal mechanism of an earthquake describes the deformation in the source region that generates the seismic waves. In the case of a fault-related event it refers to the orientation of the fault plane that slipped and the slip vector and is ...

has been assessed using contemporary seismograph records from five stations, which were published soon after the earthquake. The data suggest that the earthquake was probably along the subduction interface. Modelling of a tsunami using these source parameters shows that this earthquake was the origin of the transpacific tsunamis recorded that same day in Hawaii and Japan, rather than the almost contemporaneous

. The 30-minute time gap between the Aleutian and Chilean earthquakes is thought to be coincidental, with no causal link between the two.

Damage

The earthquake caused damage throughout

Central Chile Central Chile (''Zona central'') is one of the five natural regions into which CORFO divided continental Chile in 1950. It is home to a majority of the Chilean population and includes the three largest metropolitan areas—Santiago, Valparaís ...

, from

to Talca. There were several destructive fires in El Almendral (from Plaza de la Victoria to Cerro Barón), Mercado Cardonal, Teatro de la Victoria (Victory Theatre), the Intendencia, the Maritime Government in Sotomayor Square and the Fiscal Dock at the port. The earthquake was also felt in Santiago, the capital of Chile. The newspaper ''El Mercurio'' reported in its August 17 edition that "the earthquake was produced in a violent way since its beginning, and provoked an indescribable panic through all the four thousands of inhabitants of Santiago and an unprecedented terror in the last years. Two or three-story buildings, even the most solid ones such as the National Congress, were swinging like a vessel in the sea. The shakings were so strong that many people thought the earth was going to open itself in deep and long strips." According to the University of Chile, there were deaths. The earthquake left more than 20,000 injured. On August 19, Admiral Luis Gómez Carreño was appointed Plaza Port Chief. Gómez ordered the distribution of water and food, removal of corpses and demolition of buildings in risk of collapse, from a tent in Plaza de La Victoria. Adm. Gómez ordered the shooting of at least 15 people who had committed crimes during the aftermath. Teatro de la Victoria - Valparaíso, Chile.jpg, Teatro de la Victoria before the earthquake Terremoto Valparaíso 1906-Teatro de la Victoria.JPG, Teatro de la Victoria after the earthquake Saqueador fusilado-Terrremoto Chile 1906.JPG, Looters shot by the authorities.

Relief efforts

Despite the state of the city, authorities quickly organized themselves into relief groups. Firefighters from other cities of Chile, including Santiago, Concepción and Talcahuano, moved to Valparaíso to help the local Fire Bureau. Physician José Grossi worked to counteract the plagues that followed the earthquake. On August 25, President Germán Riesco and President-Elect

Pedro Montt Pedro Elías Pablo Montt Montt (; 29 June 1849, Santiago, Chile – 16 August 1910, Bremen, Germany) was a Chilean political figure. He served as the president of Chile from 1906 to his death from a probable stroke in 1910. His government furth ...

arrived at Valparaíso. They arrived there by train, on foot, or horseback to survey the magnitude of the disaster. Some weeks after the earthquake, a Board for Reconstruction was formed, using money received from other countries.

Aftermath

In 1906, the Seismological Service of Chile (Servicio Sismológico de Chile) was created. Its first chief executive was Fernand de Montessus de Ballore. The effects of this historic seismic event in the Valparaíso rupture zone would be studied and measurable in the context of further seismic activity in this vicinity.Korrat, (1986).

Notes

References

* Das, Shamita; John Boatwright and C. H. Scholz. (1986). ''Earthquake Source Mechanics.'' Washington, D.C.: American Geophysical Union.
OCLC 13526041

External links

in Valparaíso Fire Bureau's website

* {{DEFAULTSORT:1906 Valparaiso earthquake Valparaiso Earthquake, 1906 1906 in Chile Natural disasters in Chile Megathrust earthquakes in Chile 1906 tsunamis Valparaíso August 1906 events