5.3 on the Richter scale is 1.3 kilotons according to http://www.convertalot.com/earthquake_power__calculator.html
Hiroshima was 15 KT.
So the hiroshima bomb was like how big. On the richter scale?
This website says 5.3 Richter equates to 90 kilotons of exploding TNT.
http://www.english.ucla.edu/all-faculty/335-kelly-kiloton-index-of-earthquake-moment-magnitudes