Preparing for the AF8 Alpine Faultline Earthquake

Understanding the Alpine Fault Line and Preparing for the AF8 Alpine Faultline Earthquake.

 

New Zealand sits on a very volatile zone of the Earth's tectonic plates, and one the most significant geological features of this is the Alpine Fault Line. The Alpine Fault Line runs nearly the entire length of the South Island of New Zealand and has the potential to cause incredibly destructive earthquakes. In this blog post we will look at What the Alpine Fault Line is, the risks that it poses to New Zealand, and our way of life, its historical activities and how New Zealanders are preparing for an inevitable rupture of this fault line in the future.  

 

What is the Alpine Fault Line?

 

The Alpine Fault line is a significant geological feature that marks the boundary between two tectonic plates, the Australian Tectonic Plate and the Pacific Tectonic Plates. The Alpine Fault Line is a transformative plate boundary, which means that the two plates are grinding past each other on a horizontal axis. Along this axis there is also some compression and uplift, so much so that this is responsible for the creation of one of the South Island’s most stunning features, the Southern Alps Mountain Range.

In total, the Alpine Fault runs for about 800 kilometres across the South Island, with the straightest stretch of this running for around 500 Kilometres, from near Milford Sound in the South and towards Lewis Pass in the north. The Fault Line is active, and there are many research organisations who are actively studying its movements to get a better idea of what it is doing, how it is moving over time and what impact this movement is having on its potential to rupture and what this will entail.

 

 

How Often Does the Alpine Fault Rupture?

 

The Alpine Fault is one of the most studied fault lines in New Zealand, and an incredible amount of ground-breaking research has been done by some amazing people over the years. This study shows us that the Alpine Fault Line has a history of large, and catastrophic earthquakes, approximately every 250 – 300 years in fact. Research has shown that in roughly the last 1,100 years there have been at least four significant ruptures of the Alpine Faultline, resulting in earthquakes measuring about magnitude 8 each time. The most recent one was in 1717, and if history is anything to go by, that means we are now long overdue for another major rupture. Of course, the 250 – 300 years is an average, and within these ranges there have been some earthquakes which occurred in a shorter time period and others which occurred over a longer time period. That being said, there is a significant chance of a further rupture of this Faultline within the next 50 years, and that chance has increased with research from around 30% to 75%. It is likely that a rupture on the Faultline will involve multiple sections of the Faultline, meaning that a magnitude 8+ earthquake is highly likely.

 

 

What Are the Potential Impacts of an Alpine Fault line AF8 Rupture?

 

As the population of New Zealand has become more spread out, and more reliant on technology and infrastructure for daily life, when the Alpine Fault does rupture again, the impacts of this will be both far reaching and severe. It will not only impact the entire South Island, but it will likely impact the Lower North Island as well, just as it did when the Kaikoura Earthquake happened back in 2016.

Some of the main impacts will include,

• Intense shaking, it is estimated that a rupture of the Alpine Fault may last up to 2 minutes, or as long as 4 minutes. Compared to the Christchurch Earthquakes, this is a very long time indeed.
• Surface ruptures, there will be significant movement of the land around the Faultline, both vertically and horizontally.

Secondary impacts might include:

• Landslides and rockfalls, in the Christchurch Earthquake we saw the damage rocks falling off the Port Hills caused to the houses below, this could also impact train lines such as the Tranz Alpine train line, and our major mountain passes and ski fields.
• River disruptions, with all the movement and disruption of the ground surfaces, we could see rivers blocked, dams created and potential flooding of areas due to this.
• Liquefaction, as witnessed in the Christchurch Earthquakes also, massive damage might be expected from the sudden occurrence of Liquefaction.
• Debris flows and small tsunamis may also occur, especially around the costal areas, and local tsunamis may happen around the great lakes and fjords where large rockfalls and landslides might happen.
• Building collapse and fires due to widespread damage to infrastructure.

 

I took these photos on a recent trip to Kaikoura with my sons, the area of rock was once below the water line. This is a prime example of the power involved in one of these extreme earthquakes, and the damage that it can cause. Hard to imagine and incredible to see in person. 

 

The Alpine Fault will likely undoubtedly lead to major critical infrastructure failures, including roads, bridges, and major communication networks. This will likely result in the loss of cell phone communications and internet as well, making the passing of information and updates very difficult. It will also mean that many rural and distant communities will be cut off from the rest of the country and may be isolated for very long periods at a time. There is come great work being done by community groups such as the HF Radio Charitable Trust who is building a national network of Amateur Radio Operators who are able to set up field stations, independent of mains power, to provide HF Radio Communications capability, allowing communities to provide situation reports as well as received vital information and updates.

 

This is my current setup for the HF Alpine Fault Net - capable of transmitting on both 40 and 80 meters, the two frequencies used in this process. This setup would take around 5 minutes to complete, and with the lithium batter pack I could be up and running for a week with no need to charge else where. With the solar setup in the van I can continue to charge the battery, or I could use the engine to charge as I drive from location to location.

Phil at CERN.NZ is also doing incredible work in providing valuable information on setting up and running Community Emergency Radio Networks using PRS radio, a free radio service which would allow members of rural communities to remain in contact with each other over wider distances when other forms of communications fail.

 

There are also a lot of online communities working towards sharing information, having group catch ups and sharing tips on preparing for these sorts of events, and doing regular radio check ins and catchups. One such example is the Facebook Page Prepping for the Unexpected - South Island which is run by a chap named Greg. I have been to a number of the meet ups and also the radio check ins, they are actively working to build a community who are well educated, well prepared and as such stand a greater chance of getting through events like the Alpine Fault AF8 Earthquake, much better off than many others. His willingness to host these events, and share information free of charge is amazing and this is witness with the rapidly increasing size of his group.

 

Setting up the radio with Greg from Prepping for the Unexpected, again a 5 minute setup at the river bed. This could be setup at any location or even from the vehicle itself, and allows for nationwide and international communications. A great day out and amazing training with a good man, who is working to help the community prepare for potential and inevitable disasters, such as the Alpine Fault Line. 

 

As the Alpine Faultline runs almost the entire length of the South Island, it will have profound effects not only on the local communities closest to the fault line but across the entire region. As noted, it is also very likely that the effects may even be felt in the lower North Island, such as Wellington, just as the 2016 Kaikōura earthquake had a significant impact on the area.

 

 

AF8: Preparing for the Inevitable

 

With the high probability of a major rupture in our future, the AF8 Project was created. AF8 stands for Alpine Fault Magnitude 8, and its goal is to prepare New Zealand for the inevitable earthquake by helping communities understand the potential impacts, plan for them, and develop a coordinated response strategy.

The AF8 initiative involves the coordinated work of a wide range of stakeholders, including local and national emergency agencies, scientists, and community leaders.

The AF8 Project aims to:

1. Assess the impacts of a magnitude 8 earthquake on South Island communities and infrastructure.
2. Educate the public about the risks and necessary preparations.
3. Develop a planning framework for a coordinated and efficient response once the earthquake occurs.

While AF8 is primarily focused on the South Island, the lessons learned and response strategies are also applicable to areas in the North Island, especially in cities like Wellington, which would feel the effects of such a massive event. AF8 also encourages collaboration between local emergency management groups in both islands to ensure a united and effective response.

 

 

Is the Alpine Fault Linked to Other Faults?

 

Yes, the Alpine Fault is part of a complex system of faults that stretches across New Zealand and connects to other fault zones. To the north of the Alpine Fault, near Lewis Pass, it links up with the Marlborough Fault System, which is in turn connected to the Hikurangi Subduction Zone, located off the coast of the North Island. This subduction zone is another major geological feature, where the Pacific Plate is being forced beneath the Australian Plate.

To the south, the Alpine Fault connects with the Puysegur Subduction Zone, off the coast of Fiordland. All these faults and fault systems are interconnected parts of the Australian-Pacific tectonic plate boundary, which runs through New Zealand. The movements of these plates and faults are critical to understanding the overall seismic risk in the region.

 

What Areas Will Be Most Affected by the Alpine Fault?

 

The rupture of the Alpine Fault will not just affect the immediate areas along the fault line, but it will also be felt throughout most of the country. If not physically, then in other ways, a major rupture will affect the whole country. While the most critical damage will happen within a 100 or so kilometres of the Faultline, with a magnitude 8+ many regions across the South Island will experience widespread damage.

For example, Christchurch, Queenstown, and Dunedin will likely suffer significant damage from ground shaking, infrastructure failures, and potential landslides. Even the North Island, particularly areas like Wellington, will feel the effects due to the seismic waves traveling across the Cook Strait.

What quickly becomes clear when looking at all the research and information available is that an Alpine Fault AF8 earthquake will likely be a national emergency, with recovery and rebuilding efforts required across the country. The AF8 initiative is helping local authorities plan for this reality, focusing especially on how to handle the logistical challenges that will arise in the South Island.

 

How can we prepare for the AF8 Alpine Fault Earthquake?

 

Being ready for the next big earthquake is crucial for both individuals and communities alike. While it can seem a bit overwhelming at first, the fact you are reading this and educating yourself is a great first step. Here are some tips to help which will go a long way to help you prepare your home, family and community for what is an inevitable event.

• Secure Your Home: Remove or secure objects that could cause injury, such as TVs, furniture, and brick chimneys. Ensure your house is structurally sound and able to withstand strong shaking. There have been many instances where people, including children, have been killed or injured by falling items during an earthquake. If you have a chimney that is no longer connected to a fire, it might be worth considering taking it down, to avoid it falling on someone during an earthquake. TV’s, whiteware and the like can be affixed to wall studs using simple, inexpensive brackets and screws.
• Emergency Supplies: Prepare enough food, water, and supplies to sustain your family and neighbours for 7-14 days in case of disruption to services. The bare minimum recommend around the world is supplies to get you through for at least three days, or 72 Hours, and this is where we got our name. Events like the AF8 Alpine Fault Earthquake, is likely to cause widespread and catastrophic damage to the supply chain and infrastructure. As such having more than three days’ worth of supplies in this case will be a much needed bonus. We stock a number of long life emergency food supplies which can be added to your supplies, vastly increasing the number of days of stock you can keep on hand. 

 

• Develop a Family Plan: Practice your earthquake response plan with your family. Make sure everyone knows what to do, where to go, and how to communicate if the earthquake strikes. Your plan should also include any other disasters which are in your area. Know where you are going to meet, how you are going to get there if you must get there on foot. Make sure everyone in your household knows their place in the plan, and how to enact it. Make sure everyone knowns where your emergency supplies are located, and how to get to them even in the darkness, as disasters can strike at any time. Check out your local Civil Defence website, or follow this link to learn how to make a plan and what you need to consider. It is much easier than you would imagine, the hardest step is simply making a start to it.

 

• Community Preparedness: Connect with neighbours and local groups to create a support network. Discuss how you can help each other during an emergency. Consider making a list of skills that each of you has to offer, that might come in hand during a disaster. During major emergencies we see the worst of people and the best of people. Working together as a community will go a long way to making a disaster much more bearable, and you will be amazed at how much you can achieve together. Keep an eye out for local groups online, such as face book, consider joining up and sharing your skills, advice and experience. Keep any eye out on your neighbours too, there are a lot of people who are vulnerable in our community and a disaster will make them even more so. We need to protect the weakest in society and help them get through also.

 

AF8 Conclusion

 

New Zealand’s Alpine Fault is a significant seismic feature, and it’s inevitable rupture will have devastating effects on both the South and North Islands. The AF8 project is helping communities prepare for the worst by providing valuable information, response frameworks, and promoting awareness. With the probability of a magnitude 8+ earthquake in the next few decades, now is the time for all New Zealanders to take the necessary steps to safeguard their homes, families, and communities from the impending disaster. Understanding the risks, preparing in advance, and working together will be key to surviving and recovering from what could be one of the most powerful earthquakes New Zealand has ever experienced. Keep safe and Keep prepared.