Natural Hazards and Disasters - Part 2

Natural Hazards and Disasters - Introduction Part 2

• A smart hazard approach is needed due to economic globalization, multi-national information access, and negative human impact on the global environment.
• Examples include the 2011 earthquake in Japan, which caused a radiation leak and tsunami affecting Western North America. The 2021 BC floods and related transportation issues further highlighted these interconnected problems.
• The 2018 earthquake in Palu, Indonesia is another example of widespread damage.

A Smart Hazard Approach

• People are concerned with hazards common to their locations, like Calgary floods and Vancouver earthquakes.
• A balanced, multi-lateral approach is required for studying hazards and disasters.
• A conceptual framework for decision making includes predicting hazards via scientific analysis.
• Monitoring and mapping events for making predictions is crucial.
• It's possible to forecast future events based on past frequency, magnitude, and occurrence patterns.
• Also, risk analysis is important for understanding hazardous processes.
• Quantifiable events, including their estimated probabilities and consequences, are essential.
• Different natural hazards and their relationships to the environment are interconnected; one process can trigger another. Examples include earthquakes causing tsunamis and heavy rain causing landslides.

Damage from Hazards

• Damage from natural hazards is increasing, turning previously considered disasters into catastrophes.
• Growing populations and investments are at higher risk.
• Increased human activity and climate change are escalating the frequency and magnitude of events.
• Damage in Dawson Springs, Kentucky from a 2021 tornado is further evidence of increasing hazard impacts.

Limitations of the Conceptual Framework

• Despite good systems, some situations are unpredictable or impossible to analyze or record with definitive certainty.
• This could be due to remote locations, rapid events, forces too large to measure, or poorly understood processes.

Systems Approach

• Analyses require organization.
• Natural hazards are processes needing energy to function.
• Understanding energy source and amount is important to understanding hazards.
• Three energy sources are Earth's internal heat, energy from the sun, and gravitational attraction of Earth.

Earth's Internal Heat

• After Earth's formation, three mechanisms lead to internal heating: collisions of atoms, compression, and the radioactivity of elements.
• These mechanisms create slow mantle convection, causing plate tectonics, leading to earthquakes and volcanoes.

Energy from the Sun

• Solar energy drives atmospheric and ocean circulation, making winds and evaporating water.
• This creates climate patterns and violent weather events like hurricanes, tornadoes, hail, droughts, floods, and erosion.

Gravitational Attraction of Earth

• Earth's gravity drives mass-wasting processes: materials moving downhill such as avalanches, landslides, and mudslides.
• Earth's gravity also attracts objects from space, leading to impacts from asteroids and meteorites.

Conceptual Framework for Decision-Making - Risk Analysis

• Risk analysis helps to understand the effects of hazardous processes.
• Risk analysis quantifies events and helps to estimate probabilities and consequences.

Conceptual Framework for Decision-Making - Linkages

• Linkages exist among different natural hazards and between hazards and their physical environment.
• One process can trigger another.

Terminology - Cause vs Trigger

• Both describe what makes a hazard occur but in different time frames:
• Cause: long-term buildup of conditions creating the hazard
• Trigger: short-term event initiating the hazard's action
• Often, they are used interchangeably.

Terminology - Correlation vs Causation

• Correlation: describes the degree to which two variables move together statistically.

• Positive correlation: variables change in the same direction.

• Negative correlation: variables change in opposite directions.

• Correlation does not imply causation.

• Causation: a direct cause-and-effect relationship is established, such that a change in the first variable causes a change in the second.

Terminology - Risk vs Impact vs Vulnerability

• Risk: Likelihood of harm (probability is known).
• Impact: What happens if the risk occurs.
• Vulnerability: Weaknesses in a system (not always directly related to the hazard).

Terminology - Disaster vs Catastrophe

• Both refer to events causing serious injury or death along with property damage, but happen in a limited time frame:
• Disaster: limited in area, with direct consequences
• Catastrophe: larger scale, with direct and indirect (more often) consequences, and therefore much more costly to remediate.

Magnitude and Frequency (Earthquakes, etc.)

• People most often are concerned with how big natural hazards are and how often they happen.
• Magnitude relates to the amount of energy released, and frequency to how often events happen.
• Larger events occur less frequently, smaller events occur more frequently.
• Magnitudes and frequencies can be described mathematically.
• In the past, geologists debated whether rare, large events or common smaller events have a more significant impact on Earth's formation.

Reactive Response - Recovery

• Recovery attempts for natural disasters can vary greatly depending on the type of disaster and how often similar events occur.
• Disaster effects can be direct (like deaths, injuries, and property damage) or indirect (like crop failure, starvation, emotional distress, or loss of employment or tax revenue).
• The importance of indirect effects might not always be readily apparent.

Stages of Recovery

• Stages to recovery from disasters usually include emergency work, restoration of services and communication, and reconstruction.
• Disasters can cause long-term recovery due to weakened infrastructure and limited resources to repair damage.
• A general model illustrates the different periods in disaster recovery.

Potential Natural Hazards

• A list of natural hazards is available, by types (atmospheric, seismic, hydrologic, volcanic, wildfire, etc.) and specific examples.

Hazards by Season

• Natural hazards vary based on the time of year, latitude and hemisphere.
• Some examples are given of when specific hazards are most likely to occur. This information (along with the other parts of these notes) provides a framework for better understanding natural hazards and the associated concepts from which decisions can be made.