The Chiapas Earthquake, Mexico 2017

Home , 2017 in Mexico

GEOFILE Extension 781 The Chiapas earthquake, Mexico 2017

By Philippa Simmons Synopsis Links

This Geofile will explore the causes and impacts of Exam board Link to specification the Chiapas earthquake that occurred in Mexico in AQA September 2017, as well as the responses to it. Mexico AS Component 1 Physical Geography 3.3.1.4 is situated where the Cocos plate converges with the Seismic hazards p18 pdf version North American plate – one of the most tectonically Click here active regions in the world, with up to 40 earthquakes A2 Component 1 Physical Geography 3.1.5.4 a day. The state of Chiapas is located along the Seismic hazards p15 pdf version Click here southern shore of Mexico and borders Guatemala, it is in a subduction zone and is at risk of strong Edexcel AS 1.4c and 1.5c Social and economic impacts of earthquakes. At 23.49 local time on 7 September 2017 tectonic hazards p18 pdf version an earthquake of magnitude 8.2 struck off the coast of Click here Mexico. This was the strongest earthquake to be A2 1.4c and 1.5c Social and economic impacts of recorded globally in 2017, resulting in it being the tectonic hazards p15 pdf version Click here second strongest ever in Mexico. OCR AS Topic 2.5 Hazardous Earth 4b Range of impacts Key terms on people as a result of earthquake activity – Tectonic, tectonic hotspot, plate boundary, case studies convergent boundary, aftershock, magnitude, + 5b Strategies – case studies tsunami, vulnerability. p39 pdf version Click here Learning objectives A2 Topic 3.5 Hazardous Earth 4b There is a range of impacts people experience as a result of After working through this Geofile you should have earthquake activity – case studies learned about: + 5b There are various strategies to manage hazards from earthquakes – case studies ●● the causes of the Chiapas earthquake p51 pdf version ●● the impact of the earthquake, particularly focusing Click here on the people in Chiapas who live in an emerging Eduqas A2 3.1.3 Earthquakes, processes, hazards and their economy impacts 3.1.4 Human factors affecting risk and ●● the nature of the responses to the earthquake from vulnerability the Mexican government 3.1.5 Responses to tectonic hazards ●● the work Mexico still needs to do to improve its P30 of pdf version earthquake preparedness. Click here WJEC AS 1.3.3 Earthquakes, processes, hazards and their impacts 1.3.4 Human factors affecting risk and vulnerability 1.3.5 Responses to tectonic hazards P20 pdf version Click here A2 4.1.3 Earthquakes, processes, hazards and their impacts 4.1.4 Human factors affecting risk and vulnerability 4.1.6 Responses to earthquakes P35 pdf version Click here

Mexico – a tectonic breaking point, at which point the million people felt it and it even hotspot upper plate will spring back, lifting caused buildings to sway as far Mexico is situated in a tectonically the ocean floor. Consequently the away as Mexico City (Figure 1). region of Chiapas is at risk of both active area and its inhabitants are Earthquakes are a common large earthquakes and tsunamis. used to regular seismic activity, such occurrence in Mexico (Figure 2), as the devastating earthquake that but the causes behind the Chiapas struck Mexico City in 1985. It The causes of the earthquake were complex. One measured 8.1 on the Richter scale Chiapas earthquake factor was the depth of the and destroyed 100,000 buildings. On 7 September 2017 an earthquake, 70km, deep off the Over 5,000 people died and millions earthquake with a magnitude of southern coast of Mexico. This were left without electricity or fresh 8.2 M , as recorded by the USGS, indicated that the earthquake most w water. The earthquake was so hit shortly before midnight off the probably happened within the catastrophic because Mexico City lies southern coast of Mexico, 100 miles plate, as opposed to at the on a former lake-bed, which results (160 km) from the Chiapas region subduction zone between the North in any earthquake being amplified (Figure 1). Approximately 90 people American and Cocos plates. The by the soft alluvial soil. Research has were killed and great damage was Cocos plate is made up of crust shown that the shaking of the caused to the coastal areas around beneath the Pacific Plate and is 1985 earthquake could have been the epicentre. There was a mass sinking deeper into the earth under amplified by as much as 500%. The evacuation from the coast due to its own weight. It would seem that 1985 earthquake also demonstrated initial tsunami warnings. The this is causing fractures inside the that many buildings in the capital, intensity of the earthquake was so slab bend (Figure 3). Geologists particularly in the informal great that it was stated that nearly believe this could have been the settlements, were not earthquake- half of Mexico’s population of 120 cause of the 2017 earthquake. resistant. In response to this, the Mexican government has put a lot of resources into improving the infrastructure in the country’s main cities. Mexico lies between three tectonic plates: the Pacific, North American and Cocos plates. This not only makes it one of the most seismically active countries in the world, but also leaves it vulnerable to volcanic eruptions. The region of Chiapas lies on the boundary of the Cocos and North American plates. At this convergent plate boundary, the oceanic Cocos plate is being forced below the continental North American plate. This creates a subduction zone due to the Figure 1 The Chiapas earthquake oceanic plate being denser than the

continental plate. Converging plate Date Affected Area Magnitude Deaths Injuries boundaries can be the cause of very 23 September 2017 Oaxaca 6.1 M 6 7 large earthquakes, and because the w 19 September 2017 Mexico City, Morelos, 7.1 Mw 370 6,011 Cocos plate is being subducted, the Puebla two plates can lock, resulting in 7 September 2017 Chiapas, Oaxaca 8.2 Mw 98 300 pressure building up. The pressure will build up until it reaches a Figure 2 Notable earthquakes in Mexico, 2017

Impacts of the earthquake Following the earthquake the main areas that were affected were the neighbouring states of Chiapas, Oaxaca and Tabasco, around the epicentre. The earthquake had the following initial impacts:

●● 1.5 million people were affected.

●● In the state of Chiapas the earthquake caused damage to 41,000 homes

●● Approximately 90 people who were killed – 71 in Oaxaca, four in Tabasco and 15 in Chiapas.

●● At least 1 million people were left without electricity Figure 3 Section across the Cocos oceanic plate immediately following the earthquake, and later around There is still a lot of research to be earthquake, the Pacific Tsunami 800,000 people. done, due to the complexity of this Warning Centre issued a warning ●● Following the earthquake, tectonic zone. for the whole of the Central schools were closed in 11 American Pacific coast. It was different states to check the Tsunami hazard originally thought there could be safety of the buildings. tsunami waves of up to 3 m high Earthquakes can cause secondary ●● The states of Chiapas and Oaxaca along the coast of Mexico, but it was impacts, the most devastating of are two of the poorest states in later recorded that there were only these often being a tsunami, such as Mexico and many of the waves as high at 0.7 m along the the one that followed Japan’s 2011 communities are not only poor coast. The warning allowed time for Tohuku earthquake. Tsunamis are but also isolated. Many buildings some coastal communities to commonly created at subduction collapsed due to being made out evacuate as a precaution; eventually zones, due to the amount of of flimsy material which was the warnings were lifted, when the pressure that can build up between easily destroyed. lower threat was realised. the two plates. When this pressure ●● There were reports of buildings is released, it is often in the form of Following the tsunami warning, swaying in Mexico City, and a the overriding plate snapping back, there were a number of aftershocks highway bridge which was under which displaces the water above it, from the initial earthquake. construction near Mexico City’s creating a tsunami. The Chiapas Aftershocks are smaller earthquakes international airport collapsed earthquake was different and was which usually only last a few due to the shaking. due to stresses caused by gravity seconds and happen as the earth’s bending and dragging the Cocos crust is adjusting to the effects of Responses to the earthquake plate into the earth. It created a the main shock. In the hour Public officials were quick to give tsunami due to it being on a normal following the earthquake, at least guidance following the earthquake, fault (Figure 3), where the plate 12 aftershocks were recorded by one of the biggest since the 1985 drops down. This was similar to the the United States Geological Mexico City event. Samoa 2009 earthquake, which Service, and in the week following The Mexican government had caused a much larger tsunami. the earthquake a further 1800 learnt a lot from the 1985 aftershocks occurred, some having The tsunami was smaller for the earthquake, when many residents a magnitude of up to 6.1 on the Chiapas earthquake because it had been trapped under rubble, Richter scale. Aftershocks can often occurred in shallower water – left to fend for themselves, and the be an issue, because they can cause generally, larger tsunamis occur authorities struggled to provide buildings that have already been when they are created in deeper emergency services and aid for weakened by the initial earthquake ocean water and move to shallower people. The then ruling party’s to collapse. shorelines. Following the reputation was ruined, leading to

Many of the residents of Juchitan also had no access to running water, and clearance of rubble from the streets took officials longer than expected. Although response times were fast following the Chiapas earthquake, it would seem it has still taken a long time for people to get back to normal in the regions that were most badly affected by the earthquake. The biggest challenge has been the removal of rubble from roads, and getting machinery up to the affected areas.

The future for Mexico Figure 4 President Enrique Pena Nieto climbs over rubble to view a destroyed school On 19 September another Source: Presidenciamx/Alamy earthquake hit, 123 km from Mexico City with a magnitude of

7.1 Mw. It is thought that the their removal from power after people in rebuilding what was earthquakes are not related, 71 years of consecutive rule. In damaged: but it does demonstrate how 2017 the Mexican government had ●● In the states of Chiapas and seismically active Mexico is, how a point to prove. Determined to do Oaxaca, which saw the most vulnerable Mexico’s population is things differently, President Enrique damage, 73,000 families received to earthquakes, and how much Pena Nieto (Figure 4) and several of support to help rebuild their more the government needs to do his cabinet members visited the houses. to protect the population and state of Chiapas to help bring ●● Reconstruction of schools, which infrastructure, especially in rural confidence to the people and lead was slower in some areas as communities. the government relief efforts. To many of the schools had to be show support, the government also This earthquake, which happened demolished in order to start withdrew their offer to help victims on the 32nd anniversary of the reconstruction. Five months after of Hurricane Harvey in Texas, so 1985 Mexico City earthquake, the earthquake most children that they could support their own killed approximately 220 people. had returned back to school. population. Although there was not as ●● Mexican construction companies much damage, this earthquake, 1. Access to stricken areas gave their support, with Cemex alongside the Chiapas earthquake, One of the problems following the (a Mexican cement producer) highlighted how much more Chiapas earthquake was that it donating $1million worth of aid Mexico’s government needs to do occurred in some of Mexico’s to support the relief efforts. to ensure that buildings are poorest states, and in isolated and 3. Problems resistant to earthquakes. As noted mountainous regions. Rescue above, Mexico City is built on the Despite food rations being delivered workers struggled to reach some of sediment of ancient lakes, which to some of the worst hit states, the most isolated communities and has the characteristics of jelly when some areas complained of the had to work hard to remove fallen hit by an earthquake. rubble from some of the mountain relief being slow. Juchitan, an 1. Building regulations roads to restore access to indigenous town in the state of communities. Oaxaca, was one of these areas. Following the 1985 earthquake, Residents complained that they saw new building regulations were put in 2. Reconstruction army officials but nothing was place to meet earthquake standards Following the earthquake, being offered and house-to-house and to ensure that new buildings action was taken to support assessments were very slow. were monitored. The problem is that

2. Other measures This may paint a bleak picture of Mexico’s success in reducing the vulnerability of its population, but there have been some positive measures to reduce the effects of earthquake activity. The government has implemented initiatives in major cities; for example in 2002 the government launched a partnership with Fundacion del Centro Historico de la Cuidad de Mexico, an NGO which puts money into supporting the downtown area of Mexico City. Money is also being spent on monitoring systems to detect earthquakes, and there are now emergency plans in places to prepare the city in the event of an earthquake. These strategies are very much focused on places like Mexico City, and particularly the city centre, which completely ignores many of the rural settlements and increases the vulnerability of the poorest people in Mexico. Each of the earthquakes mentioned has had a common theme of highlighting the vulnerability of Mexico’s poorest communities, and the government’s inability to address these issues.

Figure 5 Rescue work on 20 September 2017 in Mexico City following Conclusion the 7.1M earthquake, in which about 220 people died w Mexico will continue to be affected Source: SOPA Images Ltd/Alamy by tectonic hazards, particularly large-scale ones. There is still a long way to go in terms of protecting these building regulations are often itself approximately 60% of the whole population, particularly not followed, or corners are cut buildings are informal and the urban poor and isolated, rural when constructing buildings. On top unregulated, where residents have communities, but there is evidence of that, many of the settlements are built homes out of whatever that Mexico is moving in the right informal or pre-date 1985, and have materials come to hand, meaning direction in reducing people’s not been updated to withstand that any building codes set are vulnerability to earthquakes. earthquakes. Within Mexico City, irrelevant.

Focus questions

1. Explain the causes of the Chiapas earthquake. Include an annotated diagram with information from this Geofile. 2. Using this example and others you have studied, assess the impacts of tectonic hazards in contrasting locations of the world. 3. Essay question: Evaluate the importance of governance in managing the impacts of an earthquake.

Learning checkpoint

1. Research the causes of the Chiapas 2017 4. What were the successes of Mexican government earthquake. Why is Mexico such a tectonically in their response to the Chiapas earthquake? active area? Explain one example in detail.

2. Using a diagram, explain the causes of a tsunami. 5. Following seismic activity, the worst affected people How were coastal areas affected in the Chiapas in Mexico are the urban poor and rural communities. event? Is this the same in other parts of the world? What does this suggest about Mexico as a country?

3. Why is it difficult to reach rural communities following an earthquake? Give examples. 6. How can the government reduce Mexico’s vulnerability to earthquakes? Make suggestions.

Useful websites - news report and video Wikipedia report on the Chiapas earthquake - Click here Guardian report on the 1985 earthquake - Click here

BBC report on the earthquake - Click here USGS report on the earthquake - Click here