2010 Chile Earthquake

The 2010 Chile earthquake and tsunami ( es, Terremoto del 27F) occurred off the coast of central Chile on Saturday, 27 February at 03:34 local time (06:34 UTC), having a magnitude of 8.8 on the moment magnitude scale, with intense shaking lasting for about three minutes. It was felt strongly in six Chilean regions (from Valparaíso in the north to Araucanía in the south) that together make up about 80 percent of the country's population. According to the United States Geological Survey (USGS) the cities experiencing the strongest shaking—VIII (''Severe'') on the Mercalli intensity scale (MM)—were Concepción, Arauco, and Coronel. According to Chile's Seismological Service, Concepción experienced the strongest shaking at MM IX (''Violent''). The earthquake was felt in the capital Santiago at MM VII (''Very strong'') or MM VIII. Tremors were felt in many Argentine cities, including Buenos Aires, Córdoba, Mendoza, and La Rioja. Tremors were felt as far north as the city of Ica in southern Peru (approx. away).

The earthquake triggered a tsunami which devastated several coastal towns in south-central Chile and damaged the port at Talcahuano. Tsunami warnings were issued in 53 countries, and the wave caused minor damage in the San Diego area of California and in the Tōhoku region of Japan, where damage to the fisheries business was estimated at ¥6.26 billion (US$66.7 million). The earthquake also generated a blackout that affected 93 percent of the Chilean population and which went on for several days in some locations. President Michelle Bachelet declared a " state of catastrophe" and sent military troops to take control of the most affected areas. According to official sources, 525 people lost their lives, 25 people went missing and about 9% of the population in the affected regions lost their homes.

On 10 March, Swiss Reinsurance Co. estimated that the Chilean quake would cost insurance companies between 4 and 7 billion dollars. The rival German-based Munich Re AG made the same estimate. Earthquake's losses to the economy of Chile are estimated at US$15–30 billion.

Location/Epicenter

According to the USGS, the epicenter of the earthquake was about off the coast of Pelluhue, a town in the Maule Region. This is about west of the village of Chovellén, southwest of the town of Pelluhue and at a point approximately away from the following four provincial capitals: Talca (to the north-east), Linares (to the east), Chillán (to the south-east) and Concepción (to the south). Chile's Seismological Service located the quake's epicenter at about off the coast of Ñuble Region in the Biobío Region. This is north of Concepción and south-west of Talca.

Seismology and geology

The earthquake took place along the boundary between the Nazca and South American tectonic plates at a location where they converge at a rate of eighty millimeters (3 in) a year. This earthquake was characterized by a thrust-faulting focal mechanism, caused by the subduction of the Nazca plate beneath the South American Tectonic Plates. The end-regions of the rupture zone coincided with the Andean oroclines of Maipo (33° S) and Arauco (37° S). This has been interpreted as suggesting a link between upper plate (South American plate) structure and rupture length.

Chile has been at a convergent plate boundary that generates megathrust earthquakes since the Paleozoic era (500 million years ago). In historical times the Chilean coast has suffered many megathrust earthquakes along this plate boundary, including the strongest earthquake ever measured, the 1960 Valdivia earthquake. More recently, the boundary ruptured during the 2007 Tocopilla earthquake in northern Chile.

The segment of the fault zone which ruptured in this earthquake was estimated to be over long with a displacement of almost 10 meters, or 120 years of accumulated plate movement. It lay immediately north of the segment which ruptured in the great earthquake of 1960. Preliminary measurements show that the entire South American Plate moved abruptly westward during the quake. A research collaborative of Ohio State and other institutions have found, using GPS, that the earthquake shifted Santiago 28 cm (11 in) to the west-southwest and moved Concepción at least to the west. The earthquake also shifted other parts of South America from the Falkland Islands to Fortaleza, Brazil. For example, it moved Argentina's capital of Buenos Aires about 2.5 cm (1 in) to the west. Several cities south of Cobquecura were also raised by up to 3 meters. The maximum recorded peak ground acceleration was at Concepcion, with a value of 0.65 ''g'' (6.38 m/s²).

The locality of Tirúa south of Concepción recorded a 180 cm uplift relative to sea level as result of the earthquake. This is the highest known uplift of the coast resulting from the earthquake. This uplift made a large islet emerge at the mouth of Lebu River.

Compared with past earthquakes

This was the strongest earthquake affecting Chile since the magnitude 9.5 1960 Valdivia earthquake (the most energetic earthquake ever measured), and it was the strongest earthquake worldwide since the 2004 Indian Ocean earthquake and until the 2011 Tōhoku earthquake. It is tied with the 1906 Ecuador–Colombia and 1833 Sumatra earthquakes as the sixth strongest earthquake ever measured, approximately 500 times more powerful than the 7.0 M_w earthquake in Haiti one month prior in January 2010.

Aftershocks

An aftershock of 6.2 was recorded 20 minutes after the initial quake.Latest Earthquakes M5.0+ in the World
, by USGS. Two more aftershocks of magnitudes 5.4 and 5.6 followed within an hour of the initial quake. The USGS said that "a large vigorous aftershock sequence can be expected from this earthquake". By 6 March UTC, more than 130 aftershocks had been registered, including thirteen above magnitude 6.0.

Shortly after the mainshock seismologists installed a dense network of seismometers along the whole rupture area. This network captured 20,000 aftershocks in the 6 months after the mainshock and shows a detailed picture of the structure of the Chilean margin. Seismicity is focused in the depth range 25–35 km and in a deeper band of between 45 and 50 km depth. Around 10.000 aftershocks occurred in the region of two large aftershocks in the Pichilemu region.

A 6.9-magnitude offshore earthquake struck approximately 300 kilometers southwest of, and less than 90 minutes after, the initial shock; however, it is not clear if that quake was related to the main shock. A separate earthquake of magnitude 6.3 occurred in Salta, Argentina, at 15:45 UTC on 27 February, at a depth of ; two people were injured and one died in Salta. This earthquake was followed on 1 March at 06:32 UTC by a magnitude 4.9 aftershock. Four other earthquakes above M5.0, some possible aftershocks, also occurred near the border in Argentina following the Chile earthquake; a magnitude 5.0 earthquake occurred in Mendoza on 28 February, a M5.3 earthquake in Neuquen and a M5.2 in San Juan on 2 March, and a M5.1 quake in Mendoza on 4 March.

Another strong earthquake occurred on 4 March, at 22:39 UTC in Antofagasta in northern Chile, with a magnitude of 6.3.

Minor quakes generated by the main one could be felt as far away as São Paulo, Brazil, located about away from Concepción. Since the major earthquake, and as of 15 March, at least four to forty >M5.0 earthquakes have been recorded daily in the vicinity of the main earthquake, including four above magnitude 6.0 between 3 March and 6 March.

On 5 March, two aftershocks above M6.0 were reported. The first was a 6.3-magnitude off the coast of the Biobío Region. The second was near the epicenter of the original quake at 08:47 local time with a magnitude of 6.6.

On 11 March, the March 2010 Chile earthquake (magnitude 6.9, treated by some as an aftershock of the February 2010 earthquake) was reported, followed quickly by further aftershocks measuring 6.7 and 6.0. The epicenter of the 6.9 quake was in Pichilemu, O'Higgins Region.

On 15 March, two aftershocks of the February 2010 earthquake were reported, one at magnitude 6.2 at 08:08:28 local time offshore Maule, and another at magnitude 6.7 with the epicenter located offshore the Biobío Region, near Cobquecura, at 23:21:58 local time. This tremor was followed by two minor aftershocks, one occurring 45 minutes later, measuring M5.5. No tsunami was reported and there were no tsunami warnings issued.

On 17 March, at 14:38:37 local time, an earthquake of magnitude 5.2 was recorded in Aisén, in Southern Chile. Another magnitude 5.2 earthquake was recorded in Los Lagos the next day. On 26 March, at 10:52:06 local time, a magnitude 6.2 earthquake hit the Atacama region, in Northern Chile.

The Biobio Region of Chile had strong aftershocks of this earthquake. The first one was a magnitude 6.7 M_W earthquake that struck off the coast of Biobío, Chile, at 23:21 on 15 March 2010 at the epicenter, at a depth of . The second earthquake struck on land in the region at 22:58 ( UTC) on 2 April 2010 at 5.9 M_W and at a depth of 39 km. The third struck on 10:03 ( UTC) on 23 April 2010 at 6.2 M_W. The Pacific Tsunami Warning Center said that historical data indicates that this quake would not generate a tsunami but still advised of the possibility. On 3 May, at 19:09 a 6.4 M_W earthquake magnitude struck off Biobío, Chile, at the epicenter, at a depth of . The epicenter was south of Lebu. On 14 July 2010, another 6.5 magnitude earthquake occurred in the area.

2011 aftershocks

On 2 January at 17:20:18 local time, a 7.1 magnitude aftershock occurred 70 kilometers northwest of Temuco, Chile. On Lautaro, Cañete, Nueva Imperial, Traiguén and Carahue the quake was felt at intensity VI (''Strong'') of the Mercalli intensity scale. In Temuco it was perceived at intensity V (''Moderate''). In Talcahuano, Concepción, Chillán, Osorno and Valdivia it shook at intensity IV (''Light''). According to the USGS the earthquake's epicenter was located on the ground, east of the coastal town of Tirúa in the Araucanía Region. However, according to the University of Chile's Seismological Service, the seismic event was located 134 kilometers off the coast of Tirúa, measuring a magnitude 6.9 M_L. The University of Chile also reported that the localities who received the strongest shaking (VI) were Curanilahue, Lebu and Tirúa. In Concepción, Talcahuano and Temuco it was felt at intensity V, and in Chillán and Valdivia at intensity IV.

A magnitude 6.2 M_w aftershock struck the coast of Biobío, Chile at a shallow depth of 15.1 km (9.4 mi) on 1 June 2011 at 08:55 local time (12:55   UTC). It was centered just offshore Arauco Province near a moderately populated area, with most structures in its vicinity reported to be resistant to earthquake shaking. Strong shaking registering at VI on the Mercalli intensity scale was felt in Lebu, just 7 km (4 mi) south of the epicenter, lasting for approximately one minute. Some residents in coastal areas panicked and evacuated their homes. The earthquake was followed by a moderate magnitude 5.1 M_w tremor that occurred about 52 minutes later to the northeast of the main shock epicenter at an estimated depth of 26.9 km (16.7 mi). Initial estimates from the USGS placed its intensity at a magnitude of 6.4 M_w.

Geophysical impact

Seismologists estimate that the earthquake was so powerful that it may have shortened the length of the day by 1.26 microseconds and moved the Earth's figure axis by 2.7 milliarcseconds (about 8 cm). Precise GPS measurement indicated the telluric movement moved the entire city of Concepción to the west. The capital Santiago experienced a displacement of almost west, and even Buenos Aires, about from Concepción, shifted . It is estimated that Chile's territory could have expanded as a result.

The earthquake also caused seiches to occur in Lake Pontchartrain to the north of New Orleans, United States, located nearly from the epicenter of the quake.

In Antarctica a series of icequakes were triggered by the 2010 earthquake in Chile.

Damage and casualties

People were found dead after the earthquake struck, mostly under buildings and inside cars. Many people were also seriously injured. Most injuries were reported in Santiago and Maule.

According to an Associated Press Television News cameraman, some buildings collapsed in Santiago and there were power outages in parts of the city. A fire was reported in a chemical plant on the outskirts of Santiago and caused the evacuation of the neighborhood. Santiago's International Airport seemed to have been damaged and the airport authority closed off all flight operations for 24 hours from around 12:00 UTC. On Sunday, 28 February, Ricardo Ortega, head of the Chilean Air Force, said commercial airline services had been partially re-established and aircraft were being allowed to land in Santiago.

Santiago's national Fine Arts Museum was badly damaged and did not reopen until 9 March 2010. An apartment building's two-story parking lot collapsed, wrecking 68 cars. According to one health official, three hospitals in Santiago collapsed, and a dozen more south of the capital also suffered significant damage.

File:Casa Pelluhue tras terremoto 2010.jpg, House uprooted to the streets of Pelluhue after the tsunami.
File:Chile Earthquake 2010 - Maipú 1.JPG, A severely damaged building in Maipú, Santiago.
File:Canal ifarle tsunami.jpg, Tsunami in Talcahuano, Biobío Region.
File:Vespucio Norte Highway after 2010 earthquake.jpg, Collapsed Vespucio Norte Express Highway in Santiago.
File:2010 Chile earthquake - Carretera de la fruta.jpg, Fruit Road, O'Higgins Region.

In Valparaíso, a tsunami wave of 1.29 m was reported. The port of Valparaíso was ordered to close due to the damage caused by the earthquake. The port started to resume limited operations on 28 February. In Viña del Mar, a touristic city and part of Greater Valparaíso, several buildings were structurally damaged, principally in the district Plan de Viña.

Many cities in the Maule region were seriously affected by the earthquake which triggered more than 1000 landslides, a significant contributor to earthquake fatalities. Mapped from satellite images, most landslides occurring in the Principal Andean Cordillera and a constrained area on the Arauco Peninsula. Curanipe, only 8 km (5 mi) from the epicenter, was hit by a tsunami after the earthquake and still remained isolated from outside as of 28 February. A surfer said the tsunami "...was like the one in Thailand, a sudden rise of water. One could not estimate the dimension of the wave, because it was advancing foam. There were 10 to 15 rises, the last one being at 08:30 in the morning." In Talca, the capital of the Maule region, many dead were trapped in the rubble. The administrative building was uninhabitable, and the authorities had to be set up in the parade ground. All but two of the local hospital's thirteen wings were in ruins. Dr. Claudio Martínez was quoted as saying, "We're only keeping the people in danger of dying." Hospital staff attempted to transport some patients to Santiago on Sunday morning, but roads were blocked.

Damaged buildings and fires were reported in Concepción. Rescue teams had difficulty accessing Concepción because of the damaged infrastructure. The fifteen-story residential building "Alto Río" toppled, lay on the ground horizontally, and trapped many of the residents. As the building was newly completed, 19 of the apartments were occupied and 36 were of unknown occupancy. A 2.34 m (7.68 ft) tsunami wave hit Talcahuano, a port city and part of the Concepción conurbation. The tsunami caused serious damage to port facilities and lifted boats out of the water. In the fishing town of Dichato, of 7,000 residents, it was the third tsunami wave that ended up being the most damaging.

Dilapidated buildings could be seen on the streets of Temuco, about 400 km (250 mi) from the epicenter. The adobe of some buildings fell. Façades fell in pieces and crushed cars. Two people were reported dead because of not having been able to escape from a nightclub. On 27 February, it was reported that "to find an open business is almost impossible" ("Encontrar un negocio abierto es casi imposible"). Further south, in the city of Valdivia damages to houses were restricted to areas of poor soil quality, chiefly former wetlands and artificial fills. Some pavements near the rivershore in Valdivia cracked and collapsed much like in the 1960 earthquake. Overall damages in Valdivia were few and highly localized. A survey showed that 434 persons in Valdivia had their homes damaged by the earthquake.

The earthquake also triggered more than 1,000 landslides mapped from satellite images with most landslides occurring in the Principal Andean Cordillera and a constrained area on the Arauco Peninsula Landslides are a significant contributor to earthquake fatalities. In Chile, 370,000 homes were damaged. The final death toll of 525 victims and 25 people missing was announced by authorities in January 2011. This is down from early reports on 3 March of 802 people dead.

The Chilean National Emergency Office ('' Oficina Nacional de Emergencia'') estimated that the intensity of the earthquake was 9 on the Mercalli intensity scale in the Biobío Region and 8 in Santiago. USGS put the intensity in Talcahuano at MM VIII, in Santiago and Concepción at MM VII and in Valparaíso at MM VI.

On 10 March, Swiss Reinsurance Co. estimated that the Chilean quake would cost the insurance industry between 4 and 7 billion dollars. The same estimate was echoed by the rival German-based Munich Re AG.

File:Terremoto Chile 2010-Incendio fabrica plastico.jpg, Fire at a plastics plant, Santiago, Chile.
File:2010 Chile earthquake - Hospital of Temuco.jpg, ''Hernán Henríquez Hospital'' of Temuco had to be evacuated after the earthquake.
File:2010 Chile earthquake - Car destroyed in Temuco.jpg, A car crushed by the rubble of a collapsed building in Temuco.

Modified Mercalli intensities for some localities

Notes: USGS=United States Geological Survey, SS=Chile's Seismological Service.

Identified fatalities

The records of deaths were reported by a number of different agencies at different figures immediately after the earthquake. The official total is 525 dead, 25 missing not all of which are identified in the table below.

Population with destroyed or severely damaged homes

The table below shows the percentage of the regional population whose homes were destroyed or were severely damaged by the earthquake and tsunami in the six most affected regions. The data were collected between May and June 2010.

Source:''
Casen Post-Earthquake Survey
Ministry of Planning.

South of Araucanía Region, in the city of Valdivia, 35 houses were destroyed and 44 others were damaged.

Humanitarian response

Despite President Michelle Bachelet's earlier statement that Chile would only ask for international aid once it had assessed the extent of the damage, leaders of many countries and intergovernmental organizations, including the United Nations and European Union, responded to the earthquake and sent messages of condolence to the government and people of Chile over the loss of life and property. Argentina, Mexico, the United States, United Kingdom, People's Republic of China, Singapore, Haiti, and Pakistan were among the countries that responded earliest following the quake. Appeals for humanitarian aid were issued by the UK-based Oxfam, Save the Children, and others.

Chilean television host Don Francisco led a telethon called '' Chile helps Chile'' with the goal of raising 15 billion pesos (about US$29 million) needed to build 30,000 emergency houses (" mediaguas"). The charity event, which ran for 24 hours in Santiago starting on Friday 5 March at 22:00, was summoned by the government and organized by several Chilean NGOs. At 23:00 on Saturday the goal was doubled, collecting 30.2 billion pesos (about US$58 million).

The Chilean NGO Un Techo para Chile constructed 23,886 transitional houses for families affected by the earthquake.

Conditions in the aftermath

Chaos and disorder

Nearly half the places in the country were declared "catastrophe zones", and curfews were imposed in some areas of looting and public disorder. On 28 February 2010, a day after the earthquake, some affected cities were chaotic, with extensive looting of supermarkets in Concepción. Items stolen included not only food and other necessities, but also electronic goods and other durable merchandise. To control vandalism, a special force of ''carabineros'' (police) was sent to disperse rioters with tear gas and water cannons. However, measures were taken late. The outgoing president didn't want to remind people of the Dictatorship years by militarizing the streets, thus failed to provide assistance on time to the city. When the situation became unsustainable and all sectors of the population were demanding actions, the government authorized the use of the military to control the affected cities. Despite these and other government acts (including the curfews), pillaging continued in both urban and rural areas of the affected zones. Reportedly, military police arrested 160 in Concepción on 1 and 2 March.

In Concepción, despite the militarization of the zone, mobs continued to steal from supermarkets and went as far as to set one store ablaze. The government warned looters they would face the full weight of the law, as penalties for stealing are increased under a state of catastrophe. A week after the quake the police—tipped by neighbors—arrested three people with massive quantities of looted goods stashed in their homes. Other looted goods such as mattresses, furniture, television sets and other electronic appliances were abandoned in the streets of Concepción during the following days.

According to the BBC
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