Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you:
You want to appease her because she's (しず) SUPER mad. She's pissed and she's angry and she's going to beat you up if you don't find out how to calm her down!
In order to appease the god’s anger we need to offer a sacrifice.