Why do some valcanoes explode violently

Question

Why do some valcanoes explode violently

Answer 1

It depends on how well it was sealed by the last eruption . The more hard malted rock above the magma will allow the pressure to go very high...  

Answer 2

there are a couple things.

--  how much gas is in the lava.  the more gas, the more explosive.

--  how well sealed the lava tube is.  the more force needed to start the eruption, the more explosive it will be.

you'll note that all the volcanoes along the pacific coast are explosive ones.  that's said to be caused because they are part of a subduction zone that carries water and gas down into the earth with them, priming them to explode.

Hawaii volcanoes, on the other hand, result from a plume of rock from very deep down that has less gas in it, and also, since they frequently erupt, they tend to not build up a lot of pressure.

Answer 3

This happens when there is no crack or porosity in the earth's surface.The lava cannot escape and so the pressure keeps building up.When the lava does break though,it does so forcefully and thereby violently.

Hope this helps.

Answer 4

WELL VOLCANOES ARE OF THREE DIFFERENT TYPES-

1)dormant

2)active

3)frequently active

dorment volcanoes are least active dut they explode with great intencity when they do.since concentration of lava and gases inside it increases it a long span of time.

Answer 5

It's all down to the viscosity of the lava. When you have runny lava, it comes out of the vent and can flow easily. Like the volcanoes in Hawaii and Iceland. Looks very spectacular when it sprays out up into the air. But some lava is much thicker. It can't flow out as fast. When the pressure in the magma pool underneath the volcano increases to a point when the earth/rock can no longer contain it.......KABOOM!!!! Mount St Helens! And the daddy of them all, Krakatoa

Answer 6

Some volcanoes have magma that has a high viscosity (thicker), or the magma may contain a lot of water that creates steam. Both can cause a buildup of pressure and cause an explosion. The viscosity is governed by the amount of silica the magma contains.