Earthquake and Volcanic Hazards: Impacts on People and the Environment

This document outlines the short-term and long-term impacts of earthquakes and volcanic hazards on people and the environment, relevant to the Cambridge A-Level Geography (9696) syllabus.

Earthquake Hazards: Impacts

Short-Term Impacts

Short-term impacts of earthquakes are immediate and often devastating. These are typically experienced within hours or days of the event.

• Loss of Life and Injuries: The most immediate and tragic impact. Building collapse is a major cause of fatalities.
• Physical Damage to Infrastructure: Widespread damage to buildings, roads, bridges, railways, and communication networks.
• Fire: Ruptured gas lines and electrical faults can ignite fires, often exacerbated by damaged water supplies.
• Landslides and Liquefaction: Ground shaking can trigger landslides in hilly areas and cause soil to lose strength (liquefaction), leading to building collapse.
• Tsunamis: Underwater earthquakes can generate powerful tsunamis that cause immense coastal flooding and destruction.
• Disruption of Essential Services: Power outages, water shortages, and communication breakdowns hinder rescue efforts and recovery.

Long-Term Impacts

Long-term impacts of earthquakes can persist for years and significantly alter societies and landscapes.

• Economic Disruption: Loss of businesses, jobs, and tourism revenue. Significant costs associated with rebuilding infrastructure.
• Social and Psychological Impacts: Trauma, displacement, and mental health issues among survivors. Breakdown of social structures.
• Environmental Changes: Alterations to landscapes due to landslides, ground deformation, and changes in drainage patterns.
• Changes in Land Use: Areas deemed high-risk may be avoided for development, leading to shifts in population distribution.
• Policy and Planning Changes: Increased focus on earthquake-resistant building codes, early warning systems, and disaster preparedness.
• Reconstruction Challenges: Difficulties in rebuilding damaged areas, particularly in areas with limited resources or complex geological conditions.

Volcanic Hazards: Impacts

Short-Term Impacts

Short-term impacts of volcanic eruptions are often dramatic and can have widespread consequences.

• Pyroclastic Flows: Fast-moving currents of hot gas and volcanic debris that cause immense destruction.
• Lava Flows: Slow-moving rivers of lava that can engulf everything in their path.
• Ashfall: Can blanket large areas, causing respiratory problems, damaging crops, and disrupting transportation.
• Volcanic Gases: Toxic gases (e.g., sulfur dioxide, carbon dioxide) can cause respiratory distress and environmental damage.
• Lahars: Mudflows composed of volcanic ash, debris, and water, which can travel long distances and cause significant destruction.
• Tsunamis: Volcanic eruptions in or near the ocean can generate tsunamis.

Long-Term Impacts

Long-term impacts of volcanic eruptions can reshape landscapes and influence climate patterns.

• Changes to Landscapes: Formation of new volcanic landforms, alteration of existing topography, and destruction of ecosystems.
• Soil Enrichment: Volcanic ash can enrich soils over time, making them fertile for agriculture.
• Climate Change: Large eruptions can release aerosols into the stratosphere, which can reflect sunlight and cause temporary cooling.
• Economic Impacts: Damage to agriculture, tourism, and infrastructure. Loss of livelihoods.
• Health Impacts: Long-term respiratory problems due to ash inhalation.
• Population Displacement: Permanent or temporary relocation of communities due to ongoing volcanic activity.
• Geothermal Energy Potential: Volcanic areas often have significant geothermal energy potential.

Comparison of Impacts

Impact	Earthquakes	Volcanic Eruptions
Loss of Life	High (due to building collapse, tsunamis)	Moderate to High (due to pyroclastic flows, lahars)
Infrastructure Damage	Widespread (buildings, roads, communication)	Significant (buildings, roads, agricultural land)
Environmental Changes	Landslides, liquefaction, coastal erosion	Landscape modification, soil enrichment, climate change
Economic Impacts	Business disruption, rebuilding costs, tourism decline	Agricultural losses, tourism decline, infrastructure repair costs
Social Impacts	Trauma, displacement, social disruption	Displacement, health issues, community disruption

Note: The severity and nature of impacts can vary depending on factors such as the magnitude and depth of the earthquake or eruption, the proximity to populated areas, the geological conditions of the region, and the level of preparedness and disaster management in place.