Introduction to Environmental Geology
Dec 24, 2015
Introduction to Environmental Geology
What is Environmental Geology? the application of geological data and
information for people's needs and the improvement of our environment How to avoid/minimize impacts from
geologic hazards How to find and use resources wisely:
water, minerals, etc. How to dispose of waste wisely: solid,
water, etc.
Fundamental Concepts of Environmental Geology
• Population growth• Sustainability• The earth system• Uniformitarianism• Hazardous earth
processes
• Geology as a basic environmental science
Fundamental Concepts-Population Growth
• Population Growth is the #1 environmental problem
• Why?• www.prb.org
Fundamental Concepts-Population Growth
• It is impossible to support exponential population growth with a finite resource base
1) Primary goal of environmental work is to defuse the population bomb1) Pessimistic: the earth will take care of itself through
disease and catastrophes2) Optimistic: find better ways to control population
growth within the limits of our available resources
Fundamental Concepts-Sustainability
• Sustainability is the environmental objective We are currently using most living environmental
resources faster than they can be naturally replenished What would we need for a sustainable global
economy?• Populations of humans in natural harmony with air, water,
and land• Energy policies that do not pollute or cause climatic
perturbations• Utilization plans for renewable resources (Recycling)• Utilization plans for nonrenewable resources
Fundamental Concepts-The earth system The earth system
• Understanding the earth’s systems and their changes is critical to solving environmental problems.
• The earth itself is an open system with respect to energy a closed system with respect to material
How do we predict the consequences of earth system changes?
Understand the nature of the system
Understand rates of changeConduct input-output analysis
Fundamental Concepts-The earth system
• Feedback• A system response where: System
output (something happening) is a new system input
• Positive and negative feedback
• Input-output analysis
Fundamental Concepts-The earth system
1. Positive feedback-- "vicious cycle"a. one action intensifies the next (example: erosion)
2. Negative feedback-- "self-regulating" enables the system to reach a steady state or equilibrium (example: stream morphology).
3. Threshold events -- No apparent changes until threshold levels are reached (Lake Turnover).
Fundamental Concepts-The earth system
Negative Feedback Stream
A. Increase gradient B. Increases the river's velocity, which C. Increases the rate of erosion, which D. Widens and deepens channel, which E. Slows rivers velocity F. promotes deposition G. reduces gradient
Fundamental Concepts-The earth systemExample of threshold event
Lake turnover
Fundamental Concepts-The earth system
Input-output analysesInput = output
Steady state: no net change
Input < outputInput > output
Fundamental Concepts- Uniformitarianism James Hutton, 1785
“the present is the key to the past”
Geologic processes modifying our landscape have operated in the past
Human activity is a new geological force Affects the magnitude and frequency of geologic
processes “the present is the key to the future”
Fundamental Concepts-Hazardous Earth Processes
Some geologic hazards are inevitable Planning is important The impacts of hazardous earth processes
are enhanced by spatial concentration of population and resources
Should be considered in cost-benefit analysis
Fundamental Concepts-Geology as a basic environmental science
Geology is a factor in every person’s life:
“Civilization exists by geological consent…subject to change without notice”--Will Durant
Fundamental Concepts-Geology as a basic environmental science
Branches of Environmental Geology: Geomorphology (Geologic Landforms and
Processes) Hydrogeology (Water and soil / rock interactions) Pedology (Soils) Economic geology Engineering geology Classical geology
Fundamental Concepts-Geology as a basic environmental science
Environmental problems are interdisciplinary Physical
Geography, geologic processes, hydrology, rock types, soil types, climate
Biological Plants, animals, biologic conditions, spatial analysis of
biologic information
Human interest/useLand use, economics, aesthetics, environmental law,
hazards, historical/archaeological value
Hazards & Risks
“To know one’s ignorance is the best part of knowledge.”
Lao Tzu, The Tau, #71
Types of hazards
• Natural
• Technological
• Mixed (natural influenced by humans)
Types of hazards
• Condition
• Process
• Event
To predict a hazardous event
1. Historical knowledge
2. Monitoring and data gathering
3. Understanding of hazardous process
4. Must have rules to determine success
Risk: how safe is safe?
What is risk?
What is acceptable risk?Depends on your VALUES
“What is our society willing to pay for our quality of life and life style?”
Paradox of risk reduction
RISK ASSESSMENT
An attempt to assess objectively a public health or other environmental risk
1. Source/release assessmentLikelihood and scale of a potential release of
hazardous material
2. Exposure assessmentWhat will reach whom
RISK ASSESSMENT
3. Dose-response assessmentTo estimate the impact of exposure on human
health
4. Risk characterizationTo collate all of the information in a useful way
Involves great UNCERTAINTY
Human response to hazards:Risk and Policy
1. Modify the hazards through human intervention
2. Redistribute the losses caused by a hazard
3. Decrease the vulnerability (Planning)
Magnitude vs. frequency
• Usually inversely related
• Affects “hazard perception”
Disaster prediction and warning
• Location
• Probability occurrence
• Forecasting
• Warning– Go public– Problems?
Catastrophe
• When a natural disaster results in damages (people or property) that require a long involved process of recovery
Model of recovery
• Phase 1: emergency
• Phase 2: restoration
• Phase 3: restoration I
• Phase 4; restoration II
Phase 1: Emergency(days)
• Normal activities stop
• Search and rescue
• Emergency shelter/feeding
• Capital damaged or destroyed
Phase 2: Restoration(weeks-months)
• Normal activities return but at minimal levels
• Restoration of urban services
• Return of refugees
• Capital patched
Phases 3 & 4: Reconstruction I & II
(months-years)• Normal activities return to predisaster levels
• Capital rebuilt (replaced)
• Activities improved and developed
• Capital improved beyond predisaster levels
• Disaster preparedness & response improved
Effects of Selected Hazards in the U.S. (as of 2002)
Hazard Deaths/yr. occurrenceinfluenced byhumans?
Catastrophicpotential
flood 86 yes H
earthquake 50+ yes H
landslide 25 yes M
volcano 1 no H
coastalerosion
0 yes L
expansivesoils
0 no L
Effects of Selected Hazards in the U.S. (Table 4.1, p. 91)
Hazard Deaths/yr. occurrenceinfluenced byhumans?
Catastrophicpotential
hurricane 55 no H
tornado 218 no H
lightning 120 ? L
drought 0 ? M
freeze 0 no L