Tectonic Hazards

Question 1

Armenian earthquake 1988 - tectonic mega disaster

1. What was the size of the earthquake?
2. What was the cause?
3. What were the impacts? (4)
4. Why were the impacts so big? (4)

Answer 1

1. 6.9 Richter Scale
2. Arabian plate and Eurasion tectonic plates
3. 25000 killed and 300 000 injured
   Buildings didn’t withstand quake killing many people
   200 strong aftershocks
4. No money for education
   Poor education
   Rescue teams could not get there because roads were blocked
   Buildings contradicted with weak materials

Question 2

Name 2 multiple hazard hotspots

Answer 2

Philippines and California

Question 3

1. Why is the Philippines a hotspot? (3)
   - what plate boundary?
2. Provide examples of two major tectonic events

A) name 7 hazards that occur in the Philippines (this is why it’s a multiple hazard zone or hotspot!)

Answer 3

1. •7000 islands at latitudes 5-20N of the equator. •Within a belt of tropical cyclone storms(typhoons). Approx 6-7 major storms per year. • gets a lot of rain causing landslides in areas with steep slopes.
   - Philippines is near a destructive plate boundary where Philippines plate is being sub-ducted beneath the Eurasian plate. The two plates get stuck together as one moved under the other, causing a build up of pressure.
2. 1976 tsunami - dense Oceanic Philippines plate is being subducted beneath Eurasion plate at a destructive plate margin.
   1991 Volcanic eruption of Pinatubo - killed up to 800 but many evacuated as US air base in area gave warnings and provides vehicles.

A) volcanoes, earthquakes, typhoons, tsunamis, landslides, droughts and flooding.

Question 4

Why is the Philippines vulnerable? (4)

Answer 4

• Lower middle income country - lower capacity to cope though has successes to - GDP $3300ppp
• Rapidly increasing young population has led to deforestation increasing risk of landslides
• mega city Manila (20m population) which is at sea level and country’s average density is 240km2 so vulnerable to meteorological events
• people are very poor and live coastally, making them vulnerable to locally generated tsunamis and storm surges

Question 5

1. Provide an example of a tectonic event in USA
2. What was the size?
3. What were the impacts?
4. Why are the impacts less in USA compared to Philippines or others?

Answer 5

1. Loma Prieta earthquake SAN Francisco, 17 October 1989
2. Magnitude 7.1
3. 63 dead and over 1000 homes destroyed
   - $6 billion damage
4. USA are a superpower(very high economic development) with a high capacity to cope and strong governance, infrastructure and education systems.

Question 6

1. Explain the global distribution of earthquakes?

2. The distribution of earthquakes reveals the following pattern of tectonic activity: (3)

Answer 6

1. Main earthquake zones are found around plate boundaries. 70% of all earthquakes are in the ring of fire in the Pacific Ocean.
2. • The oceanic fracture zone - a belt of activity through the oceans along the mid ocean ridges, coming ashore in Africa, the Red Sea, the Dead Sea and California.
     - The continental fracture zone - a belt of activity following the mountain ranges from Spain, via the Alps, to the Middle East, the Himalayas to the East Indies and then circumscribing the Pacific.
     - Scattered earthquakes in continental interiors. Small minority of earthquakes can occur on old fault lines.

Question 7

3. What determines the strength of a volcanic eruption.

4. Explain the global distribution of volcanoes 🌋

Answer 7

3. The violence of volcanic eruptions is determined by the amount of dissolved gases in the magma and how easily the gas can escape.
4. There are 500 active volcanoes on the world and on average 50 erupt each year. Major volcanic hotspots are in the Mediterranean, Iceland, Malaysia and japan.

Question 8

Hazard risk equation

1. Explain the difference between a hazard and a disaster
2. What’s the hazard risk equation?
3. Compare Myanmar and japan to show how some countries are more at risk than others

Answer 8

1. Hazard is a natural event that has potential to threaten life and property. Disaster is the realisation of a hazard when it causes a significant impact on a vulnerable population.
2. Risk= hazard x exposure x vulnerability/manageability
3. •Hazard/exposure - Myanmar has high natural hazard with tsunamis and earthquakes. Japan is also highly exposed to natural hazards
   •vulnerability- Myanmar has a moderate risk with undeveloped buildings. Japan has a low risk but is vulnerable with an ageing population
   •coping capacity- Myanmar has a poor capacity to cope with low level internet and mobile phone access for older people and education is poor. Japan’s is good, elderly are more educated and have high internet connections and effective government.
   •overall risk- Myanmar is ranked 7th out of 190 nations so disaster risk to elderly citizens is very high. Japan are ranked 133rd thanks to its strong coping capacity and lower levels of vulnerability.

Question 9

Tectonic hazard profiles

1. What is a hazard profile?
2. What are the physical processes of tectonic hazards? (7)

Answer 9

1. Compares physical processes that all hazards share and help decision makers to identify hazards that should be given the most attention and resources.
2. Plate boundary, magnitude, speed of onset, duration, areal extent, spatial predictability and frequency.

Question 10

Tectonic governance and management

1. What the the 4 approaches to hazard management?
2. Name 2 ways to modify the loss (recovery)
3. Name 3 is ways to modify the vulnerability (response)
4. Name 5 ways to modify the event (prevention/protection)
5. Name 3 is ways to modify the cause(prevention)

Answer 10

1. Modify the loss(recovery), modify the vulnerability(response), modify the event(prediction) and modify the cause(prevention).
2. •Aid vital for poor people (immediate such as Haiti 2010) •insurance more useful for people in richer counties
3. •prediction and warning •community preparedness •education to change behaviour and prevent hazards turning to disasters
4. •environmental control •hazard avoidance by land use zoning •hazard resistance design through building to resist earthquakes •hard engineering defences •retro fitting of homes is possible for protection
5. •environmental control •hazard prevention •only possible for small scale hazards like landslides as the cause of earthquakes and volcanoes cannot by modified.