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109 Cards in this Set

  • Front
  • Back

What are natural hazards?

Endangerment in the environment and can affect anyone anywhere

What is vulnerability?

Refers to the likelihood that a community will suffer injuries, death or property damage from a hazardous event

What is a natural disaster?

When I has her triggers vulnerability and the damage is so extensive that the affected community cannot recover through the use of its own resources

When do hazards become disastrous?

Only become disastrous when they overwhelm communities way to cope

What is a Geohazard?

A hazard post to people by the physical earth

Who is the Roman god of fire?


What is a volcano?

Conical, circular structure built by accumulation of lava flows and tephra(Volcanic ash)

Where do volcanos occur at?

1.Spreading/convergent plate margins (interplate)

2.intraplate volcanos (Not in association with plate boundaries)

What are active volcanoes?

A volcano that has a ruptured during the last 10,000 years and is likely to irrupt again

What is an extinct volcano?

a volcano that has not ruptured for tens of thousands of years and can never erupt again

What are dormant volcanoes?

Not erupted for 10,000 years or more, but could awaken again

What are three main types of volcanoes?


2. shield volcanos

3.cinder cones

What is a stratovolcano ?

A large, potentially explosive cone shaped volcano composed of alternating layers of lava and pyroclast.

What type of lava is a stratovolcano composed of?

Felsic lava

What are pyroclastic materials?

Any fragmented solid material that is ejected from a volcano

What is Ash (volcanic)?

Find volcanic powder consisting of pulverize rock particles and solidify droplets of lava

What is a shield volcano?

A broad, dome volcano form from many layers of basaltic lava.

-Much larger than stratovolcano’s

What is a Cinder cone volcano?

A small, cone shaped volcano consisting of pyroclastic that settle at the angle of repose

What is the angle of repose?

Steepest angle at which loose sediments can settle

What are Cindercone volcano is built out of?

Build from small pieces of red or black basalt

What are three main types of volcanic products?




What are three types of lava?




Mafic Lavas have ____viscosity and flow____

Low; easily

Felsic lavas have _____viscosity with ____ability to flow

Low; restrictive

What is the Viscosity?

The extent to which a fluid resists a tendency to flow

A shield volcano containing mafic lava would have ____viscosity and flow____

Low viscosity; flow easily

A stratovolcano with plug dome would have ____Viscosity and flow_____

Low viscosity; restricted flow

What is a Pahoehoe?

When mafic lava solidifies into smooth, bilowly lobes over the surface

What is ‘A’a?

When mafic lava cakes on a blocky, rough surface

The higher the silica content the ______viscosity


What are four types of pyroclasts(tephra)?




4. blocks

What is the smallest type of pyroclast?


What is the largest type of pyroclast?


What is lapilli?

Marble to golf ball sized cooled fragments of lava

What is a bomb ( volcanic)?

A streamlined fragment of lava ejected from a volcano that is cold and hardened as it moved through the air

What is a block ( volcanic)?

Fragment of rock from the volcanos cone that is ejected during an explosive irruption

What is a pumice?

A lightweight porous rock with at least 50% air content, form from felsic lava

What is the driving force that causes most volcanic eruptions?

Volcanic gases

What are 5 main volcanic gases?

1.Water vapor

2.sulphur dioxide (S02)

3.carbon dioxide (C02)

4.hydrogen sulphide (H2S)

5.hydrogen halides (HS, HCl, HBR)

What does sulphur dioxide causing the atmosphere?

Global cooling

What does carbon dioxide causing the atmosphere?

-Global warming

-trapped in low-lying areas can be lethal to people and animals

What main gas committed by volcanos is very toxic and high concentrations?

Hydrogen sulphide (H2S)

What are four common volcanic landforms?

1.Volcanic mountains

2.columnar jointing

3.large igneous provinces


What is columnar jointing?

A geometric pattern of angular columns that forms from joints in basaltic lava during cooling

What are joints?

A crack or weak plane and rock

What are large igneous provinces?

An accumulation of flood basalts that covers an extensive geographic area

What is it caldera?

A large depression that forms when a volcano is magma chamber empties collapses after the volcano irrupt’s

What type of volcano is now a large caldera in wizard island?


What are two kinds of volcanic eruptions ?

Effusive and explosive

What is an effusive eruption ?

A nonexplosive irruption that produces mostly lava (example shield volcanoes)

What is an explosive erruption?

Interruption that sends rock, Ash and volcanic gases high into the troposphere, or even into the stratosphere

How is Volcano strength ranked ?

The volcanic explosivity index (VEI)

-Scale of 1 to 9

-Ranks volcanic irruption magnitude based on the amount of the material of volcano ejects during an irruption

What are the two greatest volcanic threats?


2.pyroclastic flow

What is a lahar?

A thick slurry of mud, Ash, water and other debris that flow rapidly down to snowcap stratovolcano when it erupts

What is pyroclastic flow?

A rapidly moving avalanche of searing hot gas and Ash

What are causes for lahars?

-rapid melting of snow and ice by pyroclastic flow’s ( primary)

-Intense rainfall on loose volcanic rock deposits

-Break out of a lake damned by volcanic deposit

-Debris avalanche

What’s another word for pyroclastic flow?

Nuee ardente

What characterizes pyroclastic flow?

Outburst of hot gases and dust caused by a blocked vent

How many fatalities were there in the destruction of Pompeii?

16,000 people died (Mount Vesuvius erupted)

Can scientist predict volcanic irruption’s?

Scientist can sometimes predict in a ruptured within weeks or months if a volcano gives warning signs

What are some signs that magma is moving upward in the magma chamber?


2.widening cracks


4.earthquake activity

What is the most active volcano in the cascade range?

Mount Saint Helens

What percent of the Pacific oceans margins are subduction zones with active/dangerous stratovolcano is?

Greater than 60%

What are the most common type of volcano Found in the Pacific Ring of fire?

Explosive strato volcanos

Most earthquakes occur along plate boundaries in_____

Seismic belts

What are three types of faults?



3.strike slip

What is a normal fault?

The result of tensional for us as to four blocks move apart, causing one for block to slip down words in relation to the other fault block

What is a reverse fault?

The result of compressional force as two fault blocks are pushed together, causing one block to move upward in relation to another block

What is a strike slip fault?

The result of shearing force us as one block move horizontally in relation to another block

What percentage of the earth earthquake energy is released in the Pacific Ring of fire,Where plates are subducting?


What do you reverse a normal faults create that results from vertical movement of the fault blocks?

Fault scarp or cliff face

What is faults scarp?

A cliff face resulting from the vertical movement of a reverse or normal fault

Where is strike slip fault Crosslin your features, those features may be ____ by fault movement


How do earthquakes occur?

-When geologic stress exceeds friction, and the crust brakes (either along or pre-existing fault or along a new fault) and the blocks move

-The build up strength energy is released and travels to the crust is seismic waves, resulting in an earthquake

What is focus (Hypocenter)of an earthquake?

The location of the initial movement along a fault during an earthquake

What is an epi- center?

The location on the ground surface immediately above the focus of an earthquake, where earthquake intensity is usually the greatest

What is foreshock?

A small earthquake that sometimes proceeds a larger earthquake

What is aftershock?

A small earthquake that follows the main earthquake

What are two types of seismic waves?

1.Body waves

2.surface waves

What are body waves?

Pass through the body of earth (P waves and S waves)

What are surface waves?

Travel near the surface of the cross (R waves and L waves)

What is a seismograph?

An instrument used to detect, measure, and record ground shaking

Which type of waves produce the largest ground shaking?

L waves and are waves

Which waves arrive first ?which waves arrive last?

-P waves arrive first

- S waves follow P waves

-Rwaves and Lwaves are the last to arrive

What are two categories of seismic waves based on how waves move?

1.Compressional waves

2.shear waves

P waves are in what category of seismic waves based on how waves move?

Compressional waves

S waves are in what category of seismic waves based on how waves move?

Shear waves

R waves are in what category of seismic wave? L waves ?

Compressional; shear

What are compressional waves?

Produce movement that goes back-and-forth in a direction parallel to the direction of travel in waves

What are sheer waves?

Move back-and-forth perpendicular to the direction the waves are travelling

How is earthquake magnitude determined?

From measurements of ground movement using seismographs

What does the Richter scale measure?

Quantifies magnitude of local ( California) earthquakes

Who developed the Richter scale?

Developed in 1935 by Charles F Richter

What scale used as a decimal scale (logarithm to the base of 10) of maximum single wave amplitude recorded or not then standard seismogram at a distance of 100 km from the Eppy center?

Richter scale

The amount of ground shaking depends on what three factors?

1.The earthquakes magnitude

2. the distance from its focus

3.the composition of the ground being shaken

What is earthquake intensity?

Determined by the amount of damage in earthquake causes to a physical structure

What is the modified Makalli intensity scale (MMI)?

And earthquake ranking system based on damage done to structures (uses Roman numerals)

What is the earthquake ranking system based on the amount of ground movement?

The moment magnitude scale

____magnitude events occur less frequently than ____magnitude events

High ;low

What is liquefaction?

The transformation of sod sediments into an unstable slowly as a result of ground shaking during an earthquake

What type of sediments are susceptible to liquefaction?

Loose, wet sediments

How many deaths were there in the 2009 l’Aquila earthquake

309 deaths,Destroyed or damaged thousands of buildings

In the 2009 Italy earthquake why were seven members of the Italian national commission forecast and prevention of major risk tried for?

In accurate, incomplete and contradictory statements

The controversy of the 2009 Italy earthquake was centred around what three comments made by the civil servant?

1.The situation was certainly normal

2.pose no danger

3.the scientific community continues to assure me that to the contrary it’s a favourable situation because of the continuous dischargecharge of energy

Where are the worlds deadliest volcanos found?

-In the sunda arc, indonesia

What are the three worlds deadliest volcanos found in Indonesia called?




When was Krakatau’s most recent irruption and how many people did it kill?

1883 (VEI of six irruption killed over 36,000 people)

What volcano has the greatest know when human death toll?

Tambora 1815 (92,000 casualties)

Why was the year of 1816 nicknamed the year without a summer?

It was unusually cold in both eastern North America and in northern Europe due to Tambora’s wide reach