Tectonic Processes & Hazards - EQ3 - 1.7C Flashcards
What are some of the shared hazard zone charcateristics of California, Indonesia and Japan
- are tectonically active and so earthquakes (and often eruptions) are common
- are geologically young with unstable mountain zones prone to landslides
- are often on major storm tracks either in the mid-latitudes or on tropical cyclone tracks
- may suffer from global climate perturbations such as El Niño and La Niña
what is a multiple hazard zone
places where a number of physical hazards combine to create an increased level of risk for the country and its population
what are disaster hotspots
- Multiple Hazard Hotspots are often made worse if the country’s population is vulnerable (wealth/GDP, population density, etc.)
- or if it suffers repeated events, often on an annual basis, so that there is never any time for recovery.
- These places are often referred to as a disaster hotspot (a country or area that is extremely disaster prone for a number of reasons).
Why is identifying multiple hazard zones important
- it helps decision makers to understand a region’s hazards, to set priorities
When two or more hazards occur at the same time or in rapid succession the area faces..
- Dealing with a new hazard event whilst still recovering from a previous hazard event
- Issues with development due to the costs of recovering from multiple hazard events
What is the economic status of the Phillipines
- lower middle income nation
- $5000 per year
What is the HDI of the phillipines
0.75
What is the population of the phillipines
91 million (density 240 per km2, 2000 per km2 in Manila)
A multiple hazard zone with complex hazards is a combination of…
tectonic hazards and hydro-meteorological hazards
How does 1991 Mount Pinatubo exemplify hydrometeorlogical hazards contributing to tectonic disasters
- Famously, during the 1991 eruption of Mount Pinatubo in the Philippines the area was struck by Typhoon Yunga
- Heavy rainfall from the typhoon mobilised volcanic ash into destructive lahars.
Describe the landscape of the philippines
- It is an archipelago consisting of over 7,600 croweded coastal islands,
many very small, - spread over latitudes between 5 & 20 degrees North,
- Mountainous country
Almost ….% of the population is urban
50%
An estimated …..% of the population and ….% of the land area is vulnerable to hazard events
An estimated 74% of the population and 60% of the land area is vulnerable to hazard events
What did the Phillipines experience in 1919 & 2020
- 4 typhoons
- the eruption of the Taal volcano
- a number of earthquakes
What are the hazards experienced by the phillipines
- In typhoon belt and on mobile plate boundary
- ENSO cycles increase range of hazards
Describe tectonic activity in the Phillipines
- It is on the western edge of the Pacific Ring of Fire
- These are mainly convergent boundaries leading to both volcanoes and earthquakes
There are a number of ……………. zones around the archipelago which has led to …………
There are a number of subduction zones around the archipelago which has led to significant volcanic activity
Describe the volcanic activity in the Phillipines
- There are 24 active volcanoes on the islands
- The eruption of Mount Pinatubo in 1991 was until recently the largest eruption in the last 100 years
- Approximately 2.81 million people live within 30km of the Taal volcano
Describe Tsunamis in the Phillipines
- The location in the Western Pacific makes the Philippines vulnerable to tsunami
- Tsunami may result from both volcanic eruptions and earthquakes
- The worst tsunami in recorded history occurred in 1976 when tsunami waves of up to 5 meters struck Lebak in the southwest of the Philippines
Typhoons
Describe the hazard of Typhoons
- The Philippines is located between 5o and 20o north of the equator and lies in the tropical cyclone zone
- Typhoons can occur at any point in the year
- The most active months are June to September
- The islands are affected by between 15-20 typhoons a year
Describe the effect of landslides in the Phillapines
- The mountainous landscape of the Philippines means that landslides are common
- Earthquakes, volcanic eruptions and typhoons can all trigger landslides
What was the most powerful Typhoon in the Phillipines in recent years
- The most powerful typhoon to strike the Philippines in recent years was Typhoon Yolanda (also known as Haiyan) in 2013
- Wind speeds reached 315km/h and 6,500 people were killed
Why is the Phillipines highly vulnerable
-pop density
Increased urbanisation has led to high population densities in cities such as Manila
Why is the Phillipines highly vulnerable
- location of population
- The population is mostly coastal as inland areas are mountainous, this increases the vulnerability to storm surges, typhoons and tsunami
Why is the Phillipines highly vulnerable
-higher population
- Increasing population has led to deforestation in the upland areas as a result of clearance for settlements and agriculture –> landslides, less inteception, more surface run off
