The Pacific Tsunami Warning Centre in Hawaii issued a watch bulletin.
The Pacific Tsunami Warning Centre said if a tsunami is generated waves could reach Sri Lanka at the following times.
DONDRA HEAD 14.47GMT +5.30 =20.17SLT
TRINCOMALEE 15.02GMT +5.30 =20.30SLT
COLOMBO 15.15GMT +5.30 =20.45SLT
JAFFNA 16.25GMT +5.30 =21.55SLT
The quake took place at 16.40 Sri Lanka Time.
The Pacific tsunami centre has revised the magnitude of the quake from an initial 7.9 to 8.2 on the Richter scale.
A tsunami that hit Sri Lanka in December 2004 was generated from an earthquake that was more than 10 times as powerful.