Ok motherfuckers, here we go.
惊动= to disturb, startle. It's got the 动 so you can kind of see it coming. Don't distrub him while he's sleeping, the noise over there strartled him, you get the idea. The disturb here seems rather close to the 打扰 uses of disturb in many cases. It easy to separate out this one.
惊人 = 很惊人的， in my notes I have (likely from the dic) surprising, amazing, astonishing, always with a 的 after it. n词库 seems to confident that 惊人 errs on the side of astonishing and amazing, rather than surpising. After reading their examples I will side with them on the "incredible, amazing, awesome (not good)" flavor of this word. 很惊人的成就, but am far from wholly convinced. Their translations are very convenient. I imagine the scope of this word is fairly broad. What you need to know is it's grammatical usage.
惊讶，吃惊 - apparently synonyms = surprised, amazed. （of course n词库 goes with the translation astonished, the rarely used 极端 word in the english language which inevtiably leads to rather chinglish style translations and the "astonished" tinged chinglish you hear out of chinese mouths. Ok, I'll say it, I don't use n词库 because its got chinese editors who really suck. It's not that chinese people have to suck at explaining their language, understanding their language or mastering english, but they do, and I've been in their school system and I've lived in their society, so I know why. And I don't believe in website registration, especially shady governmentish places like n词库。)
With 惊讶 you most often see, 感到惊讶， 十分惊讶， 让人很惊讶， etc. DO YOU SEE THE DIFFERENCE IN USAGE FROM 惊人！ YOU SHOULD!
吃惊 collocations wildly similar to 惊讶， 让，使，令人吃惊， 非常，十分吃惊， NOTICE the usage and that all dictionaries will mark 吃惊 as a verb and 惊讶 as an adjective. You're not crazy, don't worry.
we're done here.