Volcanoes Lecture Notes

Overview

• Definition: Vent in Earth's crust where magma flows, cools, and forms volcanic rock.
• Formation: Occurs at destructive and constructive plate boundaries.
• Characteristics: Includes lava flows, ash clouds, lava bombs, etc.

Formation of Volcanoes

Destructive Plate Boundaries

• Tectonic plates push together; one is subducted beneath the other.
• Melting of subducted plate creates pressure, forcing magma through faults.

Constructive Plate Boundaries

• Tectonic plates diverge, creating gaps.
• Magma rises to fill the gaps, forming a volcano.

Hot Spots

• Magma plumes push through crust weaknesses, forming volcanoes.

Distribution of Volcanoes

• Concentrated along tectonic plate boundaries.
• Predominantly around the Pacific Ocean, known as the "Pacific Ring of Fire."

Measuring Volcanic Intensity

• Volcanic Explosivity Index: Measures the intensity of volcanic hazards.

Characteristics of Volcanoes

Lava Flows

• Can reach up to 10 km from the crater.
• Destroys farmland and buildings but has a low death toll.

Ash Clouds

• Thrown into the air during eruptions, carried long distances by wind.
• Can cause travel disruptions, bury buildings/crops, and cause suffocation.

Toxic Gases

• Includes sulfur dioxide, carbon monoxide, cyanide.
• Carbon dioxide contributes to global warming but is non-toxic.

Lava Bombs

• High-speed emission of large lava boulders, causing injury/death.

Pyroclastic Flow

• Fast-moving current of hot gas and lava.
• Causes damage to crops, buildings, and may lead to injury and death.

Mudslides

• Occur in areas with volcanic material.

Living Near Volcanoes

• Soil Fertility: Ash increases soil fertility, improving crop yields.
• Mineral Deposits: Volcanic areas are rich in minerals, providing income.
• Geothermal Energy: Access to renewable energy source.
• Community & Heritage: Historical settlements and family ties.

Impacts of Volcanic Events

• Location, Size, Length: Influences eruption impact.
• Preparedness: Local preparedness and emergency services can mitigate impact.
• Population Density: Higher density increases vulnerability.
• Eruption Characteristics: Varying characteristics influence severity and type of impact.

Case Study: Icelandic Volcano (2010)

• Example of ash clouds causing widespread travel disruption.