2.1 Volcanoes and Earthquakes
Structure of the Earth

The ____________ is the outer layer, broken into sections caled tectonic
plates. It is the thinnest layer and the one which we live on.

The ____________ is the thickest layer and consists of molten rock

The _____________ is molten & about 3000 degrees C.

This _____________ is solid due to the immense pressure and is about 5000
degrees C.

Both the inner & outer core consist of iron & nickle.
2.1 Volcanoes and Earthquakes
Plate movement
The earths crust is broken into
different sections which are
slowly moving about.
Collision boundary
A plate boundary where two
plates are converging. These
include destructive boundaries,
where an oceanic plate meets a
continental plate, and collision
boundaries, where the two
plates are both continental
plates.
Constructive plate
boundary
A plate boundary where new
material is being formed by the
upwelling of magma from
within the Earth’s interior.
Conservative plate
Where two plates slide past one
boundary (or transform
another without loss of
plate boundary)
material.
Destructive plate
Plate boundary where an
boundary
oceanic plate meets a
continental plate. The oceanic
plate is more dense than the
continental plate, so it sinks
below the continental crust.
Subduction zone
The area where one tectonic
plate slides beneath another, a
process known as subduction.
One plate (usually a dense
oceanic plate) plunges
underneath a less dense
continental plate. As it sinks, it
melts and is destroyed, forming
magma, which in turn may
reach the surface through
volcanic activity.
2.1 Volcanoes and Earthquakes
Volcano
A cone-shaped mountain
formed by material (magma,
ash and cinders) erupted from
below the Earth’s surface.
A volcano currently showing
signs of activity.
A volcano that has not erupted
for a very long time but could
erupt again.
A volcano that has shown no
signs of volcanic activity in
historic times.
Very fine-grained volcanic
material.
Molten magma that has
reached the Earth’s surface. It
may be liquid or may have
solidified.
Molten rock within the Earth.
When magma reaches the
surface it is called lava.
The reservoir of magma
located deep inside a volcano.
Lava
Extinct volcano
Magma
Ash
Volcano
Chamber
Dormant volcano
Active volcano
2.1 Volcanoes and Earthquakes
Steep volcano formed of sticky
(viscous) acidic lava, ash and
cinders.
A gentle, low-angled volcano
formed of runny, basaltic lava,
e.g. Mauna Loa in Hawaii. The
lava is capable of flowing long
distances before cooling.
Depression at the top of a
volcano following a volcanic
eruption. It may contain a lake.
Superhot (700°C) flows of ash,
pumice (volcanic rocks) and
steam moving at speeds of over
500 km/hr.
The natural heat found in the
Earth’s crust in the form of
steam, hot water and hot rock.
A relatively small area of the
Earth where magma rises
through a continental or
oceanic plate. As the plate
moves across the hotspot a
chain of volcanoes may form,
e.g. the Canary Islands and the
Hawaiian Islands.
Pyroclastic flow
Hotspot
Crater
Shield volcano
Geothermal energy
Cone volcano
2.1 Volcanoes and Earthquakes
Composite/Cone (strato-volcanoes)
Shield volcanoes
2.1 Volcanoes and Earthquakes
Composite/Cone (strato-volcanoes)
Shield volcanoes
2.1 Volcanoes and Earthquakes
Earthquake
A sudden movement of the
Earth’s crust.
A scale of earthquake intensity
based on descriptive data.
An open-ended scale to record
the magnitude of earthquakes:
the higher the number on the
scale the greater the strength of
the earthquake.
The point on the Earth’s
surface directly above the focus
of an earthquake. The strength
of the shockwaves generally
decreases away from the
epicentre.
The position within the Earth
where an earthquake occurs.
Earthquakes can be divided
into shallow-focus and
deep-focus earthquakes,
depending on how far below
the surface they occur.
these are the shockwaves that
move outwards from the focus.
Their energy disipates the
further they travel.
instrument that measures the
magnitude of earthquakes.
Seismic waves
Focus
Mercalli scale
Richter scale
Earthquake
Seismometer
Epicentre
2.1 Volcanoes and Earthquakes
A_________is an opening in the Earth’s crust through which hot molten
magma(lava),molten rock and ash are erupted onto the land.
________refers to molten materials inside the Earth’s interior.
The_________refers to the reservoir of magma located deep inside the
volcano.
A_______is the depression at the top of a cone volcano following a
volcanic eruption.
A______is the channel which allows magma within the shield valcano to
reach the surface in a volcanic eruption.
________________ have erupted in recent times and could erupt again.
___________________are volcanoes that have not erupted for many
centuries but may erupt again.
___________________are not expected to erupt again.
______________involve sudden,violent shaking of the Earth’s surface.
________refers to the place beneath the ground where the earthquake
takes place.
________________________are associated with subduction
zones(>300km).
2.1 Volcanoes and Earthquakes
____________________________are generally located along
constructive boundaries and along conservative boundaries(0-60km).
The___________is the point on the ground surface immediately above
the focus.
______________________in which new oceanic crust is being created;.
_______________________in which older crust is destroyed.
__________________ where plates are folded and crumpled.
_________________________where plates slip past each other
2.1 Volcanoes and Earthquakes
Why more deathes and injuries are caused by earthquakes than by
volcanic eruptions？
Why people live in areas where earthquakes/ volcanoes occur？
Explain why volcanic eruptions occur on constructive(divergent) plate
boundaries.
Explain why volcanic eruptions occur on destructive(convergent) plate
boundaries.
Why the numbers of deaths and injuries caused by earthquakes is
greater in LEDCs than MEDCs