Possible Sink Hole Explanation
When I saw the Main Trailer for the first time, I noticed something. With beautiful camera work, the 3 origami pieces in the top left corner of the Power plant shot looked like jet planes or birds or insects flying over the power plant as it was being decimated. I couldn't imagine that was coincidence. I knew that illusion in the camerawork was there for a reason.
And after the Gareth Edwards breakdown of the trailer (which you should all watch. It's about 11 minutes long) he stops specifically to talk about that scene and the origami pieces and that it was foreshadowing something.
Now, I'm going to assume here that the flying MUTO is an insect-type being and not a Rodan-type one. Based off my knowledge of insects (I'm a bio major), there are countless of different species of flying Arthropods that burrow deep within the earth to form their nests/dwellings. Maybe the origami pieces aren't symbolizing an attack from above, but from underground. We've essentially come to the conclusion that the MUTOs feed off radiation and possibly even use radiation to grow their offspring. So, they built a colony under the plant. Not just that one, but under many other nuclear sources.
I initially thought that it was Godzilla that attacked the plant- but Godzilla would obviously be seen.
Plus, the plant seems not to be blowing up, but buckling and sinking into the ground. Maybe around the sinkholes shown in the MUTOResearch website were sights of nuclear powered sources. I remember seeing the MUTOResearch pictures and in the pictures in the jungle there were buildings near the sinkholes. Perhaps they were just not taken down from the surface buckling. Plus, it seems that the MUTOs are being covered up by the government more than Godzilla is being covered up because they actually have excuses for the MUTO attacks whereas they just send test bombs into the Pacific Ocean for Godzilla hoping it'll kill him. Which is why I think Cranston is yelling at whoever is at the other end of that mirror about the MUTOs.
It's sort of like that ultimate denial real world people have. Like where we believe we're all currently safe in this very moment when way back in our heads we're aware that this world can be changed in an instant(war). In the film I think they're just trying to assume nothing will happen with the MUTOs and Godzilla but the danger always looms in the back of our heads until it finally happens and we're like "damn". Not saying I cracked a code, just speculating a bit!