There are at least three reasons. People need to live near water. Since many volcanoes are very tall, clouds gather near their peaks. The clouds cause lots of rain and snow to fall on or near the slopes of the volcanoes. The rain and snow provide a steady water supply for people who live nearby. Also, when volcanic ash and rock break down, they become part of the soil. The minerals make the soil rich and good for farming. Some countries, such as Indonesia, have large populations and a small amount of land, so the people there have no choice but to live near active volcanoes.