Two aftershocks have followed Wednesday's earthquake in Koh Yao district of Phangna, the latest felt early on Thursday morning and recorded at magnitude 4.5 on the Richter scale.
The Seismological Bureau said the latest tremor was centred 11 kilometres undersea south of Koh Yao Yai and occurred at 12.30am Thursday. The shake was felt in Phangnga, Phuket and Krabi provinces.
The first aftershock, of 3.2 magnitude, occurred at 12.25pm on Wednesday one kilometre undersea at the same place as the first, 4.6-magnitude tremblor on Wednesday at 4.18am.
After the second aftershock, Moken people on local islands, wary of a tsunami, temporarily evacuated to higher ground. Locals and tourists in Phuket, about 20 kilometres from the quake's centre, remained largely unconcerned and stayed in their homes and monitored reports.
No damage was reported.