Amazement
Admiration
noun, verbal noun
I'm so surprised that it caused me to sigh. This is like when you see something super impressive and it surprises the heck out of you. Then, you breathe out a sigh because of your great amazement and admiration for what you just saw.
驚嘆 is a formal word you'll mostly see in writing to describe something truly awe-inspiring, or the state of being amazed by an impressive thing. It's about more than just surprise — it describes the deep admiration you feel when marveling at great talent, skill, or beauty.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
彼の演技には、皆が驚嘆した。
Everyone felt wonder at his performance.
彼女の知識量には驚嘆するしかありませんよ。
One can only admire the amount of knowledge she has.
その太陽光発電所の規模に驚嘆しました。
I was amazed at the size of the solar power plant.
彼は驚嘆して、「この世界、本当によくできてる」とつぶやいた。
He marveled and murmured, "This world is really well made."