[Gideon7]

I checked Wolfram Alpha and it says 5.3 Richter = 1.3 KT

http://www.wolframalpha.com/input/?i=5.3+Richter+scale&wal=header

[JPX2011]

Interesting. Well then I’d have to agree with you that seems pretty weak for a successful test.

[Snickering Hound]

Washington Post analyst is saying at least 20-30kt.