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Accessibility: WHEELCHAIR ACCESS
WHAT'S HERE?
William Street, Petone
Remains of a beach ridge formed by storms at the back of Petone Beach about 2500 years ago and uplifted by earthquakes.
LEARN ABOUT IT
The rise in William Street
The beach ridge was formed during storms at the back of the former Petone Beach about 2500 years ago. Since then it has been left high and dry by a combination of sea level fall (1), and uplift during earthquakes (2). The Petone foreshore as a result has advanced 600 m further southward.
(1) Sea level was 1.5 - 2 m higher than present between 6000 and about 4000 years ago and at this time the beach was up near Melling Bridge. Since then sea level has progressively fallen leaving behind old beaches and ridges and many of the flat coastal terraces about 1 m above sea level around New Zealand's coast.
(2) The Hutt Valley is in a 'fault angle depression' with the Wellington Fault down-faulting it on its western side. In this depression young sediments have accumulated building up the flat floor of Lower Hutt and Petone. Much of the sediment comes down the Hutt River and has been deposited at its mouth and has helped build the valley floor plain out southwards. This subsidence of the Hutt Valley has been countered by uplift every time the Wairarapa Fault (west side of Wairarapa Valley) ruptures. The last rupture on this fault was in 1855, it uplifted the whole Wellington region and there have been several more prior to that, since the William St Rise was formed. It is a combination of the uplifts on the Wairarapa Fault and overall sea level fall that have left the beach ridge high and dry.
When Europeans first settled in Petone the flat land was much more swampy and subject to flooding than it is today. Many built their houses on the William St beach ridge because it was a little bit higher and drier. After the 1855 earthquake the whole valley floor was uplifted by about 1-1.5 m and flooding was no longer so much of a problem.
(1) Sea level was 1.5 - 2 m higher than present between 6000 and about 4000 years ago and at this time the beach was up near Melling Bridge. Since then sea level has progressively fallen leaving behind old beaches and ridges and many of the flat coastal terraces about 1 m above sea level around New Zealand's coast.
(2) The Hutt Valley is in a 'fault angle depression' with the Wellington Fault down-faulting it on its western side. In this depression young sediments have accumulated building up the flat floor of Lower Hutt and Petone. Much of the sediment comes down the Hutt River and has been deposited at its mouth and has helped build the valley floor plain out southwards. This subsidence of the Hutt Valley has been countered by uplift every time the Wairarapa Fault (west side of Wairarapa Valley) ruptures. The last rupture on this fault was in 1855, it uplifted the whole Wellington region and there have been several more prior to that, since the William St Rise was formed. It is a combination of the uplifts on the Wairarapa Fault and overall sea level fall that have left the beach ridge high and dry.
When Europeans first settled in Petone the flat land was much more swampy and subject to flooding than it is today. Many built their houses on the William St beach ridge because it was a little bit higher and drier. After the 1855 earthquake the whole valley floor was uplifted by about 1-1.5 m and flooding was no longer so much of a problem.
HAVE A LOOK!
Information sign at the William St rise.
What do you think the storm beach ridge was made of?
Have a look behind the present Petone Beach especially at its western end - is there a beach ridge there and what is it made of?
Can you trace the William St beach ridge across the valley floor? Why do you think it is not continuously present?
Can you see any sign of younger beach ridges between here and the present Petone Beach that may have been uplifted by more recent earthquakes?
Have a look behind the present Petone Beach especially at its western end - is there a beach ridge there and what is it made of?
Can you trace the William St beach ridge across the valley floor? Why do you think it is not continuously present?
Can you see any sign of younger beach ridges between here and the present Petone Beach that may have been uplifted by more recent earthquakes?
-41.2260412857741
174.888900518417
Directions/Advisory
On William St, Petone just south of intersection with Emerson St. Information sign beside the rise.
Watch out for traffic when crossing the road or taking photographs.
Google Directions
Accessibility:
WHEELCHAIR
The rise can viewed from the footpath on either side of William St.
Features
Landform
Geological Age
Holocene, about 2500 years old.
Zealandia Evolution Sequence
Pākihi Supergoup: 5 million years ago – present
Links