Model describes New Zealand's complex tectonic environment

Mar 19, 2012

At the Hikurangi fault, off the eastern coast of New Zealand's North Island, the Pacific tectonic plate sinks beneath the Australian plate. Farther south, in the Marlborough Fault System, which cuts through the country's larger South Island, the interaction between the two slabs turns such that the plates grind edge-on.

From north to south, over a relatively short length of the , the interaction switches from subduction to strike-slip. Though the fault systems near each of New Zealand's major islands have been studied extensively, the intervening region that harbors the transition between the two modes of interaction is much less well understood.

Exploring the subduction-to-strike-slip transition region could help explain how and whether the fault systems that populate the country are connected and potentially improve estimates of .

Seeking to fill out the picture of New Zealand's tectonic environment, Wallace et al. modeled the independent fragments of the Earth's crust that make up the larger plate boundary.

Using measurements of known fault locations and stresses, combined with recordings of ground velocity measurements drawn from 800 GPS ground stations distributed across the country, the authors reverse engineered the complex system of faults that crosses New Zealand.

The authors find that the switch from subduction in the north to strike-slip in the south is due to what they describe as a kink in the Australian plate that cuts across the northern South Island.

They suggest that this deformation acts as a hinge about which the northern part of the Pacific plate takes on a clockwise rotation.

Further, the authors' model allowed them to estimate the slip rate deficit for each fault, a measure of the expected but as of yet unobserved plate motion that could indicate an ongoing buildup of energy within the fault.

Explore further: Magnitude-7.2 earthquake shakes Mexican capital

More information: The kinematics of a transition from subduction to strike-slip: An example from the central New Zealand plate boundary, Journal of Geophysical Research-Solid Earth, doi:10.1029/2011JB008640 , 2012

add to favorites email to friend print save as pdf

Related Stories

Quakes warn of seismic danger closer to home

Apr 08, 2005

More earthquakes along the fault that caused the Boxing Day and Easter Monday earthquakes are “inevitable” and may cause shocks and tsunamis close to north-western Australia. Dr Wouter Schellart, who is working on mod ...

Recommended for you

Magnitude-7.2 earthquake shakes Mexican capital

Apr 18, 2014

A powerful magnitude-7.2 earthquake shook central and southern Mexico on Friday, sending panicked people into the streets. Some walls cracked and fell, but there were no reports of major damage or casualties.

User comments : 0

More news stories

China says massive area of its soil polluted

A huge area of China's soil covering more than twice the size of Spain is estimated to be polluted, the government said Thursday, announcing findings of a survey previously kept secret.

UN weather agency warns of 'El Nino' this year

The UN weather agency Tuesday warned there was a good chance of an "El Nino" climate phenomenon in the Pacific Ocean this year, bringing droughts and heavy rainfall to the rest of the world.

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...