User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-4775842-20120902221823

One thing I've never understood is how Ceadus was able to shake the entire Deserted Island. Sure, he's big, but not big enough to shake the whole island. The island is like, what, a couple tenthousands of acres? (My knowledge of acres is acre = 100 sq ft?) Ceadus is only a couple hundred metres long, and his horn is approx a little less than 200 metres (I'll need to check the monster size video again). That isn't enough to shake such a big island. At the most he could make a slight vibration under you feet from 1500 yards away and farther. Now if you were standing right on top of the ground he was scraping against, then yeah, you might get that effect.

(I think I just contradicted my own theory there, but oh well).

In order for him to shake the ENTIRE island with as much force as the quake shows, he would probably have to be closer to 1000 metres or more in length.