Godzilla was weak vs Akula

“Yes,” Dr. Nobeyama nodded.  “At first the creature was probably weak--Godzilla feeds on nuclear radiation you see.  The French nuclear tests were powerful enough to awaken him, but not powerful enough to return Godzilla to his full strength.  That is why he attacked the Russian nuclear submarine--”
“Sea Base One!”  It was Nick who interrupted this time.  “Sea Base One discovered the wreckage of that sub.  They knew Godzilla had sunk it!”