Video | Business Headlines | Internet | Science | Scientific Ethics | Technology | Search

 


Deep Alpine Fault sensitive to nearby earthquakes

MEDIA RELEASE

25 August 2014

___________________________________________________________

Deep Alpine Fault sensitive to nearby earthquakes

Victoria University of Wellington researchers have discovered that seismic waves produced by earthquakes happening several hundred kilometres away trigger activity deep beneath the Alpine Fault.

Using a network of seismic recorders called the Southern Alps Microearthquake Borehole Array (SAMBA), set up during a 2009 study, PhD student Calum Chamberlain is exploring the range of seismicity occurring in the central section of the Alpine Fault.

Calum is researching under the supervision of Associate Professor John Townend and Professor Tim Stern from the School of Geography, Environment and Earth Sciences and in collaboration with Dr David Shelly of the United States Geological Survey. This work was recently published online by the journalGeochemistry, Geophysics, Geosystems (G-Cubed).

The Alpine Fault runs along the western side of the Southern Alps and forms the boundary between the Pacific tectonic plate (to the east) and the Australian plate (to the west). Calum’s PhD research involves regular helicopter trips into the Southern Alps to download data and make sure the seismic recorders are operating reliably.

“The Alpine Fault is known from geological measurements to produce large earthquakes every few hundred years, most recently in 1717 AD, but this research is focussed on much, much smaller earthquakes happening almost every day. We are investigating how the fault is being loaded towards an eventual large earthquake,” says Dr Townend.

“Our group has recently detected very small earthquakes—smaller than magnitude one—occurring at depths of 15 to 40 km near the Alpine Fault. These earthquakes have distinctive low-frequency characteristics that enable them to be detected and monitored despite their small size, and provide one of the few signs we have of present-day faulting activity deep inside the plate boundary.”

Analysing three years of data, Calum has found that low-frequency earthquakes happen almost continuously near the Alpine Fault southwest of Aoraki Mt Cook. In addition, when a large earthquake happens elsewhere in the South Island, such as the Dusky Sound earthquake of 2009 in Fiordland or the 2010 and 2011 Canterbury sequence of earthquakes, there’s a sharp spike in the production of low-frequency earthquakes.

One example is the magnitude 6 earthquake near Christchurch in June 2011 that triggered many low-frequency earthquakes on the Alpine Fault over the course of several days. “The Alpine Fault responds to earthquakes hundreds of kilometres away, showing that it’s very sensitive to the small stresses associated with seismic waves,” says Calum.

The next stage of Calum’s study is focussed on understanding the conditions beneath the fault that make it extremely sensitive to weak triggers. This work will also add to knowledge of the fault’s structure at depth.

“Documenting how often these low-frequency earthquakes occur and how they’re triggered by very small perturbations in stress is important for determining how the Alpine Fault is loaded by tectonic processes and better understanding the hazard it poses,” says Dr Townend.

The research is funded by the Marsden Fund of the Royal Society of New Zealand and Victoria University of Wellington, and viewable online athttp://doi.wiley.com/10.1002/2014GC005436


© Scoop Media

 
 
 
 
 
Business Headlines | Sci-Tech Headlines

 

BusinessDesk: APN's NZME Sees Future In Paywalls, Growth In Digital Sales

APN News & Media has touted a single newsroom concept for its NZME unit in New Zealand, similar to what Germany's Die Welt uses, saying an 'integrated sales proposition' is helping it win market share, including ... More>>

Labour Party: Global Milk Prices Now Lowest In 6 Years

The latest fall in the global dairy price has brought it to the lowest level in six years and shows there must be meaningful action in tomorrow’s Budget to diversify the economy, says Labour’s Finance spokesperson Grant Robertson. “Dairy prices ... More>>

BusinessDesk: NZ Inflation Expectations Creep Higher In June Survey

May 19 (BusinessDesk) - New Zealand businesses lifted their expectations for inflation over the next two years, sapping any immediate pressure on the Reserve Bank to cut interest rates, and prompting the kiwi dollar to jump higher. More>>

BusinessDesk: Lower Fuel Costs Drive Down NZ Producer Input, Output Prices

May 19 - Producer input and output prices fell in the first quarter, mainly reflecting lower fuel costs and weakness in prices of meat and dairy products. More>>

Media: Fairfax Media NZ Announces Senior Editorial Team

Fairfax Media New Zealand has today confirmed its new editorial leadership team, as part of a transformation of its newsrooms aimed at enhancing local and national journalism across digital and print. More>>

Science: Flavonoids Reduce Cold And Cough Risk

Flavonoids reduce cold and cough risk Research from the University of Auckland shows eating flavonoids – found in green tea, apples, blueberries, cocoa, red wine and onions – can significantly reduce the risk of catching colds and coughs. The research, ... More>>


BusinessDesk: RBNZ House Alert Speech The Catalyst For Government Action

Prime Minister John Key all but conceded that pressure from the Reserve Bank of New Zealand for concerted action on rampant Auckland house prices was one of the main catalysts for the government's weekend announcements about tightly ... More>>

BusinessDesk: How To Fall Foul Of The New Housing Tax Rules: Tips From IRD

Just because you rented out your investment property doesn't absolve you from paying tax, says the Inland Revenue Department in a summary of commonly made mistakes by non-professional property investors when it comes to their tax liability.More>>

Legal: Superdiversity Law, Policy And Business Stocktake Announced

Mai Chen, Managing Partner at Chen Palmer New Zealand Public and Employment Law Specialists and Adjunct Professor of Law at the University of Auckland, today announced the establishment ... More>>

Housing: More House Price Gains Expected

House price expectations remain high, with a net 56% of respondents expecting house prices will increase. Fears of higher interest rates are fading, consistent with the RBNZ’s signals this year. Affordability and a lack of houses for ... More>>

TDDA: State-Of-The-Art Drug Testing Laboratory To Open In Auckland

World leading drug testing agencies, The Drug Detection Agency (TDDA) and Omega Laboratories, open New Zealand laboratory More>>

Network: Bigpipe Launches Ultra-Fast Broadband Into Wellington

Bigpipe Launches Ultra-Fast Broadband into Wellington Naked broadband provider Bigpipe has extended its national reach, announcing today, the launch of its unlimited UFB offering into Wellington. The Spark Venture business is giving Wellingtonians the ... More>>

Get More From Scoop

 
 
 
 
 
 
 
 
 
Sci-Tech
Search Scoop  
 
 
Powered by Vodafone
NZ independent news