a sudden/steep rise — a rapid increase in quantity or value over a short time.
株価が発表後に急上昇した。
Stock prices shot up after the announcement.
気温が午後になって急上昇したため、外出は控えた。
Because the temperature climbed sharply in the afternoon, I avoided going out.
商品の需要が急上昇して在庫が足りなくなった。
Demand for the product rose abruptly and stock ran short.
trending — when a topic, keyword, or hashtag suddenly becomes popular on the internet or social media.
その動画は投稿後すぐに急上昇に入った。
That video immediately made it into the trending list after it was posted.
急上昇ワードに自分の名前が出て驚いた。
I was surprised to see my name appear as a trending keyword.
ニュースで取り上げられ、話題が急上昇した。
The topic was picked up by the news and suddenly trended.