The plot of a Japanese manga has played a big role in fuelling online rumours about a “megaquake” striking Japan on Saturday, triggering fear among some Hongkongers and a decline in interest in trips to the country, a hugely popular destination for residents. But are the claims made by the comic book artist, based on her dreams, possible? The Post has gathered expert opinions to debunk the speculation. 1. Why have concerns about megaquakes arisen? The Japan Meteorological Agency last August...