A U.S. monitoring agency earlier reported that there were two earthquakes of magnitude 7.0, but then said there was only one quake and downgraded the magnitude.
There were no immediate reports of damage from the Myanmar side, a remote area where communications, even in the best of times, are difficult. The country's military-controlled government also tightly controls information.
The quakes struck along Myanmar's borders with Thailand and Laos, about 70 miles from the northern Thai city of Chiang Rai. The northern Thai city sustained a little damage, according to Thai television.
The 6.8-magnitude quake was just six miles (10 kilometers) deep, according to the U.S. Geological Survey.
There are no immediate reports of injuries.
The Pacific Tsunami Warning Center says it was located too far inland to create a destructive wave.
The Associated Press contributed to this report.