Geologists find Christchurch torn by entirely new fault

February 24, 2011 CHRISTCHURCH – A new threat of landslides has emerged near to the epicenter of the quake, where boulders loosened by the tremor have already killed two and crushed homes. An aerial survey by scientists found no surface trace of the fault, which is centered southeast of Christchurch. But the expedition found worrying evidence of slips on the crest of the Port Hills, and above Lyttelton, Rapaki and Sumner. Dr Mark Quigley, a geology lecturer at the University of Canterbury, said: “These are landslides that have the potential to carry houses down with them, or have run-outs into populated areas. “There have been rocks the size of cars which have come down, and some of them have damaged houses – one has gone right through a house. “There are still numerous boulders which have the potential to come down.” The Lyttelton Fire Service confirmed that two people had been killed on walking tracks on Tuesday after being struck by falling rocks. Dr Quigley said geologists would place monitoring stakes in the hills to measure whether the landslides were creeping towards populated areas. Early investigations have suggested that the shallow earthquake was an aftershock of the September quake in Darfield, but did not come from the same fault-line. GNS Science natural hazards platform manager Kelvin Barryman said tests indicated it occurred on a “blind” or unknown fault, which runs east to west 1km north of Lyttelton. This meant that – like the Darfield fault that had lain dormant for at least 16,000 years – the Lyttelton fault-line had been accumulating extreme pressure over centuries, before collapsing catastrophically. Experts said the enormous aftershock was statistically unusual. Generally aftershocks get smaller and less frequent as months go by. Professor Peter Malin, director of the University of Auckland’s Institute of Earth Sciences and Engineering, said: “With the decay of the Darfield event, many of us would have breathed a sigh of relief – until Tuesday.” The quake was a “strike-slip event with oblique motion“, meaning the earth moved mostly side-to-side but occasionally up-and-down. Institute associate director Eylon Shalev said the vertical acceleration of the earth, at 1.9 times the acceleration of gravity, was far greater than the sideways movement. –NZ Herald
We believe this is only the beginning of the destruction of island chains in the Pacific.
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10 Responses to Geologists find Christchurch torn by entirely new fault

  1. Heather Holland says:

    I am really wondering if the earthquake that New Zealand had is a result of a volcano coming alive, and be the reason for having new fault lines. So my question is is the people in Christchurch in grave danger if this possible volcano erupts, and if this is a volcano is there any way of finding out for sure. How safe are the people of New Zealand. I do not live there but have a friend who has family there. Just a concerning person for the will being of other human beings.

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    • Heather, the geology of New Zealand makes it one of the most turbulent regions on Earth relative to an escalation of events. I will cover this in more detail a little later with a post. The North Island is volcanically dense- the TVZ or Taupo Volcanic Zone is home to the super-volcano Lake Taupo. On the South Island, we have a strike-slip boundary. Prognosis, not good and you can follow the trail of science to potential eventualies if earthchanges escalate. All the more reason to follow updates by local geologists in New Zealand.

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  2. Lee Buhagiar says:

    The frequency and magnitude of earthquakes has not changed, there are just too many people on the planet and the chance of a natural event striking a population dense area has increased. Get a grip people.

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  3. Denise says:

    Scientists have been downplaying the appearance of hot springs in Lyttelton Harbour since the February 22nd quake (near epicentre of Christchurch’s quake). They have told us that there is no chance that the dormant volcano that once was Lyttelton Harbour will become active.
    What do you think?
    They have also told us that the aftershock sequence from both quakes in this area (September 4 and February 22) are normal. But what is normal? And what can they compare these events to for a comparison?

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    • Denise, in my book, I stressed the fact that dormant volcanoes would and are awakening during this period. This was only recently confirmed by a team of scientists this month—- please reference article: http://www.tgdaily.com/general-sciences-features/54491-many-dormant-volcanoes-could-erupt-at-any-time. I disagree with many traditional geological theories. Consigning everything to the ‘aftershock‘ concept being one of them. Why does an earthquake happen to begin with? A fault ruptures to alleviate stress? Free Dictionary.com defines an earthquake as: “A sudden movement of the earth’s crust caused by the release of stress accumulated along geologic faults or by volcanic activity.” Dictionary.com says an earthquake is: “A series of vibrations induced in the earth’s crust by the abrupt rupture and rebound of rocks in which elastic strain has been slowly accumulating.”

      If the earthquake alleviates stress, why do aftershocks happen? And why do they keep happening up to a year after the quake? If the tire on your car has a blow-out, can it have a second blow-out and a third? I believe we have to look at other causes for occurrences. This region may be at an increased risk of greater instability but people can be lulled into a false security by believing its normal activity. And one example of that is the Mount Vesuvius eruption in 79 A.D., Tremors were reported around the summit for up to 2 years before the eruption but the people in Pompeii grew accustomed to them. Four days before the eruption, the writer Pliny the Younger even wrote about the tremors saying that they “were not particularly alarming because they are frequent in Campania.”

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  4. I live in Bexley christchurch and really do wonder is there another dormant volcano out by Darfield that the scientists are keeping quite about. they havent told the public about the two in town Lyttleton harbour and Akoroa its the older citizens of Christchurch who have been telling people as far as I knew it was just a harbour until my mother told me otherwise. My query about the volcano in or by Darfield is that is where the earthquake originated from not in town, its miles away from lyttleton and Akoroa I know there are ski field here but am unsure whether they are Darfields way. I wonder if the scientists are telling us everything they know. I am a North Islander and have lived through many earthquakes and you had it and it was over, know such thing as after shocks is this a laymans term used by scientists for continuing activity your thoughts to my query would be appriciated

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    • Claire, the seismic dynamics of earthquakes- particularly mega-thrust earthquakes changed around 1960. These quakes began releasing inordinate amounts of seismic energy whenever the sea-floor was churned or ripped during an eruptive event. How many quakes does it take to destroy the country of Japan? apparently one. The geology of the planet is morphing, magma is stirring and chewing slabs of mantle even as that marks its treacherous climb to volcanic bed-chambers, tensile integrity of the crust is degrading from stresses associated with hydrocarbon reservoir extraction and increasing rainfall totals. So called ‘afterhocks‘ are increasing because the forces that created the seismic rupture originally are also intensifying. It is not numbers that should be of most concern here—- it should be the frequency cycle of how many large type quakes we have had in such close proximity. The 9.3 mega-thrust quake in the Indian Ocean in 2004, the 8.9 that hit Chile in 2010, and the 9.0 quake that struck off the east coast of Honshu Japan in 2011. This is grave cause for concern.

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      • claire pontifex says:

        can you answer my question I am not of the science field so laymans terms are best are there volcanoes near Darfield and to your reply I dont quite understand I was born in 1960 so any earthquakes I felt were after the change so why are these so different than any felt in gisborne where you got major ones without aftershocks

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      • Claire, I would have to study the geology of the South Island to understand what the volcanic history is. The danger is from faults. The dangers to the North Island are volcanic in the Taupo complex. As far as 1960 is concerned, I was referring to aftershock frequency. In the Great 9.3 Alaskan Earthquake of 1964, there were 10,000 aftershocks, the most ever recorded. This type of quake is called a mega-thrust quake and they generally occur where tectonic plates dive under each other. This is the type of earthquake Japan experienced. The South Island is not in that type of zone.

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  5. Ian S says:

    As far as one can tell there are no volcanoes near Darfield. Lyttelton & Akaroa are a very different story.

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