The Physical Environment of Kaikoura

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The Physical Environment of Kaikoura
CGTA Kaikoura Workshop2004

• Dr Martin Single
• Department of Geography
• University of Canterbury

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Setting Geology Relief and Bathymetry Climate Lan
dform Development Dynamic Processes
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Setting
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Geology

• Geology map with comments about ages and Kaikoura
  Orogeny etc. Faults and rock types

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Climate

• Sunshine hours 2068
• Temperature 8 to 17C
• Frosts do occur
• Rainfall
• 865mm/yr at coast
• 1300mm/yr in mountains
• High number of high intensity events - 100 to 150
  raindays
• Seasonal low in summer. Peak rain in Autumn,
  100mm in day not uncommon
• Snow down to 1200m for half the year

Cyclone Alison March 1975 155mm in 6 hrs, 193mm
in 12 hrs, 205mm in 24 hrs. Record high on May 6
1923 - 345mm in 24 hrs
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Winds and Waves

• Wind regime is bi-directional prevailing from
  northeast (15.3) north to east (28.5)
• southwest (16.7) - south to west (43.2)
• Calm (27.6),Norwest (0.7)
• Sea conditions
• Mainly from northeast and south east coast
  swell
• Local waves from northeast
• Swell from south
• Hslt1.0m, T 12s
• Hsgt1.5m, T 12 to 14s
• Calm (0-0.5m) 79.1 rough (2.5-4.0m) 4.4
• Sheltering effect of peninsula (lee from
  southerlies to Hapuku)
• gt1.5m 15 South Bay, 3 EPFS
• Tides 1.1m above Lyttelton datum, Spring range
  1.3m, but perigean range can be up to 2.5m

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Bathymetry
Continental shelf slopes to 100m in 6km
offshore of Kowhai R, then to 1000m in next
4km At Hapuku R shelf is 15km wide and 150m deep
at margin

• Bathymetric map

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Kaikoura Canyon
Meeting of cool antarctic waters with warmer
waters from north result in highly productive
biology. Kaikoura Canyon joins Hikurangi Trough
-range of water depths near the coast. Unstable
margins contain sites of massive submarine slides
which would result in local tsunami
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Relief
Tectonics Kaikoura Orogeny Uplift
1m/1000yrs 2.3 to 10m over last 1000yrs Erosion
- fluvial Deposition - fans/plains Erosion -
marine

• Relief map

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Landform Development
Shulmeister and Kirk 1993
McKay 1885
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The Evolution of the Kaikoura Lagoon as proposed
by Dawe (1997). A The interpretation of
Kaikoura as it may have appeared 10,000 years
B.P. with a rising sea-level then 30 metres below
present. B Kaikoura 5,500 years B.P with sea
levels higher forming cliffs into the outwash
plains. The area at this time was tectonically
lower than at present.
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C 2,500 years B.P. Erosion of the outwash
plains providing sediments for the development of
the spit, which grew and consequently formed a
lagoon on the landward side. From this point in
time the coastline began to prograde from a
combination of sea level drops and tectonic
uplift events. D The present day coastline.
(Adaption of Dawe by Boorer 2002)
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Dynamic Processes
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Dynamic Processes
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Dynamic Processes
December 25 1993
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Dynamic Processes
December 25 1993
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Dynamic Processes
Two views of South Bay pa (pre-European),
Kaikoura Peninsula. Ditches and banks enclose the
points formed by the cliff.
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Ferae Naturae