Enquiry question 1: Why are some locations more at risk from tectonic hazards? Flashcards
What is the temp, density, composition, physical state and what seismic waves do the crust have?
Temp- 400 degrees
Density- Low
Composition- Granite + Basalt
Physical state- Solid
Seismic waves- Surface and
body waves pass
through
What is the temp, density, composition, physical state and what seismic waves does the mantle have?
Temp- 870 degrees
Density- Medium
Composition- Peridotite
Physical state- Liquid/solid
Seismic waves- Body waves pass
through at
variable rates
What is the temp, density, composition, physical state and what seismic waves does the outer core have?
Temp- 4400- 6100 degrees
Density- Dense
Composition- 12% sulphur
88% iron
Physical state- Liquid
Seismic waves- P waves
What is the temp, density, composition, physical state and what seismic waves does the inner core have?
Temp- 7000 degrees
Density- Very dense
Composition- 20% nickel
80% iron
Physical state- Solid
Seismic waves- P waves
What happens at a divergent plate boundary?
- Plates move apart
- Shield volcanoes form
- Mt Nyiragongo is an example
What happens at a destructive plate boundary?
- Oceanic crust subducts beneath the continental plate
- Creates earthquakes and volcanoes
What happens at collision plate boundaries?
- Two continental plates collide
- Neither can sink and so the land buckles upwards forming mountains
- E.g. the Himalayas
- Earthquakes can occur here
What happens at conservative plate boundaries?
- Plates slide past one another
- Pressure builds up
- Energy is released causing an earthquake
What discovery was made in 1915
Alfred Wegener publishes his theory on continental drift, which states that Earth’s landmasses are constantly moving
What discovery was made in 1918
Sonar technology developed during WW1 which revealed details about the ocean floor, scientists now know that the crust exists under the world’s oceans, it becomes an assumption that the ocean floor moves as well as continents
What discovery was made in 1919
Arthur Holmes develops a theory that explains how the large landmasses move from convection currents through the mantle the same way that heated air circulates a room
What discovery was made in 1946
Scientists make use of the military sonar tech to map ocean floor
What discovery was made in 1954
First world map of volcanic eruptions and earthquake zones is published by a French seismologist J.P. Rothe
What discovery was made in 1960
Harry Hess and Robert Dietz propose the theory of sea floor spreading where magma oozes up from the Earth’s interior along the mid-oceanic ridges
What discovery was made in 1963
A pattern of magnetic striped rock on the ocean floor that provides evidence to support Hess and Dietz’s theory of sea floor spreading
