If you want a quick look at whether Thailand or anywhere in southeast Asia could be affected by a tsunami – check this website:
http://www.weather.gov/ptwc/?region=3
Region 3 is the Indian ocean – and covers Thailand’s western and eastern costs.
If you want to subscribe to receive email when there are earthquakes in your area (create an area to watch on a map – drag the outline of the area – I created a square all around Thailand from Africa to Thailand to Philippines to Australia.
https://sslearthquake.usgs.gov/ens/register
To subscribe to RSS feeds – (for your news reader) click the Indian ocean region link at this site:
http://www.weather.gov/ptwc/subscribe.php
If it doesn’t work. Hit the back button in your browser, and right click the link – copy the link – and paste it into your RSS reader.