Paper 1- Tectonic hazards Flashcards

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1
Q

where are volcanos found?

A

Wherever magma rises to the surface: conservative margins, subduction zones and hot spots

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2
Q

What three substances do volcanos emit

A

Lava, pyroclastic material, Gases

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3
Q

While magma is molten rock beneath the surface, lava is…

A

magma running over the surfcae

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4
Q

Acid lava characteristics

A

High silica content

temp around 700 degrees

very viscous, sticky

forms rhyolite or andesite rock

associated with destructive plate margins

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5
Q

Basic lava characteristics

A

Low silica content

Temp around 1200 degrees

non-viscous, runny

forms basalt rock

associated with tensional margins and hot spots

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6
Q

why are acid eruptions more dangerous?

A

Pockets of gas - when exploding its sticky

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7
Q

Example of a shield volcano

A

Mauna Hoa in Hawaii

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8
Q

Example of a composite cone (strato volcano

A

Mt Fuji

Mt Rainier

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9
Q

Lava flow primary impact

A

Eruption of Eldfell, at Haimaey, Iceland 1973

lava destroyed over 300 buildings.

But town and fishing port were saved by spraying water

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10
Q

Pyroclastic flow primary impact

A

E.g. Eruptionn of mt. Pelée, Martinique in 1902

A hot ash cloud wiped out St Pierre, over 25,000 deaths

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11
Q

Ash and ash fal primary impact

A

E.g. Eyjafallajokull, Iceland 2010

Glacier ice on top of the erupting volcano cause a huge ash cloud that caused over 100,000 flight cancelations and around 1bn dollars

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12
Q

Volcanic gases primary impact

A

E.g. Lake Nyos volcano, Cameroon in 1986

A large cloud of CO2 was released from the lake within the crater, this travelled downhill 15 miles, killing 1700 people

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13
Q

Volcanic mudflows (lahars) secondary impact

A

Eruption of Nevado del Ruiz, Colombia in 19985

Volcanic ash and rocks mixed with snow and ice on mountaintop to produce lahar

Swept across the town of Armero killing 23,000 people

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14
Q

Tsunamis secondary impact

A

E.g. Eruption of Krakatau, Indonesia in 1883

caused the collapse of the island producing large tsunamis that killed 36,000 people

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15
Q

VEI - Volcanic Explosive index

A

from 0 to 8

Each step up from 2 is a 10x increase in the volume of solid material produced by the eruption

E.g. 1km^3 Mt St Helens

Super volcano 10,000km^3

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16
Q

Earthquake definition

A

Sudden ground movements/ Earth tremors

Occurs, when crystal rock accumulates strain the suddenly moves or breaks along a fault

Energy is released in the form of Seismic waves

17
Q

“focus” of an earthquake

A

The point within the crust where the earthquake rupture starts

18
Q

Epicentre

A

The point on the ground directly above the focus

19
Q

The Richter scale

A

Measures magnitude of earthquake

Determined using seismographs

Scale is logarithmic

Tectonic forces capable of generating earthquakes no stronger than al little over nine on the richter scale

Earthquakes low on R scale are more frequent

20
Q

What is the Mercalli scale

A

Measures the devastation of an earthquake on a 12 point scale

A subjective assesment of damage done

21
Q

Primary impacts of a strong earthquake

A

Fault scarps/ surface ruptures

collapsed buildings

damaged infrastructure

22
Q

secondary impacts of an earthquake

A

fire

landslides

tsunamis

Liquefaction - makes water more liquid than solid

Disease and famine

23
Q

What is meant by primary and secondary effects of tectonic events?

A

Primary refers to direct effects on people + infrastructure

e.g. casualties and building damage

Secondary effects are triggered by the initial event

e.g lanslides due to slopes made unstable

+ Economic factors

24
Q

Immediate and long term responses to tectonic events meaning

A

Immediate refers to rapid emergency response

Long term = delayed and long duration responses

e.g. Government stratergies to rebuild

25
Q

Why do HICs fare better than LICs countries in disasters

A

HICs have more awareness

HICs have better methods of mapping and monitoring the hazards

Often corruption in LICS

HICs have more money to spend on emergency services
E.g. Mount St. Helens USA 1998 careful monitoring and evacuation resulted in less causualties (57 deaths)

E.g Nevado del Ruiz, Colombia (1985) lack of careful monitoring lead to 23,00 casualties

26
Q

Haiti background information earhtquake

A

Took place on 13th Jan 2010

Struck a local time of 16:50

Magnitude was 7.0 on richter scale

Haiti lies between Caribbean + North American plate

Arose at a fault which runs through Haiti

27
Q

Christchurch NZ background information earthquake

A

Suffered from its previous earthquake that year

Situated in South Island

Home to around 400,000 people

Hit on 22nd Feb 2011

6.3 on the Richter scale

Epicentre was around 6km from Christchurch

28
Q

Primary Haiti impacts

A

Primary: 230,000 people died,

300,000 injured,

1 million left homeless,

250,000 residential buildings + 30,000 commercial buildings were destroyed, their buildings were made cheaply, could be due to corruption

29
Q

Secondary Hait impacts

A

Secondary: impact on industry,

main production was clothing. 17th largest supplier of clothing products sold to USA in 2008,

left economy poorer and prices raised due to demand, tourism effected

e.g Cruise ships, airlines and hotels were in demand - quake destroyed this

Farming 5 - 6 million lived in rural areas 85% of those people framed

accounts for 26% of Haiti’s economic output

ruined crops, cattle + roads - slowed operation down

before the earthquake priorities were focused on feeding pop.

30
Q

Christchurch primary impacts

A

loss of buildings

old city centre was destroyed

this cost round 10$ billion to redevelop the city

the other $10 billion was for other areas

185 people killed

6000 injured

31
Q

Christchurch secondary impacts

A

Landslides

glacial falling into the seas

Rugby world cup had to be moved- effecting the local economy

32
Q

Haiti responses

A

Rescue those trapped in rubble

Main hospital was destroyed

Health needs were addressed by 6 international + 8 haitian medical teams

People desperately needed basics

UK disaster comittee donated £23 million

US sent aid by sending planes full of rescue workers and ships with thousands of soldiers

Long term respones = charities–> infrastructure + medical resources

33
Q

Christchurch response

A

needs of the local people

Plans to demolish the old city centre core

Long term responses came two years late: Job creation, innovation, well being for the locals

other support was fundraised (8.8 billion dollars)

Provided sewage, road and transport needs

Some say good came from it = oppertunity to redevelop

Planned stratergies fro Christchurch
1 = government to redevelop the town (20 billion $) e.g. economic growth, leadership, awareness

2=”Christchurch central development plan”
Aim was for a new central core, significant points to show strength of city, local people got involved, brought community closer