Ohariu Fault

from Wikipedia, the free encyclopedia
Map of the North Island Fault System with the location of the Ohariu Fault
(left black line, lower left)

The Ohariu Fault is a geological fault in the Greater Wellington region of the North Island of New Zealand .

geography

The fault, which is part of the North Island Fault System , runs parallel to the coastline of the west coast of Wellington , Porirua and along the Kapiti Coast on land . Starting on Wellington's south coast, the fault extends 70 km to Waikanae and then continues as the Northern Ohariu Fault for another 60 km to the south of Palmerston North .

geology

The North Island of New Zealand lies on the eastern edge of the Australian Plate , under which the Pacific Plate shifts in the so-called Hikurangi Trench at 38 mm to 50 mm per year in a south-westerly direction. The displacements in this subduction zone create tensions in the Australian plate, which lead to fractures, faults and, as a result, earthquakes. The Ohariu Fault , along with the Wellington Fault , the Wairarapa Fault and the Carterton Fault, is one of the larger faults in the south of the North Island.

Although the Ohariu Fault was last active around 1000 years ago, it is still one of the most active and earthquake-causing faults in the region. According to a study by New Zealand geologists and earthquake experts Van Dissen and Heron in 2003, an earthquake caused by the Ohariu Fault could occur with a probability of 68% every 2200 years and a range from 1330 to 3800 years. A quake could then cause the floor to shift 3 to 5 m to the side.

The Northern Ohariu Fault , on the other hand, is estimated to have an earthquake return of 1000 to 3000 years, with the last earthquake caused by the fault probably being between 300 and 1000 years ago.

See also

literature

  • JJ Aitken : Plate Tectonics for curious kiwis . Ed .: Institute of Geological & Nuclear Sciences Limited . Lower Hutt 1996, ISBN 0-478-09555-4 (English).
  • Tim Little, John Begg : 1855 Wairarapa Earthquake Symposium: All-day Field-trip to the Wairarapa Fault and 1855 Rupture Sites . Ed .: Greater Wellington Regional Council . Wellington 2005, ISBN 0-909016-88-7 (English, online [PDF; 12.2 MB ; accessed on October 16, 2014]).

Individual evidence

  1. ^ Major Faults in New Zealand . GNS Science , accessed October 16, 2014 .
  2. ^ Case Studies - Implementing the Guidelines - The Wellington Region's Tectonic Environment . Ministry for Environment , accessed May 5, 2019 .
  3. ↑ Little, Begg : 1855 Wairarapa Earthquake Symposium . 2005, p.  4 (English).
  4. ↑ a b c Earthquake Fault Rupture Hazards . Kapiti Coast District Council , accessed October 16, 2014 .
  5. ↑ Review of 2003 earthquake fault trace survey following filed work in Maungakotukutuku Valley and transmission gully areas . (PDF 521 kB) Kapiti Coast District Council , archived from the original ; Retrieved February 19, 2016 (English, letter from GNS Science of August 2007 to Kapiti Coast District Council ).