Nat hazards

Volcanic Eruptions

Eruptions occur when magma reaches the Earth's surface, causing lava flows, ash fall, and explosive releases.

Ring of Fire

A zone in the Pacific Ocean where two-thirds of all active volcanoes are located.

Magma vs. Lava

Magma is molten rock beneath the Earth's surface; it becomes lava when it reaches the surface.

Viscosity

The resistance of a fluid to flow; in volcanism, it's affected by silica content.

Tephra

Ejected fragments of magma during explosive volcanic eruptions.

Pyroclastic Deposit

Accumulation of tephra at the Earth's surface after a volcanic eruption.

Explosive Eruption

A violent volcanic eruption that ejects ash, gas, and molten rock.

Rhyolite

An extrusive igneous rock with high silica content (70-75%).

Andesite

An intermediate igneous rock with silica content between 60-65%.

Basalt

A low silica volcanic rock (50-55%) with lower viscosity.

Komatiite

A rare type of lava with very low silica content (below 40%).

Caldera

A large depression formed after the collapse of a volcanic summit post-eruption.

Lava Flows

Molten rock that flows from a volcano, varying in speed and shape depending on its composition.

Composite Volcano

A volcano characterized by a conical shape, composed of layers of lava and tephra.

Shield Volcano

A broad, dome-shaped volcano formed by the flow of low-viscosity basalt lava.

Cinder Cone

The simplest type of volcano, built from pyroclastic fragments and having steep slopes.

Volcanic Gases

Gases released during volcanic eruptions, including water vapor, carbon dioxide, and sulfur dioxide.

Lahars

Destructive volcanic mudflows consisting of water-saturated volcanic ash.

Volcanic Explosivity Index (VEI)

A scale to measure the size of volcanic eruptions based on volume of ejecta.

Hazards of Volcanism

Includes lava flows, ash fall, pyroclastic flows, and poisonous gases.

Pyroclastic Flow

A fast-moving current of hot gas and volcanic matter that moves away from a volcano.

Mass Wasting

The downhill movement of rock and soil due to gravity, often triggered by rainfall.

Landslide

A type of mass wasting where a large mass of earth slides down a slope.

Erosion

The process by which soil and rock are removed from the Earth's surface by natural forces.

Debris Flow

A type of landslide that moves a mixture of soil, rock, and water down a slope.

Floodplain

Flat land adjacent to a river that is subject to flooding.

Hydrologic Cycle

The movement of water through the ecosystems on Earth, including evaporation, condensation, and precipitation.

Gradient

The slope of the land over which a river flows, affecting its velocity and energy.

Discharge (Q)

The volume of water flowing through a river's cross-section per unit time, calculated as Q=A × V.

Sediment Transport

The movement of solid particles, typically due to the action of water or wind.

Evaporation

The process of converting liquid water into vapor, contributing to the hydrologic cycle.

Subsidance

The gradual sinking or settling of the ground, often resulting from activities like mining.

Karst Topography

Landscape formed from the dissolution of soluble rocks such as limestone, characterized by sinkholes and caves.

Thermokarst

Uneven ground surface formed when permafrost thaws, creating depressions and mounds.

Sinkholes

Depressions or holes in the ground caused by the collapse of a surface layer.

Mass Movements

The large-scale movement of earth material down slopes due to gravity.

Avalanche

Rapid downslope movement of snow and ice, usually triggered by natural factors.

Vegetation Impact on Slope Stability

Vegetation can stabilize slopes through root systems but can also add weight.

Quick Clay

A fine-grained material that can lose strength and behave like a liquid when disturbed.

Sediment Load

The total amount of sediment that a river transports, consisting of bed load, suspended load, and dissolved load.

Permafrost

Ground that remains completely frozen for at least two years, affecting landscape and ecosystems.

Urbanization Impact on Flooding

Increases flood risks by altering drainage systems and impermeable surfaces in cities.

Flood Insurance

Insurance coverage that compensates property owners for damages due to flooding.

Low Viscosity Lava

Lavas like basalt that flow easily, resulting in wide-spread lava flows.

High Viscosity Lava

Thicker lava, like rhyolite, that does not flow easily and tends to form steep-sided domes.

Seismometer

An instrument used to detect and measure earthquakes, often used in volcanic monitoring.

Geothermal Energy

Energy derived from the earth's internal heat, often harnessed in volcanic areas.

Flood Management Techniques

Strategies to reduce the impact of floods, including levees, dams, and channelization.

Debris Avalanche Definition

A fast-flowing, mixed mass of rock, soil, and water moving downhill.

Groundwater Contamination

Pollution of underground water sources, often exacerbated by sinkholes.

Slope Processes

Processes that influence the stability of hillsides, including vegetation, water, and climate.

Safety Measures for Avalanches

Includes rescue techniques and avoiding known avalanche-prone areas.

Soil Expansion and Contraction

Changes in soil volume due to moisture fluctuations, leading to potential structural hazards.

Slope Stabilization Techniques

Methods used to enhance the stability of slopes, including drainage control and physical barriers.

Natural Resources from Volcanoes

Includes minerals, fertile soils, and geothermal energy sources.

Volcanic Eruption Forecasting

Monitoring changes in volcanoes to predict potential eruptions.

Aquifer

A geological formation that can store and transmit groundwater.

Lava Dome

A mound-shaped volcanic feature formed by the slow extrusion of viscous lava.

Brittle Fracture

A sudden breaking of a material under stress, common in geological formations.

Hydraulic Chilling

Using water to cool and divert lava flows during eruptions.

Mass Wasting Risks

Potential threats posed by landslides, including damage to infrastructure and loss of life.

Historic Volcano Eruptions

Notable volcanic events that have shaped landscapes and influenced human history.

Lava Tube

A hollow tunnel formed by flowing lava beneath the surface of a lava flow.

Cinder Cone Characteristics

Built from volcanic ash and cinders, often having steep slopes.

Volcanic Soil Fertility

Soils enriched by volcanic ash, beneficial for agriculture.

Floodplain Regulation

Regulatory measures to manage land use and development in flood-prone areas.

Sustainable Land Use Practices

Strategies that balance human needs with environmental protection, especially in vulnerable areas.

Drought Conditions and Flooding

Periods of low precipitation can lead to more significant flooding when rain relief occurs.

Response to Flood Hazards

Actions taken to prepare for or mitigate the impact of flooding.

Soil Compaction Effects

Increased weight of soil leading to stability issues and potential landslides.

Climate Influence on Erosion

Variations in climate affect erosion rates and sediment transport processes.

Glacial Activity Impact on Erosion

Erosion driven by glaciers, often creating unique landforms.

Soil Conservation Measures

Practices designed to prevent soil erosion and maintain soil fertility.

Water Table Fluctuations

Changes in groundwater levels that can influence slope stability.

Seismic Activity and Volcanoes

Earthquakes may precede or accompany volcanic eruptions.

Monitoring Geological Activity

Observation of geological changes to predict hazards like landslides and eruptions.

Civil Infrastructure in Flood Zones

The need for robust engineering solutions in vulnerable areas prone to flooding.

Rescue Operations for Mass Movements

Techniques employed to save individuals trapped during landslides or avalanches.

Subsurface Drainage Systems

Infrastructure designed to prevent water accumulation in vulnerable slopes.

Types of Volcanoes

Characterized by their shape, material composition, and eruption style.

Landslide Prediction Techniques

Methods used to assess the likelihood of landslides occurring.

Sediment Dynamics in Rivers

Understanding how sediment is transported and deposited in river systems.

Natural Disaster Preparedness

Measures taken to minimize damage from natural hazards.

Carbon Sequestration by Vegetation

The process through which plants capture and store atmospheric carbon dioxide.

Climate Change and Natural Hazards

The influence of climate change on the frequency and intensity of natural disasters.

Geology of Canada

Diverse geological regions with different hazards, including volcanic and mass movement risks.

Natural Disaster Recovery Strategies

Plans for rebuilding and recovery following a natural disaster.

Environmental Impact Assessments

Evaluations conducted to understand potential effects of projects on the environment.

Geological Mapping Importance

Tools for assessing hazards and planning for land use.

Landslide Mitigation Measures

Actions taken to reduce the impact of landslides on communities.

Climate Adaptation Strategies

Plans to adjust practices in response to changing climate conditions.

Historical Significance of Volcanic Eruptions

Understanding past eruptions can guide future risk management.

Education on Natural Hazards

Raising awareness about risks and safety measures associated with geological phenomena.

Contaminated Water Sources Post-Flood

Risks of water pollution following floods due to debris and pollutants.

Role of Soil in Ecosystems

Soil health is critical for supporting plant life and maintaining water cycles.

Tsunami Triggered by Landslides

Landslides into water bodies can generate tsunamis, posing additional hazards.

Drainage Basin Characteristics

Land areas where water collects and drains into a common outlet.

Riverbank Stabilization Techniques

Methods used to prevent erosion along riverbanks.

Community Preparedness for Floods

Local actions and plans to prepare for potential flooding.

Impact of Urban Development on Water Flow

How city structures alter natural water drainage patterns.