Natural Disaster Review

Here's a Quizlet-style outline based on your notes:

I. OVERVIEW

A. Energy Sources for Disasters

Earth’s Internal Heat

a) Nuclear fission: Unstable radioactive atoms decay to form stable "daughter" atoms.

b) Rock cycle: Formation and transformation of Earth's rock materials through heat and pressure.

The Sun

a) Insolation: Incoming solar radiation, primarily visible light.

b) Atmospheric cycles: Includes convection and the hydrologic cycle, driven by insolation.

Gravity: Attraction between Earth and objects, crucial for events like landslides.

Impacts of Extraterrestrial Objects: Energy released when objects impact Earth, causing potential disasters.

B. Impacts on Society

Displacement of Population: Temporary or long-term relocation of people.

Personal Impact: Injuries, fatalities, and long-term emotional trauma.

Property Loss: Damage to homes, workplaces, and resources.

Relief Efforts: Immediate and long-term aid.

C. Randomness of Disasters

Cyclic vs. Random: Some disasters follow cycles, others are random.

Land Use Changes: Impact how floods and other events occur.

II. EARTH'S INTERNAL STRUCTURE

A. Earth’s Layers

Core:

Inner core: Solid, made of iron and nickel.

Outer core: Liquid iron and nickel.

Mantle:

Asthenosphere: Solid but movable rock.

Lithosphere: Rigid, brittle rock extending to Earth's surface.

Crust: Outer layer, composed of oceanic and continental crust.

B. Plate Tectonics

Basic Principles: Earth's lithosphere is divided into plates moving due to mantle convection.

Plate Boundaries:

a) Convergent: Plates collide (e.g., Cascade mountains).

b) Divergent: Plates move apart (e.g., Iceland).

c) Transform: Plates move laterally (e.g., California).

III. EARTHQUAKES

A. Types of Faults

Normal: Tensional stress, vertical displacement.

Reverse: Compressional stress, vertical displacement.

Strike-slip: Lateral displacement.

B. Elastic Rebound: Sudden release of energy after rocks "snap" back into place.

C. Seismic Waves

Body Waves:

a) Primary (P) Waves: Fastest, move through solids and liquids.

b) Secondary (S) Waves: Slower, only move through solids.

Surface Waves: Move slower, cause more damage.

a) Love Waves: Side-to-side motion.

b) Rayleigh Waves: Rolling motion, similar to water waves.

Seismometers: Devices that detect seismic waves.

Earthquake Classification:

a) Richter Scale: Measures earthquake magnitude.

b) Modified Mercalli Scale: Measures earthquake intensity.

D. Earthquake Hazards

Initial Quake

Aftershocks

Fire

Tsunami

Landslide/Subsidence

Infrastructure Disruption

E. Damage Susceptibility

Earthquake Magnitude: Larger magnitude = more damage.

Surface Characteristics: Soft soil amplifies seismic waves.

Structural Integrity: Stronger buildings resist damage.

Population Characteristics: Time of day and location affect casualty numbers.

F. Prediction and Preparedness

Seismic Risk Analysis

Seismic Gap Theory

Precursory Phenomena: Rock structure changes before a quake.

G. Major Earthquake Belts

Circum-Pacific Belt

Mid-ocean Ridge System

Mediterranean-South Asia Belt

H. Damage Mitigation

Base Isolation: Rubber bearings to reduce ground motion.

Diagonal Bracing: Cross-bracing to absorb seismic energy.

Zoning: Restricting development in high-risk areas.

I. Notable Earthquakes

Loma Prieta (1989)

New Madrid (1811-1812)

Sendai (2011)

IV. VOLCANOES

A. General Information: Volcanoes form when Earth's internal heat reaches the surface.

B. Types of Volcanoes

Cinder Cone: Steep, small volcano formed from pyroclastics.

Composite Cone: Symmetrical, large volcano with alternating lava and pyroclastics.

Shield Cone: Large, broad volcano formed by low-viscosity lava flows.

C. Volcanoes and Plate Tectonics

Spreading Centers: Diverging plates create volcanoes (e.g., Iceland).

Subduction Zones: Converging plates create magma (e.g., Cascades).

Hotspots: Intraplate volcanism (e.g., Hawaiian Islands).

D. Eruptive Styles

Icelandic-type: Effusive, low viscosity.

Hawaiian-type: Effusive, broad shield formation.

Strombolian-type: Small explosive eruptions.

Vulcanian-type: Alternating pyroclastic material and lava.

Plinian-type: Most explosive, creates huge ash columns.

E. Volcanic Hazards

Lava Flows: Destruction of property.

Aa Lava: High viscosity, slow-moving, rough-textured lava.

Pahoehoe Lava: Low viscosity, fast-moving, smooth, ropy-textured lava.

Explosive Blast: Can devastate large areas.

Lahar: Volcanic mudflow.

Pyroclastic Flow: Superheated gases and ash.

Toxic Gases: Carbon, sulfur, nitrogen compounds.

Tsunami: Water displacement from volcanic eruptions.

F. Collapse Calderas

Mount Mazama (Crater Lake)

Krakatau

G. Supervolcanoes

Yellowstone

Long Valley

H. Prediction/Mitigation

Land Use Planning/Zoning

Lava Diversion

Barriers

Evacuation/Relocation

Review Questions (Exam #1)

1. Which type of fault involves tensional stress?

A. normal C. reverse

B. strike-slip D. creep

2. Which of the following is the primary hazard associated with shield

cone volcanoes?

A. lava flows C. tephra

B. lateral blast D. none of the above

3. Which of the following eruptive styles is the least explosive?

A. Plinian C. Icelandic

B. Strombolian D. Vulcanian

4. The majority of the earth’s volcanic activity occurs in the vicinity of _____.

A. spreading centers C. hot spots

B. subduction zones D. none of the above

5. Atmospheric disasters involving the hydrologic cycle, such as tornadoes

and hurricanes, are primarily driven by which source of the energy?

A. gravity C. the Sun

B. earth’s internal heat D. none of the above

6. The volcanic activity in Hawaii is a result of which geologic setting?

A. convergent plate boundary C. subduction zone

B. divergent plate boundary D. hot spot

7. The “plastic” region of the upper mantle, which undergoes slow motion to

drive plate movement, is called the ______.

A. inner core C. asthenosphere

B. outer core D. lithosphere

8. Which type of volcano generally yields the most explosive eruptions?

A. cinder cone C. shield cone

B. composite cone

9. All of the following are potential earthquake hazards EXCEPT _______.

A. subsidence C. fire

B. tsunami D. lahar

10. The heat within Earth’s interior is a result of nuclear _________.

11. The process whereby one plate is forced beneath another is

known as ______________.

12. The Richter Scale classifies earthquakes based on ______________,

which refers to the amount of energy released during the quake.

13. Lava issued from the Hawaiian volcanoes is classified as ___________,

in terms of the chemistry.

14. Solid rock fragments ejected from a volcano are called _________________.

15. Give two reasons why subduction zones pose more of a volcanic risk

for the public than do spreading centers.

Answer: 1. Subduction zones tend to produce more explosive

eruptions.

2. Subduction zones are located closer to large

populations.

16. Does a high-magnitude earthquake equate to a high-intensity quake?

Explain.

Answer: Not necessarily. There are several factors, besides

magnitude, that determines the intensity of the quake.

Those include, depth of focus, building design and surface

geology.

17. Why do earthquakes along strike-slip faults NOT generally produce

a large tsunami?

Answer: Tsunami require a large bottom displacement (vertical)

of the seafloor. Strike-slip faults involve lateral motion.

18. Explain what made the San Francisco earthquake in 1906 so much worse.

Answer: Fires ignited all over the city after the quake.

Firefighters were unable to extinguish fires due to damage

to the infrastructure (impassable roads, broken water

mains, etc.)