Volcanic eruptions occur when temperature rises inside the earth's crust, causing an internal explosion that violently expels materials like lava, magma, and gases from the interior to the surface. The viscosity of magma is affected by its temperature, gas content, and silica content - high viscosity magmas contain low gas, high silica, and are cooler, flowing slowly, while low viscosity magmas have more gas, less silica, and are hotter, flowing more readily. These factors influence the shape of volcanic cones and how volcanoes erupt.

1. Volcanoes

2. Volcanic eruptions
Volcanic eruption is the violent expulsion of different liquid,
solid and gaseous materials (lava, magma, gases, rocks, etc.)
from the interior of the earth’s crust to the earth’s surface. This
occurs when the temperature inside the earth rises, and an
internal explosion occurs

3. Factors that affects the
viscosity of a magma
• As the temperature of magma increases, its viscosity
decreases.
• as the temperature of magma decreases, its viscosity
increases

5. Magmas with high viscosity are those with low gas
content, high silica content, and low temperature,
thus, have low mobility or slow in flowing. On the
other hand, magmas with low viscosity are those
with high gas content, low silica content, and high
temperature. These factors answer the questions
why volcanoes have different cone shapes and why
they erupt differently.

6. Types of volcanic
eruption