The National Seismological Service (SSN) reported that as of 8:00 a.m. on Thursday, there were 39 aftershocks from the Sept. 19 earthquake and 5,402 from the quake on Sept. 7.
They said that in 1980, an earthquake of the same magnitude that occurred last Tuesday, Sept. 19, happened 19 kilometers west of Acatlán de Osorio, Puebla.
They said that earthquakes in the states of Puebla and Morelos are common and that there are records of earthquakes from the year 1900 to the present day.
The institute noted that Chiapas and Oaxaca are among the states with the highest rate of seismic activity in the country, due to the convergent contact between the Cocos Plate and the North American Plate.
At the beginning of the 20th century, three major surface earthquakes with magnitudes greater than 7.0 occurred on the coast of Chiapas and Guatemala.
The first of these happened close to the Mexico-Guatemala border, on April 19, 1902 with a magnitude of 7.5. The second was Sept. 23, 1902 with a magnitude of 7.7 on the north coast of Chiapas; and the third on Jan. 14, 1903 of 7.6 on the south coast of Chiapas.
The National Seismological Service emphasized that to date there are no scientific techniques anywhere in the world that can predict when an earthquake will occur, nor its magnitude, nor the effects on the population.