Natural Hazards and Disasters Introduction Part 2 PDF

NATURAL HAZARDS AND DISASTERS Introduction Part 2 © Vecteezy  A Smart Hazard Approach Most people are concerned with hazards common to their location (e.g. Calgary floods, Vancouver earthquakes) We need a balanced, multi-lateral approach to study hazards...

NATURAL HAZARDS AND DISASTERS Introduction Part 2 © Vecteezy  A Smart Hazard Approach Most people are concerned with hazards common to their location (e.g. Calgary floods, Vancouver earthquakes) We need a balanced, multi-lateral approach to study hazards and disasters – Why? Economic globalization, multi-national information access and negative impact of humans on our global environment – e.g. 2011 magnitude 9.0 earthquake in Japan caused a radiation leak and tsunami that affected all of western North America  A Smart Hazard Approach Nov 2021 rain temporarily closed highways in southern BC, forcing ground transportation to re-route through the northern US Added to COVID supply chain problems – More time and expense involved – More than the local area affected  Conceptual Framework for Decision-Making When danger is seen or potential hazards are observed- 5 concepts make a conceptual framework for making informed decisions : 1. Hazards can be predicted through scientific analysis – Most events and processes can be monitored and mapped or recorded for predictions – Future activity can be forecasted, based on past events (frequency, magnitude, pattern of occurrence)  Conceptual Framework for Decision-Making 2. Risk analysis is an important tool in understanding the effects of hazardous processes – Most events can be quantified so probabilities and consequences can be estimated 3. Linkages exist among different natural hazards and between them and their physical environment – One process can trigger another: e.g. an earthquake can trigger a tsunami or heavy rain can cause a landslide  Conceptual Framework for Hazard Decision-Making 4. Damage from hazards is increasing – Hazards that previously were disasters now are catastrophes – As populations grow, more people and financial investments are at risk – Climate change and human activity increase both magnitude and frequency of events 5. Damage and loss of life from hazards can be minimized – Complex, interconnected systems need an integrated approach, using many disciplines and perspectives to optimize results  Limitations of the Conceptual Framework In spite of having a good system, there will always be situations we cannot record, analyze or predict with any degree of certainty Reasons are numerous: – Locations too remote – Events too rapid – Forces too large – Processes not well understood Why Use A Systems Approach? All analyses need some type of system for organization Since hazards are processes where work is done, they all need energy to function It is useful to organize analysis by the source and amount of energy – 3 sources of energy:  1. Earth’s Internal Heat After the Earth formed, 3 mechanisms caused heating and melting of the interior: – Collisions of atoms – Compression – Radioactivity of elements These produce slow mantle convection that leads to plate tectonics, causing earthquakes and volcanoes © The Atlantic October 2, 2018 earthquake damage in Palu, Indonesia  2. Energy From the Sun Heating of the Earth’s surface by the sun causes atmosphere and ocean circulation – Makes winds and evaporates water – Gives us our climate This produces violent storms (hurricanes, tornados, hail, etc.), droughts, floods, soil and coastal erosion  Damage in Dawson Springs, Kentucky from tornado December 11, 2021 © wdrb,com 3. Gravitational Attraction of the Earth Leads to mass wasting processes where materials move downslope (avalanches, landslides, mudslides, etc.) The Earth attracts objects from space (asteroid and meteorite impacts)  Recent slide on the Lougheed Highway near Agassiz, BC © Vancouver Sun  Terminology Used Many terms are used with hazards and disasters Important to understand what they mean and their limitations or ambiguity The following are examples of terms often used together, or that may be confused  Cause vs Trigger Both used to describe what makes a hazard occur, but differ in time frame Cause: long term buildup of conditions that create a hazard Trigger: short term event that initiates the action of the hazard Unfortunately, in common usage, both are lumped together as “cause” e.g. landslides, avalanches, slip on ice  Correlation vs Causation Correlation is a statistical term used to describe the degree to which two variables move in coordination with each other – Positive correlation means variables move in the same direction – Negative correlation means variables move in opposite directions – In practical terms, correlation means two things occur at the same time, without one being caused by the other  Correlation vs Causation Causation means that a direct cause and effect relationship has been established between two variables, so that a change in the first variable produces a change in the second variable  Correlation Possible? Canada has been plagued in the past few years by fires and floods Some blame climate warming as the cause Is there a correlation between these or a causation, or both?  Natural vs Anthropogenic Natural: Systems or actions that humans have no direct action or consequence on “Nature is responsible” Anthropogenic: Systems or actions that humans have a direct action or consequence on “People are responsible”  Natural vs Anthropogenic The division is not always clear; sometimes there are both natural and human causes or influences – Happens where natural processes or conditions can also be produced or enhanced by people – e.g. climate change caused by humans adding CO2 to atmosphere forces hazards – e.g. mining activity at Frank, AB produced rockslide that may have happened anyways  Hazard vs Risk Hazard: The potential to cause harm Risk: The likelihood of harm taking place (probability is known) Standing near the edge of a cliff is a hazard; the closer you get to the edge, the higher the risk becomes  Risk vs Uncertainty Risk: In decision-making situations where all potential outcomes and their likelihood of occurrence are known to the decision-maker Uncertainty: In decision-making situations where either the outcomes and/or their probabilities of occurrences are unknown to the decision-maker  Risk vs Uncertainty Living in Vancouver, BC there is a risk of earthquakes, but the probability of one happening at a given time is an uncertainty  Risk vs Impact Risk: An event that may or may not happen (probability is known) Impact: What will happen if the risk occurs Living in Vancouver, BC you know the risk of an earthquake, but the impact of it depends on your specific location and the buildings, landscape, etc.  Risk vs Vulnerability Risk: An event that may or may not happen (probability is known) Risk is independent of vulnerability Vulnerability: A weakness in a system that has no context to the impact involved This rarely happens for people, because injury and damage result from impact; vulnerability isn’t really associated with a natural risk Vulnerability vs Susceptibility Vulnerability: A weakness in a system that has no context to the impact involved Susceptibility: Something is likely to happen Susceptibility is likely to happen to people because it results from a risk, but vulnerability is not  Disaster vs Catastrophe Both refer to events that cause serious injury or death and property damage in a specific geographic area over a limited time Distinction between the two is often vague and somewhat arbitrary, but catastrophe is assumed to be a much larger event with bigger consequences  Disaster vs Catastrophe Some say disaster is limited in area and to direct consequences; catastrophe occurs on a larger scale and has direct plus indirect consequences, so is very expensive to remediate – This is not used by everyone  Magnitude and Frequency Most people’s concern with natural hazards and disasters is how big, and how often Whether we realize it or not, the impact of an event is partly a function of the magnitude (the amount of energy released) and of the frequency (how often a similar event happens)  Magnitude and Frequency We know that larger events happen less often, and smaller events happen more often This is known as the magnitude- frequency relation given by the equation: M = Fe-x Where: M is magnitude, F is frequency, e is the base of natural logarithms and x is a constant that is different for each event or event type  Magnitude and Frequency Magnitude and frequency may be related in ways people don’t expect For earthquakes, high frequency gives low magnitude – Energy is released with each quake so magnitude is low – Few quakes (frequency low) means magnitude is high (energy is stored)  Magnitude and Frequency In the past, geologists debated the importance of large, rare events shaping the Earth (catastrophism) vs the importance of many small events that happen often (uniformitarianism)  Magnitude and Frequency The size and frequency of many physical processes are inversely related. This is shown here with the peak flow (size) of Fraser River floods plotted against average return periods (frequency). After Keller et al., 2012 Natural Hazards.  Reactive Response Recovery Reactive response is a recovery attempt. Can we recover from a natural disaster? It depends on what type of disaster it is, and this depends on the magnitude and frequency of similar events Disaster effects are direct and indirect Direct effects include: deaths, injuries, displacement of people and property damage (usually around time of event) Reactive Response-Recovery Indirect effects include: crop failure, starvation, emotional distress, loss of employment, loss of tax revenues from property losses and higher taxes to pay for recovery (usually after the event) The importance of direct and indirect effects may not be obvious – e.g. the most significant effects from volcanic eruptions are indirect (crop failure and starvation, not lava or explosions)  Reactive Response Recovery Stages of recovery from a disaster are: Emergency work, restoration of services and communication, and reconstruction (in order) As seen with the June 2013 flood in Calgary, reconstruction can take considerable time as there may not be enough resources to do it Subsequent events may also damage already weakened infrastructure before it has been repaired, so reconstruction may be more costly and time-consuming than originally thought  1 yr 5 yr 10 yr Generalized model of disaster recovery. The first 2 weeks are the emergency- normal work stops or changes. In restoration phase (several months), normal work returns but not at full capacity. Finally, during reconstruction material is replaced, major new construction is completed, and life returns to normal. After Keller et al., 2012 Natural Hazards.  Potential Natural Hazards The following section lists hazards by type and then specific hazards within each type Potential Natural Hazards By type: Atmospheric Seismic Geologic Hydrologic Volcanic Wildfire Astronomic Climate Change  Atmospheric Hazards Hailstorms Ice storms/freezing rain Hurricanes and typhoons Tornadoes Tropical storms  Seismic Hazards Fault ruptures, ground shaking, lateral spreading Liquefaction Tsunamis Seiches Earthquakes Icequakes Loss of groundwater  Geologic Hazards Debris avalanches Expanding soils Landslides Rock falls Submarine slides Subsidence/sinkholes Mineral hazards: radon gas; mercury; asbestos  Geologic Hazards Contaminated groundwater from landfill Mine related accidents Failure of ice-dammed glacial lakes and jökulhlaups – Glacial lake outburst floods (GLOF)  Hydrologic Hazards Coastal flooding Desertification (natural + human cause) Drought Salinization Erosion and deposition (sedimentation) River flooding Storm surges Rogue waves  Volcanic Hazards Tephra (ash, cinders, lapilli) Gases Lava flows Mudflows Projectiles and lateral blasts Pyroclastic flows Acid rain and acidified water Starvation  Wildfire Hazards Brush Forest Grass Savannah  Astronomic Hazards Bolide impact  Climate Change Hazards Drought Floods Hurricane and tornado strengths increase Storm surges increase Forest fires increase?  Hazards by Season Hazards vary in when they occur by time, by latitude and by hemisphere Northern hemi and southern hemi are reversed; when we have winter, S hemi has summer Latitude shifts hazards- often start in lower latitudes and move to higher latitudes  Hazards by Season Wildfires: May-October – 2023 started in March, and 10X more severe than past years Floods: any time, but most common in late spring/early summer Avalanches: November-May, with most in December-March Hurricanes: Atlantic- June 1 to November 30  Hazards by Season Tropical Cyclones: Atlantic- August- September Tornadoes: April-September; worst winds June-July Landslides: November-March, or with heavy rain (El Niño years) – Seem to occur very often in November and March-April  Next Lecture Climate Forcing of Hazards