What causes a volcano to be explosive?

Answer 1

When the vocano is dormant ( not active ) for some time a crust forms ovdr the top of the volcano which has lava inside. When it becomes active then the pressure keeps building up and after some time it can't take any more and blows the crust off causing the lava and tiny crust rocks,gas and ashes to comne flying out.

Answer 2

Most magma (molten rock underground) contains some gas that is dissolved under pressure. As the magma approaches the surface the pressure decreases and the gas is released and expands rapidly, resulting in an explosion. If magma contains very little gas it will not be explosive.

Answer 3

the pressure of the gases in the magma chamber of a volcano is so high that magma is forced out of the magma chamber into the atmosphere through the vent of the volcano:)

Answer 4

Volcanos tend to erupt or explode because the magma that comes out from the earths crust breaks the crust and explodes or erupts from the active Volcano.

Answer 5

The two main factors are the viscosity of the magma and the gas content of the magma.

Answer 6

Because volcanoes are very dangerous. They are explosive, beacause, all of the lava pushes all out, and kills everything But if it's why does it kill, I don't know?

Answer 7

Expanding gases and high magma viscosity.