Hazards Flashcards
1
Q
What is a disaster:
A
The UN records a hazard event as a disaster if one or more of the following criteria are met:
- a report of 10 or more people killed
- A report of 100 or more people killed
- A declaration of a state of emergency by the relevant government
- A request by the national government for international assistance
2
Q
What is a hazard:
A
A perceived event that threatens both life and property. Often result in disasters that cause loss of life/ damage to the built environment and create severe disruption to human activities.
3
Q
Common characteristics of hazards:
A
-Origins are clear and the effects that they produce are distinctive.
-Only allow a short warning time before the event.
-Exposure is involuntary especially in less developed countries
-Most loss of life/ damage to property occurs shortly after the effects of natural hazards.
-Scale and intensity result in emergency response.
4
Q
Adaptation:
A
The attempts by people or communities to live with hazard events. By adjusting their living conditions, people are able to reduce their levels of vulnerability.
5
Q
Fatalism:
A
A view of a hazard event that suggests that people cannot influence the shape or outcome, therefore nothing can be done to mitigate against it.
6
Q
Perception:
A
The way in which an individual or a group views the threat of a hazard event.
7
Q
Risk:
A
The exposure of people to a hazardous event presenting potential threat to themselves, their possessions and the built environment in which they live.
8
Q
Reasons people put themselves at risk from natural hazards:
A
-Unpredictable
-Lack of alternatives: Social, political, economic or cultural factors.
-Changing the level of risk: Places that were once safe may become a risk.
-Cost/benefit
-Perception
9
Q
Vulnerability:
A
The potential for loss, varies over time and space.
10
Q
Factors effecting the perception of natural hazards:
A
-Socio-economic status
-Level of education
-Occupation/employment status
-Religion, culture, ethnicity
-Family and marital status
-Past experience
-Values, personality and expectations
11
Q
Wealthier perceptions of hazards:
A
The better prepared you are, the more able you will be able to withstand the impact of the hazard. Based upon government and community action, and is backed by capital that funds tech-based solutions.
12
Q
Types of perception:
Fatalism:
A
Such hazards are natural events that are part of living in an area. Some communities believe that they are ‘God’s will’. Action is therefore usually direct and concerned with safety. Losses are accepted as inevitable.
13
Q
Types of perception:
Adaption:
A
People see that they can prepare for, and therefore survive the events by prediction, prevention, and/or protection, depending on the circumstances of the area.
14
Q
Types of perception:
Fear:
A
The perception of the hazard is such that people feel so vulnerable to an event that they are no longer able to face living in the area and move away to regions perceived to be unaffected by the hazard.
15
Q
Community preparedness/ risk sharing:
A
This involves prearranged measures that aim to reduce the loss of life and property damage through public education and awareness programmes, evacuation procedures, the provision of medical food and shelter supplies and taking out of insurance.
16
Q
Integrated risk management:
A
The process of considering the social, economic and political factors involved in risk analysis; determining the acceptability of damage/ disruption; deciding on the actions taken to minimise damage.
17
Q
Lava:
A
Molten rock (magma) flowing onto the surface. Acid lava solidifies very quickly, but basic lava (basaltic) tends to flow some distance before solidifying.
18
Q
Mitigation:
A
Long-term action taken to reduce or eliminate the risk to life and property from hazard events. Action is taken before, during and after disasters to break the cycle of damage and repair in hazardous areas.
19
Q
Prediction-
A
The ability to forecast a hazardous event and the give warnings so that action can be taken to reduce their impact. Improved monitoring, information and communications tech have meant that this has become more important and accurate in recent years.
20
Q
Resilience:
A
The sustained ability of individuals or communities to be able to utilise available resources to respond to withstand and recover from the effects of natural hazard events. Communities that are resilient are able to minimise the effects of the event, enabling them to return to normal life as soon as possible.
21
Q
Integrated risk management:
A
-Identification of the hazard
-Analysis of the risks
-Establishing priorities
-Treating the risk and implementing a risk reduction plan
-Developing public awareness and a communication strategy
-Monitoring and reviewing the whole process
22
Q
Prevention:
A
Probably unrealistic although there have been ideas and even schemes such as seeding clouds in potential tropical storms in order to cause more precipitation.
23
Q
Disaster/risk management cycle:
A
This illustrates the ongoing process by which governments, businesses and society plan for and reduce the impact of disasters, react during and immediately following an event, and take steps to recover after an event has occurred. Appropriate actions at all points in the cycle lead to greater preparedness, better warnings and reduced vulnerability. Promotion of sustainable livelihoods and their protection and recovery during such events.
24
Q
FEMA:
A
Federal emergency management agency (1978). Primary purpose is to co-ordinate the response to a disaster that has occurred in the United States and that has overwhelmed the resources of local and state authorities.
25
Disaster/response curve:
To show that hazard events can have varying impacts over time, Park (1991) devised his impact/response model. This model shows an early stage before the disaster where quality of life is normal. When the event happens the quality of life drops with people taking immediate action to preserve life and the built environment. The next stage is called relief where medical attention/ services and overall care are delivered. Next is rehabilitation, where people try and return to normal. Finally comes reconstruction.
26
Frequency:
The distribution of a hazard through time.
27
Magnitude:
The assessment of the size of the impact of a hazard event.
28
Primary effects:
The effects of hazard event that result directly from the event.
29
Secondary events:
Effects that result from the primary impact of the hazard event.
30
Soil liquefaction:
The process by which saturated, unconsolidated soil or sand is converted into a suspension during an earthquake. It is then able to act like a liquid and flow, particularly when under pressure.
31
Primary and secondary effects of an earthquake:
Primary-
-Ground shaking/ cracking
Secondary-
-Soil liquefaction
-Landslides
-Tsunamis
-Effects on people/ built environment
32
What is the core made up of?
Dense rocks containing iron and nickel alloys.
33
What is the core subdivided into?
Solid inner core and molten outer one with a temp of over 5000 degrees C.
34
What produces the heat of the core?
Primordial heat which is left over from the earth's formation and radiogenic heat produced by the decay of radioactive isotopes.
35
What is the mantle made of?
Thickest layer, made of molten and semi-molten rock rich in iron and magnesium.
36
What depth is the mantel?
Between 700km and 100km
37
What is the asthenosphere?
The upper part of the mantle that lies below the lithosphere which is hot and fluid.
38
What are the two types of crust?
Thin layer of dense basalt which is found under the oceans and a thicker layer of less dense granitic rock that makes up the continents.
39
Who came up with tectonic theory, and what is it?
Alfred Wegener (1960s) who gathered evidence to suggest that just one giant continent existed about 300 million years ago. Called this continental drift.
40
Conservative plate margin-
A plate margin where two tectonic plates are moving past one another with no addition or destruction of plate material.
41
Constructive plate margin-
A plate margin where new crust is generated as the plated pull away from each other. These are found at mid-oceanic ridges.
42
Destructive plate margin-
A plate margin where crust is destroyed as two plates converge. These are usually associated with island arcs or young fold mountains.
43
Palaeomagnetism-
A record of the history of the Earth's magnetic field, preserved in magnetic minerals in volcanic rocks.
44
Plume-
A hot column of magma which rises from deep within the Earth.
45
Rift valley-
A long, deep valley found in the centre of a spreading ridge. It is formed between parallel faults where a block of the crust has sunk down.
46
Sea-floor spreading-
The theory that the ocean floor is moving away from the mid oceanic ridge and across the deep ocean basin, to disappear beneath continents and island arcs.
47
Tectonic plate-
One of a series of rigid section of the Earth's crust. They float on the upper mantle and move relative to one another.
48
How many years ago did plate movement develop?
750 million when Pangaea split up
49
What does the modern theory say allows plate movement?
The lithosphere is able to slide over the asthenosphere.
50
What did a study on the polarity of ancient magnetic particles in the rock find?
-Polarity of the rock either side of the mid Atlantic ridge alternated in a striped pattern- this was mirrored on either side.
-Oceanic rust was slowly moving away from the plate boundary
-Oceanic crust got older with distance from the mid-oceanic ridge.
51
Sea-floor spreading:
If the sea floor is spreading it implies the earth is getting bigger, this is untrue. To accommodate the growing crust, crust must be destroyed elsewhere.
52
Convection currents:
Convection currents, that occur within the molten rock in the mantle, act like a conveyor belt for the plates. Tectonic plates move in different directions. The direction of movement and type of plate margin is determined by which way the convection currents are flowing.
53
How do convection currents move lithospheric plates?
Uneven distribution of temperatures towards the base of the mantle cause convection cells which dragged the lithosphere plates with them when the moving mantle reached the surface.
This theory has been discounted as the mantle is not fluid.
54
Ridge push/ gravitational sliding:
At constructive plate boundaries, less dense, hot magma wells up and produces an ocean ridge standing 2-3km above the ocean floor. As this gets older it cools and grows more dense. Gravity acting on this causes it to slide away from the ridge down to the semi-molten asthenosphere below.
55
Slab pull:
At a destructive (subduction) boundary, older/colder oceanic plates are denser than the underlying mantle. As the subducting plate is colder/heavier it sinks into the mantle due to the gravity acting on it and pulls the whole oceanic plate into the mantle.
56
Three types of plate margin:
-Constructive (divergent)
-Destructive (convergent)
-Conservative (passive)
57
What system has been produced under the oceans due to constructive plate margins?
Ocean ridge system, comprising of underwater mountains and volcanoes, that stretches for nearly 65,000km.
58
MAR (mid Atlantic ridge) how big is it?
3km in height above the ocean floor and between 1,000 and 1,500km wide
59
What is the axial rift valley on the MAR?
It is where the crust has partially collapsed into the low-pressure zone left by the erupting magma.
60
Cause of rift valleys:
Great rift valley of East Africa is thought to have developed over a hot spot. Rising magma caused the whole region to be uplifted. This created weaknesses in the crust, through which low viscosity basalts emerged and flooded the area.
61
How are deep sea trenches formed?
Denser oceanic plate is forced under the lighter continental plate in the process of subduction. The downward displacement of the oceanic plate forms a deep-sea trench that runs parallel to the plate boundary.
62
How are young fold mountains formed?
During the subduction process, sediments that have accumulated on the edge of the continental plate are deformed by folding and faulting and then uplifted to form young fold mountains. They are parallel chains of high volcanic mountains with an inter-montane plateau between them.
63
How are island arcs formed?
Where oceanic crust meets oceanic crust, the more dense oceanic crust subducts beneath the less dense oceanic crust and a line of volcanic islands known as an island arc can appear.
64
How do conservative (passive) plate margins cause shallow earthquakes?
Where 2 plates slide past one another, parallel to the plate margins, there is no subduction and therefore no volcanic activity. The movement causes stresses between the plate margins, particularly when they get stuck. Sudden movements of the plate cause shallow focus earthquakes.
65
1970s theory to explain the presence of volcanic activity away from plate boundaries:
It proposed that localised heating at the core/mantle boundary caused a plume of magma to rise through the mantle and 'eat' into the plate above the 'hot-spot'. Where lava breaks through the surface, active volcanoes are formed.
66
What happens when tectonic plates with hot spots move away?
It takes with it the volcanoes that have formed. These volcanoes cool and subside, and over millions of years a chain of islands can form.
67
Ash:
Dust-sized particles of rock produced by the explosive eruption of some volcanoes. This material may be carried in the air for long distances from the volcano which formed it.
68
Composite volcano:
Large, steep-sided, symmetrical cone-shaped volcano formed from alternating layers of lava flows, volcanic ash, cinders, blocks and bombs.
69
Lahars:
Mudflows composed of pyroclastic material and water that flows down from a volcano, usually along a river valley.
70
Magma:
Molten rock that is found beneath the surface of the earth.
71
Pyroclastic flow:
A high-density mass of gases, hot ash and larger material that flows rapidly down the sides of the volcano.
72
Tephra:
Any type of rock fragment that is forcibly ejected from a volcano during an eruption.
73
Tsunamis:
Giant sea waves generated by shallow-focus underwater earthquakes, violent volcanic eruptions, underwater debris slides and landslides into the sea.
74
Volcanic bombs:
Rocks that are more than 5mm in diameter that are thrown into the air by a volcanic eruption.
75
Volcanic explosive index:
A scale used to measure the explosiveness of volcanoes.
76
Volcanic activity along constructive plate margins:
Plates move apart and magma is forcing its way to the surface. In some locations along oceanic ridges, where lava builds up to the ocean surface, volcanic islands form. Volcanoes also form within continental rift valleys.
77
Volcanic activity on/near subduction zones:
The line of volcanoes, or 'ring of fire' that surrounds the Pacific Ocean is associated with plate subduction. Deeper the oceanic plate descends, the hotter the surroundings become. This, with the heat generated from friction, begins to melt the oceanic plate into magma in a part of the subduction zone known as the Benioff zone. The magma exploits zones of weakness and rises as columns of magma.
78
Volcanic activity over hot spots:
The Hawaiian Islands in the north Pacific Ocean are examples of shield volcanoes that are located away from plate boundaries over a hot spot. They have low-angled slopes made from low viscosity, basaltic lava that flows great distances from the volcanic vent itself.
79
What does the type of volcano and activity depend on?
Nature of the lava , which in turn depends upon the nature of the lava, which in turn depends upon the location of the volcano with regard to the tectonic plate margins. If the lava is not viscous, the gases may escape easily. If the lava is very viscous, the gases will not move freely and can build up tremendous pressure within the volcano.
80
How do they determine the frequency of eruptions from any volcano?
Its previous history of activity can be interpreted by volcanologists using the deposits associated with the volcano itself and those within the wider region it can effect.
81
Primary effects of a volcano:
-Tephra
-Pyroclastic flows ( Nuees ardentes)
-Lava flows
-Volcanic gases
82
Tephra as a primary effect:
Solid material of varying grain size ranging from volcanic bombs to ash, all ejected into the atmosphere. Generally, the larger the tephra particles, the shorter distance they travel from the source. Volcanic bombs as large as a bus are very dangerous, but few people get in their way. Fine ash can be thrown high into the atmosphere where strong winds can blow it around the Earth.
83
Pyroclastic flows as a primary effect:
Very hot, has charged, high-velocity flows made up of a mixture of gas and tephra. These usually hug the ground and flow down the sides of the volcano with speeds of up to 700km per hour.
84
Lava flows as a primary effect:
Rarely cause injury to people due to their relatively low velocity. They are, however, often unstoppable and can therefore damage crops and buildings and block roads.
85
Volcanic gases as a primary effect:
These include carbon dioxide, carbon monoxide, hydrogen sulphide, sulphur dioxide and chlorine.
86
Secondary effects of a volcano:
-Lahars (volcanic mudflows)
-Flooding
-Volcanic landslides
-Tsunamis
-Acid rain
-Climatic change
87
Lahars as a secondary effect:
Unconsolidated ash from a recent eruption combined with water may be swept down river valleys in the form of a hot, dense, hot-moving mudflow. The water can come from rain or melting snow or ice.
88
Flooding as a secondary event:
When an eruption melts glaciers and ice caps, serious flooding can result.
89
Volcanic landslides as a secondary event:
These range in size from less than 1km³ to more than 100km³. The high velocity and great momentum of landslides allows them to cross between valleys and run up slopes several hundred metres high.
90
Tsunamis as a secondary effect:
Sea waves generated by violent volcanic eruptions such as those formed after the eruption of Krakatoa (1883).
91
Acid rain as a secondary effect:
Volcanoes emit gases which include sulphur. When this combines with atmospheric moisture, acid rain results.
92
Climatic change as a secondary effect:
The ejection of huge amounts of volcanic dedris into the atmosphere can reduce global temperatures and is believed to have been an agent in past climatic change.
93
When was the Haiti earthquake?
12th January 2010
94
Magnitude of Haiti earthquake:
7 on richter scale
95
How many died in the Haiti earthquake?
200,000+
96
Where was the epicentre of the Haiti earthquake?
Leogane
97
How many aftershocks were there of the Haiti earthquake?
52 all over 4.5
98
Haiti:
What % of the population live on less that $2 a day?
75%
99
Haiti:
Life expectancy:
52 years
100
Haiti:
What is Haiti the lowest in the N hemisphere for?
Sanitation, nutrition, and health services.
101
Haiti:
What percent of 15+ years olds are illiterate?
More than 20%
102
Haiti:
What % do not attend school?
40%
103
Haiti:
What % of the population live in rural areas?
50%
104
Haiti:
What % of the economy is based on agriculture?
26%
105
Haiti:
What was the government's priority before the earthquake and how did that change?
Before- Feed the population
After- Systems to improve farming production was halted.
106
Haiti:
What was destroyed that is vital to food production/ distribution?
-Roads
-Fishing ports
-Irrigation infrastructure.
107
Haiti:
What is their manufacturing based on?
Production of clothing
108
Haiti:
Before the quake what were the exports valued at ?
$412 million
109
Haiti:
What happened after the quake that effected production of clothes?
Factories damaged, workers injured or lost
110
Haiti:
What sector was beginning to grow but was halted after the quake?
Tourism
111
Haiti:
How many were left injured and how many homeless?
Injured- 300,000
Homeless- 1,000,000
112
Haiti:
How many residential buildings were destroyed?
250,000
113
Haiti:
How many commercial buildings were destroyed?
30,000
114
Haiti:
What is the scale of infrastructural damage partly blamed on?
Corruption in the construction industry.
115
Haiti:
Planes of what arrived in the capital?
Water, food, tents and medicine
116
Haiti:
Who sent help?
Red cross, Dominican republic, UK people: £23 million, UK government: £20 million, USA sent rescue workers and ships with soldiers.
117
Haiti:
What were lotting groups doing during this time?
With machetes, using dead bodies as roadblocks to stop police from entering neighbourhoods.
118
Haiti:
How did WHO recommend was best for people to identify bodies?
Treat the bodies with chemicals and left in open pits to be identified.
119
Haiti:
What was the spread of disease encouraged by?
Poor diet, lack of clean water, poor sanitation.
120
Boxing day tsunami:
When?
26th December 2004
121
Boxing day tsunami:
Strength of earthquake?
Richter scale 9
122
Boxing day tsunami:
Where was the earthquake?
Struck off the coast of Sumatra, Indonesia.
123
Boxing day tsunami:
What countries were effected?
Indonesia, Myanmar, India, Maldives, Sri Lanka and Thailand.
124
Boxing day tsunami:
How does physical geography mean the risk was higher to hazards?
Low land coastal plains especially vulnerable to coastal flooding especially when they were unprotected by off shore coral reefs and inshore mangrove plantations.
125
Boxing day tsunami:
How many people dead/ injured?
300,000 people died, tens of thousands injured as entire villages were wiped out meaning millions were also left homeless.
126
Boxing day tsunami:
Damage to economies:
Particularly agriculture and fishing which left hundred of thousands of people unable to eat.
127
Boxing day tsunami:
What happened with medical aid?
Hospitals/ clinics were washed away so medical aid had to be brought in from safe areas.
128
Boxing day tsunami:
Where was the worst area effected in terms of deaths?
Indonesia- 111,171
129
Boxing day tsunami:
Social effects of the quake?
-Orphaned children
-Medical science teams from UK and Australia helped those psychologically effected and tried to reunite people (easier with phones)
130
Typhoon Haiyan:
Where?
Philippines, close to Tacloban
131
Typhoon Haiyan:
When?
November 8th 2013, 4:40am
132
Typhoon Haiyan:
Strength?
Category 5 typhoon
133
Typhoon Haiyan:
Wind speed?
314km per hour/ 195 miles
134
Typhoon Haiyan:
Wave height?
45ft
135
Typhoon Haiyan:
Causes:
-Pacific ocean generated lots of warm evaporated water.
-Climate change heating the Pacific
-Philippines is by a shallow ocean shelf which made the storm surge higher
-Weathermen underestimated the storm size
136
Typhoon Haiyan:
Where took full force of the storm?
Leyte
137
Typhoon Haiyan:
How many Tacloban residents left homeless?
220,000
138
Typhoon Haiyan:
How many people killed?
63,000 people
139
Typhoon Haiyan:
How many people displaced?
600,000+
140
Typhoon Haiyan:
How many fishing boats destroyed?
30,000
141
Typhoon Haiyan:
How many people lost their source of income?
6 million
142
Typhoon Haiyan:
Secondary effects:
-Landslides/ blocked roads
-Power outages for months
-Shortages of food, water and shelter
-Hospitals, schools, shops destroyed
-Looting and violence broke out.
143
Typhoon Haiyan:
Immediate response:
-International government and aid agencies responded with food and water
-US aircraft helicopters helped with search and rescue
-UK government sent shelter kits
-French, Belgian and Israeli field hospitals set up.
144
Typhoon Haiyan:
Long-term response:
-UN and other countries donated financial aid, supplies and medical support
-Rebuilding roads, bridges and airport facilities
-Cash for work programmes
-Foreign donors supported people's livelihoods
-Home built away from flood risk areas.
145
Australian wildfires:
When?
7th February 2009, also known as Black Saturday.
146
Australian wildfires:
Causes:
-Main culprit, human error
-Power lines falling and banging together caused, in Kilmore North.
-Fire carried by 60mph winds
-Heatwave: Melbourne had 3 days above 43 degrees
147
Australian wildfires:
How many deaths?
173, many in domestic premises (trapped in houses)
148
Australian wildfires:
How many injured?
414, only 22 with major burns.
149
Australian wildfires:
How many houses/ structures damaged?
2030 houses and 1400 structures.
150
Australian wildfires:
Impacts on agriculture?
11,800 head of livestock, 62,000 hectares of grazing pasture and 32 tonnes of hay/ silage were lost in the fires.
151
Australian wildfires:
Effects on rivers?
River catchments affected by ash and contaminants.
152
Australian wildfires:
Total cost:
$4.4 billion
153
Australian wildfires:
What animal was at risk of extinction?
Possums
154
Australian wildfires:
Impact of power loss?
Indirect loss of communication, many businesses/homes were without power.
Businesses shut as power lines were down.
Phone base stations destroyed- small businesses struggled for >1 year
155
Australian wildfires:
Psychological impact:
People were traumatised and required medical support for years after.
156
Australian wildfires:
In March/April where did the smoke/ash travel over?
Antarctica
157
Australian wildfires:
What was localised climate change the result of?
Strong winds and high CO2 levels.
158
Australian wildfires:
Short term responses:
-5000 firefighters from Victorian Country, NZ and US
-Military aid from common wealth
-Told to evacuate but poor communication led to death
-Federal government went packages to hospitalised/homeless people
-$1000 AUD given to every adult an $400 to every child
159
Australian wildfires:
Long-term responses:
-Rebuilding communities/ providing medical care
-Criticism of 'stay or go' policy
-Part of the fire started sue to ageing power lines falling so billions of dollars went into upgrades.
160
Mount Mayon:
Where?
South East Asia, Philippines
161
Mount Mayon:
Volcano information:
Active
Stratovolcano- perfect cone shape
Small crater with steep slopes
Part of the Pacific ring of fire
Erupted 49 times in 400 years
162
Mount Mayon:
How do the large ash emissions effect people?
Generally settle within a few km of the volcano and affect the nearby city of Legaspi, often causing buildings to collapse.
163
Mount Mayon:
Why is there a high risk of lahars?
Ash emissions also settle in gullies on the flanks of the volcano. The high rainfall in the area (3,432 mm) means there is a high risk of lahars, which destroy anything in their path.
164
Mount Mayon:
How are the ash emissions good and bad?
Ash emissions destroy local agriculture, but in the long term they enrich the soil.
165
Mount Mayon:
When?
13 Jan 2018- The eruption began that blasted a steam and ash plume approximately 2,500 m into the air for just over 1.15 hours
166
Mount Mayon:
What was the immediate reaction on day one?
Raised the alert level from 1 to 2, approximately 40,000 residents evacuated from a 6km radius.
167
Mount Mayon:
What happened the day after the initial explosion?
3 more eruptions and 158 rockfall events were recorded. Alert level becomes 3
168
Mount Mayon:
On what day were schools and colleges shut?
After 10 days, 23rd Jan 2018.
169
Mount Mayon:
When did the eruption subside?
February/ March 2018
170
Mount Mayon:
Impacts:
-Nobody killed as a results of well organised emergency procedures
-5 February 2018 total of 86,052 people affected of which 64,895 people stayed in 58 designated evacuation centres.
-US$3.4 million worth of damages to agriculture affecting more than 10,000 farmers.
-Some roads were made impassable by landslides and ash falls.
171
Mount Mayon:
Local responses:
-The Filipino government committed US$1 million for a ‘cash for work’ programme as well as providing hygiene packages for 50,000 families for ten days. Provided food packs to evacuees for 100 days.
-The Army was called in to help- enforce evacuation and be present if there was civil disturbance.
-Philippine Red Cross set up first-aid stations and welfare desks to provide psychological support.
-The National Council of Churches in the Philippines provided immediate relief assistance to 3,446 families
172
Mount Mayon:
International response.
-The US government advised its nationals against travelling to Mayona after the level 3 alert.
-Canada and the UK also discouraged visits to the volcano.
-The US government, through the US Agency for international development, committed over US$100,000 which was used for vouchers to give to families to buy essentials and hygiene products.
173
Mount Etna:
When?
July 2001
174
Mount Etna:
What was the initial explosion?
5 fissures opened on the flank of the volcano, creating 8 lava flows.
175
Mount Etna:
Social effects:
Deaths by lightning, people stranded, destruction of homes/agriculture.
176
Mount Etna:
Economic effects;
Destruction of towns, closure of airports (Catania), tourism losses (cable car/ ski lift damage)
177
Mount Etna:
Environmental effects:
Habitat loss, pollution (water, air), health issues and asphyxiation of plants.
178
Mount Etna:
Mitigation methods?
INGV (National institute of geopolitics and volcanology)- monitoring for 20 years; recording data, testing emissions
Satellites measure ground deformation
Ground based monitoring devices
179
Hurricane Katrina:
When?
28th-31st August 2005
180
Hurricane Katrina:
How many hurricanes?
3 in succession
181
Hurricane Katrina:
Location of start?
African side of Atlantic as a tropical depression.
182
Hurricane Katrina:
What made it a category five?
12.40 am 28th Aug, reached category 4 followed by category 5 status soon after.
Max sustained winds were 172mph with gusts of 215mph
Air pressure dropped as low as 918mb.
183
Hurricane Katrina:
Day one:
Some power lost and hit the coast as category 4 with sustained wind speeds of 145mph. 2nd landfall at Louisiana, major damage in small towns by the storm surge.
184
Hurricane Katrina:
Order of places hit:
Florida
Louisiana
New Orleans
Louisiana/ Mississippi
Tennessee
Canada
185
Hurricane Katrina:
5th September, how many people evacuated New Orleans?
363,000
186
Hurricane Katrina:
New Orleans Superdome:
Used to house those fleeing their homes.
-Crime, and fear reported.
-3rd September the last 300 refugees were evacuated out of there.
-Theft and rape reported.
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Hurricane Katrina:
Red cross effort:
-356 shelters holding 107,400+ evacuees
-249 emergency response vehicles
-4,200+ red crossers left their families and 600+ workers moving into the area every day
-137,600 meals served in 24 hours
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Hurricane Katrina:
Demographic change:
-Louisiana's population is estimated to have decreased by 8.4%
-460,000 left New Orleans, only 60,000 returned
-Baton Rouge population increased by 35,000
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Hurricane Katrina:
FEMA (US Federal emergency management agency) recovery effort:
-Provided $3+ billion directly to Louisiana victims for housing assistance
-Completed 1 million housing inspections
-More than 81,000 roofs covered
-Approved $102 million in unemployment assistance for 108,000 victims.
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Hurricane Katrina:
Other recovery effort:
-US army corps of engineers removed 30 million cu m of debris
-Recovery displaced bodies from cemeteries
-US army corps of engineers provided temp classrooms.
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Hurricane Katrina:
Mississippi damage:
-At least 236 dead
-109,000 homeless
-2 years worth of timber destroyed
-300 out of 9000 poultry houses destroyed, 2400 damaged
-8 million poultry killed, value of industry fell by 6%
-20% of rice and maize harvests lost
-Government spent over $200 million.
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Signs that a volcano may erupt:
-Increase in release of gases, particularly sulphur dioxide and carbon dioxide.
-Rise in level of lava lakes in volcanic craters
-Bulging upward of surrounding land dude to pressure from below
-Increasing number of relatively small earthquakes caused by the rising magma.
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Four responses to a volcano:
-Preparation
-Mitigation
-Prevention
-Adaptation
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Risk assessments to mitigate against volcanoes:
Governments of countries at risk of volcanic hazards carry out risk assessments and produce a series of alert levels to warn the public of the threat.
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Examples of physical actions undertaken to reduce volcanic impacts:
-Mt Etna: dug trenches, dropped blocks into the lava stream to slow flow.
-1973, Icelandic people poured sea water on the front of a lava flow to solidify it before it reached a fishing port
-Hawaiian Islands have barriers across valleys to protect settlements from lava flows/ lahars.
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Strengths and weaknesses of evacuations as a way to mitigate the effects of volcanoes:
If it is carried out needlessly, future evacuations are more difficult to manage. Evacuations have been carried out successfully many times in the Philippines. Sometimes permanent evacuation may be needed.
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Adaptation to volcanic hazards:
Change crops to create more income e.g in DRC farmers moved from maize to cash crops such as cabbage and bananas and doubled their income.
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Earthquake:
As the curst of the earth is constantly moving, there tends to be a slow build-up of stress within the rocks. When this pressure is released, parts of the surface experience, for a short period, an intense shaking motion.
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Focus of an earthquake:
The point at which this pressure release occurs within the crust is known as the focus and this point immediately above that on the earth's surface is the epicentre. The depth of the focus is significant on the effects on the surface.
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Three categories of earthquake:
-Shallow focus: (0-70km deep) tend to cause the greatest damage and account for 75% of all the earthquake energy released.
-Intermediate focus (70-300km)
-Deep focus (300-700km)
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What type of plate boundary are the most powerful earthquakes associated with?
Destructive margins.
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Earthquakes as conservative margins:
The boundary is marked by transform faults and sudden differential movement along these faults produces the earthquake.
e. San Andreas
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How can human activity be the cause of some earthquakes?
Through building large reservoirs which puts pressure on the underlying rocks, or subsidence of deep mine workings or fracking (for gas).
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The moment magnitude scale:
Measures the size of an earthquake in terms of energy released. It is a logarithmic scale, which means that an increase of one step on the scale corresponds to about 32 times the amount energy released.
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How is magnitude calculated?
Using a formula that includes the rigidity of the rock affected, the distance moved and the size of the area where movement takes place.
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What does the Mercalli scale measure?
The intensity of an earthquake and impact.
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When does the measuring of seismic activity date back to?
1848
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Primary effects of seismic events (earthquakes):
Ground shaking caused by shock waves travelling through the crust from the focus up to the surface and then radiating outwards.
Sea waves.
Ground rupture, the visible breaking and displacement of the Earth's surface.
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Secondary effects of an earthquake:
Soil liquefaction
Land slides/avalanches
Tsunamis
Fires
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What is a tsunami?
Dangerous series of waves that can be triggered by any event that disrupts the sea floor. Often generated by shallow-focus earthquakes.
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Structure of a tsunami:
Very long wavelength and a low wave height in the open ocean, they travel at speeds of over 700km per hour. When they reach shallow water bordering land, they slow down and increase in height.
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What do they effects of a tsunami reaching land depend on?
-Height of the waves and distance they have travelled
-Length of event from source
-Extent to which warnings could be given
-Coastal physical geography
-Coastal land use and population density.
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What % of tsunamis are generated within the Pacific Basin?
90%
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What type of plate boundaries are most tsunamis generated at?
Convergent where subduction is taking place, particularly on the western side of the Pacific.
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Actions taken in advance of a seismic event:
-Any heavy items at home should be secured and breakable items stored at a low level
-Families create a communication plan and emergency meeting place
-Emergency supply kits at home with essentials to last a few days
-Homes should be structurally sound
-Specialised earthquake insurance
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Mitigation against earthquakes:
Early warning systems-
The damaging surface waves of earthquakes take time to travel from the epicentre to where they may impact people. Early warning systems, suc h as that in Japan, give people a short time to make themselves safe. In Japan, the 'Earthquake Early warning' systems aims to reduce earthquake related damage by slowing down trains immediately, controlling lifts and enabling people to protect themselves.
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Mitigation against earthquakes:
Hazard-resistant structures-
-Putting large concrete weight on top of the building that will more, with aid of a computer program, in the opposite direction to the force of the earthquake
-Putting large rubber shock absorbers in the foundations that will allow some movement of the building without structural failure.
-Adding cross-bracing to buildings to hold them together better when they shake.
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Mitigation against earthquakes:
Tsunami protection-
Tsunamis cannot be predicted entirely, even if the magnitude and location of an earthquake is known. Some automated systems can be installed to give warnings, which use sea-bed pressure sensors. These are common in regions with high tsunami risk.
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The pacific tsunami warning and mitigation system (PTWS) ordinated by UNESCO:
Based in Hawaii. It monitors earthquake activity and issues warnings to countries around the Pacific Edge if tsunamis are likely.
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Ways to adapt to the risk of an earthquake:
Land-use planning may include:
-Identifying areas at most risk and regulating land-use planning for those areas or limiting the way land can be used.
-Putting key buildings in low risk areas and open spaces in high-risk areas.
Emergency services must adapt to deal with EQs, e.g heavy lifting gear available and trained in first aid.
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Storm surge:
A rapid rise in sea level in which water is piled up against a coastline to a level far in excess of the normal conditions as high tide. They are produced during the passage of a tropical storm when wind-driven waves pile up water against a coastline combined with the ocean heaving upwards as a result of low air pressure.
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What pressure are tropical revolving storms and where do they develop?
Intense low-pressure.
The tropics.
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What do tropical revolving storms measure in diameter?
200-700km
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Where is there a broad area of low pressure?
Encircles the globe on either side of the equator. The winds on the N side blow from the NE and on the S side blow from the SE.
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Step by step, how a tropical revolving storm is formed:
-In a low-pressure area, air is hearted over the warm and deep tropical ocean
-Air rises in discrete parcels, causing thundery showers that may join into big thunderstorms
-Low pressure develops at the surface
-If storm is sufficient distance from equator then converging winds are acted on by the Coriolis force and the incoming air spirals into and accelerates around the depression.
-Air rises and cools, leading to condensation.
-Latent heat is released fuelling further uplift
-Then travel westwards over the ocean.
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How warm and deep does the water have to be for a tropical revolving storm to develop?
27 degrees C+
70m+
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What distance from the equator do storms have to be to develop?
5 degrees+ latitude.
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What is needed for a tropical revolving storm to develop?
Supply of latent heat and moisture to provide energy and low frictional drag on the ocean surface.
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Tropical revolving storm's central eye qualities:
Once is reaches maturity the central eye develops. 10-15km in diameter where there are calm conditions, clear skies, high tmp and descending air. Wind speed of 300km/hour around the eye.
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When do tropical revolving storms start to decline?
When they reach land or cold water polewards, as the source of heat and moisture is removed.
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Between what degrees do storm surges occur?
5 and 20 north and south of the equator.
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Where are tropical revolving storms most destructive/frequent:
-Caribbean Sea/ Gulf of Mexico (11%)
-West of Central America (17%)
-Arabian sea/Bay of bengal (8%)
-Southeast Asia (33.3%)
-North-west and north-east Australia (20%)
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Different names for tropical revolving storms depending on location:
-Caribbean Sea/ Gulf of Mexico
Hurricanes
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Different names for tropical revolving storms depending on location:
Arabian sea/Bay of bengal
Cyclones
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Different names for tropical revolving storms depending on location:
-Southeast Asia
Typhoons
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Different names for tropical revolving storms depending on location:
Australia
Willy-willies
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What scale are tropical revolving storms measured on?
Saffir-Simpson scale, a 5-point scale based solely upon wind speed.
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Why is it thought the Saffir-Simpson scale should be scrapped?
It only predicts damage from wind but recently in the US 90% of tropical storm deaths are from water.
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Average life span of a tropical storm:
7-14 days
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How many tropical storms develop globally per year? What % become tropical revolving storms?
80-100
80%
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How has climate change effected tropical storms?
Great increase in the number and proportion of very strong cycles.
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Climate change has lead to an increase in ocean temperatures, how does that effect the forming of a tropical storm?
-Air temperature above the warmer water, resulting in enhanced uplift and local lowering of atmospheric pressure
-Oceanic evaporation and a corresponding increase in atmospheric water vapour content.
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Predicted changes by 2100 to tropical storms:
-Increase of 2-11% in average intensity of storms
-A decrease of between 6 and 34% in the total number of storms
-A substantial increase in the frequency of the most intense storms.
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Why is it predicted there will be an increase in slower moving tropical storms?
As polar areas get warmer, there is increasingly less difference in atmospheric pressure between the poles and the tropics. This reduces the speed of the winds between the two areas.
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What differences are there in slower moving tropical storms?
Produce more rainfall. This is further enhanced by the greater amount of water carried by the storm due to higher ocean and air temperatures. 20% increase in ppt that will fall within 100km of the centre of a storm. Wind damage will increase. Create a larger wall of sea water.
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Factors effecting the vulnerability of people to storm events:
-Intensity of the storm (1-5)
-Speed of movement
-Distance from the sea
-Physical geography of the coastal area
-Preparations made by a community
-Warnings and community response.
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Major impacts of a tropical storm on an area:
Winds-
They can often exceed 150km/hr. Such high winds can cause structural damage to buildings and roads, bridges etc. They can bring down electricity transmission lines and devastate agricultural areas. The huge amounts of debris that are flung about are a serious threat to people's lives.
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Major impacts of a tropical storm on an area:
Heavy rainfall-
It is not unknown for rainfall to exceed 200-300mm, bringing severe flooding, landslides and mudslides. If there is high relief near the coastal area, rainfall could increase to over 500mm/day.
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Major impacts of a tropical storm on an area:
Storm surges-
High sea levels result when the wind-driven waves pile up and the ocean heaves upwards as a result of the lower atmospheric pressure. These surges can have devastating effects on low-lying coastal areas such as river deltas where the flooding can extend a long way inland. Storm surges cause the majority of deaths in such events and agricultural areas can take a long time to recover from sea water.
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Preparing for hurricanes:
Weather Bureaux are able to access data from weather satellites that give a real-time view of the location, track, size and strength of a hurricane. They also investigate potential hurricanes and gather data with specially adapted aircraft and weather balloons. Powerful super computers analyse the data from these different sources. Hurricane drills can also be practised.
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Preparing for cyclones:
Erratic so cant give more than 12-18 hours warning. In regions with unreliable communications it is hard to evacuate. Bangladesh's preparedness program:
-Awareness campaign- leaflets, posters, etc
-Early warning system
-Construction of storm shelters
-Replanting former mangrove forests
-Encouraging people to have emergency packs.
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Mitigation for tropical storms:
FEMA has a handbook with suggestions on reducing damage to infrastructure. it has also produced a factsheet for homeowners with advice on how to protect homes.
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Prevention of tropical storms failed past ideas:
-Seeding clouds with dry ice so the storm loses water over the ocean
-Cooling the ocean with icebergs
-Changing radiation balance in the storm by blowing in black soot
-Exploding the storm with hydrogen bombs or blowing it away with fans.
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Adaptation methods for tropical storms:
-Land-use planning to identify areas at high risk
-Building sea-walls and flood barriers and putting houses on stilts.
-Limiting expenditure on developments in high-risk zones and directing the population away
-Retrofitting structures so they are wind resistant and safe in an event.
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Pyrophytic (vegetation):
Pyrophtes are plants adapted to tolerate fire. Methods of survival include thick bark, tissue with a high moisture content and underground storage structures.
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Retardants:
Chemicals sprayed on to fires in order to slow them down
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Causes of wildfires:
An ignition source-
In the case of natural fires, lightning is by far and away the main cause. Climate will affect the frequency of electrical storms, particularly one in which there is hardly any rainfall. Increasingly, fires are the result of human intervention, particularly those which occur in/around settlements. Can be by; falling power lines, discarded cigarettes, bbqs, camp fires, agricultural fires or arsonists.
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Causes of wildfires:
Fuel-
The fuel has to be of sufficient quantity and dry enough to burn. Climate affects the frequency and duration of droughts during which the vegetation and plant litter has an opportunity to accumulate and dry out. Climate also effects the type of vegetation grown in an area and the rate of plant little produced.
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Distribution of wildfires:
Mediterranean climates-
Parts of Australia- SW, SE and coastal S Aus.
California
S Europe
260
Distribution of wildfires:
Savanna-
-N Australia
-Tropical regions of Africa; SA
-South America; Venezuela, Columbia
-North-eastern India
-Northern Florida
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How has wildfires only recently started effecting the Amazon and SE Asia?
Not been a hazard in tropical rainforests due to humidity but recent burning of forests has often gotten out of hand, resulting in widespread fires.
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Why are wildfires common in LA and pose a serious threat?
-Most of the area is covered by drought-resistant chaparral as the area is too dry for tree growth. This vegetation can be tinder dry.
-Dry Santa Ana wind increases dryness of the vegetation to the point where a small spark will cause a major fire.
-Most of the area outside the centre of LA has low-density building where the natural vegetation is allowed to remain between properties.
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Primary effects of wildfires:
-Loss of crops, timber and livestock.
-Loss of life
-Loss of property
-Release of toxic gases and particulates; Air pollution creating a political dimension.
-Loss of wildlife
-Damage to soil structure and nutrient content
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Secondary effects of wildfires:
-Evacuation: People flee and won't be allowed back for a long period, if not forever. Emergency shelters will have to be found.
-Increased flood risk: In certain environments, where rain comes in heavy bursts, the loss of so much vegetation and the consequent decrease in interception, can lead to flooding.
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Preparing for wildfires:
Education-
California:
-Signing up and being aware of fire warning systems
-Familiarisation with evacuation routes and roads.
-Emergency pack
-Designated room in houses that can shut out smoke
-Creating a fireproof place at home for paper documents
-Fire-resistant materials to build house extensions
-Clearing flammable materials/vegetation within 10m of buildings
-Taking out insurance
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Preparing for wildfires:
Community action-
In Australia, a community education programme has been established to help people prepare. Focusing on identifying the most vulnerable areas in fire-prone communities. Helps residents develop their own survival strategies and techniques .
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Preparing for wildfires:
Computer modelling-
This has been employed to understand and predict fire behaviour. It involves studying the ways fire behaves to comprehend and predict fire behaviour.
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Prevention (wildfires):
Education-
Education programmes, signs and posters are used to urge people to be careful:
-Not leaving a fire/bbq unattended and always extinguishing it fully with soil and water
-Not discarding lit cigarettes out car windows
-Removing litter
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Prevention (wildfires):
Managing the vegetation:
Clearing areas between trees and other vegetation ahead of wildfire events to create firebreaks helps prevent the spread of wildfire.
270
Dealing with wildfires as they happen:
Fighting the fires, sometimes results in firemen's deaths. Spraying water and chemicals is costly so firefighters also work on the ground. Retardants are often sprayed on fires to slow them down.
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Adaptation to wildfires:
Some species of vegetation have become dependent on fire to reproduce. Climate change means fire seasons are hotter and longer than ever before. In California, houses must maintain a mandatory 35m space around the home and heat-resistant building materials.
