Edexcel IGCSE Geography 復習筆記 3.2.3 Impacts of Natural Hazards
Impacts of Natural Hazards
Natural hazards are when they affect people; they have both short and long term impacts
Short & Long Term Impacts of Hazard Events
Short Term Impacts
Long Term Impacts
Damage to properties from high wind, heavy rain and storm surges, power cables and telephone lines
Rebuilding of homes, schools, infrastructure and businesses can take time
Impact on businesses, tourism and transport
Cost of rebuilding affects the economy, increased unemployment
Landslides
Stricter building codes introduced
Deaths and injuries, decrease in quality of life
Mental health, Post Traumatic Stress Disorder (PTSD)
Crops destroyed, impacting on farmers incomes and increasing food prices
Risk assessment and hazard mapping reviewed
Habitat destruction
Exam Tip
In the exam you may be asked to analyse the short and long term impacts of an earthquake event. In your answer you need to consider:
Why short and long term impacts vary - the size and magnitude of the event
What are the main short and long term impacts
How the impacts are affected by the level of development, location and accessibility of the area
What are the knock-on effects of some impacts e.g. water supplies being contaminated can lead to disease
Case Study: Impacts of Tropical Cyclones
Name - Haiyan (Yolanda)
Location - Philippines, Vietnam and Taiwan
Date - November 2013
Magnitude - Category 5
Highest wind speed - 315km/h
Storm surge - up to 6m
Rainfall - 282mm in 12 hours
Path of Tropical Cyclone Haiyan (Yolanda)
Short Term Impacts
Long Term Impacts
Estimated 6400 deaths
Cost US$5.8 billion
4.1 million people made homeless
Build Back Better launched in 2014 to upgrade buildings to reduce the damage from future tropical cyclones. However, by 2016 only 1% of target of 200,000 homes had been achieved
90% Tacloban destroyed
No build zone along the Eastern Visayas coastline
Roads blocked by debris and landslides
Storm surge warning system
Electricity supply down in some areas for six weeks
Mangroves replanted
Airport at Tacloban badly damaged
Tropical storm shelters built inland
1.1 million tonnes of crops destroyed
One year on 4 million people still in temporary shelters
33 million coconut trees destroyed
Six months after in Tacloban access to clean water was still limited
1.1 million homes damaged or destroyed
14 million people affected
Landslides
Case Study: Impacts of Earthquakes
Name - Gorkha
Location - Nepal
Date - 25th April 2015
Epicentre - Barpak village, 60km north-west of Kathmandu (capital)
Depth - 15km
Magnitude - 7.8
Plate boundary - Collision plate where Indian plate collides with the Eurasian plate
Landslides triggered by the Gorkha earthquake
Short Term Impacts
Longer Term Impacts
Approximately 8600 deaths
Cost US$10 billion
19,000 injuries
7000 schools rebuilt
Avalanches on Mount Everest and in the Langtang valley
Two years later 70% of displaced people still in temporary shelters
Roads blocked due to landslides
Stricter building codes introduced - but not always enforced
Landslides - village of Ghodatabela covered, leading to 250 deaths
Asian Development Bank (ADB) provided US$3 million grant
Over 600,000 houses destroyed and over 250,000 damaged
Grants of US$3000 for people to rebuild homes - Many have not re-paid this 5 years later
UNESCO World Heritage sites destroyed - Changu Narayan Temple and Dharahara Tower
8,300 Schools damaged or destroyed
1,000 health centres destroyed
Case Study: Impact of Volcanoes
Name - Mount Merapi
Location - Java, Indonesia
Date - 25th October -30th November 2010
Magnitude - VEI 4
Plate boundary - Destructive plate boundary where the Indo-Australian plate is subducting below the Eurasian plate
Type of volcano - Stratovolcano or composite
?Ash fall on village near to Mount Merapi
Short Term Impacts
Long Term Impacts
353 deaths
Hazard map updated and exclusion zone expanded permanently to 2.5km
577 injuries
0ver 2,500 residents moved to permanent new homes
Pyroclastic flow travelled 3km
Money given to farmers by the government to replace livestock and crops
Volcanic ash fell up to 480km away
Improved monitoring
30cm of ash covered nearby villages including Bronggang 15km from the volcano and Yogyakarta
Increased education to inform people of what to do and where to go in the event of another eruption
Exclusion zone extended to 20km
Dams built to hold back lahars
Roads blocked
Soils will be more fertile due to the minerals contained in the falling ash
Food prices increase
350,000 people evacuated
Schools and airports closed
Lahars
Decrease in tourism income
Exam Tip
Remember, whether you use the case studies here or ones you have completed in class, in the exam you will be expected to know some facts and figures from case studies. These are place specific details and is what the examiner will be looking for in higher level answers.