The Alpine Fault: Is New Zealand Prepared? (Post 1 of 2) Jesse Dykstra Nov 20

The central section of the Alpine Fault. Source:

The central section of the Alpine Fault (Source:

This post is the first of two articles which explore the potential impacts of the next great earthquake on the Alpine Fault, and consider how prepared New Zealand is for that event.  This builds on a previous post which describes the physical properties of the Alpine Fault in more detail.

Improved Understanding of Earthquake Hazards in New Zealand

Damage in Christchurch following the 22 Feb. 2011 earthquake

Damage in Christchurch following the 22 Feb. 2011 earthquake

One of the positive outcomes of the Canterbury earthquakes of 2010 and 2011 is an increased focus on improving our understanding of earthquake risk in other seismically active regions of New Zealand,  including the Wellington area, and the West Coast of the South Island, where our largest and most active fault, the Alpine Fault, is due to rupture.

The imminent rupture of the Alpine Fault is a subject which has recently been the beneficiary of increased research focus in the scientific community. Several recent studies have improved our understanding of the rupture history of the Alpine Fault, including significantly extending the record of great earthquakes (i.e. > Mw 8) out to about 8,000 years before present. This research, which has been published in the leading journal Science, has confirmed a recurrence interval of 330 years for great earthquakes on the Alpine Fault, and that the probability of such a rupture occurring within the next 50 years is about 30%.

Has Public Awareness About the Alpine Fault Been Skewed by Our Perceptions of the Canterbury Earthquakes?

Has this improvement in our understanding of the behavior of the Alpine Fault translated directly into enhanced public awareness of the risks associated with the next great earthquake? Well, perhaps not as much as scientists and risk analysts would like to believe. Certainly the average person in New Zealand is well aware of the devastation caused by the Canterbury earthquakes, as well as the recent damage and aprehension caused by the Cook Strait earthquakes (centered near Seddon), but I would argue that those events, while increasing our general awareness of the inevitability of a future great earthquake on the plate boundary, have actually skewed our overall perception of the risks associated with the next Alpine Fault Rupture.

I sensethat many of us continue to have a sense of complacency about seismic hazards in New Zealand – we have “gotten through” the recent earthquakes, so we must have had the “get ready” part sorted, right? Having ridden out the Darfield (Mw 7.1) and Christchurch (Mw 6.3) earthquakes, and thousands of aftershocks, we have a pretty good idea of what mother nature can throw at us, right? After all, how much worse can an earthquake get than the virtual destruction of a city’s entire CBD? 

In the aftermath of the 22 February 2011 earthquake in Christchurch

In the aftermath of the 22 Feb. 2011 earthquake in Christchurch

We must remember that while large parts of Christchurch were devastated by the recent earthquakes, one only has to drive an hour in any direction from the CBD to find areas that appear to be completely uneffected by the earthquakes; there simply isn’t any evidence of significant earthquake damage beyond about a 50 km radius from Christchurch City.

This will not be the case following a great (Mw 8) earthquake. An Alpine Fault earthqauke will be a very different beast than the Canterbury earthquakes, with a resulting truely national-scale disaster of much greater impact than any historical earthquake in New Zealand.  The entire South Island will be effected in some way, with indirect, but profound impacts to the entire country.   

Gobally, large earthquakes have caused some of the worst natural disasters over the last 50 years, including:

  • 2011  Mw 9 Tōhoku earthquake and tsunami (Japan),  18,000 deaths
  • 2010 Mw 7.0 Haiti earthquake, ~ 200,000 deaths
  • 2008 Mw 7.9 Sichuan earthquake (China),  ~90,000 deaths
  • 2005 Mw 7.6 Pakistan earthquake,  ~100,000 deaths
  • 2004 Mw 9.3 Sumatra-Andaman earthquake & tsunami (Indian Ocean),  ~275,000 deaths
  • 1995 Mw 6.9 Great Hanshin earthquake (Kobe, Japan),  5,500 deaths
  • 1976 Mw 8  Tangshan  earthquake (China),   240,000 - 800,000 deaths

In addition to causing much loss of life, these earthquake disasters also had significant and far-reaching economic impacts. The Chinese government has estimated the cost to repair the damage caused by the 2008 Sichuan earthquake at about $150 Billion U.S. dollars (approximately the same as New Zealand’s GDP).

If the Alpine Fault were to rupture in the near future, the most severely-affected areas along the West Coast will be sparsely populated, so it is likely that the associated death toll will be much lower than that resulting from large earthquakes in heavily populated regions of the world. This is a benefit of living in an area with low population density; however, regardless of how many people loose their lives, we can be sure that there will be significant social and economic impacts following an Alpine Fault earthquake. 

Regional, Rather than Local Impact

Length of Fault Rupture & Total Energy Released

In general, the severity of ground shaking during an earthquake is directly related to the area of rock within the fault slip zone – the larger the area which slips, the more energy is released, with stronger and longer-lasting ground shaking as a result. The main section of the Alpine Fault is up to 450 km long; when that length of fault ruptures we can expect to see horizontal displacements of up to over 8 m, and vertical displacements of up to over 4 m.

These displacements could tear open the earth along hundreds of kilometres of the fault trace, and approximately 1000 times more energy will be released during such an earthquake than was produced by the Mw 6.3 earthquake that devastated Christchurch’s CBD on 22 February, 2011. The intial ground shaking will likely last 2-3 minutes, with subsequent strong aftershocks (up to >Mw 7) going on for days and up to weeks after the main event.

Modeled Earthquake Shaking Intensities, with Alpine Fault clearly visible running along the spine of the Southern Alps.  Source:

Modeled Earthquake Shaking Intensities, with Alpine Fault clearly visible running along the spine of the Southern Alps. Source:

The last Alpine Fault rupture, which generated an earthquake of magnitude 8.1, occurred in 1717. At least 380 km of the fault ruptured, from Milford Sound to the Haupiri River; although this predates written records in New Zealand, geological records preserve evidence of wide-spread landscape damage caused by this event.  These records include enhanced periods of sedimentation (due to increased landsliding on hillsides) or gravel aggradation in river valley bottoms which caused the burial and death of forests, inundation of river valleys caused by sudden changes in channel geometry.

Similar landscape changes occured after the 2008 Sichuan earthquake (Mw 7.9), which involved a rupture length of about 240 km, and affected an area approximately 900 km long by 600 km wide (i.e. an area significantly larger than the South Island).

Communities at Risk: Ground Shaking & Liquefaction

The magnitude of a future great earthquake on the Alpine Fault is likely to be such that at least “strong” (MMI VI) ground shaking will be experienced in even the furthest reaches of the South Island, as well as the lower North Island. Close to the fault trace catastrophic shaking intensities (up to MMI XII) will occur (see table below for description of shaking intensities). 

Fortunately, there aren’t any major cities very near to the Alpine Fault, but many smaller communities from Springs Junction  through to Franz Josef and Fox Townships and as far south as Haast are all located very close to the fault trace, and will probably experience severe ground shaking during an Alpine Fault earthquake, at least as intense as that which damaged Christchurch’s CBD during the 22 February 2011 event.  

A bit further away from the fault, communities such as Queenstown, Wanaka and Greymouth will likely experience significant and destructive ground shaking (up to MMI VIII). The largest South Island cities of Christchurch and Dunedin will likely experience ground shaking of up to MMI VII, similar to that felt in many parts of Christchurch during the September 2010 Darfield earthquake. That level of shaking caused significant damage to unreinforced masonry buildings in Christchurch, but most infrastructure damage was caused by liquefaction and lateral spreading over susceptible soils throughout the greater Christchurch region.


Moment Magnitude Scale of Earthquake Shaking Intensity

While the intensity of shaking felt in Christchurch during an Alpine Fault great earthquake may be similar to that felt during the Darfield earthquake, the duration will be much longer (2-3 minutes compared to 40 seconds), so extensive liquefaction should be expected again.

New construction in Christchurch should benefit from updated building standards and a much-improved understanding of the effects of ground shaking on liquefiable soils, but other communities which are relatively distant from the Alpine Fault (e.g. Invercargill, Dunedin, Timaru, Nelson, Blenheim) are also at least partially built on liquefiable soils. Assets built on susceptible soils will likely suffer some damage during prolonged moderate ground shaking, especially unreinforced masonry buildings and underground utilities.

Impact on Lifelines & Critical Infrastructure

In addition to causing widespread damage to land, buildings and underground utilties across much of the South Island, a future Alpine Fault earthquake will almost certainly sever the major lifelines that cross the fault, including State Highways 6 and 73, and the sole rail link to the West Coast, through Arthur’s Pass. Ground shaking during the intial event, and subsequent aftershocks, will trigger many large landslides, especially on steep hillsides within perhaps 100 km of the fault line.

GNS Science estimate that great earthquakes (i.e. >Mw 8) can trigger large landslides up to 300 km away from the fault rupture, and documented over 400 new landslides following the 2003 Fiordland earthquake (Mw 7.2) . Where lifelines cross the actual fault trace, ground offset and rupture will directly damage roads and rail lines; however, there are also a number of indirect ways that ground shaking can damage lifelines:

  • bridges damaged by intense ground shaking
  • bridges damaged by debris flows which travel down valleys following slope failures in mountainous catchments (especially on the West Coast, where there are many rivers crossing the narrow swath of gently sloping land between the mountains and the sea)
  • road and rail lifelines rendered impassable by landslides in steep or mountainous areas (e.g. near Haast Pass and Arthur’s Pass, as well as Lewis Pass and the Buller Gorge)
  • flooding damage to road/rail links due to river channel avulsion or landslide-dam-break in valley headwaters

    Landslides and bridge collapse following 2008 Mw 7.9 earthquake in Sichuan Province, China (source: University of Deleware)

    Landslides and bridge collapse following 2008 Mw 7.9 earthquake in Sichuan Province, China (source: University of Deleware)

Immediately following the next Alpine Fault rupture, isolated communities which rely on these lifelines will likely become effectively cut off from the rest of the country. West Coast communities may be particularly hard hit, especially given their proximity to both the Alpine Fault and the western slopes of the Southern Alps, the number of rivers/bridges between communties, and the limited number of transport routes, all of which travel through steep mountainous passes or river valleys. Depending on the time of day, and time of year when the earthquake occurs, thousands of people could become stranded on roads or rail lines which are impassible,  and some may be directly impacted by landslides, falling rock, road collapse, or bridge failure.

It will probably take several weeks to months to fully restore lifelines and access to the most isolated communities, during which time land-based transport will be very difficult, especially to the West Coast. Ongoing large aftershocks (up to >Mw 7) will continue for weeks and months after the intial earthqauke, meaning areas that could be affected by landslides or rockfall will not be safe to work in. Following the Sichuan eartquake, 158 relief workers were killed by landslides as they tried to repair roads in the weeks immediately following the main earthquake. How long after the main earthquake will it be before it is safe enough for roading crews to begin repair work? This is very difficult to predict, but eventually, many bridges will have to be at least temporarily repaired, and dozens (if not hundreds) of large landslides cleared through through the main passes. 


Landslide blocking road following 2008 Mw 7.9 earthquake in Sichuan Province in western China (

The intial emergency response will require massive mobilisation of resources from communities that are less affected (e.g. Nelson, Christchurch, Dunedin, Invercargill, Wellington). Port facilities and airports may be severely damaged as well, so there is no gaurantee that critical emergency supplies and fuel and equipment will be readily available, or be able to be transported to communties in need. Services that we normally take for granted, such as electricity, clean drinking water and telephone will likely be severely damaged, particularly close to the fault. While some communities may be able to quickly establish temporary drinking water supplies, restoration of electricity may take weeks, or even longer, as power lines will likely be extensively damaged by landslides, and some power stations and storage facilities will require damage assessment (at a minimum), to become operational.

Milford Sound and Displacement Waves

Poster from upcoming Norwegian film based on Tafjord Disaster of 1934 (source:

Poster from upcoming Norwegian film based on Tafjord Disaster of 1934 (source:

I believe that the potential impact of an Alpine Fault earthquake on the iconic tourist destination of Milford Sound deserves consideration – located within some of the most rugged mountain ranges of Fiordland, Milford Sound receives up to over 600,000 visitors per year. The seaward entrance of the 13 km-long fiord is crossed by the Alpine Fault, and there is ample geological evidence of many very large prehistoric landslides preserved both in the valley bottoms near the head of the fiord (where the Milford village, new visitor centre/cruise boat terminal, airport and docks are located), and on the fiord bottom itself. Most of these landslides were probably triggered by large earthquakes, and some of them would have fallen from the steep mountainsides high above the fiord, generating large displacement waves (tsunami) upon impact with the water.

If such an event were to occur during a peak tourist time at Milford Sound, several hundreds or thousands of people could be killed; landslide displacement waves up to 70 metres high have killed hundreds of people in the Norwegian Fjords during the last century. Other fiords and steep-sided glacial lakes of southern New Zealand are also susceptible to displacement waves caused by coseismic landslides (e.g. Doubtful Sound, Te Anau, Manapouri, Queenstown, Wanaka, Hawea).  This under-appreciated hazard in New Zealand is the subject of my recently-completed doctoral thesis, and I will cover some of the implications of that work in more detail in future posts.

 to be continued…

Typhoon Haiyan: how does it compare? Jesse Dykstra Nov 13

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(note dates as of 8 Nov. 2013)


The Guardians’ Ami Sedghi has written a nice blog comparing Typhoon Haiyan, which has caused devastating damage and loss of life in the Philippines over recent days, to historical tropical storms;  Haiyan has been widely reported in the media as one of the largest tropical storms in history. Ami has also clarified the use of varying names for tropical storms (e.g. typhoon, hurrican, cyclone), depending on where they are. 

Turns out that Haiyan looks like the fourth strongest tropial storm in history, and the strongest where it made landfall. Thanks Ami!

Could Wellington be Next? Jesse Dykstra Jul 22

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Recent Seismic Activity Beneath Cook Strait

Over the past three days, earthquakes have been rattling central New Zealand, with the epicentres of many of the tremors between Seddon and Wellington. According to GNS, the largest earthquake had a magnitude of 6.5, and was located beneath Cook Strait at a depth of 17 km, some 55 km from Wellington, and 45 km from Blenheim. There have been several dozen significant aftershocks, leaving some residents fearing that the recent seismic activity could be a precursor to a much larger earthquake in central New Zealand.


Recent Earthquake activity (accessed 22/07/2013 12:30am)
Source: GNS

Wellington and the Marlborough Fault System

Normally, when seismologists talk about a future earthquake in Wellington, they tend to focus on the closest active faults (i.e. the Wellington or Wairarapa faults). However, to the south of Cook Strait (and probably at least partially crossing it) there are also several major active faults, including the Hope, Clarence, Awatere and Wairau faults of the Marlborough Fault System.


The Marlborough Fault System

The Awatere Fault and the 1848 Marlborough Earthquake

Much of the recent seismic activity beneath Cook Strait appears to converge directly offshore of the Awatere Valley. The Awatere fault is a major active strike-slip fault which last ruptured in 1848, producing an earthquake of around Mw7.5. That event caused three fatalities and widespread damage in Wellington, which would have been subjected to shaking intensities of up to MM8 (see here for a description of MM shaking intensities).


Awatere valley. The linear trace of the Awatere fault is clearly visible on the left side of the valley.

Minor Damage in Wellington

As a result of the recent swarm of earthquakes, some damage has been confirmed in the capital city, with reports of brick facades crumbling, sink holes opening up in the CBD, and goods falling off of supermarket shelves. Thankfully, there are no reports of serious injuries or deaths (at least not yet). While some earthquake-hardened Christchurch residents may raise an eyebrow at all the commotion caused by a M 6.5 earthquake centered 50 km out at sea, residents of central New Zealand could be counting their lucky stars; a similar magnitude quake under an urban area could cause massive damage (particularly in Wellington’s CBD).  

There have been 117 Mw6-7 earthquakes in New Zealand since 1960 (or about 2 per year), and Mw7-8 earthquakes occur about once per 2.5 years, so residents should also be prepared for a more powerful earthquake.

Historical records show that larger earthquakes (Mw7-8) occur about once for every five earthquakes of Mw6-7 in New Zealand. So while the recent seismic activity beneath Cook Strait is unlikely to be a precursor to a larger event, that possibility certainly can’t be ruled out yet.


Source: GNS




Alpine Fault 101: Getting acquainted with New Zealand’s greatest natural hazard Jesse Dykstra May 28

Modeled Earthquake Shaking Intensities for New Zealand, with Alpine Fault clearly visible running along the spine of the Southern Alps (red band).  Source:

Modeled Earthquake Shaking Intensities for New Zealand. Zone of maximum shaking along Alpine Fault indicated by red band.

The Alpine Fault will rupture in the near future (quite possibly in your lifetime), without any prior warning. When it does, the scale of the immediate disaster will be unprecedented in New Zealand, and secondary effects will probably continue for decades. The Canterbury earthquakes of 2010 and 2011 served a brutal reminder of how vulnerable we are to strong ground shaking, so perhaps now is the perfect time to collectively improve our understanding of our greatest seismic hazard, and to prepare and build resiliency in vulnerable communities.

What is the Alpine Fault?

The collision of two great tectonic plates is building up strain along New Zealand’s Alpine Fault, which traces the western flanks of Southern Alps. The Alpine Fault is a dominant geomorphic feature  of the South Island, extending some 450 km from Milford Sound to near Springs Junction, where it branches off into the Marlborough Fault System. One of the world’s major fault lines visible on land, it is clearly visible from space, as a remarkable lineament which defines the western edge of the Southern Alps.

The central section of the Alpine Fault. Source:

The central section of the Alpine Fault.

The Pacific Plate is moving roughly westwards, and the Australian plate is moving roughly eastwards, at a relative rate of about 45 mm per year.  Along the Alpine Fault, the collision is oblique, so the plates are slipping past one another, rather than one being forced beneath the other (a process called subduction). The relative movement of the plates past one another is not a continuous or gradual slip, but rather a long-term average of much larger, episodic slips (or “ruptures”), which occur every few hundred years. The two plates are currently locked together along the Alpine Fault by friction, but the buildup of energy is not sustainable for much longer.

Plate Boundary and Slip Rates. Source: Davies & McSavenay

Plate boundary and average slip rates.
Source: Davies & McSaveney, 2006

Eventually, the strain accumulated over hundreds of years will exceed the strength of the rocks on either side of the fault, culminating in catastrophic failure, and a gigantic release of energy. When the Alpine Fault next ruptures, the land on either side of the fault will separate by about 8 m in the horizontal direction, and up to 4 m in the vertical direction. These huge displacements will result not only in intense shaking, but will likely also tear open the earth over hundreds of kilometres along the fault.

Rock deformation, buildup of strain, and eventual rupture along a fault line.  Source: Source:

Rock deformation, buildup of strain, and eventual rupture along a fault line.

The Alpine Fault is similar in character to the San Andreas Fault in North America; the last major rupture in 1906 devastated the city of San Fransisco, where at least 3,000 people died.  While there aren’t any major cities directly on the Alpine Fault, there are many smaller communities that are very close to the fault (e.g. Franz Josef township). Further away from the fault, places like Queenstown and Greymouth will experience significant and destructive ground shaking. Equally important are the major lifelines that cross the fault, including State Highways 6 and 73, and the sole rail link to the West Coast. The isolated nature of the West Coast will become more poignant as secondary effects like landslides and flooding will affect large areas following the initial earthquake, and with subsequent aftershocks.

Fence offset over the San Andreas Fault following the 1906 San Francisco Earthquake (Magnitude ~7.9). Rupture length was 475 km, maximum horizontal offset 6m. Source: unknown

Offset fence following the 1906 San Francisco Earthquake (Magnitude ~7.9, Rupture length 475 km, maximum horizontal offset 6m).

When did the Alpine Fault Last Rupture?

The last Alpine Fault earthquake occurred about 300 years ago, (most likely in 1717), generating an earthquake of magnitude 8.1, when at least 380 km of the fault ruptured, from Milford Sound to the Haupiri River. Although this event pre-dated written records in New Zealand, scientists from the University of Canterbury and GNS Science were able to trace the 1717 rupture length using a variety of techniques, including analyzing tree ring records along the fault trace, and radiocarbon dating of the most recent fault scarp (link here).

For How Long Have Great Earthquakes Been Occurring Along the Alpine Fault?

This cycle of strain accumulation and eventual rupture along the Alpine Fault has been occurring with remarkable consistency for many millenia. Scientists have known for decades that the Alpine Fault has ruptured 3-4 times over the past 1000 years, but that record has recently been extended. A 2012 article published in Science (link here) detailed an 8000 year record of large earthquakes on the southern portion of the Alpine Fault. The authors documented 24 surface ruptures, for an average recurrence interval of 330 years, and estimated the probability of a similar rupture occurring within the next 50 years at 30%. Of course, this probability doesn’t actually tell us when the next great earthquake will occur, but merely how surprised we will be when it does happen.


Record of Great Earthquakes on major faults, from Berryman et. al. 2012 (Science)

Comparison of record of Great Earthquakes on selected major faults, from Berryman et. al. 2012 (Science)


The Next Alpine Fault Rupture

The latest science confirms that the Alpine Fault is late in its recurrence cycle, and that it will likely rupture again in the near future, generating an earthquake of about moment magnitude (Mw) 8. To put that in perspective, such an event will release approximately 30 times more energy than the Mw 7.1 Darfield earthquake of 4 September, 2010, and up to 1000 times more energy than that produced by the Mw 6.3 earthquake that devastated Christchurch’s CBD on 22 February, 2011. An Alpine Fault earthquake will be felt throughout New Zealand, and probably in Australia as well.

Potential shaking intensities (roman numerals) resulting from a rupture of the central section of the Alpine Fault. Source:

Potential Modified Mercalli shaking intensities (roman numerals) resulting from a rupture of the Alpine Fault (dashed line).

How Will the Next Alpine Fault Rupture Compare to the Christchurch Earthquake of 22 Feb, 2011?

From the perspective of assessing risk, the ground shaking intensity associated with an earthquake is more important than the total energy released, as shaking intensity at a given location is what causes damage. The primary reason that the 22 February earthquake caused so much damage in Christchurch is that the fault rupture was close to the city, and very shallow (5 km deep). This resulted in extremely high ground shaking intensities (Modified Mercalli scale) of MM 8-10, relative to the magnitude of the earthquake. By comparison, seismologists estimate that during an Alpine Fault earthquake, the ground shaking intensity will be around MM 9-10 near the Alpine Fault, and MM 6-7 in more distal locations such as Christchurch and Dunedin. Equally important to the intensity of shaking is the duration; the shaking during an Alpine Fault earthquake will last 2-3 minutes, compared to less than one minute for the Darfield and Christchurch earthquakes. So, while the shaking intensity felt in Christchurch during an Alpine Fault Rupture may be significantly less than during the 22 February (2011) earthquake, the duration will likely be much  longer, so there will still be potential for serious damage.

Looking Ahead: Are We Ready?

Is New Zealand prepared for the next great earthquake on the Alpine Fault? Have our experiences with the recent Canterbury earthquakes made us more capable of dealing with the truly national-scale disaster that will result when the Alpine Fault ruptures? What major short term and lasting effects can we expect from a great earthquake on the Alpine Fault, and who will be most affected? I will address these specific questions in my next post.

Cruel Irony in EQC Privacy Breach: information on 83,000 claimants leaked Jesse Dykstra Mar 27


As widely reported in the media yesterday, details of EQC claimants and claims have been leaked in a privacy breach that effects 83,000 Christchurch households. That’s details of every claim between $10-100k, arising from the 4 September 2010 and 22 February 2011 earthquakes. The leaked spreadsheet included details of EQC repair cost estimates and associated contractor quotes.

If this information gets into the hands of building contractors or other rebuild stakeholders, the ability to obtain a fair settlement could be compromised for many claimants. For example, if Fletcher Building (who are managing most of the leaked claims) gets their hands on the EQC numbers, then any incentive for Fletcher to manage repairs in the best  interest of the claimant, rather than EQC, could be lost.

Despite the potential ramifications of such a massive breach of sensitive financial information, EQC boss Ian Simpson, Earthquake Recovery Minister Gerry Brownlee and Prime Minister John Key have all downplayed the seriousness of the leak, and brushed aside suggestions that this is simply the latest manifestation of a systemic lack of security in government storage of sensitive private information.

This particular leak of private information is cruelly ironic for many EQC claimants, who have been trying for years to get EQC to release the most basic of information on their claims, such as the estimated cost of repair. This is not trivial information; there are probably thousands of disputed “under cap” claims where repair estimates from private insurers and/or independent builders are double, or triple the $100k cap. Knowing what the EQC numbers are based on would be a big step in resolving these disputes; unfortunately the standard line from EQC has been “we can’t provide that information”.

Actually, it seems that they can. And why not? Shouldn’t the EQC and the private insurers be working together to get claims resolved as quickly as possible? Rather than barricading themselves behind locked doors, barring windows and installing razor wire, perhaps EQC staff should focus on their mandate, which is to resolve claims in a fair manner, and in a reasonable time frame. Surely such genuine efforts would do more to appease irate claimants than spending ratepayer money to fortify themselves against the people that they are meant to be looking after? Now that the very information that homeowners have been clamoring for over the past two years has been inadvertently leaked into the public domain, shouldn’t it be made available to all, so that at the very least, claimants can keep builders and private insurers honest?

I fully understand the frustration felt by so many people over this privacy breach. For many Cantabrians living with broken homes, dealing with the EQC has been one of the most stressful and time-consuming process that they have ever undertaken. In fact, I am a case in-point; “make-safe” repairs on our severely damaged, and unsafe (according to a structural engineers report completed right after the September earthquake) home were finally completed in January of this year, 28 months after the damage occurred. Let’s just say that sleeping beneath a shattered, teetering un-reinforced double-brick masonry wall for over two years has not been fun.

Ironically, the only way that we could get any information on our file was to go through the Official Information Act, after hundreds of phone calls and dozens of emails to EQC were futile – we were met with resistance at every corner.

Yet now, claim details which so many people have fought tooth-and-nail to have released, have been leaked into the public domain. Which kind of does feel like (as Green Party Christchurch spokeswoman Eugenie Sage noted), a “slap in the face”.

Many Cantabs  had such high hopes for EQC and the insurance industry, but that has steadily eroded away to wide-spread disillusion and anger. From my perspective as a natural disaster scientist, the most troubling sign is that apathy has started to creep into the once positive and proud psyche of the region. Many people are exhausted and depleted in every conceivable way, not by the thousands of aftershocks, but by the far more harrowing experience of trying to get a fair claim settlement, and many have simply given up, in an effort to get on with their lives. And many people are understandably starting to ask if the insurance industry has been actively facilitating that beaten spirit by stalling on claim settlements.

Even in the face of these challenges, Cantabs are generally very resilient, and remain passionate about rebuilding their beloved city. Fortunately, these are exactly the attributes that allow disaster-ravaged communities to adapt to adversity, and I fully expect the region to flourish in the coming years.

Climate change complicit in scorching heat, bushfires, flooding and tornadoes of disastrous Australian summer Jesse Dykstra Jan 29

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From a natural disaster perspective, Australia is having a much worse year than New Zealand, despite our apparent penchant for earthquakes, volcanic eruptions, flooding, and the occasional crippling winter storm on this side of the ditch. To date, the Insurance Council of Australia has officially declared three natural disasters in 2013 (the Tasmanian bush fires, New South Wales bush fires, and cyclone Oswald). But is Australia’s exceptional season for extreme weather just a blip on an otherwise “normal” climate regime, or is it perhaps a harbinger of worse things to come as our climate continues to warm?

Worse than the Queensland flooding of 2011?

Our poor neighbours across the ditch have been enduring scorching temperatures and raging bush fires for nearly a month, and now the east of the country is being thrashed by extreme weather, this time of the wet variety, courtesy of cyclone Oswald.  Just over a year after Australian Prime Minister Julia Gillard called the Queensland floods (December 2011 version) “the worst natural disaster in our history” , Queensland and northeastern NSW are once again being battered by extremely stormy weather, including widespread flooding and tornadoes.

Four people have been already been killed by flooding and storm-related hazards in Queensland, since cyclone Oswald made landfall. Communities such as Bundaberg in Queensland and Grafton in New South Wales are experiencing the worst flooding on record, while parts of Sydney have seen the heaviest rainfalls in over a decade.

The link between extreme weather and climate change

So do these recent extreme-weather-related natural disasters indicate that Australia’s climate is becoming more extreme in a broader sense? After all, heat waves and bush fires have historically been a regular fixture of the Australian climate; the same can be said for tropical storms which affect the east coast of Australia.

Actually, these types of extreme weather have become more frequent, and more severe in recent decades. A few decades ago in Australia, the number of new record high temperatures each year was approximately balanced by the number of new record low temperatures. Recently, the ratio of new record highs to new record lows has increased to 2:1. In 2010, 19 countries set new all-time record highs, but no new low temperature records were set.

Climate warming doesn’t directly cause natural disasters like heat waves, bush fires and tropical storms, but it can contribute to more extreme weather in several ways, including:

  • A warmer atmosphere can hold more water vapour, increasing the risk of extreme precipitation,
  • Higher temperatures increase the rate of evaporation from soil and water surfaces, as well as evapotranspiration by plants, increasing the frequency and intensity of droughts,
  • Higher sea-surface temperatures can cause changes in oceanic and atmospheric circulation patterns, which are driven by gradients in temperature and salinity,
  • Warming oceans provide more energy for the development of tropical storms,
  • Rising sea level due to melting ice means that many populated areas are increasingly at risk from tsunami and storm surges.

Weather now develops in different climatic conditions than it did just a few decades ago; heat waves are longer and hotter, tropical storms are more frequent and more intense, as are periods of drought.  The cold(?) hard reality is that extreme weather events that can contribute to natural disasters are on the increase.

The graph below illustrates why a small increase in mean annual temperature can shift the climate curve so that extreme heat events become more severe, and much more frequent. Case in point; the extremely hot conditions of this Australian summer are difficult to attribute to a simple blip on an otherwise normal climate regime; far from just a few days of unusually hot weather, much of Australia has been baking for months. A new record was set for average maximum daytime temperatures during the last 4 months of 2012 (which were 1.6 degrees above average ).

Solomon et al. 2007


The hottest day ever in Australia: blistering heat and bush fires

Since the new year, fire-fighting crews have battled hundreds of bush fires in south-east Australia, including in New South Wales, Victoria and Tasmania. Prolonged extreme heat combined with high winds to create ideal fire conditions. Average maximum temperatures across the country soared to 40.33 degrees on 7 January, the hottest day ever recorded over the Australian continent; even the Tasmanian capital Hobart reaching nearly 41 degrees. For the first time ever, the continent recorded five consecutive days with an average temperature exceeding 39 degrees; each of the first six days of 2013 were amongst the 20 hottest days on record.

The heat dome over Australia, 7 Jan, 2013 (Image courtesy of Australia’s Bureau of Meteorology)

1.6 degrees above average is a startling increase when averaged over a four month period, but it isn’t just Australia that has been experiencing a warmer climate: according to the Climate Change Research Centre (University of NSW), the number of very warm days (defined by the warmest 5% of days between 1950 and 1980) has increased by nearly 40% globally since 1983.

Whatever the sceptics may say, our climate is becoming more extreme, and Australia is merely the latest place to suffer from the effects of global warming.

Spectacular Footage of Yesterday’s Tongariro Eruption – Risk Remains High Jesse Dykstra Nov 22

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Mount Tongariro Eruption. Source: TVNZ

A Geonet webcam at Mt. Tongariro has captured spectacular footage of yesterday’s eruption, which lasted approximately 5 minutes, ejecting an ash column and plume some 3-4 km above the Te Maari crater. There have not been any reports of injuries or damage, beyond a light dusting of ash falling near the volcano.

The volcano burst into life again yesterday without any warning; seismic monitoring stations near the vent recorded no activity before the eruption. Tongariro has been returned to an Alert Level 2 (i.e. minor eruptive activity), with an aviation colour code of orange (minor ash ejection).

Since yesterday’s eruption (the first since 16 August; that eruption was from the same vent) activity has been low, but GNS scientists believe that the risk of further eruptive activity remains high, with a significant probability of additional eruptions over the next week.

In the late 1880s through to 1896, Tongariro erupted several times. If yesterday’s eruption is indicative of a similar eruptive sequence, we could be in for a prolonged period of volcanic acitivity at Tongariro.

In addition, nearby Mt. Ruapehu has shown signs of increased pressure buildup beneath the Crater Lake over the past week, and GNS Science has warned visitors to the mountain that there is an increased likelihood of an eruption there as well. Ruapehu is currently on an alert level of 1 (i.e. signs of volcano unrest).

Volcanologists remain uncertain as to whether or not recent activity at the two volcanos is linked, and Geonet is advising visitors to the area to stay out of designated restricted zones.





Mount Tongariro eruption – sleeping giant awakens Jesse Dykstra Aug 07


Seismic signature of Tongariro eruption. GeoNet

Last night Mount Tongariro burst into life, erupting for the first time in over 100 years. The eruption raised the Geonet volcanic alert from level 1 to 2, with an accompanying aviation colour code of red. The Tongariro alert level had been upped to level 1 on 20th of July 2012, due to increased seismic activity and other signs of volcanic unrest.  However, according to GNS volcanologist Michael Rosenberg, last night’s eruption was still a surprise, as seismic activity under the volcano appeared to be on the decline in recent days.  He warned that although the volcano seems relatively quiet at the moment, this early in the eruptive sequence it is impossible to know whether Tongariro’s activity will escalate in to a full-scale eruption.

According to GNS science, Tongariro is a large volcanic complex consisting of many cones that have been constructed over the past 275,000 years. There have been five recorded prior eruptions from the Te Mari craters, the last one in 1897.  Some 12 homes on the southern shores of Lake Rotoaira (~6 km away from the eruption) had a spectacular view of last night’s event, and eyewitness accounts confirm that the current eruption began around 11:50 pm yesterday with a violent explosion, accompanied by a red glow and flashes of lightning. Rocks and sand-like ash were apparently ejected from the volcano, causing concern for some residents, who reported seeing new vents on the side of the mountain ( The prevailing westerly winds have so far been driving the ash cloud to the east and south, with ash falls reported as far away as Napier. There aren’t any evacuation orders at present, but GNS and Civil Defence continue to monitor the situation closely.

Ash fall near Tongariro. Peter Drury photo.

A level 2 alert indicates the onset of “minor eruptive activity”, while the red aviation code means that significant ash is being ejected into the atmosphere. An ash plume extended up to 7 km high following the eruption, with up to 5 cm of ash settling near Mt. Tongariro. Both State Highway 46 and the Desert Road have been closed due to poor visibility. Volcanic ash dispersion is especially disruptive to air traffic; in addition to the dangers of lightning and reduced visibility within ash clouds, abrasive ash particles can damage aircraft engines, instruments and windscreens. Ingestion of ash into jet turbine engines can result in melting of the particles, which can then re-solidify and accumulate on the turbines, potentially causing engine stall.

So far, relatively minor air traffic delays are being reported by Auckland International Airport, with most international flights operating as scheduled. However, there are some delays and cancellations to domestic flights, particularly those from the eastern-southeastern North Island, where the ash cloud is having the most impact (e.g. Napier, Gisborne, Palmerston North). Civil Defence is cautioning people affected by the ash cloud to remain indoors and close all windows and doors.

No ash has yet been reported on the Whakapapa or Turoa ski fields, which are open for business as usual today.

A time lapse sequence of images from GNS’s Tongariro volcano camera is available at; the images do not appear to capture the actual eruption, likely because cloud cover had obscured the mountain.

Stay tuned for further developments.

Mount Tongariro prior to the eruption. GNS.

Flooding and Landslides Pummel the top of the South Island Jesse Dykstra Dec 15

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Tourists stranded by floodwaters in Nelson.   Source: The Nelson Mail

Tourists stranded by floodwaters in Nelson. Source: The Nelson Mail

Rain-laden clouds from the north Tasman sea settled over the top of the south island several days ago, and have been drenching the Nelson and Golden Bay regions ever since. Extreme rainfall has been recorded in Takaka, Richmond and Nelson, with the Kotinga gauge at Takaka recordind an unprecedented 423mm in 24 hours. The estimated 24 hour rainfall for a 1-in-100 year event at Takaka is 380mm (Tasman district council here). The previous highest recorded 24-hour rainfall from the Kotinga gauge was 216.5mm in 1995.

Saturated hillsides have given way in many locations, with landslides and debris torrents reportedly causing widespread damage in the region ( story here).

Flooding, Nelson.    Photo: Tim Bow

Flooding, Nelson. Photo: Tim Bow

Debris Torrent, Nelson.   Source:

Landslide, Nelson.     Source: The Nelson Mail

Landslide, Nelson. Source: The Nelson Mail

Flooding, Nelson.    source:

Flooding, Nelson. source:

Backyard Swimming Hole.   Source:

Backyard Swimming Hole. Source:

Fortunately, all the news is not bad, as the rain has been easing, with heavy precipitation moving towards the North Island, where Taranaki, Northland and the Bay of Plenty can expect up to 150mm of rain.

Flooded Hard-Drives and Hondas: Economic Implications of Thailands’ Latest Natural Disaster Jesse Dykstra Oct 28

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Flooding in Thailand     Source:

Flooding in Thailand Source:

Global Economic Hub
Thailand is a global manufacturing hub, and a leading exporter of automobiles, electronics, textiles, clothing and food. Exports of goods and services accounting for approximately 70% of Thailands’ GDP in 2010. Tourism has largely recovered following the Indian Ocean tsunami (which claimed more the 5000 lives in Thailand), accounting for about 6% of GDP in 2010.

Many of the world’s largest auto manufacturers have major factories in Thailand, including Toyota, Honda, Nissan and Ford. As the world’s largest manufacturer and exporter of hard-disk drives, Thailand hosts hard-disk giants Western Digital, and Seagate Technology. Sony, Toshiba, Apple and Canon also rely on their Thailand manufacturing facilities to supply the global demand for consumer electronics.

Worst Flooding in 50 years

Since flooding began in northern Thailand in July of this year, the country has been coping with another deadly natural disaster; one that will also have global economic implications. With a mean rainfall of nearly 800 mm for the three-month period from August to October, Bangkok is no stranger to flooding, but an exceptionally wet monsoon season in the north has brought the worst flooding in over 50 years. Swollen rivers and floodwaters have gradually made their way towards the south, threatening the most populated regions surrounding the bay of Bangkok. Thailand is a country of 67 million people, with an estimated 9 million living in the capital city of Bangkok, where much of the city is merely 2 metres above mean sea level. The immediate impacts of the disaster have only begun to materialize:

• nearly 400 lives lost to date

• more than 100,000 people displaced from homes

• one-third of the country inundated, including major agricultural and industrial areas

• damage estimates >$6 billion US dollars

As Bangkok braces for another day, 1.2 billion cubic metres of flood water is expected to peak around the same time as high tide. Government officials have thrown in the towel in the fight to contain the rising flood waters. As low-lying areas of the city become inundated, thousands of people continue to flee the capital for higher ground. Tourism officials issued travel warnings earlier today advising tourists that “flooding in Bangkok now appears imminent”. Indeed.

Submerged Cars at Honda Factory in Thailand

Submerged Cars at Honda Factory in Thailand

Global Economic Implications
It may be the long-term economic impacts of this disaster that are most damaging. Consumers around the world will soon face the consequences of the temporary crippling of Thailand as a global manufacturing hub. Only time will tell what the extent of physical damage will be in Bangkok, but the economic impacts are already beginning to mount. The Thai government has imposed a 5 day “weekend” to allow people to cope with the disaster, and production at many major companies has already been stalled for much longer than that. Toyota has had to keep its’ Thai production suspended for nearly 4 weeks so far, reducing its’ ability to supply the Asian, North American and South African markets. In turn, the loss of parts produced in Thailand has forced Toyota to slow down its’ operations in other countries, including Japan, the Unites States, and Indonesia.

Toyota is not alone. Many other manufacturing companies spanning a wide range of industries have been impacted by the flooding. The economic impacts of this disaster will soon be brought home to us all, in the form of decreased availability, and higher prices on many goods, including automobiles, electronics, clothing, and food.

As has been the case with many recent flood disasters (eg. Pakistan in 2010), this years flooding in Thailand may have been exacerbated by human activity (or inactivity in this case). Despite high precipitation in northern Thailand at the beginning of the monsoon season, some down-steam water storage reservoirs were not drawn down enough in the early stages of flooding, leaving less capacity for temporary storage of flood waters. But that is a topic for another post.

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