Alpine Fault

What’s on our Plates?

Leave a Comment / Earth Science Curriculum, Julian's Blog, Teacher Education / / , , , ,
Researching tsunami deposits on the East Coast

New Zealand has thousands of active faults each of which will produce an earthquake of some magnitude when it ruptures. However the two giants are the Alpine Fault and the Hikurangi Subduction Fault. They each form a segment of the plate boundary – the Alpine Fault can be traced across land, the length of the South Island, whilst the Hikurangi Subduction Fault is lying in wait under the Eastern part of the North Island, with its surface trace hidden deep underwater along the bed of the Hikurangi Trough and Kermadec Trench. Kekerengu Fault rupture in Nov 2016 (J.Thomson / GNS) Each of these plate boundary faults is capable of causing a massive earthquake greater than magnitude 8, thereby wreaking major destruction and disruption across New Zealand. It makes sense then that a lot of research effort is going in to understanding the past history of these faults. This allows us to gain insight into the probabilities of future ruptures and the sorts of impacts that could occur when one or the other of them next produces a big ‘quake. It also makes sense that if you are living in New Zealand, you should be interested in learning about how the scientists go about their research and what they have been discovering! What’s On Our Plates? is a set of free multimedia learning modules designed to enable anyone to explore Aotearoa New Zealand’s active plate boundary online, including the Alpine Fault and Hikurangi Subduction Zone. The modules are for any interested non specialist who would like to know more about out Plate Boundary research, but they also include notes for teachers who would like to use them as an educational resource. So get ready to dig in to the fascinating story of our two colliding tectonic plates. You can access the modules here.   The resource has been created by a collaboration of AF8 (Alpine Fault Magnitude 8) and East Coast LAB (Life At the Boundary). AF8 is undertaking a comprehensive study of the impacts a rupture of the Alpine Fault would have on infrastructure and the people living in communities across the South Island. It is a collaboration between the South Island Civil Defence Emergency Management (CDEM) groups and scientists from six universities and Crown Research Institutes, emergency services, lifelines, iwi, health authorities and many other partner agencies. The programme is managed by Emergency Management Southland. East Coast LAB (Life at the Boundary) is also a collaborative programme. It brings together scientists, emergency managers, experts and stakeholders across the East Coast to help us better understand and prepare for the natural hazards such as earthquakes and tsunami that may affect us. https://youtu.be/L8UXkQmbHZw

What’s on our Plates? Read More »

Digging into the Alpine Fault

Leave a Comment / Earth Science, Julian's Blog / / , , ,

The Alpine Fault has been the focus of a lot of research over recent years, including the Deep Fault Drilling Project, Alpine Lake Sediment Research and the Earthquake Records at Hokuri Creek amongst them. These are building a much clearer picture of the history of previous fault ruptures, and allowing better estimates of the size and likelihood of future earthquakes. The Alpine Fault is a long, straight, geologically  fast moving fault that typically produces very large earthquakes rupturing along large segments of its total length. At its northern end the Alpine Fault branches into a number of different faults that cross Marlborough and are known as the Marlborough Fault System. This means that here the Alpine Fault only takes up a proportion of the total displacements in this region and is likely to have a different earthquake history compared to thecentral and southern parts of the fault. Recently a GNS Science expedition to the northern part of the Alpine Fault near Springs Junction, involved digging two trenches across it to better understand its local earthquake history through some careful investigation. This location features as one of our GeoTrips that you can visit. www.geotrips.org.nz/trip.html?id=59 . This image shows the trenches (left of centre foreground) from the air. The trace of the Alpine Fault passes through the trenches and into the distance between the hills. Once the trench has been dug out,  the walls need to be cleaned up carefully so that the fine detail of the different sediments and structures can be observed and recorded. A string grid is pinned against the walls of each trench to help map them out, and markers are placed to highlight significant features that can sometimes be very hard to discern. The leader of this project is Rob Langridge, shown here having a close look at the detail. Many hours are spent drawing accurate maps of the trench walls as well as taking high resolution panoramic images of them. These are taken in order to document the excavation so that later interpretation of the data can continue once the trench has been filled up and the team has returned to the office. This image shows the Alpine Fault in section with the line of the fault shown.  The scarp or slope at the ground surface has been produced by earthquakes uplifting the left hand (eastern) side.You can also see the effect of fault movements on the river sediments below the ground. The grey clay layer on the left has been cut off at the fault and the overlying gravel layer has been dragged out of shape by repeated fault movements. This is a close up view showing the complexity of the sediments and structures close to the fault. When earthquakes uplift ground on the left side of the fault, loose material at the surface collapses across the fault and forms a wedge shaped pile of sediment on the ground called a colluvial wedge.These earthquake associated layers later get buried by younger material. They can be very hard to identify, but are a critical record of past ruptures. They can form repeatedly, so that wedges from earlier earthquakes may have more recent colluvium laid over the top of them. Once the colluvial wedges have been identified, the next step is to look for plant or animal material that has been trapped in them at the time they were created. These carbon rich specimens are carefully collected for dating in the lab using the radiocarbon dating method. (See below for a video that explains carbon dating) When a major fault ruptures during an earthquake, it can branch out near the ground surface to produce a number of smaller faults close to the main fracture. Here is an example that showed up in the trench wall a few metres from the main fault. The layers on the right have been pushed up  relative to those on the left. By carefully observing which layers have, or have not been affected by these secondary faults, the earthquake record can be further clarified. Once all the data and specimens have been gathered and logged, the trenches are filled in once more so that the surface can revegetate back to its original state. Here is a 3 minute video of the project: And this video explains radiocarbon dating: Finally click here for the TVNZ news report on the trenching.

Digging into the Alpine Fault Read More »

Precarious Boulders and Earthquakes

Leave a Comment / Earth Science, Julian's Blog / / , , ,

The National Seismic Hazard Model is the result of lots of work by scientists to indicate the likelihood of earthquakes happening in different parts of New Zealand. It is made with reference to the historic record of earthquakes that have happened across the country, combined with research into the rupture histories of many individual active faults. Work is done to continuously ‘ground truth’ and improve the Hazard Model through ongoing research and addition of data. Mark Stirling has developed a way of testing the model at particular locations using ancient landforms known as tors that occur in places around the country. These isolated boulders stand like statues. There are many of them near Clyde in Otago, occurring on the flat, uplifted surfaces of nearby ranges, such as the Old Man Range, shown here. You can see that some of these features are quite imposing and have a lot of character. Although some of them are solid looking, there are others that are very delicate.These are the ones that Mark is interested in. The basic idea is to use the beryllium 10 exposure dating method to find out how old these fragile features are, and then to work out the amount of earthquake shaking it would take to knock them down. This tells Mark the minimum amount of time that has lapsed since the occurrence of an earthquake capable of knocking down the feature. This information is then matched with the National Seismic Hazard Model to see if the calculations give similar hazard estimates. Making a numerical calculation of the fragility of the precarious feature is a matter of working out the angles between the centre of mass and the rocking points at the neck (narrowest point) of the tor. For making these calculations with maximum precision, Mark makes a 3D computer model of the tor, by first taping key points on its surface, and then taking many photos from all angles, which are later stitched together. This is what the model of the above tor looks like on the computer screen once completed . During fieldwork with Mark last month, we were able to use a quadcopter drone to get good images of some of the more inaccessible fragile landforms. Here is our video of the project:

Precarious Boulders and Earthquakes Read More »

Bottom Hole Assembly

Leave a Comment / Earth Science, Julian's Blog / / , , , , ,

About 10 days ago, drilling was stopped at the Alpine Fault drill site so that geophysical measurements could be made down the borehole, and the bit could be replaced. This involved lifting all of the drill rods out one by one and stacking them next to the rig. Next to come up was the bottom hole assembly (BHA) comprising these thick steel pipes that Rupert Sutherland is describing to the camera in this image. Last to appear was the business end of the drill string including the drill bit itself. This photo shows the bit being replaced using some impressive sized hand tools: The view looking down into the top of the borehole – 400 metres deep and filled with mud. Here is the video of Rupert explaining the Bottom Hole Assembly: Once the geophysical measurements were taken down the hole (more about these later), the Bottom Hole Assembly was put back together and lowered back down the borehole. Unfortunately disaster struck when the wire snapped and 7 tonnes of unattached BHA dropped down the hole. To cut a long story short, this delayed progress for about a week, until finally the detached parts were fished out of the hole using a variety of highly specialised methods. You can read a little more about these events here in Rupert’s Blog:1.The Calamity.  2. Landing the Fish 

Bottom Hole Assembly Read More »

Phase 2 Alpine Fault Drilling

Leave a Comment / Earth Science, Julian's Blog / / , , , ,

Rupert Sutherland with DFDP-2 flags Whilst researchers continue to pull together the history of past Alpine Fault earthquakes, the Deep Fault Drilling Programme is well underway in Whataroa on the West Coast of the South Island. For an introduction to this project have a look at my blog and video here, or check out the DFDP-2 Facebook page or project leader Rupert Sutherland’s blog for updates over the next few weeks. The first phase of the drilling process was to penetrate down through a thick sequence of gravel and mud left behind in the Whataroa Valley after the retreat of ice at the end of the last ice age. This was surprisingly challenging because of a thick sequence of very sticky mud that was deposited in the valley at a time when it was a deep fiord or lake. DFDP-2 drill site   J.Thomson@GNS Science Eventually the team struck bedrock 240 metres below the surface, and the second phase could commence. This involves drilling down towards the fault plane, thought to be about a kilometre below the rig, without trying to retrieve any large intact pieces of the rock at this stage. (That process is the goal of phase three, which will start when the geologists see from the minerals in the rock fragments that the drill is closing in on the Alpine Fault.) DFDP-2 drill site   J.Thomson@GNS Science This is a view of the drill site on a nice morning with Phase 2 well established and the drill at a depth of 340 metres. Behind the rig you can see the drilling mud ponds. The science labs are on the right and spare drilling rods that are added as the drill gets deeper are in the foreground. The labsin the background are where the scientists  study the rocks being brought up by the drill, and make geophysical measurements taken by equipment that is lowered down the borehole. Close up to the rig you can see the vertical drill rod (or pipe) that is rotating and gradually descending down the drill hole. The next rod is lined up ready for connecting when the drill is a few metres deeper. The speed of drilling is roughly 1 to 4 metres an hour at this stage, and a new drill rod is added about every 6 hours. Next to the drill is this pond of muddy water, which is a vital part of the system used for cutting down into the rock. The mud is specially formulated to have the right viscosity and density and is sucked up by a very powerful pump. After having large particles sieved out of it, it is sent down the centre of the drilling pipe right down to the cutting face of the drill bit. The drill bit on the right has cut through about a hundred and twenty metres of bedrock, and is about to be replaced by the nice shiny one on the left. The drilling mud is forced out of the holes that you can see, and then flows up the outside of the drill pipe back to the surface, bringing with it the rock chips and also carrying heat away from the cutting face at the same time. This is the base of the drill rig, with a section of the rotating drill pipe visible. Drilling mud is flowing down the centre of it on its way down to the drill bit. After its return journey on the outside of the drill pipe, loaded with rock fragments, it emerges at ground level and is carried away in the pipe that extends to the right. The drilling mud flows into a collection pond. The sieve that you see is for collecting samples of the rock fragments for analysis. The samples are first carefully washed of fine mud or clay. They are then sorted by hand. After being glued to a microscope slide, the rock samples are ground down to a thickness of 30 microns. They are then transparent and can be analysed using an optical microscope. The mineral content can then be studied in detail. As the drill gets closer to the fault, the scientists expect to be able to see changes in the types of minerals present. In this way they will be able to judge the right time to change the drilling system to phase 3 and start retrieving intact rock cores. DFDP-2 drill site   J.Thomson@GNS Science Finally here are a couple more views of the DFDP-2 drill site looking up the Whataroa Valley. DFDP-2 drill site   J.Thomson@GNS Science

Phase 2 Alpine Fault Drilling Read More »

Nature’s Earthquake Recorders

Leave a Comment / Earth Science, Julian's Blog / / , , , , ,

In order to make sense of the sediment cores that can be retrieved from lakes near to the Alpine Fault such as Lake Christabel, it is worth having a think about what happens to the environment when the fault ruptures in a large earthquake. Under normal conditions, alpine lakes fill up very slowly with sediment that is fed into them by rivers. The particles settle onto the lake bed gradually, to create a sequence of finely layered mud. When an earthquake occurs, a number of consequences affect the landscape. The soft surface sediment on the bed of the lake gets deformed and folded, and the shallower slopes at the side of the lake collapse to create flowing avalanches (turbidites) that sweep down and across the lake floor. In the nearby mountains, large landslides occur that choke the river valleys with a chaotic mix of large and small rock fragments. In the months and years following the earthquake, the landslide debris is gradually washed into the lake, to form a recognisable layers on top of the turbidite deposit. Eventually, conditions return to normal, with the finely layered sediments gradually covering over all of the evidence of the earthquake and its aftermath. It may be hundreds of years before another earthquake sttikes that is near enough and strong enough to leave its mark in new layers of the lake sediment. Now lets have a look at the real thing – an example of a sediment core that has been retrieved from a New Zealand’s alpine lake. Back in the lab at the University of Otago in Dunedin, Jamie Howarth opens a core tube to reveal the layers of sand and mud from Lake Christabel. Here is a section of the core that shows the finely laminated lake sediments formed in normal conditions (on the right). In the centre you can see that the layers are slightly folded – this is the indication of an earthquake that has deformed these layers. They would have been at or just below the surface of the lake floor at the time. Here Jamie is indicating the remains of a leaf next to the blade of the knife. This is not far below the earthquake layer, and can be used to get a radiocarbon age which will help to date the earthquake event. This dark coarse layer is the next layer that was added to the sequence on top of the folded sediment. It is the base of an earthquake generated turbidite deposit. The material gets gradually finer to the left (‘upwards’) as the cloud of particles slowly settled onto the lake floor. The section shown here is the landscape recovery phase. Dating of the base and top of this layer in several cores has shown that it can take 50 years for the landscape to recover from an Alpine Fault earthquake. During that time, hillsides are destabilised, debris flows cover flat areas near to the mountains, and rivers are prone to changing course due to being overloaded with sediment. Finally we see the thinly layered sediment  indicating that normal conditions have returned to the lake environment. This map shows what can be done when this research is carried out at a number of lakes along the Alpine Fault. The coloured lines (purple, orange, green etc) show earthquake records that have been identified so far in some of the lakes along the length of the fault. You can see that the last earthquake rupture (in 1717 AD) was over 300 km long. The one prior to that around 1600 AD ruptured the northern end of the fault. Information about previous earthquakes is still incomplete, but the picture is starting to become clearer. With more research, Jamie and his colleagues will be able to show a more detailed history of the last 10 Alpine Fault earthquakes including the dates, lengths of rupture and magnitudes of the events.

Nature’s Earthquake Recorders Read More »

Lake Christabel

Leave a Comment / Earth Science, Julian's Blog / / , , , , ,

Lake Christabel   J.Thomson@GNS Science This is Lake Christabel in New Zealand’s South Island. It is one of the many beautiful alpine lakes  to be found close to the Alpine Fault. Lake Christabel was formed when a huge landslide blocked the valley, thus damming the river that then backed up to form the lake.The present day outlet runs over the old landslide deposit of large chaotic boulders. Hidden beneath the waters of Lake Christabel are very distinctive sediment layers that tell the story of huge earthquakes that rocked the nearby mountains during ruptures of the Alpine Fault. Jamie Howarth from GNS Science, and Sean Fitzsimons from Otago University, have been investigating several such lakes to read the earthquake histories. I joined them on a recent expedition along with Delia Strong and Rob Langridge from GNS Science. The aim was to retrieve sediment cores from the lake to investigate the earthquake records. First of all a seismic survey was undertaken to find the best spots to sample on the lake bed. Sean is in the lead boat, towing a second dinghy that carries the equipment. The survey uses an acoustic source that sends pulses down into the water. The boat is towed along so that noise interference produced by a nearby motor is avoided. As the sound pulses are reflected back from the lake bed and its layers of underlying sediment, they are translated into a two dimensional vertical section image of the lake floor. A number of survey lines are made across the lake to give some idea of the 3 dimensional structure of the lake sediments. Once the best locations for sampling have been chosen from the survey results, the corer is prepared with a fresh 6 metre pipe that will be pushed into the lake floor to retrieve a sediment core. The corer is transported to the chosen point on the lake surface, and then dropped off the side of the boat once it is in position. After being connected with several airlines which are required to control the pressure coring process, the corer is lowered the 90 metres to the lake floor. The large barrel sits at the bottom, and is sucked into the mud to create a stable platform for coring. High pressure air is then applied to the piston which pushes the 6 metre coring pipe into the mud, releasing clouds of bubbles up to the surface. These bubbles allow Sean and Jamie to monitor what is going on with the corer at depth. Lake Christabel Corer Retrieval J.Thomson@GNS Science When the coring is complete, an airbag is attached to the line and filled up with air so that it  pulls the whole assembly out of the mud. The airbag bursts up to the surface from below in a spectacular fashion. Lake Christabel Corer Retrieval J.Thomson@GNS Science About a minute later, the corer assembly also emerges from the depths. It is not a good idea to be too close to this as it could easily sink a boat that was in the wrong place. The corer is then plugged and loaded into the boat to be brought back to shore, with its precious cargo of sediment. The PVC tube containing the core is then cut into 1.5 metre lengths for ease of transport. Each tube is carefully labelled to avoid any confusion  about where it was taken from and its relationship to the other samples. Lake Christabel Flight  J.Thomson@GNS Science Once all the sampling has been completed, the expedition is over. It takes several helicopter loads to transport the two boats, safety gear, corers, generators, samples and all our personal equipment back to the road end. The samples are then taken to Otago University for analysis. My next post will describe how alpine lakes like Lake Christabel have shown themselves to be very useful natural seismometers through this research approach.

Lake Christabel Read More »

Jumping Faults

Leave a Comment / Earth Science, Julian's Blog / / , , , ,

The Alpine Fault is divided into several segments based on changes in its tectonic structure and earthquake history along the plate boundary. The northern end of the Alpine Fault is much less straightforward in comparison to the southern and central sections. This is in the area where other faults of the Marlborough Fault System branch off the Alpine Fault and take up a large amount of the total slip. There is still a lot to find out in terms of their combined earthquake histories and how these faults interact in relation to each other. In 1964, a concrete wall was built across part of a paddock next to the Maruia River, near Springs Junction (see yellow dot on the map above). The wall is 24 metres long, about 1.5 metres high, and at first sight seems pointless, standing alone and unconnected with any other structure. I visited this location recently with Rob Langridge, earthquake scientist at GNS Science, 50 years after the wall was built. If you would like to go there have a look at our GeoTrips website: www.geotrips.org.nz/trip.html?id=59 The wall was built directly across the Alpine Fault by scientists who wanted to test whether it would be gradually pulled apart by slow sideways creep along the fault. As you can see – it has suffered no damage due to any gradual movement since it was built.This very clear finding is in accordance with our present understanding that most New Zealand active faults are locked. They do not gradually creep between rupture events, but do all their moving in sudden jumps – during earthquakes. Right next to the experimental wall, there is an overgrown stream channel that has been offset sideways by about 10 metres along the line of the fault. Some years ago, a series of pits were excavated to assess the age of the offset river features. In one pit a piece of buried wood was found and then radiocarbon dated, showing that the surface is about 1200 years old. This means that the 10 metre offset has occurred since this time, giving an annual slip rate (rate of movement) of the alpine fault about 8 mm at this location.  This compares with about 27mm per year for the central and southern sections of the Alpine Fault, further south. The last rupture here at Springs Junction in about AD 1600 offset a nearby river terrace by about 1.5 metres. This suggests that at least two earthquakes will have accumulated the 10 metres of offset of the stream channel.

Jumping Faults Read More »

A Ticker Tape Record of Alpine Fault Earthquakes

Leave a Comment / Earth Science, Julian's Blog / / , , , ,

The famous NASA image of New Zealand’s South Island clearly shows the trace of the Alpine Fault along the straight western edge of the Southern Alps. This oblique Google Earth view of the West Coast shows the relative uplift on the eastern side of the fault that has created the Southern Alps. The Hokuri Creek location indicated on the image is the site of a very important record of Alpine Fault earthquakes going back for the last 8000 years. A significant feature on this part of the fault is that it has actually been uplifting on its western side, instead of to the east as it does along most of its length. These diagrams show how the amazing record of earthquakes was created at Hokuri Creek. The first picture shows how the low fault scarp blocks the stream, ponding the water and creating a swamp. This gradually fills up with carbon rich plant material (peat) so that eventually the surface of the swamp becomes level with the top of the scarp and the river flows straight across it. When an Alpine Fault earthquake occurs, the fault uplifts by about a metre, creating a space into which the creek brings loose rock debris (gravel, sand and silt) washed down the river from landslides caused by the groundshaking. A new swamp develops once the land stabilises until the peat layer again reaches the level of the top of the scarp. Another Alpine Fault earthquake uplifts the scarp, and a new earthquake debris layer is deposited, adding another record to the fault rupture history. The great thing about peat layers is that they provide plenty of carbon material for radiocarbon dating.The time of past earthquakes is at the horizon where the peat changes upward into landslide derived sand and silt, so by taking samples at this layer, the earthquakes can be dated. At Hokuri Creek, by a quirk of fate, the river found a new outlet several hundred years ago, eroding downwards and exposing the sequence of peats and earthquake debris layers like pages in a book.This does mean however that the record of the two or three most recent earthquakes is not available here. You can see how  scientists used a ladder to access good sampling points. Amazingly, they were able to trace 24 earthquakes going back over the last 8000 years. Records of the two or three most recent ‘quakes, missing from this sequence, have been found in a more recent study at the nearby John O’Groats swamp. Scientists were able to recover several sediment cores there that complete the sequence. Carbon dating gives a date range within which the most likely date is at the peak of the probability curve. (To understand radiocarbon dating have a look at this GNS Science video. ) The dating results that you can see on this graph show how the Alpine Fault at Hokuri Creek has been rupturing in a very regular cycle over the last  8000 years. The intervals do vary – from 140 to 510 years, but the average is 330 years. In fact the most common actual interval between Alpine Fault earthquakes is 300 years, which is sobering when you realise that the last Alpine Fault rupture was in 1717, just under 300 years ago. EQ histories compiled by U.Cochran@GNS Science To give you some idea of the significance of this Alpine Fault history, here is a comparison with three other major transform faults. This shows clearly how the Alpine Fault exhibits by far the most regular earthquake behaviour of a big fault anywhere in the world. This map shows the location of Hokuri Creek in the southern section of the Alpine Fault. The earthquake record it provides tells us a history of large  events in the southern and central section of the fault. In northern South Island, the Alpine Fault divides into a number of separate faults know as the Marlborough Fault System. The slip rate (average movement) on the Alpine Fault drops down from about 27mm per year to less than 10, with the remainder being taken up by the other faults nearby. This means that the Hokuri Creek history cannot be applied to the northern (Marlborough) end of the Alpine Fault. This project has been led by GNS Scientists Kelvin Berryman, Ursula Cochran and Kate Clark. The media release about it can be found here, or go to the GNS Science website learning pages here.

A Ticker Tape Record of Alpine Fault Earthquakes Read More »

Drilling into New Zealand’s most dangerous fault

Leave a Comment / Earth Science, Julian's Blog / / , , ,

The Alpine Fault forms the plate boundary in New Zealand’s South Island, and is a very significant fault on a global scale. It last ruptured in 1717 AD and appears to produce large earthquakes on average every 330 years. Its next rupture has a high probability (28%)  of occurring in the next 50 years. Each time the Alpine Fault ruptures, there is roughly 8 metres of sideways movement and about 1 to 2 metres of vertical uplift on the eastern side. These magnitude 8 (M8) earthquakes can rip the fault along about 400 kilometres of its length. Slowly, over millions of years, this is what has created the Southern Alps, and offset rock formations on each side of the fault sideways by a phenomenal 480 kilometres. Massive and continual erosion of the Southern Alps keeps them relatively small (below 4000m) inspite of about 20 kilometres of uplift over the last 12 million years. For a lot more information about the Alpine Fault and its earthquakes, check the GNS Science website. Later this year, scientists plan to drill through the Alpine Fault at a depth of more than one kilometre  to sample the rocks and fluids of the fault at depth, and to make geophysical measurements down the borehole to better understand what a fault looks like as it evolves towards its next earthquake rupture. This is phase two of the Deep Fault Drilling Project (DFDP-2). The first phase of the project (DFDP-1) was successfully carried out in 2011 when two shallow boreholes were drilled through the fault to about 150m and the first observatory set up at Gaunt Creek.  DFDP-2 will involve drilling a short distance away in the Whataroa River valley, not far upstream from the road bridge on State Highway 6. This short video gives some background and information about the project:  You can also find out lots more detailed information about DFDP-2 at the GNS public wiki site here. The prospect of drilling through a massive fault could  sound alarming to some people. Is there a possibility that this project could cause a damaging earthquake? Check this next video to hear about the safety review:

Drilling into New Zealand’s most dangerous fault Read More »