How do people know if a volcano is still active or not?

How do people know if a volcano is still active or not?

i was wondering how people decide to live remotely close to a volcano, cuz what if it erupts? How do people know that where they moved to the volcano isn't active anymore?

Additional Details

me and my boyfriend were thinking of what's the worst natural disaster, and we think a volcano is, so it got me thinking about it Active volcanoes have craters that spouts clouds of ash steam every time. People living near active volcanoes may smell an odour similar to the stench of rotting eggs because of the element suflur.

Dormant volcanoes are sleeping volcanoes. Their crater is blocked with rock and you won't see them spout steam. But they can still erupt. Extinct volcanoes are volcanoes that won't erupt anymore. They look like mere mountains. They have no more craters and are sometimes covered with trees up to the area that was noce the crater.

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