Exam 1 (Pearson and Notes) Flashcards
Hazardous event that occurs over a limited time in a defined area.
Disaster
What are the 4 requirements for a hazard to become a disaster?
- There must be more than 10 people killed
- 100 or more people affected
- The area must be in a state of emergency
- The area must require international assistance.
Massive disaster
Catastrophe
Modern Homo sapiens rose about _________ years ago, having only a few thousand people.
200,000
There was a flat population curve until about _________ years ago. This also included the domestication of plants and animals, and the growth rate was 0.036% a year.
8,000
________ years ago, there were 200 million people. They had shelter, food, water supplies, and the growth rate was 0.056% a year.
2,000
By ________, the population had grown to 800 million. They were public health principles, and the causes of diseases were recognized.
1750
The worlds population grows about ____ million people a year.
80
Mortality (death) rate subtracted by fertility (birth) rate
Growth rate
The theory that mortality and fertility rates decline from high to low levels because of economic and social development.
Demographic transition theory
The risk of mega killer ________ increases with population and increased organization.
Earthquakes
Per capita income and percent of disasters conclude that storms are more frequent than other disasters in ________ income areas.
High
Per capita income and percent of disasters conclude that floods are more frequent than other disasters in ________ income areas.
Medium/Low
More economic loss and less death is associated with ________ developed economies.
Highly
More deaths in ________ income areas.
Low
Only a little more death than economic loss is seen in ________ income areas.
Medium
What are the five truths about natural processes as hazards?
- Science helps us predict hazards.
- Knowing hazard risks can help people make decisions.
- Linkages exist between natural hazards.
- Humans can turn disastrous events into catastrophes.
- Consequences of hazards can be minimized.
Are there benefits to hazards? Name some.
Yes; volcanoes create new land, flooding provides nutrients for soil, and landslides form dams or create lakes
Type of plate tectonic: coming together.
Convergent
Type of plate tectonic: growing apart.
Divergent
Type of plate tectonic: sliding past.
Transform
California straddles the boundary between two tectonic plates. Name them.
San Andreas Fault: North American Plate and Pacific Plate
What are the four main layers of the earth in order from most inner to most outer?
Inner core, outer core, mantle, and crust
Solid layer of earth that is 1300 km, has a high temperature and pressure
Inner core
Liquid layer of earth, 200 km thick
Outer core
Solid layer of Earth rich in silicon rocks, up to 35 km
Crust
Solid layer of earth, 3000 km thick, rich in iron and magnesium rocks
Mantle
Solid, strong, brittle, and cold layer of Earth
Lithosphere
Solid, hot, flowing, and plastic layer of Earth
Asthenosphere
What are the differences between the continents and the oceans? Compare their densities, thickness, and age.
Oceans are more dense than continents. Continents have varying thicknesses (1-35 km), while oceans have relatively similar thickness (6-7 km thick). Oceans are 200 million yeas old, but continents are 4 billion years old.
Discrete pieces of lithosphere
Tectonic plates
Melted rock within the earth
Magma
Melted rock on the earths surface
Lava
This person noted parallel lives of Atlantic coast lines of Africa and South America in 1620.
Francis Bacon
This person suggested a supercontinent in the late 1800s.
Edvard Suess
This person came up with the theory of continental drift.
Alfred Wagner
The theory that all of the continents had once been a supercontinent called Pangaea, but had drifted apart.
Theory of Continental Drift
Why was the theory of continental drift rejected?
The mechanism for the movement of the continents could not be visualized.
These two people produced maps of the ocean floor between 1957 and 1977.
Marie Tharp and Bruce Hezzen
At mid-ocean ridges, new crust is added to the edges of lithospheric plate. The crust is destroyed along with other plate edges.
Seafloor spreading
True or false: continents are carried along plates.
True
Sinking plates generate ________ and ________.
Volcanoes; earthquakes
How are volcanic arcs formed?
Sinking ocean plates, which are wet and cold, come in contact with the hot asthenosphere. The plates melt to generate magma, and magma rises to produce volcanoes.
________ occur along the path of the descending plate.
Earthquakes
Region where there is melted rock, and plates move over them
Hot spots
List the plate tectonic types based on smallest to largest produced earthquakes.
Divergent (smallest), Transform, Ocean Continental Convergent (largest)
_____ million years ago, Pangaea broke apart.
180
What are the two possible driving mechanisms for plate tectonics?
Ridge push and slab pull
Gravitational push away from crest of mid ocean ridges
Ridge push
When cool, dense ocean plates sink into hotter, less dense asthenosphere
Slab pull
Earthquakes occur along faults where:
There is a weakness in Earth’s crust, or places where rocks are broken and displaced.
The block below the fault plane (where miner would stand)
Footwall
The block above the fault plane (hang a lantern here)
Hanging Wall
Process of fault rupture
Faulting
Force that results from plate tectonic movements, including tensional, compressional, and shearing.
Stress
Causing changing shape or location
Strain
What are the three main types of faults?
Normal, reverse, and strike-slip
A fault with tensional stress, hanging wall down, and vertical motion
Normal Fault
A fault with compressional stress, hanging wall up, vertical motion
Reverse Fault
A fault with shearing stress, horizontal motion
Strike-slip
Which of the two main types of files are considered dip-slip faults?
Normal and Reverse Faults
What are the stages in the earthquake cycle?
- Long period of inactivity
- Accumulated elastic strain
- Foreshocks
- Mainshock
Type of earthquake that occurs hours or days before a large earthquake, and may not necessarily occur with major earthquake.
Foreshocks
Major earthquake that includes aftershocks that can continue to occur from minutes to a year later.
Mainshock
The center of an earthquake, within the earth
Hypocenter
The center of an earthquake, located on the surface above the rupture
Epicenter
Point of initial breaking or rupturing (earthquake)
Focus
The ________ of an earthquake causes seismic waves.
Focus
Caused by a release of energy from rupture of a fault
Seismic waves
Waves including compressional and fast primary waves, and sheer, slow secondary waves
Body Waves
Waves that move along earth’s surface contributing to shaking felt and damage, even slower than secondary waves.
Surface Waves
Gradual movement such that earthquakes are not felt. Produces slow earthquakes, and can occur for days to months
Tectonic Creep
Shaking experience of an earthquake depends on:
- Earthquake magnitude
- Location in relation to epicenter and direction of rupture
- Local soil and rock conditions
Magnitude estimator recorded with seismograph (S wave ground shaking)
Richter Scale
Depends on where and specific to only one location
Local Magnitude
Absolute size of earthquake and measurement of actual energy released
Moment magnitude scale
Both Local Magnitude and Moment Magnitude Scale are ________ and used in ________.
Logarithmic; tandem
What is the difference between the Richter scale and then moment magnitude scale?
Richter: immediate. Moment: days to months.
Scale 1 to 12 based on damage to structures and people’s perceptions
Modified Mercalli Scale
Show where the damage is most severe
Modified Mercalli Intensity Map
________ ________ use high-quality seismograph data to show areas of intense shaking.
Shake Maps
The ________ of the focus influences the amount of shaking.
Depth
____ waves occur first.
P
How many stations do you need to find the exact epicenter?
3
The method of using 3 stations to find the epicenter.
Triangulation
________ waves move fast through consolidated bedrock. (Move slowest through unconsolidated bedrock with water.)
Seismic
Earthquakes that occur within plates
Intraplate Earthquakes
Has the biggest potential magnitude
Reelfoot Rift in New Madrid
Name two types of failed rifts.
Genevieve fault zone and Wabosh Valley fault zone
Some ancient ruins separated the landmass in Pangaea. This caused the formation of the ________ Ocean.
Atlantic
Name the primary effects of earthquakes.
Ground shaking and surface rupture
Name the secondary effects of earthquakes.
Liquefaction, landslides, fire, tsunamis, and disease.
What are some potential natural service functions of earthquakes?
Underground flow of groundwater and energy resources, mineral resources that can develop as veins in the fault systems, landform development, and future earthquake hazard reduction.
How earthquakes caused by human activity?
Loading Earth’s crust by building a dam and reservoir, injecting liquid deep into the ground through disposal wells or fracking, or creating underground nuclear explosions.
How can you minimize the earthquake hazard?
Forecasting and warning, location of houses, and consider seismic safety measures.
What are some short-term predictions for earthquakes?
Patterns and frequency of earthquakes, deformation of ground surface (foreshocks), seismic gaps along faults (areas that have not seen recent quakes), and geophysical and geochemical changes (gas and groundwater levels).
What are the five fundamental concepts?
- Science helps us predict hazards.
- Knowing hazard risks can help people make decisions.
- Linkages exist between natural hazards.
- Humans can turn disastrous events into catastrophes.
- Consequences of hazards can be minimized.
How can earthquakes cause a tsunami?
Seafloor movement or triggering a landslide
How does a tsunami created by a earthquake form?
- The earthquake uplifts or downshifts the seafloor.
- The tsunami moves rapidly in deep ocean (up to 450 mph).
- It nears land, loses speed, and gains height.
- It moves inland, destroying everything in its path, runup (furthest horizontal and vertical distance of the largest wave).
Tsunamis that can travel long distances with little loss of energy.
Distant
Tsunamis that travel toward land very quickly.
Local
Type of landslide that occurs when landslides happen underwater, causing tsunamis.
Submarine landslides
True or false: All oceans and some lake shorelines have some tsunami risk.
True
What are the primary effects of tsunamis?
Inundation of water and resulting flooding and erosion
What are the secondary effects of tsunamis?
Fire, contaminated water, and disease.
What natural services do tsunamis provide?
May bring nutrients and sediments needed by soil. Also may bring sediment needed to build shoreline.
Does human activity affect frequency or magnitude of tsunamis?
No
How can we minimize tsunami hazards?
Detection/warning, structural control, tsunami runup maps, and land use.
A type of structural control against tsunamis to prevent the tsunami from moving inland.
Seawalls
True or false: Seawalls help prevent tsunamis from reaching areas that it guards.
False - seawalls bring false sense of security
How can land use potentially help prevent or lessen tsunami damage?
Natural vegetation may provide defense (partial protection)
Fragments ejected from volcanoes
Pyroclastic
True or false: Volcanoes, earthquakes, landslides, and flooding can result in/ be resulted from each other.
True
The location of 2/3 of active volcanoes
The Ring of Fire
What are the three types of magma generating processes?
Decompression melting, addition of volatiles, and addition of heat
When attempting to form magma, which process relieves pressure from hot rocks?
Decompression melting
When attempting to form magma, which process uses chemical compounds to lower the melting temperature in subduction zones (this is also responsible for the creation of the Ring of Fire)?
Addition of volatiles
When attempting to form magma, which process induces melting if temperature exceeds melting temperature in continental hotspots?
Addition of heat
What are the three types of magma? List them in order of lowest to highest.
Basaltic, andesitic, and rhyolitic
How are magma properties explained?
Silica content and amount of dissolved gases
When the silica content is raised (basalt to andesite and or andesite to rhyolitic), what other aspects raise?
Viscosity, volatile, and explosivity
When the silica content is raised (basalt to andesite and or andesite to rhyolitic), what aspect lowers?
Temperature
Impacts how explosive eruption will be
Volatile content
Volcano types very greatly. What aspects create different types of volcanoes?
Size, shape, composition, number of eruptions, how/where magma forms, and volatile content.
What are the two primary control of eruption explosiveness?
Viscosity and volatile content
How does the Volcanic Explosivity Index (VEI) rank volcanoes?
0-shield (not that explosive)
4-stratovolcano
8-continental hotspot (very explosive)
Volcanoes with conical shapes, can be extremely explosive, mixture of explosive activity and lava flows, and common in the Ring of Fire
Stratovolcanoes
Small dome with steep sides, made from highly viscous magma, common in the a Ring of Fire
Lava Domes
Largest volcanoes in the world, associated with basaltic magma, common at hotspots in the oceanic lithosphere and divergent plate boundaries, continental rifts
Shield volcanoes
When magma heats ground or surface water to the point of flash vaporization
Phreatic eruption
Cone-shaped volcano with summit crater (accumulation of tephra). Common on larger volcanoes, normal faults, or along cracks and fissures.
Cinder cones
Large summit depression caused by collapse of land surface or volcanic edifice
Continental caldera
About ____ volcanoes erupt a year worldwide.
50
There are about ___ to ___ volcanic eruptions in the U.S.
2; 3
What are the primary effects of volcanoes?
Lava flows, ash fall, pyroclastic flows, lateral blasts, and release of volcanic gases
What are the secondary effects of volcanoes?
Debris flows, mudflows, landslides, debris avalanches, floods, fires, and tsunamis
Also global cooling of atmosphere in a large eruption
When magma reaches the surface through a crater or from a vent
Lava flows
A natural process or event that is a potential threat to human life and property
Hazards
Explosive volcanism that blasts magma and rocks from a vent
Pyroclastic Activity
________ is the most abundant type of magma.
Basaltic lava
Basaltic lavas are the most rapid at ___ to ___ km/h (or ___-___ mph)
15-35 km/h; 10-30 mph
Pyroclastic debris
Tephra
Accumulation of pyroclastic debris
Pyroclastic deposit
The vertical collection of debris shot straight up out of a volcano during eruption
Eruption column
Name some poisonous gases emitted by volcanoes.
CO2, water vapor, and sulfur dioxide
Volcanic smog
Vog
Volcanic debris and mud flows
Lahars
What are lahars?
The product of loose, volcanic ash becoming saturated with water and moving down the volcano due to instability.
What are linkages with other natural hazards of volcanoes?
Fire (lava igniting plants, structures), earthquakes (accompanying or preceding), landslides (mudflows, ashflows), or climate change (gas and debris leading to global cooling)
What are some natural service functions of volcanoes?
Volcanic soil, geothermal power (energy to urban areas), mineral resources, recreation (hot springs), and creation of new land (islands)
Are there human interactions that affect the frequency or severity of volcanic eruptions?
No
How can we detect volcanic activity?
Seismic activity, thermal, magnetic, and hydrologic conditions, gas emissions, and tilting and swelling of land surface
How many eruptions does Iceland encounter?
One every 3-4 years
When did Mt. St. Helens erupt?
1980
