On April 20th, 20 13, an earthquake of magnitude 7.0 occurred in Ya 'an, Sichuan, causing huge losses. Regarding secondary disasters, the following statement is correct.

A, when the landslide occurs, the height of debris decreases and the speed increases, so the gravitational potential energy of debris is converted into kinetic energy; Therefore, A is correct;

B. When the Yuxi River and Jinjixia in Lushan County have formed dammed lakes, the water level rises, so the potential energy of water increases; Therefore, B is correct;

C, the buoyancy of floating objects on the surface of the dammed lake is equal to gravity, so C is wrong;

D, because the flowing flood has speed, the flowing flood has great kinetic energy; Therefore, d is correct.

So I chose ABD. ..