The mammoth 8.4 magnitude quake struck 54 miles off the coast of Mexico, at a depth of 43 miles, the United States Geological Survey (USGS) said.
With tremors reportedly lasting up to a minute, at least two people have been confirmed dead while photos show buildings reduced to rubble.
And residents must now brace themselves for the tsunami which is following in its wake.
A tsunami warning has been issued for Mexico, Guatemala, El Salvador, Costa Rica, Nicaragua, Panama and Honduras.
Peru and Ecuador have now been added to the list.
Tweets from Salina Cruz, a Mexican city in Oaxaca, have reported: “The height of the tsunami waves continues to rise.”
The Pacific Tsunami Warning Centre issued a tsunami threat.
Live updates
Friday 7.50am: So far there have been six aftershocks, the first measuring 6.1 at a depth of 19 miles, and the latest 5.