After the East Japan Great Earthquake occurred in Japan on 11th March 2011, many messages related to the earthquake were posted to social media. Especially, in Asian countries, a lot of messages about the earthquake were posted, so that different topics such as concerning about damages by the earthquake, afflicted people were observed, etc. observed. These topics can be recognized as reactions to the earthquake. Therefore, exploring topics related to the earthquake on social media in Asian countries gains a rich insight into the Asian social context. The goal of our research is to analyze Asian people reactions to the East Japan Great Earthquake on social media using data mining technique. As the first step, this paper targets Thai language and conducts the preliminary approximation to investigate topics on Thai social media. We analyze how Thai people reacted to the earthquake and compare with reactions in Japan.