Here are the key points your group discussed about fault lines and earthquakes in the local area: 1. A fault line is a fracture or break in the Earth's crust along which movement has occurred. 2. Major local fault lines include the Waimea, Grampians, Flaxmore, Sharland, and 88 Faults. 3. Earthquakes are caused by movement along fault lines. When the rocks on either side of a fault slip or grind past each other, energy is released in waves that cause the shaking we feel during earthquakes. 4. Historical earthquakes in the Nelson area, such as in 1848, 1868, 1893, 1929 and 1968, were likely caused by movement along local faults

1. Plate Tectonics

2. Major Tectonic Plates
Boundaries between
plates are just lines on
maps, but the stresses
caused by moving plates
affect vast areas of rock
near the boundaries.
Major Earthquakes
Compare the two figures.
What relationship is there
between the tectonic plate
boundaries and
earthquakes?

3. Normal Fault
A normal fault drops rock on one side of the fault
down relative to the other side. Take a look at
the side that shows the fault and arrows
indicating movement. See the block farthest to
the right that looks kind of like a foot? That’s the
foot wall. Now look at the block on the other
side of the fault. See how it’s resting or hanging
on top of the foot wall block? That’s the hanging
wall.
Now, consider this: if we hold the foot wall
stationary, gravity will normally want to pull the
hanging wall down, right? Faults that move the
way you would expect gravity to move them
normally are called normal faults! Not so hard,
is it?
Take a look where the fault has ruptured the
Earth surface. Notice that movement along the
fault has produced an elongate cliff? That fault-
generated cliff is called a fault scarp.

4. Reverse Fault
We classify faults by how the two rocky blocks
on either side of a fault move relative to each
other. The one you see here is a reverse fault.
Along a reverse fault one rocky block is pushed
up relative to rock on the other side.
Here’s a way to tell a reverse fault from a
normal fault. Take a look at the side that shows
the fault and arrows indicating movement. See
the block farthest to the right that is shaped kind
of like a foot? That’s the foot wall. Now look at
the block on the other side of the fault. See how
it’s resting or hanging on top of the foot wall
block? That’s the hanging wall.
Think about this: if we hold the foot wall
stationary, where would the hanging wall go if
we reversed gravity? The hanging wall will slide
upwards, right? When movement along a fault is
the reverse of what you would expect with
normal gravity we call them reverse faults!

5. Strike-slip Fault
Strike-slip faults have a different type
of movement than normal and reverse
faults. You probably noticed that the
blocks that move on either side of a
reverse or normal fault slide up or
down along a dipping fault surface.
The rocky blocks on either side of
strike-slip faults, on the other hand,
scrape along side-by-side. You can see
in the illustration that the movement is
horizontal and the rock layers beneath
the surface haven't been moved up or
down on either side of the fault.
Take a look where the fault has
ruptured the Earth surface. Notice that
pure strike-slip faults do not produce
fault scarps. There are other tell-tale
changes in the landscape that signal
strike-slip faulting.

6. Fault Illustrations
Fault Movement
Normal Movement
Reverse and Thrust Faults
Earthquake Focus

7. Fault Movement Activity
A
B
Copy and complete the following Table
Photo Fault Land Human
Affect Affect
A
B
C
C

8. Earth’s Crust

9. Earthquakes
The Nelson urban area lies within the most tectonically active zone of
New Zealand. The area has experienced damaging earthquakes,
those since European settlement being in 1848, 1868, 1893, 1929,
and 1968. They could originate from local or distant fault movement.
1. In what ways will an earthquake
affect people’s immediate
surroundings in Nelson (inside
houses, buidlings) ?
2. In what way will an earthquake
affect our local landscape?
3. What can we do to minimise the
damage that an earthquake
may cause?

10. Earthquake Location Patterns
Study this map to answer the
following questions
1 What did scientists measure to
make these maps?
2 What pattern do you observe?
3 Are the earthquakes more
frequent and/or bigger in the
North Island than the South
Island?
4 In which place would you expect
to see the greatest number of
fault lines?
5 On the outline map of NZ, draw
fault lines in where you think
they run.

11. Local Fault Lines
The Nelson urban area lies within the most
tectonically active zone of New Zealand.

12. Richmond & Stoke
GRAMPIAN
88 FAULT
WAIMEA
FLAXMORE
HESLINGTON
The faults looking across Richmond towards Mackay’s Bluff.
The Waimeai, Grampians and Flaxmore Faults are clearly seen

13. Waimea Fault
WAIMEA
88 FAULT
JENKINS
BISHOPDALE
The faults near the Brook Street volcanics

14. Nelson Area
GRAMPIAN
88 FAULT
WAIMEA
FLAXMORE
BISHOPDALE
Over Nelson College and Bishopdale. There are several faults in this area.

15. Sharland Fault
FLAXMORE
SHARLAND
Sharland Hill over to the Boulder Bank.

16. Fault Line Activity
In groups discuss the following questions:
1. What is a fault line?
2. List all the major fault lines in our local
area.
3. Explain how earthquakes relate to fault
lines.
4. Research how earthquakes have
affected the local area.