PLANETARY TREMORS: Massive Shift In Alpine Fault In New Zealand, Much More Than Previously Thought - New Research!

The Alpine Fault, which runs up the spine of the South Island, has ruptured five times in the past 1100 years -
producing an earthquake of between magnitude 7 and 8 each time. © GNS Science

March 8, 2016 - NEW ZEALAND - The Alpine Fault has moved much more than previously thought, and more than any other known fault on land in the world, new research shows.

In the past 25 million years, the two sides of the South Island have shifted more than 700 kilometres relative to each other along the Alpine Fault. That is 250km more than previously thought.

The full extent of the movement was masked because the rocks first moved 250km in one direction, then went back the other way - retracing the first 250km and adding a further 450km.

GNS Science earthquake geologist Robert Langridge has been studying why the Alpine Fault is so susceptible to earthquakes - it's since been discovered that it may be the world's fastest-moving known fault line.

The extent of the movement was worked out by researchers from Victoria University and GNS Science, with the findings published in the American Geophysical Union journal G-Cubed.

GNS Science earthquake geologist Robert Langridge studying layers in the trench across the Alpine Fault at Springs Junction. New research has found that the
fault line may be the world's fastest-moving, having shifted around 700km in 25 million years. © Joanne Carroll/Fairfax NZ

"I don't think anybody in their wildest dreams would have thought that displacements on the fault could be so large, and also change direction so dramatically through time," Associate Professor Dr Simon Lamb, from Victoria's School of Geography, Environment and Earth Sciences, said.

The researchers made the discovery by looking at geological maps together with studies of the direction of magnetisation in the rocks.

The finding underscored the fact the Alpine Fault was the big seismic hazard in the South Island and had been for a "very, very long time", Lamb said.

The findings may have implications for why the Alpine Fault is so prone to earthquakes.© GNS Science

Other faults in central and southern parts of the South Island had played only a small role in the movement of the tectonic plates.

The next largest known fault displacement on land was on the Altyn Tagh Fault in Tibet, with a total movement of about 475km.

The new theory about the Alpine Fault was a major shift in thinking and the researchers had needed to provide convincing arguments to get it published.

GNS Science earthquake geologists studying layers in the trench across the Alpine Fault at Springs Junction.© GNS Science

The idea occurred to him only about six months ago, Lamb said. "I was calculating the motion of the tectonic plates through New Zealand and realised they were so much bigger than the movement everyone was saying had taken place on the Alpine Fault."

His advantage was that coming from the UK he wasn't wedded to a particular way of thinking about it.

"We put together this team of people who came at it from lots of different directions to make sure this was right, that we hadn't made some terrible mistake and missed something." The idea was exciting but it was followed by a large amount of work. "You spend a lot of time checking. You have to go through an enormous amount of information to look at what other people have discovered. You do a lot of testing. In you mind you play devil's advocate," Lamb said.

"It will be interesting to see what the reception is."

The Alpine Fault started as part of the break-up of the supercontinent Gondwana, with New Zealand starting to drift away from Antarctica about 80 million years ago.

That resulted in about 250km of movement along the Alpine Fault but in the opposite direction to the way the fault is moving today. Then "nothing" happened for tens of millions of years, Lamb said.

About 25 million years ago a new plate boundary formed and the Pacific Plate and Australian Plate started moving relative to each other "in a big way".

"That's the situation today. You have the Alpine Fault breaking up this fragment of continent that split away from Gondwana," Lamb said.

It had been thought movement along the Alpine Fault was getting faster. "Basically what we showed was that from the moment the Alpine Fault started to move in the direction it's moving today it more or less moved at the same rate." That was an average speed of about 3cm a year. - Stuff.

PLANETARY TREMORS: Major Global Seismic Uptick - Very Strong 6.3 Magnitude Earthquake Strikes New Zealand, Causing Panic And Minor Structural Damage, Halting Local Transportation Services, Setting Of Alarms And Knocking Food Items Off Shelves! [MAPS + TECTONIC SUMMARY]

USGS earthquake location.

April 24, 2015 - NEW ZEALAND - A strong magnitude 6.3 earthquake has hit 40 kilometers off the New Zealand town of Kaikoura, GeoNet reported. Witnesses described feeling tremors all across central regions of the country.

BREAKING: A magnitude 6.3 earthquake has struck inland from Kaikoura. Did you feel it? #eqnz pic.twitter.com/quREdLyr0x
— Stuff.co.nz News (@NZStuff) April 24, 2015

The quake centered in Nelson region at the depth of 80 kilometers, according to GeoNet. The US Geological Survey, meanwhile, reported a lower magnitude of 5.9 at the epicenter.

That was a long Earthquake! 6.3, 40km north west of kaikoura 76km deep. I picked up my daughter so fast and ran for the doorway #earthquake
— Anna (@AnnaTaunton) April 24, 2015

There were no immediate reports of any major damage caused by the quake; however, local public transport services were temporarily halted.

USGS shakemap intensity.

started as a rolling one, then stop, then got violent. hope all is okay. #eqnz
— Guy Smiley (@GuySmiley11) April 24, 2015

The power of the earthquake's tremors knocked food items from their shelves in the stores and set off alarms.

Locals reported that the temblor lasted longer than usual, forcing houses to creak, which caused some people to panic.

A 6.3 quake 40km for Kaikoura has been felt widely across central NZ. http://t.co/jW46qMOdqQ pic.twitter.com/fWJLxKVFo1
— Dominion Post (@DomPost) April 24, 2015

GNS Science spokeswoman Caroline Little said the quake was labelled as "strong."

"We've classed it as a strong quake so a small amount of structural damage, but more likely things falling off shelves and that sort of thing," she said.

Little warned that some aftershocks are to be expected.

"The general rule of thumb with aftershocks is they'll be up to one magnitude less than the main shock, so we might have some fives and fours and threes as well," she said.

The tremor was felt across central New Zealand and Wellingtonioans said it was really big and lasted for a long time. http://t.co/bYGvWx7xm9
— Morgan Sassworth (@morganeleanor) April 24, 2015

Kaikoura's store manager, James Hills, described the chaos in his shop after the quake hit.

"Fair bit of panic - get out of the shop, everything was falling off the shelves. There's been a little bit of damage, certainly not heaps, but yeah, there's a lot of stuff fallen over."

"Well, initially, we were up on the second floor and felt a slight movement, we thought, 'that's okay, that's it,' so we just took our seats, then it came on - to me, it was a rolling motion, quite firm, quite solid," Kaikoura's mayor, Winston Gray, told Radio New Zealand News, adding that there were some reports of minor damage throughout the city. - RT.

Tectonic Summary - Seismotectonics of the Eastern Margin of the Australia Plate

The eastern margin of the Australia plate is one of the most sesimically active areas of the world due to high rates of convergence between the Australia and Pacific plates. In the region of New Zealand, the 3000 km long Australia-Pacific plate boundary extends from south of Macquarie Island to the southern Kermadec Island chain. It includes an oceanic transform (the Macquarie Ridge), two oppositely verging subduction zones (Puysegur and Hikurangi), and a transpressive continental transform, the Alpine Fault through South Island, New Zealand.

Since 1900 there have been 15 M7.5+ earthquakes recorded near New Zealand. Nine of these, and the four largest, occurred along or near the Macquarie Ridge, including the 1989 M8.2 event on the ridge itself, and the 2004 M8.1 event 200 km to the west of the plate boundary, reflecting intraplate deformation. The largest recorded earthquake in New Zealand itself was the 1931 M7.8 Hawke's Bay earthquake, which killed 256 people. The last M7.5+ earthquake along the Alpine Fault was 170 years ago; studies of the faults' strain accumulation suggest that similar events are likely to occur again.

North of New Zealand, the Australia-Pacific boundary stretches east of Tonga and Fiji to 250 km south of Samoa. For 2,200 km the trench is approximately linear, and includes two segments where old (greater than 120 Myr) Pacific oceanic lithosphere rapidly subducts westward (Kermadec and Tonga). At the northern end of the Tonga trench, the boundary curves sharply westward and changes along a 700 km-long segment from trench-normal subduction, to oblique subduction, to a left lateral transform-like structure.

USGS plate tectonics for the region. (PDF)

Australia-Pacific convergence rates increase northward from 60 mm/yr at the southern Kermadec trench to 90 mm/yr at the northern Tonga trench; however, significant back arc extension (or equivalently, slab rollback) causes the consumption rate of subducting Pacific lithosphere to be much faster. The spreading rate in the Havre trough, west of the Kermadec trench, increases northward from 8 to 20 mm/yr. The southern tip of this spreading center is propagating into the North Island of New Zealand, rifting it apart. In the southern Lau Basin, west of the Tonga trench, the spreading rate increases northward from 60 to 90 mm/yr, and in the northern Lau Basin, multiple spreading centers result in an extension rate as high as 160 mm/yr. The overall subduction velocity of the Pacific plate is the vector sum of Australia-Pacific velocity and back arc spreading velocity: thus it increases northward along the Kermadec trench from 70 to 100 mm/yr, and along the Tonga trench from 150 to 240 mm/yr.

The Kermadec-Tonga subduction zone generates many large earthquakes on the interface between the descending Pacific and overriding Australia plates, within the two plates themselves and, less frequently, near the outer rise of the Pacific plate east of the trench. Since 1900, 40 M7.5+ earthquakes have been recorded, mostly north of 30°S. However, it is unclear whether any of the few historic M8+ events that have occurred close to the plate boundary were underthrusting events on the plate interface, or were intraplate earthquakes. On September 29, 2009, one of the largest normal fault (outer rise) earthquakes ever recorded (M8.1) occurred south of Samoa, 40 km east of the Tonga trench, generating a tsunami that killed at least 180 people.

Across the North Fiji Basin and to the west of the Vanuatu Islands, the Australia plate again subducts eastwards beneath the Pacific, at the North New Hebrides trench. At the southern end of this trench, east of the Loyalty Islands, the plate boundary curves east into an oceanic transform-like structure analogous to the one north of Tonga.

Australia-Pacific convergence rates increase northward from 80 to 90 mm/yr along the North New Hebrides trench, but the Australia plate consumption rate is increased by extension in the back arc and in the North Fiji Basin. Back arc spreading occurs at a rate of 50 mm/yr along most of the subduction zone, except near ~15°S, where the D'Entrecasteaux ridge intersects the trench and causes localized compression of 50 mm/yr in the back arc. Therefore, the Australia plate subduction velocity ranges from 120 mm/yr at the southern end of the North New Hebrides trench, to 40 mm/yr at the D'Entrecasteaux ridge-trench intersection, to 170 mm/yr at the northern end of the trench.

Large earthquakes are common along the North New Hebrides trench and have mechanisms associated with subduction tectonics, though occasional strike slip earthquakes occur near the subduction of the D'Entrecasteaux ridge. Within the subduction zone 34 M7.5+ earthquakes have been recorded since 1900. On October 7, 2009, a large interplate thrust fault earthquake (M7.6) in the northern North New Hebrides subduction zone was followed 15 minutes later by an even larger interplate event (M7.8) 60 km to the north. It is likely that the first event triggered the second of the so-called earthquake "doublet". - USGS.

PLANETARY TREMORS: Strong 5.1 Magnitude Earthquake Hits Just East Of Seddo, New Zealand! [MAPS + TECTONIC SUMMARY]

© Geonet

April 24, 2015 - NEW ZEALAND - More tremors are likely following two earthquakes which hit central New Zealand, a GNS scientist says.

Seismologist Dr John Ristau said it was likely there would be more quakes following Thursday's shakes, but it was impossible to say whether they would be stronger or weaker than the 5.1.

"You have to remember this whole area is seismically active to begin with," he said.

"It's likely there's be an aftershock around 4. There's also a chance there'll be something bigger.

"If you think back to July 2013 when those quakes started you first had one around 5, a little bit above 5, and then a couple weeks later was the first of those two 6.6 quakes." - Stuff.

Tectonic Summary - Seismotectonics of the Eastern Margin of the Australia Plate

The eastern margin of the Australia plate is one of the most sesimically active areas of the world due to high rates of convergence between the Australia and Pacific plates. In the region of New Zealand, the 3000 km long Australia-Pacific plate boundary extends from south of Macquarie Island to the southern Kermadec Island chain. It includes an oceanic transform (the Macquarie Ridge), two oppositely verging subduction zones (Puysegur and Hikurangi), and a transpressive continental transform, the Alpine Fault through South Island, New Zealand.

Since 1900 there have been 15 M7.5+ earthquakes recorded near New Zealand. Nine of these, and the four largest, occurred along or near the Macquarie Ridge, including the 1989 M8.2 event on the ridge itself, and the 2004 M8.1 event 200 km to the west of the plate boundary, reflecting intraplate deformation. The largest recorded earthquake in New Zealand itself was the 1931 M7.8 Hawke's Bay earthquake, which killed 256 people. The last M7.5+ earthquake along the Alpine Fault was 170 years ago; studies of the faults' strain accumulation suggest that similar events are likely to occur again.

North of New Zealand, the Australia-Pacific boundary stretches east of Tonga and Fiji to 250 km south of Samoa. For 2,200 km the trench is approximately linear, and includes two segments where old (greater than 120 Myr) Pacific oceanic lithosphere rapidly subducts westward (Kermadec and Tonga). At the northern end of the Tonga trench, the boundary curves sharply westward and changes along a 700 km-long segment from trench-normal subduction, to oblique subduction, to a left lateral transform-like structure.

USGS plate tectonics for the region.

Australia-Pacific convergence rates increase northward from 60 mm/yr at the southern Kermadec trench to 90 mm/yr at the northern Tonga trench; however, significant back arc extension (or equivalently, slab rollback) causes the consumption rate of subducting Pacific lithosphere to be much faster. The spreading rate in the Havre trough, west of the Kermadec trench, increases northward from 8 to 20 mm/yr. The southern tip of this spreading center is propagating into the North Island of New Zealand, rifting it apart. In the southern Lau Basin, west of the Tonga trench, the spreading rate increases northward from 60 to 90 mm/yr, and in the northern Lau Basin, multiple spreading centers result in an extension rate as high as 160 mm/yr. The overall subduction velocity of the Pacific plate is the vector sum of Australia-Pacific velocity and back arc spreading velocity: thus it increases northward along the Kermadec trench from 70 to 100 mm/yr, and along the Tonga trench from 150 to 240 mm/yr.

The Kermadec-Tonga subduction zone generates many large earthquakes on the interface between the descending Pacific and overriding Australia plates, within the two plates themselves and, less frequently, near the outer rise of the Pacific plate east of the trench. Since 1900, 40 M7.5+ earthquakes have been recorded, mostly north of 30°S. However, it is unclear whether any of the few historic M8+ events that have occurred close to the plate boundary were underthrusting events on the plate interface, or were intraplate earthquakes. On September 29, 2009, one of the largest normal fault (outer rise) earthquakes ever recorded (M8.1) occurred south of Samoa, 40 km east of the Tonga trench, generating a tsunami that killed at least 180 people.

Across the North Fiji Basin and to the west of the Vanuatu Islands, the Australia plate again subducts eastwards beneath the Pacific, at the North New Hebrides trench. At the southern end of this trench, east of the Loyalty Islands, the plate boundary curves east into an oceanic transform-like structure analogous to the one north of Tonga.

Australia-Pacific convergence rates increase northward from 80 to 90 mm/yr along the North New Hebrides trench, but the Australia plate consumption rate is increased by extension in the back arc and in the North Fiji Basin. Back arc spreading occurs at a rate of 50 mm/yr along most of the subduction zone, except near ~15°S, where the D'Entrecasteaux ridge intersects the trench and causes localized compression of 50 mm/yr in the back arc. Therefore, the Australia plate subduction velocity ranges from 120 mm/yr at the southern end of the North New Hebrides trench, to 40 mm/yr at the D'Entrecasteaux ridge-trench intersection, to 170 mm/yr at the northern end of the trench.

Large earthquakes are common along the North New Hebrides trench and have mechanisms associated with subduction tectonics, though occasional strike slip earthquakes occur near the subduction of the D'Entrecasteaux ridge. Within the subduction zone 34 M7.5+ earthquakes have been recorded since 1900. On October 7, 2009, a large interplate thrust fault earthquake (M7.6) in the northern North New Hebrides subduction zone was followed 15 minutes later by an even larger interplate event (M7.8) 60 km to the north. It is likely that the first event triggered the second of the so-called earthquake "doublet". - USGS.

PLANETARY TREMORS: Seismic Swarm - Spate Of Moderate To Strong Earthquakes Rattle New Zealand's South Island! [MAPS + TECTONIC SUMMARY]

This GNS map shows the location of the 6.4 magnitude quake in red, with some of the first 'felt reports' it received from around the region.
© GNS Science

January 6, 2015 - NEW ZEALAND - A spate of strong earthquakes have struck the central South Island this morning.

Four quakes measuring between 6.4 and 4.1 in magnitude hit the Methven and Arthur's Pass area between 6.48am and 6.59am.

The first tremor, measuring 6.4, struck 35km north of Methven at 6.48am, GNS Science reported.  USGS has the first earthquake as being 5.6 magnitude.

The tremor, which was 11km deep, was classified as severe.

A southern police communications spokesman said they had not received any reports of damage.

Four minutes later at 6.52am, a second quake measuring 4.1 in magnitude rocked the region.

It was centred 30km west of Arthur's Pass and was 5km deep.

GNS classified the quake as strong.

At 6.58 a third quake, measuring 4.1 hit the same spot, GNS said.

USGS shakemap intensity.

It was 5km deep.

Then, a minute later at 6.59am, another strong quake hit the same location, measuring 4.2 in magnitude. It was also shallow, centred 5km deep.

St John spokesman Ian Henderson said there had not been any calls relating to this morning's earthquakes and there had not had any increase in calls because of them.

There were also no reports of injuries, he said.

Seismologist: Another big aftershock possible

GNS seismologist John Ristau told Radio New Zealand the quakes were widely felt, with so far nearly 2000 people reporting feeling the tremors.

The initial 6.4 quake generated the aftershocks, he said.

"With an earthquake of this size it wouldn't be unexpected that an aftershock above magnitude 5 [would hit] - so it's quite possible that we could see an aftershock of that size at some point."

The tremors were felt in Canterbury and the West Coast, he said.

Landslides could also have been triggered from the quakes.

"We'll probably end up sending people down there to have a look."

Residents describe early morning shakes

New Zealand Herald readers have been sending in their experiences of the earthquakes.

Tony Foote said the quakes were "disturbing".

"It rolled on a bit, quite heavily and I felt a bit sea sick as my chair moved about. A bit like being on a rising and falling wave in a small boat.

"There was a worry it might be something bigger on the way as an ornament I hung to see when quakes were happening swung 100mm side to side for several minutes, and the water in my cats bowl moved up and down 20mm or so."

Graham Walker said he felt the quakes in Timaru.

"As I was eating breakfast house was rolling around for about 10-15 seconds."

Brian Feary tweeted: "Big earthquake here in Arthur's pass! My dog ran in from outside and jumped on bed... No damage so far #eqnz".

The Queen of Cobden wrote: "That #eqnz just felt like the house was at sea (in Christchurch)".  - NZ Herald.

Tectonic Summary - Seismotectonics of the Eastern Margin of the Australia Plate

The eastern margin of the Australia plate is one of the most sesimically active areas of the world due to high rates of convergence between the Australia and Pacific plates. In the region of New Zealand, the 3000 km long Australia-Pacific plate boundary extends from south of Macquarie Island to the southern Kermadec Island chain. It includes an oceanic transform (the Macquarie Ridge), two oppositely verging subduction zones (Puysegur and Hikurangi), and a transpressive continental transform, the Alpine Fault through South Island, New Zealand.

Since 1900 there have been 15 M7.5+ earthquakes recorded near New Zealand. Nine of these, and the four largest, occurred along or near the Macquarie Ridge, including the 1989 M8.2 event on the ridge itself, and the 2004 M8.1 event 200 km to the west of the plate boundary, reflecting intraplate deformation. The largest recorded earthquake in New Zealand itself was the 1931 M7.8 Hawke's Bay earthquake, which killed 256 people. The last M7.5+ earthquake along the Alpine Fault was 170 years ago; studies of the faults' strain accumulation suggest that similar events are likely to occur again.

North of New Zealand, the Australia-Pacific boundary stretches east of Tonga and Fiji to 250 km south of Samoa. For 2,200 km the trench is approximately linear, and includes two segments where old (greater than 120 Myr) Pacific oceanic lithosphere rapidly subducts westward (Kermadec and Tonga). At the northern end of the Tonga trench, the boundary curves sharply westward and changes along a 700 km-long segment from trench-normal subduction, to oblique subduction, to a left lateral transform-like structure.

USGS plate tectonics for the region.

Australia-Pacific convergence rates increase northward from 60 mm/yr at the southern Kermadec trench to 90 mm/yr at the northern Tonga trench; however, significant back arc extension (or equivalently, slab rollback) causes the consumption rate of subducting Pacific lithosphere to be much faster. The spreading rate in the Havre trough, west of the Kermadec trench, increases northward from 8 to 20 mm/yr. The southern tip of this spreading center is propagating into the North Island of New Zealand, rifting it apart. In the southern Lau Basin, west of the Tonga trench, the spreading rate increases northward from 60 to 90 mm/yr, and in the northern Lau Basin, multiple spreading centers result in an extension rate as high as 160 mm/yr. The overall subduction velocity of the Pacific plate is the vector sum of Australia-Pacific velocity and back arc spreading velocity: thus it increases northward along the Kermadec trench from 70 to 100 mm/yr, and along the Tonga trench from 150 to 240 mm/yr.

The Kermadec-Tonga subduction zone generates many large earthquakes on the interface between the descending Pacific and overriding Australia plates, within the two plates themselves and, less frequently, near the outer rise of the Pacific plate east of the trench. Since 1900, 40 M7.5+ earthquakes have been recorded, mostly north of 30°S. However, it is unclear whether any of the few historic M8+ events that have occurred close to the plate boundary were underthrusting events on the plate interface, or were intraplate earthquakes. On September 29, 2009, one of the largest normal fault (outer rise) earthquakes ever recorded (M8.1) occurred south of Samoa, 40 km east of the Tonga trench, generating a tsunami that killed at least 180 people.

Across the North Fiji Basin and to the west of the Vanuatu Islands, the Australia plate again subducts eastwards beneath the Pacific, at the North New Hebrides trench. At the southern end of this trench, east of the Loyalty Islands, the plate boundary curves east into an oceanic transform-like structure analogous to the one north of Tonga.

Australia-Pacific convergence rates increase northward from 80 to 90 mm/yr along the North New Hebrides trench, but the Australia plate consumption rate is increased by extension in the back arc and in the North Fiji Basin. Back arc spreading occurs at a rate of 50 mm/yr along most of the subduction zone, except near ~15°S, where the D'Entrecasteaux ridge intersects the trench and causes localized compression of 50 mm/yr in the back arc. Therefore, the Australia plate subduction velocity ranges from 120 mm/yr at the southern end of the North New Hebrides trench, to 40 mm/yr at the D'Entrecasteaux ridge-trench intersection, to 170 mm/yr at the northern end of the trench.

Large earthquakes are common along the North New Hebrides trench and have mechanisms associated with subduction tectonics, though occasional strike slip earthquakes occur near the subduction of the D'Entrecasteaux ridge. Within the subduction zone 34 M7.5+ earthquakes have been recorded since 1900. On October 7, 2009, a large interplate thrust fault earthquake (M7.6) in the northern North New Hebrides subduction zone was followed 15 minutes later by an even larger interplate event (M7.8) 60 km to the north. It is likely that the first event triggered the second of the so-called earthquake "doublet". - USGS.

PLANETARY TREMORS: Indiana Fault System - New Earthquake Fault In New Zealand "Similar To Alpine"!

August 02, 2013 - NEW ZEALAND - An Otago geologist's draft manuscript suggests there's a tectonic fault system off the South Island's east coast potentially comparable in size to the Alpine Fault.

'INDIANIA FAULT SYSTEM': A diagram showing the approximate location of the
proposed Indiania fault in black and red paired lines.

University of Otago geologist Phil Ford has privately written a draft proposal, as yet unpublished, detailing the possibility of the major South Island intra-plate fault, with possible seismic and tsunami hazard implications.

His draft uses previous research that identified beach deposits on the coast east of Milton as potential evidence of tsunami relating to the Akatore fault, or another, hitherto unidentified, offshore system.

Proposing to name it as the Indiania Fault System (IFS), he says it appears to run for most of the offshore length of the South Island, similar in size to the Alpine Fault.

Using New Zealand Institute of Water and Atmospheric Research bathymetric charts, some portions of a fault parallel with the coast were apparent, the paper says.

"It is immediately apparent that portions of the suggested system must be covered by South Island river run-off sediment, at least in places, just as the active and earthquake-related fault in the Christchurch area is covered in gravels and other... sediments onshore."

East of Canterbury and Otago the seafloor feature runs south off southeast Southland and down towards northwest of the Auckland Islands.

"A strike length of greater than 1000km is clear, more than comparable with the Alpine Fault at about 800km south-southwest of the South Island.

"Both the southern IFS elements and southern Alpine Fault offshore continuations are clear and readily visible on seafloor bathymetry displays."

He said the potential of that suggested system warranted immediate research and if shown to be an active fault system then the scale must be "very significant" given a potential overall length of 1600km.

"If the proposed system is accepted by the New Zealand geological fraternity then early notice of serious tsunami vulnerability needs to be passed to governing authorities and civil defence organisations."

GNS Science engineering geologist David Barrell said he was not aware of the proposal but scientists recognised a system of faults off the southeast coast.

The faults, many apparently inactive or remnants of geological activity from the formation of New Zealand, were parallel to the coast and associated with, for example, the Great South Basin or the Waipounamu fault zone.

"It's a fault system that has a history that starts back not long after New Zealand parted company from Australia and Antarctica more than 100 million years ago.

"It's got more of the appearance of a fossil fault rather than anything we would regard as major relating to the present tectonic setting of New Zealand."

Unpublished manuscripts needed peer review and publication in a reputable journal before being accepted as official, he said.

University of Otago geophysicist Dr Andrew Gorman said he would want much more data before making such an assertion and there were other theories.

"I still think the major worry in Otago and Southland is the Alpine Fault itself, and also from the sorts of smaller faults through the South Island." - Stuff.

PLANETARY TREMORS: Major Alert - Officials Tell New Zealand Residents That It's Time To Prepare For An Alpine Fault Earthquake!

July 24, 2013 - NEW ZEALAND - The faultline behind the swarm of quakes in central New Zealand may be much longer than previously realised and therefore capable of larger quakes.

ALPINE FAULT: "An earthquake on the Alpine Fault in the near future would not be a big surprise."

The National Institute of Water and Atmospheric Research is heading into Cook Strait tomorrow to map the area around the swarm of earthquakes that has been rattling Wellington and Marlborough since Friday.

It is hoped the work will identify the faultline from which the quakes have been generated.

GNS Science seismologist John Ristau said that, because the quakes appeared to be happening between the known Vernon and Needles faultlines, it seemed increasingly likely that the London Hill fault was to blame.

In 2003 a Marlborough District Council geotech report described London Hill as a one of "several relatively small faults near the east coast between Seddon and the Waima River".

Dr Ristau said it now appeared the faultline might be much longer than originally thought, which meant it could be capable of creating much larger earthquakes.

"That means it's actually considerably longer than initially thought ... the larger a faultline is, the larger the earthquake."

It was important scientists were able to determine exactly which fault the earthquake had occurred on, as it would allow them to establish whether other nearby faults could now produce large earthquakes as a result.

It appeared the level of stress had not greatly effected the other Wellington faults, but there were a few lines in the Marlborough region that were capable of creating quakes of magnitude 7 or greater.

"If they increase stress, it could trigger a similar-sized earthquake or even a much larger earthquake ... hopefully by the end of the week we'll be able to be a lot more definitive."

Niwa research ship Tangaroa was diverted from survey work in the nearby Pegasus Basin overnight and will spend part of today measuring whether the earthquakes have triggered any landslides in the Cook Strait Canyon.

"We have previously identified an area of potential instability in the middle of the canyon and this will give us the opportunity to see if there have been any changes," marine geologist Scott Nodder said.

An area crossing the earthquake epicentre will also be surveyed to see if the sea floor has changed. Dr Ristau said that mapping would help determine the faultline.

The probability of another big quake, of magnitude 6 or greater, has fallen to 4 per cent within the next day, 13 per cent in the next seven days and 33 per cent in the next year.

The probabilities would continue to fall the longer the region went without a large event, Dr Ristau said.

Aftershocks were likely to continue for about a week.

EARLIER CONCERN OVER IMPACT ON ALPINE FAULT

Yesterday, GNS Science seismologist Stephen Bannister said scientists could not rule out the possibility that the quakes could stir up other faults and "kick off" the Alpine Fault.

He said the biggest misconception the public had when it came to earthquakes was that small ones minimised or took "the edge off" the possibility of a large one occurring.

 However, GNS Science spokesman John Callan said the recent swarm of quakes east of Seddon was "not increasing or decreasing the risk of a quake on the Alpine Fault".

He said the quakes were too far away to affect the Alpine Fault, which stretches 600 kilometres from Milford Sound along the western Southern Alps to Marlborough and is the on-land boundary between the Pacific and Australian tectonic plates.

Recent research led by GNS Science found it last ruptured 296 years ago, and it predicted a 30 per cent chance of a big quake along it in the next 50 years.

The average interval between large quakes on the fault was 330 years.

In the past 8000 years it had ruptured 24 times and caused magnitude-8 quakes, including four in the past millennium. The longest gap between major quakes was 510 years and the shortest 140 years.

"An earthquake on the Alpine Fault in the near future would not be a big surprise. Equally, it could be many decades away, based on its past behaviour," Callan said.

"There is no better time than the present to prepare for the next quake on the Alpine Fault. The more thoroughly we prepare, the lower the eventual impact will be."

He said work was under way to prepare to drill a deep borehole into the fault early next year to study processes taking place at depth inside a major plate boundary fault.

GNS Science is jointly leading the Deep Fault Drilling Project with Otago and Victoria universities, and it involved 22 organisations from eight countries.

An extensive network of seismic instruments, including six "down-hole seismometers" and about 40 surface instruments was recently installed near the planned drilling site so scientists could record the normal level of small quake activity.

The first stage was completed in 2011 with two holes drilled 101 and 105 metres into river terraces next to Gaunt Creek near Whataroa in South Westland.

West Coast tourist town Franz Josef straddled the fault ,but residents were unfazed by quakes in far away regions, such as Wellington, Franz Josef Development Society Incorporated chairman Marcel Fekkes said.

"Everyone is so used to the thing being here, we don't think about it much,'' he said.

"You can't live having fears like that really. When you think about it, the whole country is rather volatile from natural hazards."

Many Franz Josef residents have been fighting Westland District Council plan to establish fault-avoidance zones, which would impose significant restrictions on the township. Submissions closed last September, but a date for public hearings has yet to be set.

EQC BRACED FOR CLAIMS

The Earthquake Commission is bracing itself for an expected flood of claims from property owners throughout the upper South Island and Wellington region.

However, the commission says the quake swarm will not affect the processing of unsettled claims in Canterbury, while Prime Minister John Key says the country can "in principle" afford another earthquake.

EQC has received more than 350 claims after the quakes centred east of Marlborough that shut down central Wellington yesterday and left nerves across the region frayed.

It is already handling 459,198 claims from the Canterbury quakes.

Commission customer services general manager Bruce Emsom said most of the claims were for minor quake damage.

He said there was sufficient cover through levies, reinsurance and the Crown guarantee to provide for all valid claims.

EQC would bring in more field staff, if required, to deal with the influx of claims, so Cantabrians still waiting for their claims to be settled should not be affected.

"There is unlikely to be any impact on processing existing claims from the Canterbury quakes," he said.

Labour's EQC spokesman, Clayton Cosgrove, said that with the commission struggling to keep up with its workload it was important the Government moved swiftly to ensure it had extra resources and personnel so that claims resulting from the Wellington quakes could be dealt with efficiently and without causing any delay to the processing of Canterbury claims.

"You don't want anyone's claim held up," he said.

"Three years into a major catastrophe like this, one would have thought EQC would be well-practised now and have the systems up to deal with this.

''You would hope the mistakes that have been made down here ... would not be replicated and they could expedite claims faster."

Meanwhile, a Christchurch City Council offer to send personnel to Wellington to help authorities assess the extent of the damage has so far not been taken up.

RESEARCH ON SEDDON FAULTS INTENSIFIES

GNS Science seismologist Stephen Bannister said yesterday that intensive research was being carried out to pinpoint where the recent swarm of earthquakes had come from.

It was possible the recent quakes had come from a fault called the London Hill Fault, a relatively small fault near the South Island's east coast between Seddon and the Waimea River, he said.

Scientists would deploy nine extra seismic instruments in coastal Marlborough over the next few days to enable more accurate measurements of the aftershocks.

Seismologists expected to have a clear understanding of the size and geometry of the fault that ruptured on Sunday by the end of the week, along with knowledge of the level of stress change that had occurred on neighbouring faults.

Bannister said the fault the quakes were coming from had the capability to produce magnitude 7s, especially in northern Marlborough, on the Awatere and Clarence faults.

"Yesterday's earthquake may have a flow-on triggering effect to other nearby faults in the vicinity," he said.

"We're quite confident that the earthquakes are not occurring on the major fault between the Pacific and Australian plate, which we call the ‘subduction interface'."

Bannister said aftershocks could reasonably be expected to go on for days. A similar cluster of quakes that occurred just north of Seddon in 1995 had continued for about 11 days.

Probability forecasts for aftershock sequences had been "strongly tested" by the Canterbury sequence, he said.

There was a small possibility that some of the "busy network" of faults in Cook Strait could pose a tsunami threat, prompting a reminder to those near the coast that they should move to higher ground if they felt a strong earthquake shaking the ground for more than 30 seconds, he said. - Stuff.

MONUMENTAL EARTH CHANGES: Disaster Impact - New Zealand's 6.9 Earthquake Released Energy Equal To 100 Nuclear Bombs The Size That Devastated Hiroshima!

July 22, 2013 - NEW ZEALAND - This evening's magnitude 6.9 earthquake released energy equivalent to 100 nuclear bombs of the size which devastated Hiroshima, scientists say.

GNS Research seismologist Stephen Bannister said the quake, which was centred in the Cook Strait, 20 kilometres east of Seddon at a depth of 17 kilometres, was one of more than more than 230 earthquakes recorded in the area since Friday, with about 15 rating above magnitude 4.

It was likely linked to a fault in the Cook Strait capable of generating far more severe shaking, GNS Science said.

Dr Kelvin Berryman, GNS Science director of Natural Hazards, said the severe shaking over the past three days was probably linked to one of several faults capable of generating shakes of magnitude 7.0 or more.

The most likely candidate was the Needle fault, although the location of the quakes over the past three days did not quite match up.

He said a larger quake was unlikely but the swarm that kicked off on Friday morning was not following the normal aftershock pattern, in which the tremors became progressively less severe.

This afternoon's 6.9 magnitude shake, the biggest in the latest swarm, meant the shaking was not following the usual pattern, he said.

GNS should have a clearer idea of the probability of another big, or even bigger, quake by tomorrow, he said.

Bannister said a magnitude 6.9 earthquake releases energy equivalent to 100 nuclear bombs of the size which devastated Hiroshima.

"People will be feeling shocks that register above [magnitude] 3, and we have had about 50 of those since Friday.

"It's not a simple main shock followed by aftershocks, it's an evolving sequence," Bannister said.

He said with earthquakes of this size, aftershocks should be anticipated in the coming days.

"We would just encourage people to make sure they have their emergency kits and rations ready for future events. We can't say how many more large ones to expect."

Victoria University geophysics professor Euan Smith said much of Wellington's city centre was reclaimed land which meant it was not as stable as other areas.

"Where rubble has come down in Featherston St, there was no land there before the 1855 earthquake in Wellington.

"Reclaimed land shakes more easily and is not as strong as hard ground. From Lambton Quay and towards the harbour is also reclaimed land, and these areas will shake much more strongly than other areas."

The Hutt Valley was similarly on softer ground.

"If this evening's was the first then I would say we could expect them to decay in the usual way, but given we had the earlier ones we should still be anticipating that there could be quite large earthquakes for the next few days."

South Island still being reshaped

The South Island is still buckling and shifting to the rhythms of the earth nearly three years after titanic seismic forces began reshaping Canterbury.

High-precision satellite readings gathered from afar afield as the Southern Alps and analysed by scientists as part of an Earthquake Commission-funded project show that despite the apparent settling down of aftershocks, the ground keeps moving.

While it's 14 months since the last magnitude 5-plus earthquake shook Canterbury, the longer-term effects of the barrage of quakes are continuing to affect the landscape.

In the past 18 months, North Canterbury has been budged about 10mm further east towards Pegasus Bay compared with Christchurch, Banks Peninsula and parts of the region further south.

But researchers say the overall movement of the crust across the quake zone is slowing down, which they believe is a good sign for Canterbury residents.

On Friday, the country's biggest quake of recent months, a magnitude 5.7 event centred in Cook Strait at a depth of 8km, frightened Marlborough and Wellington residents. A second quake of 4.5 magnitude followed hours later.

GNS Science spokesman John Callan said there were several active faults under the seabed in Cook Strait.

Seismologists say post-seismic deformation in Canterbury is quite different from "slow-slip" or "silent" quakes that have been discovered in parts of the North Island, such as Poverty Bay, Hawke's Bay and offshore of the Kapiti Coast, over the past decade using global positioning system technology.

University of Texas research scientist Laura Wallace said the most recent GPS data recorded across what has become known as The Gap near Christchurch showed regional movement had slowed by 50-70 per cent from an earlier survey.

The Gap, an area around Prebbleton and Lincoln southwest of Christchurch, is a physical void between the eastern end of the Greendale Fault and the western end of the Port Hills Fault.

Scientists have calculated there is a shortfall in the amount of energy released by quakes there compared with that released close to the two big faults on either side.

Some scientists have advocated monitoring of The Gap to discover whether hidden and shallow faults there could generate a quake of magnitude 6 or more.

However, recent attempts to secure research funding for ongoing work have failed.

Wallace said it was clear The Gap and the surrounding region was still moving as a result of the long quake sequence.

"Basically there was six to 10mm of movement between January 2012 and January this year across the region from south of the aftershock [zone] to the region north of the aftershocks [zone]. This contrasts with a slightly faster 10mm or so movement across that region in the nine months between June 2011 and March 2012.
So The Gap area is still adjusting, but at a slightly lower rate than it was before. [It's] interesting, but not super exciting, which is good for you guys," Wallace said.

GNS Science seismologist Caroline Holden believed The Gap was not as potentially hazardous as previously thought. "There's faults everywhere, but if they were to be going off they would have gone by now, although the risk of a [magnitude] 5 is still quite high."

The last aftershock of that size was a magnitude 5.2 on May 25, 2012. GNS Science forecasts there is a 61 per cent chance of a quake of more than magnitude 5 in the aftershock zone in the next year.

"The ground is still trying to settle down but the rate is now a bit smaller. It is a horizontal relative motion, where the northern side of the aftershock zone is moving roughly east-northeast relative to Banks Peninsula.

However, compared to regional deformation before the whole earthquake sequence started in September 2010 it is still a lot more active."

‘The September 2010 quake was 7.1 magnitude and the February 2011 quake, which killed 185 people, was a 6.3 magnitude. - Stuff.

PLANETARY TREMORS: The Alpine Fault - Geologists Says Mega-Earthquake In New Zealand Could "Melt Rocks"; Fault Line Could Get As Hot As 1,000 Degrees!

March 17, 2013 - NEW ZEALAND - The next time the Alpine Fault "goes", it is likely to be a big one, but the earthquake on the surface will be a tiny fraction of the power unleashed beneath.

University of Canterbury researcher Carolyn Boulton is finishing her research on the plate boundary that splinters the South Island and what happens underground when it ruptures.

ALPINE FAULT: An 800 kilometre-long fault which runs along the western
edge of the Southern Alps from Marlborough to Milford Sound.

The energy that went into surface shaking was less than 5 per cent of the energy released by the fault rupturing, she said.

"A lot of it is just used up on the fault itself,'' she said.

"Most of [it] is used up as heat on the fault and it's also used up to crush and pulverise [rocks]. The remainder, whatever is left, that's what's sent out as seismic waves."

Dry parts of the fault line can get so hot - about 1000 degrees Celsius - that the rock melts.

The "main divide" of the Alpine Fault is that dry only at great depths, but branches at its northern end - the Hope, Clarence, Wairau and Awatere faults - also have little water.

Boulton recreated Alpine Fault conditions at three university laboratories in the United States and China for her research and built an instrument to simulate quake shaking here.

"We have a machine [in Christchurch] that we put the rocks into and we simulate earthquake conditions,'' she said.

"We have learnt that the fault gets stronger with increasing temperature and pressure with increasing depth [and] that when an earthquake occurs, the Alpine Fault's strength dramatically decreases."

The Alpine Fault's last major quake was in 1717 and had a magnitude between 7.9 and 8.1.

GNS Science estimates there is a 30 per cent probability of the next quake on the fault occurring in the next 50 years. - Stuff.

PLANETARY TREMORS: New Zealand Rattled By 11,000 Aftershocks, Following The 2010 Earthquake?!

January 18, 2013 - NEW ZEALAND - A magnitude-3.3 earthquake that struck Christchurch this afternoon could be the 11,000th tremor since September 4, 2010.

The quake hit at 12.55pm, 15 kilometers east of Christchurch at a depth of 6km. Over 163 people reported feeling the “moderate” shake on the GeoNet website. According to Christchurch Quake Map, the quake was the 11,000th the region has experienced since the magnitude-7.1 struck early on September 4 2010. GNS Science geological hazard modeler Matt Gerstenberger said 11,000 quakes was a significant but expected number for the region to have experienced.

“Anyone living there knows what it has been like. However, it is in the range of what we would have expected for a region which has had a large earthquake.” Many of those quakes would not have been felt, he said. “Many would have been so small they wouldn’t have been noticed. Also, I’m not sure what the minimum magnitude for a quake is that is mapped on that website, but that [11,000] figure would be in the range, I suspect.” He did not expect the number of quakes mapped to go up greatly. “According to the aftershock sequence, the aftershocks will now be further apart and so the number will go up slowly over time,” he said. “There won’t be a huge or sudden increase.” - Stuff.

ICE AGE NOW: Global Cooling Across The World - Unseasonable Snow Falls In South Island, New Zealand; As Australia Faces Heatwave!

January 03, 2013 - NEW ZEALAND - A sodden South Island will have the chance to dry off over the next few days, after a front which brought gales, torrential rain, thunderstorms and unseasonal snow to the south moves off the country.  MetService this afternoon said weather conditions had now settled and the storm had abated. 

Thirsty Creek near Inchbonnie. Photo / Kasey Miles.

The winter-like weather brought down a vital bridge and fibre optic cable on State Highway 6, just north of Harihari, cutting off communication for about 1000 residents.  Floodwaters prevented structural engineers from inspecting the bridge today.  "Teams of contractors are working 15 hours while there's daylight to clear the flood debris and divert the river," New Zealand Transport Agency (NZTA) spokesman Mark Pinner said. "Once water levels drop we can get in quickly to inspect the bridge and then start re-building that section of the highway lost in the flood."  NZTA was hoping to have a clearer picture tomorrow on how long it would take to reopen the road, although it was expected to take days.  The West Coast road via Lewis Pass through Murchison also had to be closed, forcing travellers to make a seven-hour detour around Blenheim and Kaikoura to get to the east coast of the South Island.

State Highway 65 between Murchison and Springs Junction remains closed due to flooding, Mr Pinner said.  State Highway 6 in the upper Buller Gorge had been closed due to flooding, but that reopened this afternoon.  Last night, eight vehicles spent four hours stranded in the remote Buller Gorge after slips trapped them.  Four trampers spent a cold and wet night stranded in the Kahurangi National Park when they were cut off by a landslip.  They camped for the night above the slip, and were winched to safety this morning when the Nelson Marlborough Rescue Helicopter was able to fly into the area.  More than half a metre of rain fell in some areas of the West Coast over the past two days.  Snow fell on the Lindis Pass in Otago overnight, forcing travellers to abandon their vehicles near the summit.  MetService forecaster Peter Kreft said weather conditions had generally settled down, and New Zealand now had a ridge of high pressure sitting over it for today and tomorrow.  The weekend was likely to be warm just about everywhere, with temperatures in the east of both islands expected to be around the 30 degree mark, Mr Kreft said.  However, come Monday a south-west flow would reach the country, cooling things down again.  "Timing of weather events beyond Monday is still a little uncertain,'' he said. - NZ Herald.

Australia Faces Heatwave.

As Australians swelter in a heatwave, it's been snowing in New Zealand's South Island. For the second summer in a row, snow has fallen in Central Otago in January. But forecasters say the winter woollies will not be needed for long.  Kids were pictured making snowmen, the Gimmerburn range near Ranfurly looked like a winter postcard and travellers near the summit of Lindis Pass abandoned vehicles on Wednesday night.  "There was quite a lot of snow but it's not landing on the town. It's on the hills surrounding," Misha Wilkinson of Misha's Vineyard near Cromwell told AAP.  She said the snow did not damage the vineyard, which was about two weeks behind a normal season due to cooler weather.  She said unseasonably hot temperatures are predicted for a wine and food festival in the Old Cromwell town precinct on Saturday.  A hailstorm was also reported in Oamaru late on Thursday afternoon.  The snow came after heavy rain and gales disrupted travellers on the West Coast of the South Island from Wednesday but the MetService says a ridge of high pressure will bring fine weather on Friday.  "The weekend is likely to be warm just about everywhere," MetService Chief Forecaster Peter Kreft says. - Herald Sun.

DISASTER IMPACT: Christchurch Earthquake Cost $13 Billion And Rising!

December 12, 2012 - NEW ZEALAND - The Christchurch earthquake is going to cost the Government more than $13 billion, Parliament has been told.

Earthquake Recovery Minister Gerry Brownlee explained the latest figures today, saying huge resources have been committed to rebuilding the city.

The Christchurch quake will cost the Government $13 billion.

Fixing road and rail networks will cost about $2.5 billion, with $500 million already spent, and paying out 5212 red zone homeowners has cost more than $1 billion.

The Earthquake Commission has paid out more than $4 billion and the total will reach more than $12 billion, with $7 billion of it coming from the Government.

"The final cost is not yet known," Mr Brownlee said.

"We know it will cost the Government somewhere in excess of $13 billion but the total economic cost is likely to be about $30 billion." - 3NEWS.

PLANETARY TREMORS: Global Seismic Uptick - 6.3 Magnitude Earthquake Shakes Tokoroa, New Zealand!

December 07, 2012 - TOKOROA, NEW ZEALAND - As if the world has not shaken enough. New Zealand falls victim to Friday’s onslaught of earthquakes throughout the globe. A strong Magnitude 6.3 earthquake jolts residents of Tokoroa, New Zealand. The quake hit 19km SE of Tokoroa.

On December 22nd of last year a series of strong earthquakes struck the New Zealand city of Christchurch. It too was on a Friday although it is Saturday presently in that country.  Last years quake rattled buildings, sending goods tumbling from shelves and prompting terrified holiday shoppers to flee into the streets. There was no tsunami alert issued and the city appeared to have been spared major damage.

Again speaking of last year’s tremor, the first 5.8-magnitude quake struck on a Friday afternoon, 16 miles (26 kilometers) north of Christchurch and 2.5 miles (4 kilometers) deep, the U.S. Geological Survey said. Minutes later, a 5.3-magnitude aftershock hit. About an hour after that, the city was shaken by another 5.8-magnitude temblor, the U.S.G.S. said, though New Zealand’s geological agency GNS Science recorded that aftershock as a magnitude-6.0. Both aftershocks were less than 3 miles (5 kilometers) deep. New Zealand is part of the Pacific Ring of Fire, which is geologically active. No damage has been reported as the seismic event just occurred 10 minutes ago. As soon as we have word of news from that area in the world we will provide an immediate report. - The Guardian Express.

Seismotectonics of the Eastern Margin of the Australia Plate.
The eastern margin of the Australia plate is one of the most sesimically active areas of the world due to high rates of convergence between the Australia and Pacific plates. In the region of New Zealand, the 3000 km long Australia-Pacific plate boundary extends from south of Macquarie Island to the southern Kermadec Island chain. It includes an oceanic transform (the Macquarie Ridge), two oppositely verging subduction zones (Puysegur and Hikurangi), and a transpressive continental transform, the Alpine Fault through South Island, New Zealand. Since 1900 there have been 15 M7.5+ earthquakes recorded near New Zealand. Nine of these, and the four largest, occurred along or near the Macquarie Ridge, including the 1989 M8.2 event on the ridge itself, and the 2004 M8.1 event 200 km to the west of the plate boundary, reflecting intraplate deformation. The largest recorded earthquake in New Zealand itself was the 1931 M7.8 Hawke's Bay earthquake, which killed 256 people. The last M7.5+ earthquake along the Alpine Fault was 170 years ago; studies of the faults' strain accumulation suggest that similar events are likely to occur again.

North of New Zealand, the Australia-Pacific boundary stretches east of Tonga and Fiji to 250 km south of Samoa. For 2,200 km the trench is approximately linear, and includes two segments where old (greater than 120 Myr) Pacific oceanic lithosphere rapidly subducts westward (Kermadec and Tonga). At the northern end of the Tonga trench, the boundary curves sharply westward and changes along a 700 km-long segment from trench-normal subduction, to oblique subduction, to a left lateral transform-like structure. Australia-Pacific convergence rates increase northward from 60 mm/yr at the southern Kermadec trench to 90 mm/yr at the northern Tonga trench; however, significant back arc extension (or equivalently, slab rollback) causes the consumption rate of subducting Pacific lithosphere to be much faster. The spreading rate in the Havre trough, west of the Kermadec trench, increases northward from 8 to 20 mm/yr. The southern tip of this spreading center is propagating into the North Island of New Zealand, rifting it apart. In the southern Lau Basin, west of the Tonga trench, the spreading rate increases northward from 60 to 90 mm/yr, and in the northern Lau Basin, multiple spreading centers result in an extension rate as high as 160 mm/yr. The overall subduction velocity of the Pacific plate is the vector sum of Australia-Pacific velocity and back arc spreading velocity: thus it increases northward along the Kermadec trench from 70 to 100 mm/yr, and along the Tonga trench from 150 to 240 mm/yr. - USGS.

MASS ANIMAL DIE-OFF: 28 Pilot Whales Stranded on Farewell Spit, Golden Bay in New Zealand - 12 Died in the First Hour; Others to be Euthanised!

November 15, 2012 - NEW ZEALAND - A pod of 28 pilot whales stranded on Farewell Spit in Golden Bay are to be shot by DOC staff. The Department of Conservation told ONE News that it was first alerted about a beaching at 9am, and when volunteers arrived to rescue a second whale, they discovered 28 stranded on the beach.

A pod of 28 whales stranded at Farewell Spit, Golden Bay.

Twelve whales died in the first hour and DOC staff said the unusually high death rate and the fact that the next high tide is not until tomorrow lunch time forced them to make the decision, along with local iwi and Project Jonah volunteers, to euthanise the rest of the stranded whales. Staff will use a high-calibre rifle to euthanise the whales and this process will start in the next hour. "It's really sad and not a situation we take lightly but anything else is inhumane and would prolong their suffering," DOC biodiversity manager Hans Stoffregen said. "They don't look that flash so putting them all through another two days of this is inhumane."

The pod was lying almost amongst the driftwood and the next high tide at midnight probably would not reach them, he said. The whales will be left on the beach to be savaged and rot. Stoffregen said it would possible more whales might also come in, and he asked anyone seeing more whales out at sea or beached to contact DOC. This stranding is said to be earlier than usual, with the main season for whale strandings from around the end of the year through until March, he said. Whale strandings are not uncommon in Golden Bay, at the top of the South Island. A pod of 99 pilot whales stranded at Farewell Spit in Golden Bay in January. Many died while more than 90 volunteers worked to refloat others. Project Jonah chief executive Kimberly Muncaster says the geography of Golden Bay is confusing for whales and they often end up stranded again after being refloated. - TVNZ, ONE News.

PLANETARY TREMORS: The Alpine Fault - Researchers Find New Zealand More Seismically Unstable Than Previously Thought!

Researchers have discovered New Zealand's earthquake-prone landscape is even more unstable than previously thought, recording deep tremors lasting up to 30 minutes on its biggest fault line. Scientists measured the so-called "creeping earthquakes" when they investigated a puzzling lack of major seismic jolts along a section of the Alpine Fault, which runs the length of the South Island. 

The quakes, which caused no surface damage, occurred 20-45 kilometres (12-28 miles) beneath the Earth's crust and continued for as long as half an hour, much longer than ordinary earthquakes. In contrast, the 6.3-magnitude quake that killed 185 people in the South island city of Christchurch in February last year lasted just 37 seconds and struck at a depth of about five kilometres. The quakes could not be measured by regular seismic monitoring devices and researchers from Wellington's Victoria University had to place sensors in boreholes 100 metres deep to pick them up. Seismologist Aaron Wech said the research showed the Alpine Fault, regarded as New Zealand's most hazardous, did not remain still between major earthquakes but was constantly shifting.  Wech said the implications for future earthquakes were unclear. 

"It could be that constant tremor builds up stress and may trigger a major fault movement (earthquake) or, alternatively, the activity may decrease the likelihood of a major quake by acting as a release valve for stress," he said.  "What's important is that we find out more about these tremor events, such as where they happen and how often, so we can better predict the hazard the Alpine Fault poses."  The research was published this week in the US journal Geophysical Research Letters.  The government's GNS Science agency estimates the Alpine Fault has generated four quakes of magnitude 8.0 or higher in the past 900 years, most recently in the early 1700s, and another is overdue.  It says there is a high probability one will occur in the next 40 years, producing "one of the biggest earthquakes since European settlement of New Zealand (which) will have a major impact on the lives of many people".  The Christchurch earthquake was not caused by the Alpine Fault but a previously unknown fault line, part of a network of seismic fractures criss-crossing New Zealand, which lies on the junction of two tectonic plates. - AFP.

PLANETARY TREMORS: Swarm of Earthquakes Rattle South Island, New Zealand!

A swarm of earthquakes has rattled the South Island but seismologists don't believe there is any cause for alarm.  The latest quake struck just before 3pm and was centred in the Christchurch suburb of Cashmere. It measured 3.9 on the Richter scale but was strongly felt across the city as it occurred at a depth of just 5km. 

There were no immediate reports of damage from the quake but it left residents rattled as it was the first big aftershock to hit the city in some months.  Online notice boards immediately lit up with comments from residents spooked by the quake: ''Biggest felt in ages,'' one poster wrote. ''The noise was huge,'' said another.  ''I have been waiting for another biggie, let's hope it isn't a foreshock but just in case I am filling my water bottles and getting things ready,'' another person said.  British actress Miriam Margoyles was doing a matinee performance of her show Dickens' Women when the quake hit but continued with the show, apparently unfazed by the rumbling beneath her feet.  ''She paused briefly as the audience gasped and then continued without skipping a beat,'' said Ali Jones, who was in the auditorium watching the show.  ''The whole building really shook and there was quite a bit of noise with it.'' 

Earlier in the day Southland was struck by two quakes, the largest of which measured 5.5 and was centred 40km west of Tuatapere at a depth of 12km.  Craig Rutland, who runs the backpackers at Tuatapere, said the ground shook vigorously but it was not a violent quake.  ''It was very strong but nothing was thrown off the walls or fell off the shelves,'' Rutland said.  One of his guests was just sitting down to breakfast when the quake struck at 10.07am and was a bit unnerved by the experience. When it started we were a bit worried about what was going to happen, Rutland admitted, but it dissipated pretty quickly.  Others spoken to in the small Southland settlement reported the quake as a fairly big rumble but said they were unaware of any damage occurring as a result.  The quake was preceded by a magnitude 2.8 quake centred in roughly the same area.  A magnitude 4.3 quake also struck the Kaikoura region this morning. It was centred 30km east of Kaikoura at a depth of 15km.  GNS seismologist Mark Chadwick said it was not unusual to see so many earthquakes in one day and it was unlikely the quakes were a forerunner to a more significant seismic event. - Stuff.

FIRE IN THE SKY: Solar System Disturbances - Fiery "Meteor" Blazes Across the Night Skies of New Zealand!

Reports have come in of a bright light seen moving over the sky in Wellington and Christchurch.

There have been numerous reports of what appears to be a meteor shooting across the sky in the South Island and lower North Island. Sightings of a "ball of coloured flame" or "silver fireball" have been witnessed in Christchurch, Whanganui, Wellington, Kapiti Coast, Nelson and Kaikoura between 6pm and 7pm on Monday. One witness in Canterbury wrote on Weatherwatch.co.nz: "Was like a flying ball left with a jet stream sort of thing in the sky and was really bright!"

"Fantastically big, bright, and racing across the sky," said another witness in Otaki, Kapiti Coast. Simon Holtham wrote on the website: "I saw this too, it was like something out of a movie, ball of coloured flame shooting towards the earth from west to east, a couple of flashes, lots of smoke which stayed in the sky for ages, and then gone." Another person said: "Seen bright light flying in high speed with huge tail over looking the Cook Strait." - 3 News.

WATCH: Meteor over New Zealand.

ANIMAL BEHAVIOR: Mass Stranding and Die-Off - 100 Pilot Whales Stranded at Farewell Spit in New Zealand, Third Time in Two Months in the South Island, 34 Died Overnight!

Another effort is to be made today to try to free a group of pilot whales stranded on Farewell Spit. Around 100 whales stranded at the Spit, on the northwest tip of the South Island, around midday on Monday.

Pilot whales are stranded in the South Island for the third time in two months.

Thirty-four whales died overnight Monday, and while some did free themselves at high tide, about 40 remained beached yesterday. Efforts to refloat those whales at high tide yesterday were unsuccessful, and early today the Department of Conservation reported 35 live animals and four dead. DOC Golden Bay area manager John Mason said the whales that were still alive were in reasonable condition, and another attempt to refloat them would be made at high tide.

About 200 people, including DOC staff, Project Jonah members and volunteers, had tried to encourage the whales to swim away yesterday. But when the tide came in the animals had not wanted to leave from the area where they stranded, and when the tide went out they had remained beached. "We have a very short period of time to try to persuade them to leave. We tried very hard yesterday to physically push them out to sea. They didn't go." The spot where the whales were stranded is close to where 25 were stranded early in January. Seven of those whales died, while 65 whales died after becoming stranded in the same area in November. - Stuff.

WATCH: Pilot whales beached on Farewell Spit.

WATCH: Fight to save stranded New Zealand whales.

ANIMAL BEHAVIOR: Mass Stranding - More Whale Stranding at Farewell Spit in New Zealand, Third Time in Two Months in the South Island! UPDATE: Stingray Bites Boy at Theme Park in Australia!

A group of whales has been stranded around Farewell Spit, near the top of the South Island, for the third time in two months.

Pilot whales are stranded in the South Island for the third time in two months.

About 90 pilot whales were seen milling close to the shore around noon on Monday and have since grounded on a receding tide, Project Jonah chief executive Kimberly Muncaster says. Ms Muncaster says volunteers will care for the whales until nightfall, when the fast incoming tide will be a danger to the people. "There's a small chance the whales may refloat on tonight's high tide at 11pm, but we will be back at first light to assess the situation and assist DOC (the Department of Conservation) in their rescue response," she said on Monday.

"Hopefully we'll be able to keep as many whales as possible alive until nightfall." Project Jonah marine mammal medics have also been called to give the whales first aid. Volunteers with wetsuits are wanted, as are those who can work at the beach. They're asked to check out Project Jonah's website for a list of items they will need, which includes food, water, sunscreen and appropriate clothing. The spot where the whales were stranded is close to Farewell Spit, where 25 were stranded early in January. Seven of those whales died, while 65 whales died after becoming stranded in the same area in November. Farewell Spit is known as a whale stranding hotspot. - MSN New Zealand.

UPDATE: Stingray Bites Boy at Theme Park in Australia!

A six-year-old boy has been bitten on the finger by a stingray at a theme park on Queensland's Gold Coast. It happened at a Sea World exhibit yesterday morning. The boy's wound was treated by a nurse at the theme park and he was taken to hospital as a precaution.

Sea World says it is the first time such an injury has occurred since the Ray Reef attraction opened in 2009. The theme park says the exhibit will remain open. - ABC Australia.

ANIMAL BEHAVIOR: Mass Stranding of Whales in New Zealand - 7 Long-Finned Pilots Die, 18 Rescued at Farewell Spit!

Seven long-finned pilot whales died after being beached in New Zealand, but rescuers were confident Saturday they had saved the other 18 marine mammals that stranded.

Seven of the 25-strong pod died after they stranded late Friday on Farewell Spit at the northwest corner of South Island, conservation officials said. The surviving whales were floated off the beach at high tide. They were well offshore by late Saturday afternoon and heading toward deeper waters after earlier swimming north toward more shallow waters on the ebbing tide, said John Mason, area manager for the Department of Conservation. "They were quite lethargic at the start and ... we thought they could well strand on the outgoing tide," he said. Boats were used to try to point the whales to deeper waters, and people got into the water to encourage the animals to head toward the deep sea, Mason said.

"Then, just in the nick of time, they started moving eastward out of danger, and they're now well off Farewell Spit tracking southward into deeper water," he told National Radio. Mason said the pod's movements will be tracked during the night because there was still a risk the whales could come back into the shallow waters of the long, sloping headland spit area. But he said he was "confident" the 18 pilot whales wouldn't restrand. Project Jonah whale rescue group chief executive Kimberly Muncaster said volunteers would be checking beaches to "help locate further strandings before it is too late to save the animals." Adult male pilot whales measure up to 20 feet (6.1 metres) and weigh up to 3 tons, while adult females measure up to 16 feet (4.9 metres) and weigh up to 1.5 tons, according to the American Cetacean Society. New Zealand has several whale strandings along its coastline each summer, with mass strandings of as many as 450 whales occurring. Since 1840, more than 5,000 strandings of whales and dolphins have been recorded on New Zealand's coast. In November, 47 pilot whales died and 18 were euthanized after they stranded on tidal flats at the tip of Farewell Spit. Whale experts have been unable to explain why the mammals swim into dangerously shallow waters. - CTV.