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14,000
earthquakes
About 14,000 earthquakes are recorded in and around New Zealand
each year. Most of them are small, but 100 to 150 are strong
enough to be felt.
Cover
image: the Awatere Fault Zone at Tarndale looking south-west
up the Wairau River to the Spenser Mountains (the Main Divide)
in the Nelson Lakes National Park.
Many earthquakes occur in the Axial
Tectonic Belt, where most of the deformation caused by the collision
of the Pacific and Australian tectonic plates takes place.
Deep earthquakes in the North Island and the south-west
of the South Island relate to the active subduction of the oceanic
plates. See
map at IGNS: the deepening of the earhquakes towards the
west (North Island) and the east (South Island), corresponding
to the dip of the tectonic plates, is clearly visible.
A high rate of shallow seismicity in the North Island
is related to the arc volcanism and active spreading that is
taking place in the Taupo Volcanic Zone. See
map at IGNS.
Movements
of major faults
| Fault/area |
Rate
of movement |
Periodicity
of big quakes |
Last
big quake |
| Alpine
Fault |
2.5-4.5
mm/y |
250-400
years |
no
movement in the last 100 years |
| Wellington
Fault |
|
600
years |
300-500
years ago |
| Wairarapa
Fault |
|
|
1855
magnitude 8-8.2 |
| Hope
Fault |
15-25
mm/y |
|
1888
magnitude 7-7.3
|
Some
historical New Zealand earthquakes
| Earthquake |
Year |
Magnitude |
| Wairarapa |
1855 |
8-8.2 |
| Hope
Fault |
1888 |
7-7.3 |
| Buller |
1929 |
7.8 |
| Napier |
1931 |
7.8 |
| Inangahua |
1968 |
7.1 |
| Edgecumbe |
1987 |
6.1 |
| Weber |
1990 |
6.1 |
| Arthur's
Pass |
1994 |
6.7 |
More details: map of locations
of large historical earthquakes at IGNS.
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NZ'S
HISTORICAL EARTHQUAKES
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Location
of shallow earthquakes, 1990-1994.
Their greater concentration in the most tectonically active
areas (Axial Tectonic Belt and Taupo Volcanic Zone) is clearly
visible.
Based on
map by IGNS.
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