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