🔹 What is a Volcano?

A volcano is an opening in the Earth’s crust through which magma, gases, and ash are expelled.

🔹 Structure of a Volcano

• Magma Chamber – Storage of molten rock
• Vent – Opening through which magma escapes
• Crater – Bowl-shaped depression
• Lava – Magma that reaches the surface

🔹 Types of Volcanoes

1. Based on Activity

1. Active Volcano
   • Erupts frequently
   • Example: Mount Etna
2. Dormant Volcano
   • Sleeping but can erupt
   • Example: Mount Fuji
3. Extinct Volcano
   • No eruption in historical times

2. Based on Shape

1. Shield Volcano
   • Broad and gentle slopes
   • Example: Mauna Loa
2. Composite (Stratovolcano)
   • Steep slopes
   • Alternating lava and ash layers
3. Cinder Cone Volcano
   • Small and steep

🔹 Causes of Volcanic Eruptions

• Movement of tectonic plates
• Pressure of gases in magma
• High temperature inside Earth

🔹 Types of Volcanic Eruptions

• Effusive Eruption – Lava flows slowly
• Explosive Eruption – Violent, releases ash and gases

🔹 Distribution of Volcanoes

• Mostly found along plate boundaries
• Major zone: Pacific Ring of Fire

🔹 Effects of Volcanoes

🌟 Positive Effects

• Formation of fertile soil
• Creation of new land
• Mineral resources
• Geothermal energy

⚠️ Negative Effects

• Loss of life and property
• Air pollution
• Climate change (ash clouds)
• Lava destruction

🔹 Volcano Disaster Management

• Monitoring volcanic activity
• Evacuation plans
• Hazard mapping
• Public awareness

🔁 Difference Between Earthquake & Volcano