Hobbies And Interests
Composition
In volcanoes, the magma builds in chambers until pressure becomes so great it has to force its way to the surface through the vents and cracks. If magma contains large quantities of silicon and oxygen, silica is formed. Silica forms strong covalent bonds which create polymerization or internal friction within the magma, reducing its ability to flow. Magmas with low amounts of silicon and oxygen flow more easily so their eruptions are usually not intense.
Viscosity
The viscosity of the magma is a measure of how thick and sticky it is. For example, water has a low viscosity while molasses has a high viscosity, so it flows slower than water does. In a volcano, magma with a high viscosity, primarily created by strong silica bonds, is more likely to explode with extreme intensity than magma with low viscosity. This is because hot gases trapped inside of the high viscosity magma aren't released quickly enough into the atmosphere to dissipate their explosive force.
Temperature
The magma's temperature works for and against the volcano's intensity level. High temperatures lower viscosity levels, enabling the magma to flow quicker, dissipating some of the intensity of the eruption. However, as magma gets hotter, the vapor pressure of the dissolved gases within it increases. If the magma's internal vapor pressure becomes higher than the external pressure of surrounding rock formations, vesiculation, or gas bubbles, will occur. This event can cause an explosive volcanic eruption.
Trapped Gas
The amount of trapped dissolved gasses inside of magma affects the intensity of a volcanic eruption. Dissolved gases lower the magma's viscosity, but increase its instability when vesiculation occurs. In general, the higher the amount of hot gases trapped in the magma, the more intense the eruption will be. These gases include chlorine, carbon dioxide, water vapor, hydrogen and nitrogen.