They struck seconds apart at 1355 GMT and were centred about 70 miles (110 km) from the northern Thai city of Chiang Rai, the agency said.
The first quake was shallow, at a depth of 6.2 miles (10km), while the second was much deeper at 142.5 miles (230km).
Tremors could be felt as far away as Bangkok and Hanoi.
THIS HAPPEN 8:55 pm Thailand time 24 /3/2011
Posted: at | |