Tectonics
Earthquakes: Most earthquake zones are found at, or close to,
tectonic plate boundaries, often in clusters. About 70% of all
earthquakes are found in the ‘Ring of Fire’ in the Pacific Ocean.
The most powerful are associated with convergent or
conservative boundaries.
Intra-plate earthquakes do not occur at plate boundaries.
Intraplate earthquakes are caused by stresses within a plate.
Since plates move over a spherical surface, zones of weakness are
created. Quakes can happen along these zones of weakness.
Volcanoes: Occur close to or at tectonic plate boundaries and
hotspots such as Hawaii. Plates subducting (in subduction zones)
create fold mountains so more volcanoes.
In Hawaii, there is a plume rising under the surface which creates
a hotspot on the surface. Over millions of years magma has
cooled and created land.
Tsunamis: Around 90% of all events occur within the Pacific Basin,
associated with activity at the plate margins. Most tsunamis are
generated at subduction zones on convergent boundaries.
,Tectonics
Plate boundaries:
Collision:
- Caused when two continental plates move towards each
other. Fold mountains are created.
- Causes destructive earthquakes.
- Himalaya Mountain Range, Nepal
Destructive:
- Caused when the oceanic plate is subducted underneath
the less dense continental plate. The oceanic plate melts as
it reaches the subduction zone and can force its way to the
surface as magma.
- Causes highly destructive earthquakes, volcanoes, and
tsunamis.
- Nazca Plate, South America
Constructive:
- Caused when two plates move apart from each other.
Magma wells to the surface to fill the gaps left by the
plates, forming new crust.
- Causes destructive earthquakes and volcanoes.
- Mid-Atlantic Ridge, Iceland
Conservative:
- Caused when two plates move past each other in opposite
directions or in the same direction at different speeds.
- Causes highly destructive earthquakes.
- San Andreas Fault, California, USA
, Tectonics
Mantle convection= The heat inside the Earth’s Mantle creates convection currents, when they rise
to the top of the mantle, they push and move the plates.
Seafloor spreading= new rock forms along the ridges and is pushed apart when newer rock forms.
Subduction= when the oceanic plate subducts under the continental plate as it is denser.
Slap pull= oceanic lithosphere sinks into the mantle which pulls slabs of the lithosphere apart at
divergent boundaries.
Paleo-magnetism=
Earthquakes: Most earthquake zones are found at, or close to,
tectonic plate boundaries, often in clusters. About 70% of all
earthquakes are found in the ‘Ring of Fire’ in the Pacific Ocean.
The most powerful are associated with convergent or
conservative boundaries.
Intra-plate earthquakes do not occur at plate boundaries.
Intraplate earthquakes are caused by stresses within a plate.
Since plates move over a spherical surface, zones of weakness are
created. Quakes can happen along these zones of weakness.
Volcanoes: Occur close to or at tectonic plate boundaries and
hotspots such as Hawaii. Plates subducting (in subduction zones)
create fold mountains so more volcanoes.
In Hawaii, there is a plume rising under the surface which creates
a hotspot on the surface. Over millions of years magma has
cooled and created land.
Tsunamis: Around 90% of all events occur within the Pacific Basin,
associated with activity at the plate margins. Most tsunamis are
generated at subduction zones on convergent boundaries.
,Tectonics
Plate boundaries:
Collision:
- Caused when two continental plates move towards each
other. Fold mountains are created.
- Causes destructive earthquakes.
- Himalaya Mountain Range, Nepal
Destructive:
- Caused when the oceanic plate is subducted underneath
the less dense continental plate. The oceanic plate melts as
it reaches the subduction zone and can force its way to the
surface as magma.
- Causes highly destructive earthquakes, volcanoes, and
tsunamis.
- Nazca Plate, South America
Constructive:
- Caused when two plates move apart from each other.
Magma wells to the surface to fill the gaps left by the
plates, forming new crust.
- Causes destructive earthquakes and volcanoes.
- Mid-Atlantic Ridge, Iceland
Conservative:
- Caused when two plates move past each other in opposite
directions or in the same direction at different speeds.
- Causes highly destructive earthquakes.
- San Andreas Fault, California, USA
, Tectonics
Mantle convection= The heat inside the Earth’s Mantle creates convection currents, when they rise
to the top of the mantle, they push and move the plates.
Seafloor spreading= new rock forms along the ridges and is pushed apart when newer rock forms.
Subduction= when the oceanic plate subducts under the continental plate as it is denser.
Slap pull= oceanic lithosphere sinks into the mantle which pulls slabs of the lithosphere apart at
divergent boundaries.
Paleo-magnetism=
