There are over 160 potentially active volcanoes in the US, and 1500 worldwide.

美国有 160 多座潜在活火山，全世界有 1500 座。

Of the more than 1,500 potentially active volcanoes on Earth, only a small fraction are actively monitored, and fewer still have erupted since scientists started watching.

在地球上 1,500 多座可能活跃的火山中，只有一小部分受到积极监测，而且自科学家开始观察以来，仍然爆发的火山更少。

It's underwater where eruptions can and do occur, like the massive explosion in the waters off Tonga, just one of the over 30,000 potentially active volcanoes worldwide, capable of creating earthquakes, tsunamis and entirely reshaping the landscape.

火山喷发可能也确实发生在水下，比如汤加附近水域的大规模爆炸，它只是全球3万多座潜在活火山中的一座，能够制造地震和海啸并完全改变地貌。