Natural Hazards Final Exam
How much water do you need each day, to survive? How much (if you're in the US) do you use, and where does that go? You should know the big water sink that I pointed out in class
- 5 liters for fluid replenishment - Average U.S. per capita usage: 4,455L daily - 24% toilet, 20% shower, 19% faucet
What have we observed at Mauna Loa, Hawaii?
- Atmospheric carbon dioxide - Annual cycle: growth of forests in spring/summer, release CO2 again in winter
Which event occurs more rapidly: an earth flow or a debris flow? Which has a larger average particle size?
- Debris flow moves faster than earth flow - Debris flow has a larger average particle size
How do we predict how climate will change with increased levels of greenhouse gases in the atmosphere?
- Generalized circulation models or global climate models - Break the atmosphere into grids and boxes attempting to model different green house gas concentrations
How has climate change impacted Iowa's weather, and if temperatures increase 1 degrees C, how will this impact corn yields?
- Iowa summer air holds 13% more moisture than 35 years ago and gives us 8% more precipitation since 1870's - 1 deg C increase = 15% decreased corn yields
How might climate change impact weather (hurricane intensity, atmospheric water vapor, droughts)?
- More severe weather - Dry areas get dryer, wet areas get wetter - Warmer SST = more powerful hurricanes - Increased severity and duration of droughts
What are the different faunal changes associated and anticipated (and in many cases, already observed) as a result of climate change?
- Ocean acidification - Coral bleaching - Shifts in ranges of species (grolar/prizzly bears) - Extinction of less-resistant species (golden toads) - Extinction of species at the poles
What kind of a reaction occurs during a fire? You should know both that this is an example of oxidation (and therefore requires oxygen) and also that it is exothermic.
- Oxidation (requires oxygen) - Exothermic (reaction process that releases heat) - Rapid, high temperature oxidation (combustion) - Combustion (process of burning something) results in fast break down of organic material MOST IMPORTANT
Generally, what signs might we see that could indicate that a slope could be likely to fail ("Predicting slope failure")?
- Past failures - Steep slopes - Changes in slope - Potential triggers (rainfall, earthquakes, volcanic events)
What has the United States done, in terms of how we have treated wildfires over the years? How has this impacted fuel availability, as well as the likelihood of fires becoming crown fires?
- Policy of fire supression has led to more intense fires due to small bushes (fuel for fires) - Crown fires more likely (fires that climb trees and go tree top to tree top)
Be able to recognize examples of negative and positive feedback cycles
- Positive feedback cycles amplify warming and cooling trends - Negative feedback cycles provide checks and balances on warming and cooling Positive example: CO2 increases the growth of forests Negative example: When ice caps grow, albedo increases
How does a rock slide differ from a rock fall?
- Rock fall: The rock falls - Rock slide: Rock slab detaches and slides along surface, fast but slower than a rock fall
Know our different kinds of slope failure as well as how they are defined
- Rock falls: free falling rocks - Rock slides: rocks slide against defined plate - Creep: gradual, related to freeze-thaw - Flows: material behaves as a fluid, including earth flows, debris flows, avalanches - Landslides: material slides along defined plane 3 Factors for classifying mass wasting 1. How material moves (falls vs. flow vs. creeps vs. slides) 2. Type of material (solid vs. unconsolidated) 3. Rate of movement (fast = flows & slides, slow = creep)
Know the processes that can trigger slope failure (we mentioned several)
- Seismic events (earthquakes) - Volcanic events (can trigger lahars) - Heavy rainfall - Snowmelt - Undercutting
What are the major greenhouse gases present in the atmosphere?
- Water vapor - CO2 (carbon dioxide) - CH4 (methane) - NO2 (nitrous oxide) - Fluorinated gases
How much has climate warmed since the 1880s, globally?
0.85 degrees since 1880
Know the different global climate drivers
1. Changes in incoming solar insulation - Early sun 30% less luminous 2. Configurations of continents - used to be connected; Great passage 3. Changes in albedo - Albedo: ability to reflect (higher albedo = more reflective, so more energy sent back to space) - Soil: 0.17 - Forest: 0.09-0.15 - Ice: 0.45 - Green Grass: 0.25 - Fresh snow: 0.8-0.9 4. Changes in atmospheric composition (reservoirs) - Water vapor, CO2, CH4, NO2, Fluorinated gases - Greenhouse gases are trapped in the atmosphere 5. Milankovich cycles - Earth's orbit around Sun
How do fires transfer energy? Be able to match terms and definitions here
1. Conduction: Heat passes through materials (drives off moisture) 2. Convection: Heated air and gases rise (pulls in air at lower levels) 3. Radiation: Radiated heat through space
What kinds of weather patterns and conditions make an area likely to have a severe wildfire? This explanation should include general trends between having a wet vs. dry climate as well as topography and winds.
1. Fuel: Fire supression (fuel buildup) 2. Topography - Southfacing slopes are warm and dry, lower moisture content favors combustion - Mountainous areas, wind moves upslope - Fires on steep slopes preheat fuel upslope 3. Weather - Dominant influence on wildfires (large fires common after droughts) - Winds influence spread, intensity and form of wildfire
How can we prevent mass wasting? You should know how the different processes work, and how they relate to things like slope cohesion, water content, and angle of repose
1. Hazard mapping and zoning restrictions 2. Revegetation (Holds slopes together by adding new soil) 3. Regarding: Stabilizing slopes (get closer to angle of repose) 4. Reinforcement (rock bolts, rock nets) 5. Improved drainage
What 3 factors are used to classify mass wasting events?
1. How material moves (falls vs. flow vs. creeps vs. slides) 2. Type of material (solid vs. unconsolidated) 3. Rate of movement (fast = flows & slides, slow = creep)
Know the different local climate drivers
1. Latitude (incoming solar radiation) - Latitude determines incoming solar insulation 2. Proximity to large bodies of water - Stabilize climates - Warm currents can heat high latitudes 3. Elevation - Higher the elevation, the more air loses heat (air is not a good conductor) - Higher altitudes: Particles are farther apart 4. Topography - Windward: gets precipitation (where winds come off of water) - Leeward: Where cold, dry air descends (where deserts form)
What are the three legs of the fire triangle?
1. Oxygen: Needs >16% oxygen to sustain combustion 2. Heat: Temperature must be high enough to cause combustion 3. Fuel: Combustible substance
You should be able to match the three phases of a wildfire to their descriptions/definitions.
1. Preignition: Fuel is brought to a temp & water content favoring ignition - Preheating: Fuel loses water - Compounds Pyrolysis: Processes that chemically degrade fuel 2. Combustion: Preignition absorbs energy, then we get ignition and combustion - In combustion phase, exothermic reactions release energy as heat and light - Drive preignition of surrounding materials 3. Extinction: Combustion, including smoldering, ceases
What percentage of the global energy budget does the US use annually? What percentage of the world's population lives within the US?
20% of the global energy budget, 5% of the world's population lives within the US
How did climate change impact Iowa's economy in 2011 and 2012?
2011: Flood on Missouri caused $85 million in direct damages 2012: Drought closed locks on the Mississippi, barges ran aground ($275 million)
What two factors contribute to sea level rise, and how much is sea level anticipated to rise (worst case scenario) by 2100?
25-50% thermal expansion, melting glaciers - Approximately 72 inch. rise in sea level
What percentage of the Forest Service budget goes towards fighting fires?
50%
What percent of greenhouse gas emissions are absorbed by oceans and forests each year?
55% absorbed by oceans and forests
How much do mass wasting events cost us each year?
> $1 billion in damages
Does any place in the US experience water scarcity?
American Southwest
Why don't we call prescribed burns controlled burns anymore, like we used to?
Because they are not always controlled - Prescribed burns: Controlled and confined fires set to reduce fuel and improve habitat/forest health
What is a life cycle assessment?
Birth to death costs of different items
What engineering mistake made the Vaiont Dam landslide in 1963 more likely (what factor in terms of the surrounding slopes did engineers know about, but think that they could control)?
Block of limestone slid into the reservoir creating a wave that went over the wall (engineers knew about this) Purpose: Hydroelectric power
What does it mean to be a poikilotherm?
Body temperature & size is dependent on ambient temperature (cold blooded)
What do hotshot fire fighters do, as part of their job (what are they building on the ground)?
Build fire breaks (obstacles to the spread of fire) on the ground
What can we directly measure in ice cores?
CO2 and methane concentration in ice - Oxygen isotope: Temperature when snow fell
What is the deadliest wildfire in California state history?
Camp Fire - 42 civilian fatalities - 6,453 residence destroyed - 5,319 personel involved
What is a carrying capacity (concept) and an ecological footprint?
Carrying capacity: The number of people, other living organisms, or crops that a region can support without environmental degradation Ecological footprint: Measures human consumption in terms of the biologically productive land needed to provide the resources and absorb the wastes of the average global citizen
What is "enteric fermentation" and what percent of methane does it contribute to the United State's annual emissions?
Cow farts, 25% of methane emissions
What is sustainability, broadly defined?
Development which meets the needs of the present without compromising the ability of future generations to meet their own needs
What is a mass wasting event (definition)?
Downward movement of material (rocks, soil, etc.) under influence of gravity - Can be slow, fast, catastrophic
Know how driving forces vs. resisting forces are related to slope failure. Also, know the main driving and resisting forces.
Driving force = Gravity Resisting force = Friction & cohesion - If gravity (driving force) is greater than friction/cohesion (resisting force) then slope moves
How does physical water scarcity differ from economic water scarcity, and how many people experience each of these conditions?
Economic scarcity is due to poverty 1.2 billion people live in areas of physical water scarcity 1.6 billion people live in areas of economic water scarcity
Be able to recognize the three different ways that we classify fires. Which is the most difficult type of fire to stop?
Fires classified according to layer of fuel allowing fire to spread: 1. Ground fires: Subsurface (burn organics in soil, mostly smouldering combustion) 2. Surface fires: Above ground (burn grass, shrubs, can move rapidly) 3. Crown fires: Burning in crowns of trees - Flaming combustion carried through canopies - Generated by strong winds & steep slopes - Hardest to stop
Is material more rapidly oxidized during flaming combustion or smouldering combustion?
Flaming combustion - Flaming combustion: Rapid oxidation processes, pyrolysis of wood materials - Smouldering combustion: Carbon & ash blanket new fuel inhibiting flames (charcoal glows)
What process is creep related to, and how might you recognize a hillside that was experiencing this phenomenon?
Freeze-thaw cycles, hillsides with fences/trees tilting downward have creep (drunken trees)
You should be familiar with the "good" and the "bad" of wildfires
Good - Some plants need fire for seeds - Increases soil nutrients - Successional communities - Bad for ticks Bad - Property destruction - Increased landslide risk (devegetation) - Increased flood risk (hydrophobic soil layers) - Release of soot/ash into the atmosphere
What is crossdating?
How we get exact years
What (or whom) is driving climate change?
Human activity is the primary cause for the warming - Changes occur in synchrony w/ human industrialization and population growth
With the higher emissions scenario, how much warmer will Iowa be by 2100? You should know the degrees F value for the worst case scenario
Iowa will be 10 deg F warmer
What is the distinguishing characteristic of a flow? What are the differences between earthflows, debris flows, and avalanches?
Material moves and behaves like a liquid - Earthflows: Fine grained, water supported (can outrun) - Debris Flows: <50% fine grained material, moves fast, water supported - Avalanches: Air supported can be snow/rocks, moves fast All three flow like liquids
What is the defining characteristic of a slide?
Material moves as a cohesive (whole) along a defined plane, it stays together
Is a high albedo surface more or less reflective than a low albedo surface?
More reflective
How has the length of the fire season changed over the past several decades?
On average 78 days longer than they were in 1970
What is the deadliest landslide in US history, excluding landslides related to volcanic events, earthquakes and dam failures? Why did this event occur (what set the stage for this slide), and was there any preceding indicators that this event might be likely to occur?
Oso (steelhead) landslide - Weekly consolidated sediments, soil saturation from heavy rainfall + groundwater influx - Many landslides occurred here in the past
How does carbon dioxide correlate with temperature (or not correlate with temperature) in ice core records?
Positive correlation, but not perfectly matched up
What occurs during pyrolysis, and which phase of a wildfire does it happen during?
Processes that chemically degrade fuel (Occurs in ignition phase)
Be able to distinguish between renewable and non-renewable resources
Renewable: Replenished or regenerated on a human time scale (wood, solar, biomass, etc) Non-renewable: Will only be replenished on a geological time scale such as fossil fuels - Fossil fuels: Organic matter trapped in sedimentary rocks "low-cost dense energy source)
From the standpoint of greenhouse gases, what does the process of combustion do?
Sets our trapped organic material free
What are some observations that you might make that would indicate that creep is occurring?
Slow, continuous movement of material down slope
What do scientists predict will happen to snake size as a result of a warming climate?
Snakes will get bigger
How does the greenhouse effect work, and how does this relate to greenhouse gases?
Some infared radiation passes through the atmosphere but most is absorbed and re-emitted by green house gases (warms the Earth's surface)
How does water content impact sediment cohesion? How does this change as we go from adding a little to a lot of water, starting with totally dry material?
Some water increases cohesion (surface tension holds grain together) Too much water pushes grains apart (loss of frictional contact)
What areas of the globe are heating most rapidly, and how does this relate to sea level rise?
The poles are heating up most rapidly (sea levels rise)
What is dendrochronology, and what do we use it to learn about? What do we need (at a regional scale) for this to work?
The science that uses tree rings dated to their exact year of formation to analyze climate - Need seasonal variation
What is the angle of repose? How does grain size, grain shape and water content impact angle of repose?
The steepest angle at which a sloping surface formed of a particular loose material is stable Factors: 1. Grain size: (finer/small = shallower slope) - Fine sand = 35 deg - Coarse sand = 40 deg - Angular pebbles = 45 deg 2. Angularity of grains (more angular = steeper slope) 3. Water content
What do packrats build, and what kinds of information can we get from studying these deposits?
They build midden (cluster of anything cemented by their urine, amberat) 1. Changes in animal species abundance 2. Changes in plant communities (reflects climate)
How does climate differ from weather?
Time - Weather: minutes to months changes - Climate: Long term pattern
Approximately how much of the world's total energy budget is used by the US, every year?
U.S. Total: 28.5 trillion kwh/year (97 quads) World Total: 511 quads
What are Milankovitch cycles? You should know the names of the three different cycles
Variations of the Earth's orbit/tilt to sun that caused variations in weather throughout time 1. Eccentricity (path of orbit) - Earth encounters more variation in the energy that it receives when Earth's orbit is elongated 2. Tilt (angle) - The greater the tilt angle, the more solar energy the poles receive 3. Precession (wobble) - Gradual change in the Earth's axis affects the Earth's tilt and eccentricity
What is an avalanche?
Very fast downhill movement of soil, snow, or rock usually in mountainous or volcanic regions (speed results from high air contents & steep slopes)
What percentage of the global oceans have we impacted? What percentage of fisheries stocks are collapsed or overexploited?
We have impacted 100% of oceans 58% fishery stocks collapsed or overexploited
Why do we observe ocean acidification?
We observe it because it shows climate change - Ocean acidification: when the ocean absorbs CO2, pH is lowered
How long has it taken us to increase in population size from 1 billion people to where we are now, at approximately 7.7 billion?
We reached 1 billion in 1804, so about 215 years
What is the Anthropocene?
We're the first species that's become a planet-scale influence and is aware of that
Over the past several decades, how have wildfires in the United States changed in terms of both intensity and size?
Wildfires are increasing in size and intensity
If you do the math, can 10% of the population choosing to live more sustainably in a few areas actually make a measurable difference
Yes
Are we at risk for mass wasting anywhere in Iowa?
Yes, but it's rare
