In the month of August 2018, the National Seismological Service (SSN) reported a total of 2063 earthquakes with epicenters within Mexican territory; of which at least 1233 had their epicenter in Oaxaca. The magnitudes of these events are in a range of 1.9 to 5.3 and the epicenters are distributed throughout the national territory, concentrating mainly on the Pacific coast and in the Gulf of California.
Oaxaca thus becomes the state in Mexico where the largest number of earthquakes occurred that were reported during the month of August 2018, some of which continue to be replicas of the earthquake of magnitude 8.2 that happened on September 7, 2017.
The largest magnitude earthquake in August was of magnitude 5.3 with epicenter 42 km southwest of Ometepec, Guerrero, at Barra de Tecoanapa. This earthquake occurred on August 22 at 13:03, and was felt in the towns near the epicenter.
The coast of the Guerrero is characterized by being part of the convergent contact between the tectonic plates of Cocos and North America. Where the oceanic plate subducts under the continental plate. The seismicity in this state is daily. Throughout the month, 272 earthquakes were reported with an epicenter in the state of Guerrero.
They are considered replicas when they occur in the same zone of rupture of the fault that originated the main earthquake. They can occur for days, months and even years after the main earthquake.