1985 Mexico City earthquake

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The 1985 Mexico City earthquake was one of the most devastating earthquakes in the history of the Americas. On Thursday, September 19, 1985, at 7:19 AM local time, Mexico City was struck by an earthquake of magnitude 8.1 [1] on the Richter scale. The epicentre of the earthquake was off the Pacific coast of the Mexican state of Michoacán, a distance of 350 km, in the Cocos Plate subduction zone. It was felt as far away as Los Angeles, California.^[1]

As a result of the earthquake, according to official government statistics, over 9,000 people were killed, 30,000 injured, and 100,000 left homeless. 416 buildings were destroyed and over 3,000 seriously damaged.

Contents 1 Damage 2 Death count 3 Aftershock 4 Emergency response 5 Structural engineering issues 6 Effects 7 Cultural responses 8 Notable victims 9 References 10 External links

[edit] Damage

Although the epicenter of the earthquake was more than 300 km away, Mexico City suffered the most damage. Shaking from the quake lasted three to four minutes and was felt over 825,000 square kilometres. The most damaged zones in the city were those in the bed of the historic Lake Texcoco, where the prevailing silt and volcanic clay sediments amplified the shaking. Building damage was worsened by soil liquefaction which causes the loss of foundation support and contributes to dramatic settlement of large buildings. The buildings most damaged were from 6-15 stories in height. The extensive damage was due in part to lax enforcement of building codes and the lack of deep foundations in many Mexico city buildings. Adding to this damage, the water and sewage systems were destroyed, contaminating the city's water supply. Electricity lines were also destroyed and the sparking edges of the wires caused fires. Additionally international communications were severely disrupted due to the collapse of the Central Communications Center of the Ministry of Communications and Transport isolating the city from immediate help and assistance.[2]

[edit] Death count

Many residents of Mexico City dispute the official statistics, and believe that deaths from the quake exceeded 60,000 and more likely approached 100,000. Their reason for doubt is that their one-party government (at the time) was infamous for under-playing negative statistics whenever possible .

A precise count of those killed in the two quakes has never been determined, and reported numbers tend to vary widely:

• 4,200: BBC [3]
• 4,541: Mexican Government [4]
• 10,000: Christian Science Monitor [5]
• 10,000: CNN [6]
• 40,000: SNN Mexican National Seismological Centre [7]

One hundred thousand housing units were destroyed, together with many government buildings, schools, parts of the Televisa Chapultepec campus, the famous Cafeteria Superleche restaurant, a trio of 28-story towers "Complejo Pino Suárez", The famous 1900's Hotel Regis, the Continental Hilton, the two buildings of the Nuevo León section of the Tlatelolco housing development near the Plaza de las Tres Culturas and at least three large hospitals. Between $9-12 billion dollars of damage were caused in just over three minutes.

The quake caused major portions of three of the city's largest hospitals to collapse, burying some 1,200 people. Loss of these hospitals severely limited the city's ability to care for quake-injured patients. Juárez Hospital completely collapsed, and survivors were retrieved from the structure as late as ten days after the earthquake by tunneling through the debris between the floor slabs. [8].

[edit] Aftershock

There was an additional magnitude 7.5 aftershock 36 hours later (the evening of Friday, September 20), which caused widespread panic among the already battered population of the city. A magnitude of 7.5 is enough to destroy buildings within a radius of 150 kilometers.

[edit] Emergency response

A dramatic emergency response was immediately mobilised. The people of the city were trapped, and many completely inert in their homes. Assistance from neighbouring Mexican states and from abroad was received, and was followed by international relief. Aid came in the form of 296 flights originating from 45 countries, assistance by land from six nations, and relief in the form of cash donations [9].

Several heads of state traveled to the city, among them the President of Brazil, José Sarney, the President of Venezuela, Jaime Lusinchi, the head of the Spanish government, Felipe González, Alan García, from Peru. The wife of United States president Ronald Reagan, Nancy, also traveled to the city and brought a gift of one million dollars.

[edit] Structural engineering issues

The main causes of building loss included: corner building failure (42%), collapse of intermediate floors (40%), collapse of upper floors (38%), `pounding:' (one building repeatedly striking another during earthquake vibrations) (15%), and foundation failure (13%) [10].

Several notable buildings were relatively untouched by the quake, having been constructed based on codes with earthquake resistant provisions. One such building is the Torre Latinoamericana building in downtown. As a consequence, earthquake survivability has been an issue of serious consideration ever since. When Torre Mayor was built in 1999, numerous safety mechanisms, including dramatic internal truss structures, were included to assure safety in the event of another major tremor. Torre Mayor was built to survive an 8.5+ magnitude earthquake.

[edit] Effects

The quake is still well-remembered by most city residents today, as it led not only to massive structural damage and human loss, but also to the complete failure of many under-insured businesses in a mostly informal economy. Countless people whose livelihood was lost in the quake left the city. But while Government help was trickling down day after day, a massive as much as unexpected active civil solidarity emerged among the Mexico City population, producing heroic acts on a daily basis. The now world-famous "Topos" (groundhogs) corps were formed, and saved countless lives up to one week after the quake. A bumper-sticker campaign began with the slogan "Mexico sigue en pie" (Mexico is still standing).

In an effort to be better prepared for future devastating earthquakes, the Mexican government funded a state-of-the-art alert system, Sistema de Alerta Sísmica (SAS)^[2] that sends early-warning messages to Mexico City electronically from sensors located along the coastal subduction zone in Guerrero. A similar system is being built in Oaxaca^[3] to the south. In the event that seismic activity is detected, warning sirens will sound, giving city residents up to a minute's warning that a quake is coming.

The last considerable earthquake in Mexico City had a magnitude of 7.4 on the Richter scale, on September 30, 1999 at 11:27 am. Only one death was reported, caused by a falling pipe. Many buildings were severely damaged.

[edit] Cultural responses

The Mexican poet José Emilio Pacheco published his poem "Ruinas de México (Elegía del Retorno)" as a direct response to the 1985 quake. Divided into five sections, his poem chronicles the destruction of the capital as a natural disaster and human crisis. He also mentions the buildings that were constructed with sub-standard materials by corrupt politicians. In 1988 the journalist Elena Poniatowska published her testimonial-style book on the aftermath of the earthquake titled "Nada, Nadie. Las Voces del Temblor."

[edit] Notable victims

• Plácido Domingo's aunt, uncle, baby nephew, and two of his cousins were killed in the collapse of the "Nuevo León" building.
• Rock musician Rodrigo "Rockdrigo" González was killed in the quake.
• Gustavo Armando "El Conde" Calderón - Presenter and producer of the radio show: "Batas, pijamas y pantuflas". (on air as the earthquake was happening)
• Sergio Rod - Presenter on the radio show: "Batas, pijamas y pantuflas". (on air as the earthquake was happening)
• Felix Sordo - Presenter on the TV morning show "Hoy Mismo" (Guillermo Ochoa and Lourdes Guerrero) was killed "on air" as the earthquake was happening.
• Famous singer Rigo Tovar also known as "El Idolo de Mexico" lost Brother Everardo Tovar during earth quake. It is believed Rigo Tovar's emotional health and career began a steady decline shortly after.

[edit] References

[edit] External links

• Images from the earthquake aftermath
• Image album from the Mexican National Seismology Service at UNAM