1985 Mexico City earthquake
Overview
 
The 1985 Mexico City earthquake, a magnitude 8.0 earthquake
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...

 that struck Mexico City
Mexico City
Mexico City is the Federal District , capital of Mexico and seat of the federal powers of the Mexican Union. It is a federal entity within Mexico which is not part of any one of the 31 Mexican states but belongs to the federation as a whole...

 on the early morning of 19 September 1985 at around 7:19 AM (CST), caused the deaths of at least 10,000 people and serious damage to the greater Mexico City Area. The complete seismic event consisted of four quakes. A pre-event quake of magnitude 5.2 occurred on 28 May 1985. The main and most powerful shock occurred 19 September, followed by two aftershocks: one on 20 September 1985 of magnitude 7.5 and the fourth occurring seven months later on 30 April 1986 of magnitude 7.0.
Encyclopedia
The 1985 Mexico City earthquake, a magnitude 8.0 earthquake
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...

 that struck Mexico City
Mexico City
Mexico City is the Federal District , capital of Mexico and seat of the federal powers of the Mexican Union. It is a federal entity within Mexico which is not part of any one of the 31 Mexican states but belongs to the federation as a whole...

 on the early morning of 19 September 1985 at around 7:19 AM (CST), caused the deaths of at least 10,000 people and serious damage to the greater Mexico City Area. The complete seismic event consisted of four quakes. A pre-event quake of magnitude 5.2 occurred on 28 May 1985. The main and most powerful shock occurred 19 September, followed by two aftershocks: one on 20 September 1985 of magnitude 7.5 and the fourth occurring seven months later on 30 April 1986 of magnitude 7.0. The quakes were located off the Mexican Pacific coast, more than 350 km away, but due to strength of the quake and the fact that Mexico City sits on an old lakebed, Mexico City suffered major damage. The event caused between three and four billion USD in damage as 412 buildings collapsed and another 3,124 were seriously damaged in the city. While the number is in dispute, the most-often cited number of deaths is an estimated 10,000 people but experts agreed that it could be up to 40,000.

The seismic event

The earthquake occurred in the Pacific Ocean, off the coast of the Mexican state of Michoacán
Michoacán
Michoacán officially Estado Libre y Soberano de Michoacán de Ocampo is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 113 municipalities and its capital city is Morelia...

, a distance of more than 350 km from the city, in the Cocos Plate
Cocos Plate
The Cocos Plate is an oceanic tectonic plate beneath the Pacific Ocean off the west coast of Central America, named for Cocos Island, which rides upon it.-Geology:...

 subduction zone, specifically in a section of the fault line known as the Michoacán seismic gap
Seismic gap
A seismic gap is a segment of an active fault that has not slipped in an unusually long time when compared with other segments along the same structure. Seismic gap hypothesis/theory states that, over long periods of time, the displacement on any segment must be equal to that experienced by all...

 at coordinates 18.190 N 102.533 W. The Cocos Plate pushes against and slides under the North American Plate
North American Plate
The North American Plate is a tectonic plate covering most of North America, Greenland, Cuba, Bahamas, and parts of Siberia, Japan and Iceland. It extends eastward to the Mid-Atlantic Ridge and westward to the Chersky Range in eastern Siberia. The plate includes both continental and oceanic crust...

, primarily along the coasts of the states of Michoacán and Guerrero
Guerrero
Guerrero officially Estado Libre y Soberano de Guerrero is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 81 municipalities and its capital city is Chilpancingo....

 in Mexico. Volatile trenches along the Cocos plate generally have had seismic events 30 to 70 years before 1985. This subduction zone outside the Michoacán gap was the source of 42 earthquakes of magnitude 7.0 or stronger in the 20th century prior to the 1985 event. However, this particular section of the subduction zone had not had an event for a much longer time. Shockwaves from the earthquake hit the mouth of the Río Balsas on the coast at 7:17 am and hit Mexico City, 350 km away, two minutes later at 7:19 am. The 19 September quake was a multiple event with two epicenters and the second movement occurring 26 seconds after the first. Because of multiple breaks in the fault line, the event was of long duration. Ground shaking lasted more than five minutes in places along the coast and parts of Mexico City shook for three minutes, with an average shaking time of 3–4 minutes. It is estimated the movement along the fault was about three meters. The main tremor was foreshadowed by a quake of magnitude 5.2 on 28 May 1985, and was followed by two significant aftershocks: one on 20 September 1985 of magnitude 7.5 lasting thirteen seconds and the third occurring seven months later on 30 April 1986 with magnitude 7.0 lasting ten seconds. However, at least twelve other minor aftershocks were associated with the seismic event.

The energy released during the main event was equivalent to approximately 1,114 nuclear weapons exploding. The earthquake was felt over 825,000 square kilometers, as far away as Los Angeles
Los Ángeles
Los Ángeles is the capital of the province of Biobío, in the commune of the same name, in Region VIII , in the center-south of Chile. It is located between the Laja and Biobío rivers. The population is 123,445 inhabitants...

 and Houston in the United States.

In the port of Lázaro Cárdenas
Lázaro Cárdenas, Michoacán
Lázaro Cárdenas is a port city that with its surrounding municipality is located in the southern part of the Mexican state of Michoacán. It was formerly known as Los Llanitos, but changed its name as a tribute to Lázaro Cárdenas del Río, a Michoacán-born politician who was president of Mexico from...

, near the epicenter, the 19 September event registered as IX on the Modified Mercalli Intensity scale
Mercalli intensity scale
The Mercalli intensity scale is a seismic scale used for measuring the intensity of an earthquake. It measures the effects of an earthquake, and is distinct from the moment magnitude M_w usually reported for an earthquake , which is a measure of the energy released...

; in parts of Mexico City, it registered the same, even at a distance of about 400 km away. There was no historic record of such a strong quake in Mexico.

While the fault line was located just off the Pacific coast of Mexico, there was relatively little effect on the sea itself. The earthquake did produce a number of tsunami
Tsunami
A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake...

s but they were small, ranging between one and three meters in height. Ecuador
Ecuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...

 reported the highest waves of 60 centimeters.

Mexico City’s vulnerability to earthquakes

Much of Mexico’s volcanic and seismic activity stems from the movement of the North American plate against the Cocos and Pacific plate
Pacific Plate
The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At 103 million square kilometres, it is the largest tectonic plate....

s and it is one of the most active trenches in the world. Each year more than 90 temblors above magnitude 4.0 are recorded in this zone.

While not on or near any fault line like San Francisco or Los Angeles
Los Ángeles
Los Ángeles is the capital of the province of Biobío, in the commune of the same name, in Region VIII , in the center-south of Chile. It is located between the Laja and Biobío rivers. The population is 123,445 inhabitants...

, Mexico City is vulnerable to earthquakes. The main reason for this is the surface geology of the area, especially the downtown area. The city grew from an island in the middle of Lake Texcoco
Lake Texcoco
Lake Texcoco was a natural lake formation within the Valley of Mexico. The Aztecs built the city of Tenochtitlan on an island in the lake. The Spaniards built Mexico City over Tenochtitlan...

 outward, as this lake was eventually drained. The near surface geology of this area is classified into three sections: the old lake bed which is soft clay from volcanic ash
Volcanic ash
Volcanic ash consists of small tephra, which are bits of pulverized rock and glass created by volcanic eruptions, less than in diameter. There are three mechanisms of volcanic ash formation: gas release under decompression causing magmatic eruptions; thermal contraction from chilling on contact...

 with a high water content, a piedmont area, much of which is capped by 5 to 30 meters of lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

 less than 2,500 years old, and an old river delta area.

The downtown of Mexico City mostly lies on the silt and volcanic clay sediments of the bed of the historic Lake Texcoco
Lake Texcoco
Lake Texcoco was a natural lake formation within the Valley of Mexico. The Aztecs built the city of Tenochtitlan on an island in the lake. The Spaniards built Mexico City over Tenochtitlan...

, which are between seven and thirty-seven meters deep and have a high water content. Above this is a layer of sand and above this is a layer of sand and rock. The western and northwestern parts of the city are outside the old lakeshores and are located on sands from eroding volcanic cone
Volcanic cone
Volcanic cones are among the simplest volcanic formations. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and size of the fragments ejected during the eruption...

s that surround the Valley of Mexico
Valley of Mexico
The Valley of Mexico is a highlands plateau in central Mexico roughly coterminous with the present-day Distrito Federal and the eastern half of the State of Mexico. Surrounded by mountains and volcanoes, the Valley of Mexico was a centre for several pre-Columbian civilizations, including...

. The southern part of the city rests on hardened basalt
Basalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...

 lava flows. The old lakebed, with its high water content, is easily moved or compressed. The old lakeshore area also has a fairly high water content, allowing movement, though not as much as the lakebed. The old lava flows have little water content or movement in comparison and are therefore stable.

On the bed of the historic lake, the prevailing silt and volcanic clay sediments amplify seismic shaking. Damage to structures is worsened by soil liquefaction
Soil liquefaction
Soil liquefaction describes a phenomenon whereby a saturated soil substantially loses strength and stiffness in response to an applied stress, usually earthquake shaking or other sudden change in stress condition, causing it to behave like a liquid....

 which causes the loss of foundation support and contributes to dramatic settlement of large buildings.

Another factor is that the old lakebed resonates with certain seismic wave
Seismic wave
Seismic waves are waves of energy that travel through the earth, and are a result of an earthquake, explosion, or a volcano that imparts low-frequency acoustic energy. Many other natural and anthropogenic sources create low amplitude waves commonly referred to as ambient vibrations. Seismic waves...

s and low frequency signals. This lakebed has a natural "pitch" of one cycle every 2.5 seconds making everything built on the bed vibrate at the same frequency. Unfortunately, this is the same “pitch” as a number of shallow earthquake waves. This resonance amplifies the effects of the shock waves coming from an earthquake far away.

However, only certain types of structures are vulnerable to this resonance effect. Taller buildings have their own frequencies of vibration. Those that are six to fifteen stories tall also vibrate at the 2.5-second cycle, making them act like tuning forks in the event of an earthquake. The low-frequency waves of an earthquake are amplified by the mud of the lakebed, which in turn, is amplified by the building itself. This causes these buildings to shake more violently than the earthquake proper as the earthquake progresses. Many of the older colonial buildings have survived hundreds of years on the lakebed simply because they are not tall enough to be affected by the resonance effect.

Localization of the damage

Mexico City is divided into boroughs
Boroughs of the Mexican Federal District
Mexico City — politically and administratively constituted as the Federal District — is divided into sixteen boroughs for administrative purposes. They constitute second-level administrative divisions, on par with the municipalities of Mexico. However, unlike municipalities, they do not have...

. Eighty percent of the earthquake damage was confined to four of them: Venustiano Carranza
Venustiano Carranza, D.F.
Venustiano Carranza is one of the 16 delegaciones of Mexico's Federal District. The borough was formed in 1970 when the center of Mexico City was subdivided into four boroughs...

, Cuauhtémoc
Cuauhtémoc, D.F.
Cuauhtémoc, named after the former Aztec leader, is one of the 16 boroughs of the Federal district of Mexico City. It consists of the oldest parts of the city, extending over what was the entire city in the 1920s. This area is the historic and culture center of the city, although it is not the...

, Benito Juárez
Benito Juárez, D.F.
Benito Juárez is one of the 16 delegaciones into which Mexico's Federal District is divided. It is a largely residential area, located to the south of historic center of Mexico City, although there are pressures for areas to convert to commercial use. It was named after Benito Juárez, president in...

 and Gustavo A. Madero
Gustavo A. Madero, D.F.
Gustavo A. Madero is one of the 16 delegaciones into which Mexico's Federal District is divided.-Origins:Founded as "Villa de Guadalupe" in 1563, it became the city of "Villa de Guadalupe Hidalgo" in 1828, and finally a delegación in 1931; as such, it was named after Gustavo A. Madero, the brother...

. The damage area corresponds to the western part of the lake zone within two to four kilometers of the Alameda Central
Mexico City Alameda Central
Alameda Central is a public municipal park in downtown Mexico City, adjacent to the Palacio de Bellas Artes, between Juarez Avenue and Hidalgo Avenue.-Description:...

. Nearly all the buildings that collapsed were located in this lake zone that extended from Tlatelolco
Tlatelolco (Mexico City)
Tlatelolco is an area in the Cuauhtémoc borough of Mexico City, centered on the Plaza de las Tres Culturas, a square surrounded on three sides by an excavated Aztec archaeological site, a 17th century church called Templo de Santiago, a former convent, and office complexes that used to belong to...

 in the north to Viaducto Miguel Alemán
Viaducto Miguel Alemán
Viaducto Miguel Alemán is a crosscutting freeway, opened in September 1950, that runs east-west across the middle of Mexico City. In the center of the road is a river encased in cement to control flooding...

 in the south, Chapultepec Park in the west and to a short distance east of the Zócalo
Zócalo
The Zócalo is the main plaza or square in the heart of the historic center of Mexico City. The plaza used to be known simply as the "Main Square" or "Arms Square," and today its formal name is Plaza de la Constitución...

 or main plaza.

Building damage in the city

Cuauhtémoc, which includes the historic downtown suffered the most damage. In this particular area, 258 buildings completely crumbled, 143 partially collapsed and 181 were seriously damaged. The next seriously affected area was Venustiano Carranza where 83 buildings collapsed, 128 partially collapsed and 2,000 structures were seriously damaged. Damage was localized to the center parts of the city, leaving much of the residential outer rim unscathed, but the damage in the affected area was extensive. Over 720,000 tons of debris was removed during the first six weeks after the event. The Metropolitan Commission for Emergencies of the Federal District reported 2,831 buildings damaged for the entire city: 31% or 880 were completely ruined, 13% were reinhabitable with major repairs and the rest, totaling 1581, were recoverable with minor repairs. This translates to more than 30,000 housing units completely destroyed and another 68,000 units damaged.

Infrastructure

Infrastructure was severely affected. The number of people with potable water went from six million to 90,000. as 6,500 meters of primary and secondary water and drainage pipes suffered breaks in 163 places, cutting off water and contaminating it. 516,000m2 of asphalt was damaged, and 137 schools collapsed. The number of jobs lost due to the event was estimated at 200,000. Forty percent of the population was without electricity and seventy percent without telephone service.

1,687 school buildings were damaged. Interruption of classes, either to the lack of facilities and/or the need to help with rescue efforts, affected over 1.5 million students.

Metro service

On the day of the quake, the Metro
Mexico City Metro
The Mexico City Metro , officially called Sistema de Transporte Colectivo, is a metro system that serves the metropolitan area of Mexico City...

 stopped service and completely shut down for fear of electrocution. This caused people to get out of the tunnels from wherever they were and onto the street to try to get where they were going. At the time, the Metro had 101 stations, with 32 closed to the public in the weeks after the event. On Line 1, there was no service in stations Merced
Metro Merced
Merced is an underground station on Line 1 of the Mexico City Metro. It is located in the Venustiano Carranza borough, slightly to the east of the centre of Mexico City. The station building was designed by Félix Candela, and it was opened on 5 September 1969.The station logo depicts a box with...

, Pino Suárez
Metro Pino Suárez
Metro Pino Suárez is a station on Line 1 and Line 2 of the Mexico City Metro system. It is located in the Cuauhtémoc borough of Mexico City, on the southern part of the city centre....

, Isabel la Católica
Metro Isabel la Católica
Metro Isabel La Católica is a metro station on the Mexico City Metro. It is located in the Colonia Centro neighborhood in the Cuauhtémoc borough in Mexico City's downtown.Its logo represents one of Christopher Columbus's three caravels...

, Salto del Agua
Metro Salto del Agua
Metro Salto del Agua is a metro station on the Mexico City Metro. It is located in the Cuauhtémoc borough in the centre of Mexico City....

, Balderas
Metro Balderas
Metro Balderas is an underground station on the Mexico City Metro. It is located in the Cuauhtémoc borough in the center of Mexico City. It is a transfer station along Lines 1 and 3...

 or Cuauhtémoc
Metro Cuauhtémoc
Metro Cuauhtémoc is a metro station on the Mexico City Metro.It is located at the northern extreme of Avenida Cuauhtémoc, in the Cuauhtémoc borough, in the centre of Mexico City.The station logo depicts the head of an eagle...

. On Line 2, there was no service between stations Bellas Artes
Metro Bellas Artes
Metro Bellas Artes is a station along Line 2 and Line 8 of the Mexico City Metro system. It is located in the Colonia Centro district of the Cuauhtémoc borough of Mexico City, on the junction of Avenida Juárez and Eje Central Lázaro Cárdenas, on the eastern end of the Alameda Central, west of the...

 and Taxqueña. On Line 3 only Juárez
Metro Juárez
Metro Juárez is a metro station on the Mexico City Metro. It is located in the Cuauhtémoc borough of Mexico City.The station logo depicts the bust of Benito Juárez , who served as president of Mexico for a long period in the 19th century. This station's name, along with Metro Guelatao, refers to...

 and Balderas were closed. Line 4 continued to operate normally. All of the closed stations were in the historic center area, with the exception of the stations of Line 2 south of Pino Suárez. These stations were located above ground. The reason these stations were closed was not due to damage to the Metro proper, but rather because of surface rescue work and clearing of debris.

Damage to hospitals

The area most severely hit by the earthquake had the highest concentration of hospitals. Most of the damages occurred in secondary and tertiary hospitals. Thirteen hospitals of six or more floors were partially or totally destroyed, most of these public institutions. One out of every four then-available beds were lost.

The National Medical Center of the Mexican Social Security Institute (IMSS
Mexican Social Security Institute
The Mexican Social Security Institute is a governmental organization that attends to public health, pensions and social security in Mexico operating under Secretaría de Salud .-History:...

) was considered the most important hospital complex in Latin America with over 2,300 beds and the largest medical library in the country. It had to be evacuated because all of its 25 buildings suffered severe damage. Most of the beds that it lost were dedicated to tertiary, high-technology care. The ISSSTE hospital for government workers lost 36 percent of its capacity. The 2,158 beds of the Ministry of Health (SSA) were lost, representing 43 percent of its capacity in the city. This included the 700 beds lost with the complete collapse of Juárez Hospital and the gynecology-obstetrics tower of the General Hospital of Mexico. In total, the city lost more than 4,000 public hospital beds in the earthquake, severely disrupting these institutions’ ability to handle the crisis. In addition, five of the largest private hospitals had to be evacuated. More than 900 patients, physicians, nurses and paramedical workers died in the initial shock.

In contrast, the network of twenty four community general hospitals with 1,600 beds belonging to the city (federal district) were not affected as these were spread out beyond the city center and the old lakebed.

Human toll in the city

To this day, the death toll has been in dispute. About 5,000 bodies were recovered from the debris and represent the total of legally certified deaths but does not include those who were missing and never recovered. Reports have numbered the dead anywhere from 5,000 to 30,000 (claimed by a number of citizens’ groups) to 45,000 claimed by the Mexican National Seismological Centre
Mexican National Seismological Centre
The Mexican National Seismological Service , was founded on September 5, 1910, by the Mexican government as part of an international effort to monitor seismic activity...

. However, the most commonly cited figures are around 10,000. While high as an absolute number, it compares to other earthquakes of similar strength in Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

 and other parts of Latin America
Latin America
Latin America is a region of the Americas where Romance languages  – particularly Spanish and Portuguese, and variably French – are primarily spoken. Latin America has an area of approximately 21,069,500 km² , almost 3.9% of the Earth's surface or 14.1% of its land surface area...

 where death tolls have run between 66,000 and 242,000 for earthquakes of magnitude 7.8 or above. Part of the explanation for that was the hour in which the earthquake struck, approximately 7:20am, when people were awake but not in the many schools and office buildings that were severely damaged.

However, the death toll was great enough to necessitate the use of the IMSS
IMSS
IMSS may refer to:* Istituto e Museo di Storia della Scienza, Florence, Italy* Instituto Mexicano del Seguro Social, Mexico* Integrated Maritime Surveillance Systems, an integrated network of coast-line radars...

 baseball field as a morgue
Morgue
A morgue or mortuary is used for the storage of human corpses awaiting identification, or removal for autopsy or disposal by burial, cremation or otherwise...

, using ice to conserve bodies for identification.

The main reason that the figures have been disputed is the government’s response to the tragedy. President Miguel de la Madrid
Miguel de la Madrid
Miguel de la Madrid Hurtado is a Mexican politician affiliated to the Institutional Revolutionary Party who served as President of Mexico from 1982 to 1988.-Biography:...

  ordered a news blackout and did not address the situation at all for 39 hours after the event. When the government did give estimates of the number dead, they vacillated between 7,000 to 35,000 people. Consequently, most of the populace believes that the true numbers have never been revealed.

According to government figures, approximately 250,000 people lost their homes directly due to the earthquake. Unofficial sources put that figure much higher. Some sources state that more than 50,000 families lost their homes, and INEGI
National Institute of Statistics, Geography, and Data Processing
The National Institute of Statistic and Geography is an autonomous agency of the Mexican Government dedicated to coordinate the National System of Statistical and Geographical Information of the country...

 reports that 700,000 people in the Federal District and the suburbs in the State of Mexico lost their homes.

Emergency response

In the hours and days immediately after the first shock, there was an enormous response and solidarity among the city population of 18 million people. Ordinary citizens organized brigades to help with rescue efforts and to provide food, clothing and emotional support to the homeless.

Patients had to be moved from damaged hospitals, especially the National Medical Center. Many of these patients were very ill. 1,900 patients were successfully moved from here, without any deaths, in just four hours.

More than 4,000 people were rescued alive. 9,600 injured people received treatment, including 1,879 who needed hospitalization. Despite the loss of 5,000 hospital beds, there was never a shortage of facilities for the injured. Some of the reason for this was that those with postponable care were discharged, but mostly because the public and private facilities unified de-facto during the crisis. There were also people rescued as late as ten days after the initial event.

Hospital Juárez

One of the most visible government institutions to fall in the event was the tower of Hospital Juárez, one of the oldest hospital institutions in Mexico. It was founded in 1847, converting the old convent of San Pablo to treat wounded soldiers from the Mexican-American War. It originally was called San Pablo Hospital but its name was changed to Juárez Hospital in 1872.

The “Torre de Hospitalización” was built in 1970 with the main building being twelve stories tall. It had two wings, one facing north and the other south, with an inpatient capacity of 536 beds. At the top was a helipad. It was also surrounded by a number of other buildings belonging to the hospital complex such as a blood bank
Blood bank
A blood bank is a cache or bank of blood or blood components, gathered as a result of blood donation, stored and preserved for later use in blood transfusion. The term "blood bank" typically refers to a division of a hospital laboratory where the storage of blood product occurs and where proper...

, teaching facilities, offices as well as the original convent. At the time of the earthquake, the hospital was 80% full, and it was shift change time for nurses, doctors and residents. Within minutes, the steel-frame structure collapsed, crushing and trapping many people inside.

Those who were rescued first were taken to another building for treatment, as the ambulances were trapped inside the collapsed tower. The hospital did not have an emergency plan but nonetheless, surviving hospital workers and neighbors quickly improvised, under the management of the hospital, setting up aid stations and scavenging supplies. Rescue workers soon arrived to take start digging through to rubble. A second quake made rescue work slower, because of fear of further collapse. Most bodies were identified by personal effects, some by dental records and some were so mangled that they wound up being cremated without ever being identified, due to the lack of morgue facilities. 561 bodies were found and 188 were never identified. 266 were hospital workers and 44 were medical residents. The majority who were rescued were found in the first five days. The number of bodies recovered was high during those first days as well but the numbers dramatically increased between days 17 and 31.

Heavy machinery was unable to get to the site until 5 days after the earthquake. Numbers of dead did not include unidentified body parts found. Most of the injured had contusion injuries and many suffered from dehydration, with the severity of the dehydration increasing with those rescued later.

However, the most memorable story to come from this event was the rescue of nearly all the newborn babies that were in the nursery at the time. These babies were pulled out of the wreckage mostly unscathed but lost their mothers. These babies were found seven days after the initial event and came to be known as the “Miracle Babies” or the “Miracle of Hospital Juárez.” The reason for this was that these babies survived without nourishment, water, warmth or human contact for all that time.

Sewing factory

On Manuel José Othón Street, in the Colonia Obrera
Colonia Obrera
Colonia Obrera is an administrative neighborhood of the borough of Cuauhtémoc in the center of Mexico City. It was established in the late 19th and early 20th centuries and became home to many artisans and industrial workmen...

 neighborhood, near Metro station San Antonio Abad
Metro San Antonio Abad
Metro San Antonio Abad is a station on Line 2 of the Mexico City Metro system. It is located in the Colonia Tránsito and Colonia Obrera neighborhoods of the Cuauhtémoc borough of Mexico City, to the south of the city centre, in the median of Calzada San Antonio Abad.The station logo depicts Saint...

, was one of the many garment factories located in the city center area. It was destroyed along with approximately 1,200 other workshops.

It was one of three buildings that collapsed on this block, and called “Topeka”. The magazine Proceso
Proceso
Proceso may refer to:* Proceso , a Mexican political magazine* National Reorganization Process , the dictatorship that ruled Argentina between 1976 and 1983...

reports that by the time rescue workers got to the building, the owners were already in a hurry to demolish it, without trying to rescue or recover the seamstresses that were trapped inside. About 150 bodies of workers had already been pulled from the wreckage by other workers with their bare hands.

The collapse of this factory exposed the deplorable conditions that many of these seamstresses were subject to. The building that collapsed, as well as many others, were found to be decrepit. It came to be known that many of these women had to work extended hours with little or no compensation, and few, if any of the labor laws on the books were being followed. This event made the garment industry a labor embarrassment.
All that is left to remind of the factory is a small empty lot with a bronze statue of a woman sewing to commemorate the event. On the rest of the property, apartments have been built.

Central Communications Center

On Eje Central
Eje Central
The Eje Central is part of a system of roadways built by Carlos Hank González to make Mexico City more automobile-friendly....

 and Xola Avenue, at the southern end of the lakebed zone was (and is) the Secretaría de Comunicaciones y Transportes (Ministry of Communication and Transportation), a reinforced concrete
Reinforced concrete
Reinforced concrete is concrete in which reinforcement bars , reinforcement grids, plates or fibers have been incorporated to strengthen the concrete in tension. It was invented by French gardener Joseph Monier in 1849 and patented in 1867. The term Ferro Concrete refers only to concrete that is...

 structure with its microwave tower. This structure failed, causing the near total collapse of long distance communications between Mexico City and the rest of the world.

Conjunto Pino Suárez

One of the most spectacular building collapses was that of the Conjunto Pino Suárez, which was a complex of five steel frame buildings. A 20-story tower, Tower Four, doubled over at the third floor and fell south onto a fourteen-story building. The fall left a huge piece of concrete blocking the road that leads to the Zócalo. People at the scene stated that there was simply no time to run and escape the building’s fall. The other three 20-story buildings were closed because of damage, as well as the Metro entrance next door. The building was occupied by family courts and offices of the public defender. The area now is a commercial center.

Hotel Regis

The Hotel Regis was built in the beginning of the 20th century as a luxury hotel in neo-Classical
Neoclassicism
Neoclassicism is the name given to Western movements in the decorative and visual arts, literature, theatre, music, and architecture that draw inspiration from the "classical" art and culture of Ancient Greece or Ancient Rome...

 style. It had its own cabaret
Cabaret
Cabaret is a form, or place, of entertainment featuring comedy, song, dance, and theatre, distinguished mainly by the performance venue: a restaurant or nightclub with a stage for performances and the audience sitting at tables watching the performance, as introduced by a master of ceremonies or...

, gourmet restaurant and a small but luxurious cinema with wide reclining armchairs.

It was located at the corner of Balderas and Avenida Juárez in the historic center and completely collapsed within moments of the quake. Shortly after its collapse, it began to burn due to a gas leak, which made it extremely difficult to rescue survivors. Nothing has survived of the hotel except for a wall with a mural done by Diego Rivera. The space is now the Plaza de la Solidaridad park. On the north side of this park is a wall from the hotel, containing a mural done by Diego Rivera
Diego Rivera
Diego María de la Concepción Juan Nepomuceno Estanislao de la Rivera y Barrientos Acosta y Rodríguez was a prominent Mexican painter born in Guanajuato, Guanajuato, an active communist, and husband of Frida Kahlo . His large wall works in fresco helped establish the Mexican Mural Movement in...

. It is now housed there in a small museum.

Apartment complexes in Tlatelolco

There were two apartment complexes in the area of the city called Tlatelolco
Tlatelolco (Mexico City)
Tlatelolco is an area in the Cuauhtémoc borough of Mexico City, centered on the Plaza de las Tres Culturas, a square surrounded on three sides by an excavated Aztec archaeological site, a 17th century church called Templo de Santiago, a former convent, and office complexes that used to belong to...

 to the north of the historic center that became major scenes of disaster, the Unidad Habitacional Nonoalco-Tlatelolco
Unidad Habitacional Nonoalco-Tlatelolco
The Unidad Habitacional Nonoalco-Tlatelolco is the largest apartment complex in Mexico, located in the Cuautemoc borough of Mexico City. It was built in the 1960s by architect Mario Pani. Originally, the complex had 102 apartment buildings, with its own schools, hospitals, stores and more, to make...

 and the "Multifamiliar Juárez". Together, these apartment complexes were a large percentage of the 30,000 units lost, with the city losing about 30% of its living space.

Nonoalco Tlatelolco was located on Paseo de la Reforma
Paseo de la Reforma
Paseo de la Reforma is a wide avenue that runs in a straight line, cutting diagonally across Mexico City. It was designed by Ferdinand von Rosenzweig in the 1860s and modeled after the great boulevards of Europe, such as Vienna's Ringstrasse or the Champs-Élysées in Paris...

 Norte #668,
covering an area of about two km2. It had 102 buildings with seven medical facilities, twenty-two schools and about 500 small businesses, serving the 80,000 people that lived there. Constructed under the presidency of Adolfo López Mateos
Adolfo López Mateos
Adolfo López Mateos was a Mexican politician affiliated to the Institutional Revolutionary Party who served as President of Mexico from 1958 to 1964...

, it was considered the most important complex of its kind in the country. In the Conjunto Urbano, two of the three modules of the building called "Nuevo León," at thirteen-stories tall, completely collapsed, while the other one was severely damaged. In other buildings, dozens of people terrified by the event jumped from high windows to their death, trying to escape. People became trapped in stairwells, elevators and their apartments without any way to contact the outside world. At the collapsed building lines of 50–100 men passed rubble by hand and buckets, trying to reach victims. During these rescue efforts, a nearby building, called Oaxaca, began to creak noisily, causing everyone to run and abandon the site temporarily, but it did not collapse.

All the buildings suffered damage but along with the collapsed Nuevo León building, buildings such as those called Veracruz, Coahuila, Zacatecas, Oaxaca, Puebla, Jalisco, Churubusco, Guelatao, 2 de Abril, 15 de Septiembre, Chihuahua, Tamaulipas, ISSSTE 11, Querétaro, Guanajuato, Ignacio Comonfort, Ignacio M. Altamirano, Jesús Terán, Ponciano Arriaga, Niños Heroes and 20 de Noviembre suffered severe damage such as severely cracked foundations. In the days after the quake, military and police cordoned off ten buildings to keep people out, leading a number of them to sleep on the streets. Twelve buildings in the complex were so severely damaged that they were demolished in the next six months.

Buildings A1, B2 and C3 of the Multifamiliar Juárez complex partially collapsed with a total of nine structures eventually being demolished.

Televisa studios

One of the famous images of the event was the live broadcast of Hoy Mismo, a news program in the Televisa
Televisa
Televisa is a Mexican multimedia conglomerate, the largest mass media company in Latin America and in the Spanish-speaking world. It is a major international entertainment business, with much of its programming airing in the United States on Univision, with which it has an exclusive contract...

 television network, when the earthquake struck. In the video, movement can be seen, especially in the lights above the newscasters. The three newscasters were María Victoria Llamas (substituting for Guillermo Ochoa), Lourdes Guerrero and Juan Dosal. As the movement began Llamas reports grabbing the underside of the desk, and whispering quickly to Guzmán that she hoped no one could see how scared she was.
The last image broadcasted from that studio was that of Lourdes Guerrero stating “… it still moves a little (un poquitito) (referring to the lights above the studio), but we must take it quietly. We must wait for a while to talk.” Then the image disappeared. The transmission ended because a nearby 10-ton antenna
Antenna (radio)
An antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...

 had bent over and noisily crushed parts of Televisa’s buildings that were located on Niños Héroes and Dr. Río de la Loza Streets in Colonia Doctores
Colonia Doctores
Colonia Doctores is an official neighborhood just southwest of the historic center of Mexico City. It is bordered by Avenida Cuauhtémoc to the west, Arcos de Belen Street to the north, Eje Central to the east and Eje 3 Sur José Peón Contreras to the south....

.
Everyone ran from the studio but Llamas and Guerrero stayed, hiding under their anchor desks. After the shaking stopped, they both left the Televisa studios through a back door, and hours later they were back on the air in the studios of Canal de las Estrellas
Canal de las Estrellas
Canal de las Estrellas is one of the cornerstone networks of Televisa, with affiliate stations all over Mexico, flagshipped at XEW-TV in Mexico City. Many of the programs of Canal de las Estrellas are seen in the United States on Univision, Telefutura, and Galavisión...

 to broadcast live what was happening. Some members of the Hoy Mismo staff died, including producer Ernesto Villanueva and engineer David Mendoza Corcega, who had just parked at the Televisa building, but had no time to escape from his car. The falling debris also killed street vendors who worked just outside the studio building. Reconstruction of the studio building began in 1995 and ended in 2000.

Other structures

  • Televicentro (now Televisa Chapultepec)
  • Los Televiteatros (now Centro Cultural Telmex)
  • Hotel D'Carlo and Hotel Prado, which were located in the Alameda Central area near the Hotel Regis

Geological and structural engineering issues

Most of the earthquake damage was to buildings. Two reasons are the resonance in the lakebed sediments and the long duration of the shaking. The buildings most damaged were from 6 to 15 stories in height. These buildings tended to resonate most with the energetic frequency band of the lakebed motions. One interesting characteristic was that many buildings had their upper floors collapse, leaving the lower floors relatively undamaged. In many damaged buildings, just one floor had collapsed, In some cases, the damage was caused by the top of a lower, adjacent building banging against the walls and the supporting columns of its neighbor. Eventually, the columns gave way. In other cases, the first few floors of buildings were designed as parking garages, open lobbies or large shopping areas. These "soft" stories were particularly flexible and tended to collapse after prolonged shaking. Some types of foundations, particularly those involving piles driven into clay and held in place by friction, turned out to be weak. One 9-story building, for example, overturned. Its piles were pulled entirely out of the ground.

A survey of the damage done by the government found that few buildings from one to five stories suffered serious damage; the same was true for buildings over fifteen stories. When the buildings were built seemed to have an effect as well. Before the 1957 earthquake, there were no building code
Building code
A building code, or building control, is a set of rules that specify the minimum acceptable level of safety for constructed objects such as buildings and nonbuilding structures. The main purpose of building codes are to protect public health, safety and general welfare as they relate to the...

s with respect to earthquake resistance
Earthquake engineering
Earthquake engineering is the scientific field concerned with protecting society, the natural and the man-made environment from earthquakes by limiting the seismic risk to socio-economically acceptable levels...

. Some regulations were passed in that year and more in 1976 after another, stronger earthquake shook the city. However, none of these regulations had an event like 1985’s in mind when passed. Most of the seriously damaged buildings were built between 1957 and 1976, when the city was starting to build upwards, in the six-to-fifteen floor range. In second place were buildings from before 1957, possibly because they were weakened by the earlier earthquakes. Buildings from 1976 to 1985 suffered the least damage.

At the time of the earthquake, Mexico City had one of the most stringent building codes, based on experience gained from earthquakes in 1957 and 1979. However, the codes were not designed for seismic activity of the intensity experienced in 1985. The event was one of the most intense of any recorded in the world, allowing for macroseismic waves to arrive in the Valley of Mexico with unusually high energy content. Prior to the event, estimates about ground movement on the lakebed were generally accepted and a number of buildings were built on these estimates.

Several notable buildings were relatively untouched by the quake. One significant example is the Torre Latinoamericana
Torre Latinoamericana
The Torre Latinoamericana is a building in downtown Mexico City, Mexico. Its central location, height and history make it one of the city's most important landmarks...

. Despite being 44 stories tall, it survived the 1985 event almost undamaged. It was constructed with two hundred piles extending down over a hundred feet into the stable earth stratum.

Government response

The military was deployed to patrol streets to prevent looting
Looting
Looting —also referred to as sacking, plundering, despoiling, despoliation, and pillaging—is the indiscriminate taking of goods by force as part of a military or political victory, or during a catastrophe, such as during war, natural disaster, or rioting...

 after a curfew
Curfew
A curfew is an order specifying a time after which certain regulations apply. Examples:# An order by a government for certain persons to return home daily before a certain time...

 was imposed, as well as rescue, sanitary efforts and other, with 1,836 soldiers initially sent in and another 1,500 conscripts sent later. The federal government’s first public response was President de la Madrid’s declaration of a period of mourning for three days starting from 20 September 1985.

The earthquakes created many political difficulties for the then-ruling Partido Revolucionario Institucional (PRI) or Institutional Revolutionary Party
Institutional Revolutionary Party
The Institutional Revolutionary Party is a Mexican political party that held power in the country—under a succession of names—for more than 70 years. The PRI is a member of the Socialist International, as is the rival Party of the Democratic Revolution , making Mexico one of the few...

. The crisis was severe enough to have tested the capabilities of wealthier countries, but the government from local PRI bosses to President de la Madrid himself exacerbated the problem aside from the lack of money. The Ministry of Foreign Affairs declared it would not request aid; it specifically rejected aid from the United States. It was also widely reported in the days after the earthquake that the military assisted factory owners in retrieving their machinery rather than in removing the bodies of dead factory workers. At many levels of the government, who was helped and by how much was determined by one’s standing vis-à-vis the PRI. Those belonging to the party received preference and those considered opposition received the runaround. President de la Madrid refused to cut foreign debt payments to use the money to help with the recovery effort. The government’s response to the earthquake was widely criticized at various levels of Mexican society, being seen as both authoritarian and incompetent. As most of the collapsed buildings were of recent construction and public works projects, the government was seen at fault due to mismanagement and corruption in these constructions. The government itself realized that it could not handle the crisis alone through already-established institutions and decided to open the process up to “opposition groups.”

Community response

On the other hand, the disaster created an opportunity for political opponents, especially at the grassroots level. Much of the community organizing focused on helping those left homeless by the earthquake. The three largest and most effective organizations were based in Tlatelolco and Colonia Roma
Colonia Roma
Colonia Roma is a colonia or neighborhood located in the Cuauhtémoc borough of Mexico City just west of the city’s historic center. The area was a very shallow part of Lake Texcoco, dotted with tiny islands and one small island village of Aztacalco during the pre-Hispanic period...

. These consisted of families from the “Multifamilar Juárez” housing project, which completely collapsed and the combined colonias (neighborhoods) of Centro, Morelos, Guerrero, Doctores
Colonia Doctores
Colonia Doctores is an official neighborhood just southwest of the historic center of Mexico City. It is bordered by Avenida Cuauhtémoc to the west, Arcos de Belen Street to the north, Eje Central to the east and Eje 3 Sur José Peón Contreras to the south....

, Obrera, Peralvillo, Asturias, Nicolás Bravo among others which housed the working and lower classes. These groups along with the Sindicato Nacional de Costureras united to form the Coordinadora Única de Damnificados (CUD).

CUD and other popular movement representatives met with head of the Secretariat of Urban Development and Ecology (SEDUE) Guillermo Carrillo Arena on 27 September 1985. Carrillo Arena at first insisted that the movements incorporate themselves into the PRI before gaining any concessions. This was refused. Many media outlets expressed support for the popular movements and marches like that of 2 October 1985, demanding that the reconstruction process be more “democratic,” meaning the inclusion of non-PRI political organizations into the decision-making process. On 11 October 1985, the President granted a seven-minute audience to the heads of a dozen popular movements, which turned into a 45-minute meeting where de la Madrid was handed a document outlining what would remain the movements’ core demands: expropriation of all condemned buildings, followed by a “popular” and “democratic” reconstruction project which would include the active participation of the community movement. De la Madrid conceded some with the expropriation of 5,500 properties in the four most affected boroughs.

After the government created the Programa de Renovación Habitacional Popular (PRHP) on 14 October to help deal with the crisis, friction between the government and community groups grew again, PRHP used PRI-membership as a requirement to be included into the census of earthquake victims. More protests followed on 26 October calling for, among other things, the firing of SEDUE head Carrillo Arena. Things got worse through February 1986, mostly due to the ineffectiveness of SEDUE and PRHP. Finally Carrillo Arena was fired from SEDUE and replaced by Manuel Camacho Solís
Manuel Camacho Solís
Manuel Camacho Solís is a Mexican politician who served in the cabinets of presidents Miguel de la Madrid and Carlos Salinas...

.

In March, only weeks after taking office, Camacho Solís changed the charged atmosphere between SEDUE and the community groups. He actively integrated Tlateloloco citizen groups into a new program meant for that area, defusing the most volatile area of the city. Camacho Solís continued to work to integrate and smooth relations between his agency and the community groups. On 16 May 1986, Camacho Solís met with the heads of all the major groups. He offered a commitment to build 48,000 housing units in one year if the groups would all sign a “Convenio de concertación democrática para la reconstrucción de vivienda” (Democratic agreement for the reconstruction of housing). Basically, this document required the cooperation of community groups in exchange for solid commitments from the agency. All sides would compromise in order to get something done. The deal generally worked; movements like CUD moderated their stances and agencies like SEDUE and PRHP made progress in rebuilding housing, regardless of political affiliation.

Weakening of the PRI

At the time of the earthquake, Mexico was in its fifth year of a foreign debt crisis, and a contracting economy causing serious political problems for the PRI. Much of the PRI’s authoritarian nature was tolerated because the country had seen four decades of economic expansion of six percent or better. When this disappeared, the PRI’s power base began to shrink. Its reputation was damaged further when the government seemed to be deliberately downplaying the number of earthquake victims. President de la Madrid made relatively few public appearances afterwards and during those he did, he received strong heckling, in contrast to the near-reverence that past presidents enjoyed at such events.

The severe damage in so many buildings, including many public works projects construction to house the rapidly growing population of Mexico City, were blamed on lax enforcement of building codes. Critics argued that the lack of enforcement of such codes was indicative of corrupt practices in all levels of government.

The stepping-in of non-PRI organizations to take over where the government could not also took its toll on PRI’s reputation. Burton Kirkwood states “Out of the disaster emerged the realization that a viable civil society existed in Mexico. This revelation also caused many to consider why they needed a centralized state that so obviously could not care for its people. As a consequence, the opposition movements pointed to the government’s shortcomings and advanced candidates for the greater goal of defeating the PRI.”

Shortly after the event, the PRI began to face serious challenges at the polls, forcing it to rig elections, sometimes in an embarrassingly messy way.

Effects of earthquake in other parts of Mexico

Although much closer to the epicenter, the states of Jalisco
Jalisco
Jalisco officially Estado Libre y Soberano de Jalisco is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is located in Western Mexico and divided in 125 municipalities and its capital city is Guadalajara.It is one of the more important states...

, Colima
Colima
Colima is one of the 31 states which, with the Federal District, make up the 32 Federal Entities of Mexico. It shares its name with its capital and main city, Colima....

, Guerrero and Michoacán suffered only mild to moderate damage. Landslides caused damage at Atenquique, Jalisco, and near Jala, Colima. Rockslides were reported along highways near Ixtapa
Ixtapa
Ixtapa is a beach resort in the municipality of Zihuatanejo de Azueta, in the Mexican state of Guerrero. It is located to the northwest of the municipal seat, Zihuatanejo, and some northwest of Acapulco....

, Guerrero, with Sand volcano
Sand volcano
A sand volcano or sand blow is a cone of sand formed by the ejection of sand onto a surface from a central point. The sand builds up as a cone with slopes at the sand's angle of repose. A crater is commonly seen at the summit...

s and ground cracks in Lazaro Cardenas. Students at the Universidad de las Américas
Universidad de las Américas
Universidad de las Américas may refer to:*Fundación Universidad de las Américas, Puebla , university in Cholula, Puebla state, Mexico*Universidad de las Américas, A.C., university in Mexico City, Mexico....

 in nearby Puebla
Puebla
Puebla officially Estado Libre y Soberano de Puebla is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 217 municipalities and its capital city is Puebla....

 reported feeling as if the cafeteria had been lifted and rocked back and forth, shattering windows and injuring some people but mostly causing panic. A small tsunami caused only mild damage to Lázaro Cárdenas and Zihuatanejo
Zihuatanejo
Zihuatanejo or Ixtapa-Zihuatanejo, is the fourth-largest city in the Mexican state of Guerrero. Politically the city belongs to the municipality of Zihuatanejo de Azueta in the western part of Guerrero, but both are commonly referred to as Zihuatanejo...

. Some fishing boats were reported missing but these reports were never confirmed. One exceptional case was in Ciudad Guzmán
Ciudad Guzmán
Ciudad Guzmán is a city in the Mexican state of Jalisco.It is located at , 124 km south of Guadalajara, at a height of 1,507 metres above sea level...

, Jalisco, where about 60 percent of the buildings were destroyed, with about 50 dead. Some damage also occurred as far away as the states of Mexico, Morelos
Morelos
Morelos officially Estado Libre y Soberano de Morelos is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 33 municipalities and its capital city is Cuernavaca....

 and parts of Veracruz
Veracruz
Veracruz, formally Veracruz de Ignacio de la Llave officially Estado Libre y Soberano de Veracruz de Ignacio de la Llave , is one of the 31 states that, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided in 212 municipalities and its capital city is...

, on the Gulf
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...

 coast. Coastal and most inland damage was moderated by the fact that most of the west of Mexico sits on bedrock
Bedrock
In stratigraphy, bedrock is the native consolidated rock underlying the surface of a terrestrial planet, usually the Earth. Above the bedrock is usually an area of broken and weathered unconsolidated rock in the basal subsoil...

, which serves to transmit the shockwaves without amplifying them. La Villita, and Infiernillo Dam
Infiernillo Dam
The Infiernillo Dam , also known as Adolfo Lopez Mateos Dam, is an embankment dam on the Balsas River near La Unión, Guerrero, Mexico. The dam supports a hydroelectric power station containing six turbine-generators for a total installed capacity of 1,120 MW. The dam is high, long and is owned by...

s, near the coast, were superficially damaged and undamaged respectively.

Off the coasts of Michoacán and Guerrero, the 19 and 20 September events caused a rupture in the seabed 240 km long and 70 km wide, located between the subduction trench and the coastline. This is an intertidal zone
Intertidal zone
The intertidal zone is the area that is above water at low tide and under water at high tide . This area can include many different types of habitats, with many types of animals like starfish, sea urchins, and some species of coral...

 and the event caused widespread mortality in a number of species living in the area such as algae and shellfish.

Legacy

One preparation that was made for future events was the alert system, Sistema de Alerta Sísmica (SAS), which sends early-warning messages electronically from sensor
Sensor
A sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument. For example, a mercury-in-glass thermometer converts the measured temperature into expansion and contraction of a liquid which can be read on a calibrated...

s along the coastal subduction zone in Guerrero. It was expanded to a similar area on the coast of Oaxaca. An alarm is supposed to go off in Mexico City (similar to an air-raid siren) when an earthquake of 6.0 or higher is detected. However, it does not always work.

To better help deal with major disasters, the Civil Protection Committee was created. This committee organizes drills in cooperation with rescue workers, police, hospital staff and even metro personnel. Affiliated with the Civil Protection Committee is the “Brigada de Topos de Tlatelolco” (Mole Brigade of Tlatelolco)
Topos de Tlatelolco
The Técnicos en Urgencias Médicas, Seguridad y Rescate 19 de Septiembre , better known as the Topos de Tlatelolco is a professional Mexican rescue team....

. This group arose from youths who spontaneously volunteered to risk their lives crawling into collapsed buildings to look for survivors. Despite having no equipment, training or knowledge of rescue tactics, these youths were instrumental in saving a number of lives, including the babies rescued from the collapse of the Juárez Hospital. Shortly thereafter, these youths decided to formally band together in February 1986. These “topos” have developed into highly trained specialists in times of disaster, with branches in other parts of Mexico. They are now expertly trained and even have scent dogs to help them. They have gained international fame as they have helped in disasters in San Salvador
San Salvador
The city of San Salvador the capital and largest city of El Salvador, which has been designated a Gamma World City. Its complete name is La Ciudad de Gran San Salvador...

, Taiwan
Taiwan
Taiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...

, in the countries of the rim of the Indian Ocean
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...

 after the tsunami there in 2004, and most recently in the January 2010 Haiti Earthquake
2010 Haiti earthquake
The 2010 Haiti earthquake was a catastrophic magnitude 7.0 Mw earthquake, with an epicentre near the town of Léogâne, approximately west of Port-au-Prince, Haiti's capital. The earthquake occurred at 16:53 local time on Tuesday, 12 January 2010.By 24 January, at least 52 aftershocks...

.

Despite warnings and predictions, in 2005, an estimated 32 million people live in the high-risk lakebed area.

As of 2005, there are still two camps where approximately eighty families are still waiting for relocation from the earthquake.

Centuries-old structures have been reinforced across the city and new construction must comply with very strict codes. There are several instances of tall buildings in Mexico City incorporating earthquake-resistant engineering. A few notable examples are: the Torre Latinoamericana
Torre Latinoamericana
The Torre Latinoamericana is a building in downtown Mexico City, Mexico. Its central location, height and history make it one of the city's most important landmarks...

, one of the first buildings in Mexico City to do so, the Torre Ejecutiva Pemex
Torre Ejecutiva Pemex
The Torre Ejecutiva Pemex is a skyscraper in Mexico City. The building was originally designed as a pair of 26-story towers, but was later transformed into a single 52-story, international style tower. On September 19, 1985, the tower was able to resist the 8.1 earthquake that struck Mexico City...

, built before the 1985 earthquake, and the Torre Mayor
Torre Mayor
The Torre Mayor is a skyscraper in Mexico City, United Mexican States. With a height of 225 metres to the top floor and 55 storeys, it's the second tallest building in Latin America, surpassed by Ocean Two in Panama City with 236 metres...

, built in 2003.

Every 19 September, in all public buildings at Mexico City and all the nation the civil protection authorities conduct evacuation drills to evaluate the evacuation response in the case of an earthquake.

Televisa's San Angel studios
Televisa San Angel
Televisa San Angel is a motion picture and television studio located in Mexico City. It was originally built by Jorge Stahl as a motion picture studio, and in the 1970s would be sold to the Azcárraga family, which, through ownership of the Televisa networks, continues to own the studios...

, one of the few Televisa facilities in Mexico City not damaged by the earthquake, became the new home of two long-running series, Siempre en domingo and En familia con Chabelo
Chabelo
Xavier López , better known as "Chabelo," is a Mexican actor and a TV host. He has been working on television for about 45 years. "Chabelo" has participated in more than thirty motion pictures and recorded more than thirty musical albums. He also has produced many shows like La Cuchufleta and La...

,
both of which saw their studios at Chapultepec damaged. The earthquake also inspired the creation of another long-running Televisa series, Silvia Pinal
Silvia Pinal
Silvia Pinal is a Mexican actress, who had roles in several of Luis Buñuel's movies such as El ángel exterminador and Viridiana...

's Mujer, casos de la vida real
Mujer, casos de la vida real
Mujer, casos de la vida real is a television show produced by Hispanic television Televisa for Canal de las Estrellas. The show first aired after the Mexican earthquake of 1985 as a method to assist victims of the natural disaster...

,
which was also produced at Televisa San Angel.
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