On March 20, 2012, around midday, an earthquake hit  the south and central part of Mexico. The quake was felt more intensively in the states of Oaxaca, Guerrero, Morelos and Mexico City. According to the Mexican National Seismological Service  (@SimsologicoMx) [es] the earthquake presented the following characteristics:
SISMO 7.8 Richter 29 km al SUR de OMETEPEC, GRO 20/03/12 12:02:50 Lat 16.42 Lon -98.36 Pf 15 km
EARTHQUAKE 7.8 Richter 29 km SOUTH of OMETEPEC, GRO 03/20/12 12:02:50 Lat 16.42 Lon -98.36 Pf 15 km
The quake caused anguish among a society that is used to earthquakes, but not as strong as this one. In some areas of Mexico City people panicked as citizens waited on the streets to go back to their offices. Since there were power outages in some neighborhoods, people turned to the Internet to contact family members and report the situation on the ground.
Jazmin Fajardo  (@jazminfajardo) [es], for example, said:
En la condesa [barrio al centro de la ciudad de méxico] todos afuera de los edificios polvo y olor a gas
In La Condesa (a neighborhood close to downtown Mexico City) everybody is outside the buildings, dust and gas smell
Nayeli Roldán  (@nayaroldan) [es] reported that some took refuge at the Zocalo (the square that sits at the heart of Mexico City) of Mexico's capital city:
La gente desalojando los edificios cercanos al Zócalo
People emptying buildings near the Zocalo
User RankiaoRecordsHD shared the following video of the earthquake on YouTube:
Juliana Rincón gathered more citizen videos of the quake at a post  for Global Voices.
Amidst the panic, the Twitter account of Walmart Mexico (@WalmartComMx) published:
Ahora sí, pusimos a temblar a las otras tiendas con nuestros precios
This is it, we made other stores shake with our prices
The tweet was erased by the company; however Gavo Ayala  (@gavowonka) [es] shared a screenshot where you can read the tweet:
The deed generated outrage among the Twitter community who strongly condemned it using the hashtag
#OfertasWalmart  (Walmart Sales)
In the state of Oaxaca, in southern Mexico, 25 municipalities reported damages  [es], and in the state of Guerrero 800 houses  [es] were counted as ruined. Meanwhile in the state of Morelos a church suffered  [es] severe destruction.
Despite those damages and some power cuts in Mexico City, the aftermath of the earthquake was significantly less than the disastrous quake of September 19, 1985 , after which there were several and serious actions to improve the country's preparation for such events. The efforts seem to have paid off since no casualties have been reported up to the moment this post was published.