The highly active Shinmoe volcano on the southwestern Japanese island of Kyushu has spewed a column of hot ash and smoke more than 3km into the air.
The area northeast of its crater, 14km away, is covered in small rocks and pumice, NHK reported.
Local authorities have warned of the danger of lava flows.
The 1,420m-high Shinmoe volcano has been rocked by earthquakes since late June. It has erupted several times since October 2017, and ash emissions from its crater have repeatedly disrupted local air traffic. There are about 50 active volcanoes in Japan.
A magnitude 6.0 earthquake was recorded in Mexico, the country's seismological service reported.
According to the agency, the epicenter of the earthquake was 139 km southwest of the city of Ciudad Hidalgo in the state of Chiapas. The epicenter was at a depth of 38.5 km.
There were no reports of casualties or damage.