A strong quake shook the southwest corner of Mexico on Friday evening, sending residents rushing out into the streets.
The 7.2 magnitude natural disaster and a magnitude 5.8 aftershock - both with epicenters in Oaxaca state - struck the region Friday, the US Geological Survey reported. There is no verified evidence of the depth of the natural disaster, the information is between 10 and 45 km.
Then on September 19 - the 32nd anniversary of a huge 1985 quake that killed 10,000 people - a 7.1-magnitude quake rocked the country, leaving 369 people dead.
Pictures on social media showed minor damage to roads and some buildings, but there were no reports of injuries. There is no tsunami alarm.
A magnitude 5.9 aftershock hit almost an hour later.
Thirteen people died and 15 were injured Friday night after a military helicopter carrying government officials assessing quake damage crashed in southern Mexico, said the Oaxaca state prosecutor's office.
The helicopter was carrying Interior Secretary Alfonso Navarrete and Oaxaca State Gov. Alejandro Murat, who were both reportedly unharmed.
The department said the victims had been waiting for the helicopter, but did not provide more details.
A television reporter who was on board said the helicopter suddenly dropped after generating a large cloud of dust on its landing field.
The powerful, sustained shaking on Friday gave way to 225 aftershocks, the national seismology service said, and caused widespread panic.
The deadliest quake in the region happened on September 19, 1985, in Michoacan state, about 300 miles northwest of Friday's tremor.
The Popocatepetl volcano south of the capital sent a kilometer-high column of ash into the sky, said Mexico's disaster prevention agency.
The natural disaster triggered a seismic alert of the country's capital, prompting residents to evacuate their homes and offices to take shelter in streets and parks.
Mexican leaders were assessing the damage left by the massive quake that rocked Mexico City and neighboring states to the south Friday evening.