Section A - Tectonic Hazards Flashcards
What is Convection Current Theory?
cores temperature is 6000 degrees causing magma to rise in the mantle and sink towards the core when cools. The current flow beneath the lithosphere builds up lateral pressure moving plates with them but there is limited evidence of this.
What is Ridge Push and Slab Pull Theory?
The process that results when magma rises at a mid-ocean ridge and pushes oceanic plates in two different directions away from the ridge. Slab Pull is when at destructive margins the denser oceanic plates are pushed down under influence of gravity thus it pulls the rest of the plate behind it into the mantle where it’s melted.
What are the Earth’s Structures in order?
Crust; Mantle; Outer Core; Inner core
What is the Distribution of Tectonic Hazards?
Earthquakes and Volcanoes occur along plate margins
What are Hotspots?
where some volcanoes and earthquakes occur in the middle of plates as the crust is particularly thin for example Hawai
Define Oceanic Plates.
Forms on oceans. Thin: 5–10 km, denser. Young: usually less than 200 million years old. Formed of basaltic rock Sinks when it meets continental crust
Define Continental Plates
Forms on land, Thick: 20–200 km, less dense, Old: Up to 3.8 billion years old, Composed mainly of granite rock, Cannot be destroyed
Explain Conservative Plate Margin. Give Example
Tectonic plate margin where two tectonic plates slide past each other. E.g.- Juan de Fuca vs NA Plate, San Andreas Fault in California
Explain Constructive Plate Margin. Give Example.
Tectonic plate margin where rising magma adds new material to plates that are diverging or moving apart. E.g.- North American plate vs Eurasian Plate, Iceland / Mid Atlantic ridge
Explain Destructive Plate Margin.
Tectonic plate margin where two plates are converging or coming together and the oceanic plate is subducted. It can be associated with violent earthquakes and explosive volcanoes. E.g.- Continental North American Plate vs Oceanic Pacific Plate, West Coast of North American Ring of Fire
Explain Collision Plate Margin. Give Example.
Caused by Destructive plates where the melted oceanic plate is melted so there is more magma which creates more pressure thus pushing the continental plate upwards to form mountains. Or two continental same density plates push against each other and push upwards. E.g.- Himalayas/Andes
LIC Nepal Earthquake Case Study- Time and Date?
6:11 am / 25-04-15
LIC Nepal Earthquake Case Study- Location?
80KM North West of Kathmandu
LIC Nepal Earthquake Case Study- Magnitude?
7.8 Magnitude
LIC Nepal Earthquake Case Study- Plate Boundary Type?
Collision-Destructive Boundary
LIC Nepal Earthquake Case Study- Name 3 Primary Effects.
9000 killed, 20000 injured, 8 million affected, 3 million homeless, 7000 schools and hospitals destroyed and overwhelmed, International airport became congested as aid arrived, Cost $5 Billion.
LIC Nepal Earthquake Case Study- Name 3 Secondary Effects.
Triggered avalanches in Mount Everest killed 20 people, an avalanche in the Langtang region left 250 people missing, Landslide blocked the Kali Gandaki River- many people evacuated in case of flooding.
LIC Nepal Earthquake Case Study- Name 3 Immediate Responses.
300 thousand migrated from Kathmandu to seek shelter with family and friends, half a million people tents were needed to provide shelter for the homeless, Social Media was widely used in search and rescue operations and satellites mapped damaged areas
LIC Nepal Earthquake Case Study- Name 3 Long-Term Responses.
stricter controls in building codes, Over 7000 schools to be repaired or to be rebuilt, ~In June 2015 Nepal hosted an international conference to discuss reconstruction and seek technical and financial support from other countries, Tourism- a major source of income to be boosted by July 2015 some heritage sites reopened and tourists were starting to return
HIC Chile Earthquake Case Study- Time and Date?
3:34 am / 07-02/10
HIC Chile Earthquake Case Study- Location?
Chile - Port of Talcahuano
HIC Chile Earthquake Case Study- Magnitude?
8.8 Magnitude Earthquake
HIC Chile Earthquake Case Study- Plate Boundary Type?
Destructive Plate Boundary
HIC Chile Earthquake Case Study- Name 3 Primary Effects.
500 killed, 12000 injured, 800000 affected, 220000 homes, 4500 schools, 53 ports, 56 hospitals, and other public buildings were destroyed, Santiago Airport was Badly Damaged, Cost $30 Billion.
HIC Chile Earthquake Case Study- Name 3 Secondary Effects.
1500 km of roads damaged- remote communities cut off for many days, Several coastal towns devastated by Tsunami, A fire at a chemical plant near Santiago
HIC Chile Earthquake Case Study- Name 3 Immediate Responses.
Emergency services responded quickly. International support provided field hospitals, satellite phones and floating bridges. Within 24 hours, the north-south highway was temporarily repaired, allowing aid to be transported from Santiago to areas affected by the earthquake. Within ten days, 90% of homes had had power and water restored. US$60 million was raised after a national appeal, which funded 30,000 small emergency shelters
HIC Chile Earthquake Case Study- Name 3 Long-term Responses
Chile’s government launched a housing reconstruction plan just one month after the earthquake to help nearly affected 200,000 families. Chile’s strong economy reduced the need for foreign aid to fund rebuilding. The recovery took over four years.
Nepal vs Chile GDP?
Chile - 38th Highest
Nepal - 109th Highest
Nepal vs Chile HDI?
Chile - 41st highest
Nepal - 145th Highest
Name 3 Benefits of living near a tectonic Hazard (Iceland)
Hot Water from within the Earth’s Crust produces heat and hot water for 90% of all buildings in Iceland, Geothermal Energy is used to generate 25% of the country’s electricity, Thousands of tourists visited Iceland after the recent eruption of E15 in 2010, Roughly 1 million visited the country the following year
What are the M3P and give a brief definition?
Monitoring- using scientific equipment to detect warning signs of tectonic event
Prediction- using historical evidence and monitoring, scientists can make predictions on when and where a tectonic hazard may happen
Protection- Designing Buildings that will withstand tectonic hazards
Planning- Identifying and avoiding places at most risk
Explain Protection.
Hard to protect against the sheer power of volcanoes and earthquakes as they are also unpredictable. CAn use earth embankments and explosives to divert lava such as on the slopes of Mount Etna in Italy.
What are the 6 scientific equipments for Monitoring and explain them.
Remote Sensing- satellites detect heat and changes to volcano shapes
Seismicity- seismographs record earthquakes
Ground Deformation- changes to shapes of volcanoes are measured using laser beams
Geophysical measurements- detect changes to gravity as magma rises to the surface
Gas- instruments detect gases released as magma rises
Hydrology- measurements of gases dissolved in water
Scientists are yet to discover more reliable ways of1 detecting earthquakes
Explain Planning.
Volcanoes- Hazard maps show the likely area to be affected. Can be used to restrict certain land uses or plan out evacuations.
Earthquakes- Maps produced to show the effects of earthquakes and identify areas most at risk of damage. High-value lands can then be protected in vulnerable areas.
