so who or what woke godzilla up?

90% sure it is the Castle Bravo test (the one that was more powerful than predicted and caused fallout that affected the Lucky dragon 5 crew) 100% sure it is a hydrogen bomb test in 1954

The annoyance of 98 film that took his name

GodzillaFan1995 is probably spot on.

Castle Bravo is the test that most fans think woke Godzilla in the original movie. The test was conducted mid-1954, and that's when Watanabe's character said they woke Godzilla in the trailer.

i did a little research on nuclear testing in the pacific and there was only 1 test in 1954 which was the one i mentioned, the reason i'm explaining this is becuase i thought that i could've been a underwater bomb that woke up godzilla, but becuase godzilla was awaken in 1954 then castle bravo is the only canidate if it was a nuke test that woke him, all other 'tests' in the pacific after 54 were attempts to kill him. thats all i can tell, we will know the truth when the Godzilla: The Awakening prequel comic is released.

Edit: i didn't research it good enough, i confused the names of the operations for the tests, there was 6 tests under the name of Operation Castle (which included Bravo, which was the first test of the operation) 1 in 1955 (operation Wigwam) 17 in 1956 (Operation Redwing), 35! in 1958 (Operation Hardtack I) and 36!! in 1962-3 (Operation Domonic), wow now that is a lot of tests, you can't tell me that ALL those tests were attemps to kill godzilla, 1. that means they tried it for 10 year and 2. that is a lot of nukes used against godzilla add all those nukes in the pacific from 54-63 and you get 95 NUKES!!!

also after 54 there have been only 4 nuclear weapon testing in the pacific in the spam of 7-9 years, this can work in the movie i suppose

Godzilla final wars tells how it woke Godzilla because humans have done horable things to this planet that makes him mad.

also from bomb testing in tokyo and mutated a Dino named Godzillasaurus when the nuke hit the body it mutaded him to a epic master peace of art.

guys if you paid attention to the dialogue, then you would know that serizawa said 'In 1954, We awoken something' which means that godzilla was and is not a mutaion of a dinosaur, and 'those nuclear tests in the pacific... not tests' 'they were trying to kill it' means that after 1954 all tests in the Pacific were actually nuclear weapons used to try and kill godzilla, they must have faild beccuase he come back in the present time, and must have gained his atomic breath due to the exposure of 95 nuclear weapons