Simulation of a Magnitude 8.4 Megathrust Quake in New Zealand

[@slooob23]

Thank you for this Yoshihiro, and thank you for helping us out in NZ, it is great to see that we are working with Japan for the benefit of both our nations with the earthquake risks we share. I hope you enjoy your time in NZ.

[@davidplumb9549]

simulation of this Megathrust quake is also how large the Chile earthquake on September 16, 2015 was-8.4

[@Battleneter]

Magnitude is only 50% of what matters, just like a bomb how close you are to the epicenter really matters

[@119beaker]

Well done on the pronunciations of the place names.

[@julsh8837]

So concise, good voice, and thank you. I live in Wellington. Have you another one in regard to the 'slow slip' event that is currently occuring all along the Hikurangi Subduction zone and in between our two Islands?

[@evilkidd1876]

Thanks for the information on this. 6years later and this is still being talked about

[@gregmorley1997]

So what's the chances of a shake of that size settings the mega volcano just to the North of there ??

[@vaa7514]

I hope the current government and future government have done something to prepare for this event and not just ignoring it. Thanks for this very important and informative video. Bless you and your work.

[@Derek_Gunn]

An excellent simulation. An electronic warning system with a sensor near Waipukurau could provide Wellington with a good minute's warning. More than time enough to stop, drop and hold. Clearly, we need a grid of sensors like Taiwan.

[@Derek_Gunn]

+Subhashis Mukherjee Yes, a severe earthquake, however if one can get clear of buildings, one can survive.

[@Derek_Gunn]

+Subhashis Mukherjee Yes, as you say - but one must try. The alternative is to give up and die.

[@ashutoshbhakuni303]

Why do concentric circles of waves appear repeatedly when the origin is a single point?

[@Derek_Gunn]

Ashutosh Bhakuni There will be more than one movement from the epicentre as it will have its own momentum.

[@GNSscience]

The origin is actually along one or more planes (faults) - along which the rupture spreads over a period of time. Therefore the seismic waves keep getting generated as the rupture progresses

[@spadgm]

Would this event have the potential to set off the Wairarapa or Wellington faults or even both? And is it overdue to happen?

[@loosecannon12345]

Wairarapa and Wellington are not overdue! Earthquakes occur on the Wairarapa Fault approximately every 1200 years on average, with the last 160 years ago. Earthquakes occur on the Wellington Fault approximately every 700 to 1000 years on average, with the last between 170 and 370 years ago. There is no evidence that both Wellington and Wairarapa fault lines have, could or would rupture simultaneously.

[@English_Speaking_Fox]

You’re a very effective communicator. Thank you.

[@freedomthroughspirit]

Very well done (except why does the image cut off so we can't see the waves complete hitting the south island?).

[@shankhoniyogi9597]

Hi !! It is a very good simulation indeed. Can you please tell in what software this was generated ?

[@GNSscience]

+Shankho Niyogi The seismic wave propagation software is called SPECFEM3D (github.com/geodynamics/specfem3d). The tsunami simulation software is called COMCOT. The loss modelling is done using RiskScape (riskscape.niwa.co.nz/).

[@shankhoniyogi9597]

+GNS Science Thank you for the information. Keep up the good work. :)

[@MyCrossfitJourney]

Well you were sure right!! We just had a 8.1 earthquake on the east coast of the north island 😳

[@Screamblade_]

I don't know how but is man must be a god.

[@Mwc07]

This isn’t the same

[@twinflowerhare9047]

Hope all is well many prayers to you and all of you strong, brave people. Healing love sent to all

[@doc2kiwidig663]

No we didn’t 🙄

[@AP-kn1mp]

No you didn't.

[@barneymaurirere9592]

Very very good. Thank you.

[@DrumApe]

Very informative. Thank you

[@leannelenz6651]

Fascinating, thank you for this.

[@artemis1style]

I liked this presentation.

[@maurasmith-mitsky762]

Great video. Thanks. 👍🏽👍🏽👍🏽❤️

[@allgood6760]

Scary! ...just a matter of time. thanks for this👍🇳🇿

[@malcyj56]

Has it been modeled, what would happen to the central plateau and its many volcanoes, if a quake like this were to hit?

[@GNSscience]

+malcyj56 At present there is no clear research to show a direct connection between a large regional earthquake and the initiation of volcanic activity in the North Island. That is, the historic record does not show this has happened.

[@bobhiatt7260]

malcyj56 Hhh

[@squidwords]

If 185 people died in the 2011 Christchurch earthquake, why are the estimated deaths only 30?

[@DoubleMonoLR]

It does seem low, but the vast majority of deaths in Chch were caused by 2 poorly designed buildings, and I think a large portion of the remainder were due to very old brick buildings.

[@vzgsxr]

So Sir mix-a-lot was correct. "Long & Strong, down to get the friction on."

[@ecowanderer6099]

How long ago in geological terms was the last major Earthquake along the Hikurangi fault?

[@jasonwilliam2125]

A blink of an eye. Big lagoon cores may represent 2 major breaks in this fault in the last 1000 years. There is not a good record of this fault to date but time shall fix that. I believe our geonet scientists here in NZ are taking "not if ,but when" approach to another event on this fault. I should probably note that the Big Lagoon cores also showed tsunami followed both of these ruptures.

[@justsomeyoutubecommentorwi4378]

Could it affect the fault line

[@jackharris31]

When did the last event of this kind of magnitude to occur? Also how long can a fault rupture be (maximum possible lenght)?

[@chrisgould101]

Look up the gisborne earthquake

[@ENZEEVIDS]

what should you do in an earthquake? having experienced a few i can say that whatever you do it aint gonna make much difference so just relax and enjoy the rhythym

[@blaneharrison6341]

Can you do a simulation for the hikurangi treanch just off east cape north island plzzzz...worst case scenario

[@Mar7Coda6]

Could the earthquake in that area get bigger then that?

[@GNSscience]

+Mar7Coda6 Yes - it is potentially possible to get a larger earthquake involving the rupture of even more of the plate boundary fault in a single event.

[@Mar7Coda6]

Just how big could it get?

[@ecowanderer6099]

Probably somewhere between 8.3 to 8.9

[@Tui1x]

@@Mar7Coda6 It's a megathrust fault, highest ever potential is a 9, all megathrust subduction zones can have the capability of generating quakes at that kind of size.

[@bremnersghost948]

Very interesting, At what Depth did you have the Quake strike in this Sim? As obviously that would seriously change the results & damage done, Would love to see the results from a 10km, 50km and 200km deep Sims

[@GNSscience]

Check the video from about 30 to 40 sec

[@bremnersghost948]

@@GNSscience TY for prompt reply GNS, Merry Christmas, So this is pretty much a worst case scenario for the Magnitude? As a Brit, That makes me feel much better for Family near Wellington.

[@GNSscience]

@@bremnersghost948 This is certainly a very major / extreme scenario. We have also modelled an even larger quake (mag 8.9) which you can find on this channel. These are towards the upper levels of possible quake magnitudes.

[@bremnersghost948]

@@GNSscience Will check it out, As a new subscriber I have a lot of videos to catch up on lol Cheers

[@zabaleta66]

Gee, I live in the Manawatu! Scarey.

[@MegaTanielu]

Incredible information 👌

[@nzsmithsi]

Im in Taupo wonder if it could produce a Tsunami in our lake?

[@GNSscience]

+nzsmithsi A tsunami is generated by the displacement of water eg through deformation (movement) of the seafloor or lake bed. It is possible that a small tsunami (or seiche) could be caused by this earthquake in this way, but it is unlikely that it would be large enough to cause significant damage around Lake Taupo. .Large regional earthquakes can also cause landslides. Historic landslides in to Lake Taupo have caused seiches in the lake.

[@camman9213]

What is the likelihood a major quake may cause renewed volcanic activity under Taupo?

[@chrisgould101]

Seems a body of water would encapsulate the kinetics but I think is possible. Eg a plate rupture through the middle of the lake could produce an inland flood tsunami. I don't think it could have nearly the power of an ocean tsunami though

[@John13verse35]

Thanks for sharing this. Just wondering about the velocity scale - are those numbers representing about 100km? i.e. the slow, red waves look like they are going around 10km/s?

[@GNSscience]

The velocity scale represents the peak ground velocities. This is a measure of the severity of groundshaking at a given location rather than the speed of propagation of the earthquake waves through the crust.

[@John13verse35]

Ah, right. So this is the transverse movement?

[@jasonwilliam2125]

I suspect you would be looking at 3km/s or there abouts

[@Footrotflats251]

This will be the ultimate test of the civil defence SMS warning system, where I am on the South Island we would have about 4-5 minutes warning in this simulation, in reality it will be 9+ on the alpine fault and we will have mere seconds to find cover

[@Footrotflats251]

I live on the high side of a hydroelectric dam, I fear for those below, it was built to withstand an earthquake but that’s not a guarantee

[@noelburland7169]

I don't want to be nit picky and this video is very informative, but the title is misleading. Megathrust earthquakes only happen in subduction zones on the main plate boundaries and are the type of earthquake most likely to exceed 9.0 in magnitude. The Wellington and Wairarapa faults highlighted in this video are not part of the plate boundary. The actual plate boundary is along the Hikurangi Trench which is a subduction zone and runs parallel to the east coast of the North Island, which forms a part of the Kermadec Trench, which is also a subduction zone and goes as far north as Tonga.

[@GNSscience]

Thanks for your comment. The plate boundary extends west of the trench and passes under the east and lower North Island. It is about 25kms below Wellington for example. The Wellington and Wairarapa Faults extend through the crust in the overlying plate above the plate boundary. This simulation is modelling a subduction earthquake on a segment of the plate interface (boundary) as described.

[@noelburland7169]

Ok thanks for your reply. I guess that would explain the two major faults in the North Island, one of which this simulation is run from, that run parallel to the subduction zone to the east under the sea. I've read on Wikipedia that the 1855 Wairarapa earthquake was unusually strong, presumably because it is directly above the subduction zone? If a rupture ever happened out at sea would we see an earthquake bigger than the predicted one on this model? The Hikurangi Trench is much shallower than the Kermadec because of the land mass of the North Island. As devastating as the Kaikoura and Christchurch earthquakes were if the fault ruptures under the ocean and is strong enough to reach 9.0 or more in magnitude then the resulting Tsunami could cause utter devastation.

[@ethancoster1324]

Actually the ground shaking velocity was twice as much as this in chch at 2.2 times that of gravity at its fastest hence the damage

[@mrcake00]

If you are talking about gravity that's acceleration not velocity.

[@lizmonard]

I was thinking of moving to masterton..😬

[@crochetingaroundnewzealand]

We had a 7.4 last night way up north but felt in the south island, downgraded to 7.3.

[@sarnyboy2133]

I’m in Hastings. Idk how bad it’s gonna be over here!

[@Viagra_risk_PERMANENT_insomnia]

Shock absorbers that you can put in the walls of your house quakeproofyourhome.com/

[@suehowie152]

Have an immediate plan and don't hesitate..

[@wayneisherwood5202]

Could Trigger Volcanic activity as well

[@ashutoshbhakuni303]

Why do concentric circles of waves appear repeatedly when the origin is a single point?

[@GNSscience]

The shock waves are actually produced along the fault plane (the fracture in the earth's crust), that takes some time to rupture along its full length and breadth, In this example, the seismic waves are thus being produced over a period of about two minutes. In addition there are different types of seismic waves that radiate from the source, and these travel at different speeds, so the waves start to spread apart even more as they travel.

[@ashutoshbhakuni303]

Thank you!

[@zacccharlton2205]

Well when will it happen?

[@draemcewen1933]

well it said tht every 500-1000 years in the lower north Island but because we are over due for an earthquake in the lower north Island well don't be surprise if it hits in a couple of years

[@ianpiper2369]

+Drae McEwen or today

[@draemcewen1933]

Ian Piper Hahahaha yeah

[@ianpiper2369]

+Drae McEwen I now

[@draemcewen1933]

***** well.. What?

[@kevinsmith467]

The speed of the 1929 Karamea was reported as been vastly different than the modelling here. Why is there such a difference ? In Karamea it took 2 days from the earthquake landslide event until the formation of the wave. It then took a further 8 days for the wave to travel the 70 miles to Cape Farewell to do the damage reported. You are talking minutes and hours whereas the history is showing us the speed is much slower. They were saying it took a day to travel about 18 kilometres. That fact is published in dozens of scientific articles here in NZ. Why are we now seeing this new thinking ?

[@joyfuljoyful6598]

Your text covered the majority of the simulation, we saw little of it's effects?

[@mrakodrap7816]

atleast i don't have to worry about volcanoes(which my country hasn't),tsunami (because it would be unable to reach through Poland or Germany and Mountins all over our border) or earthquake because we don't have fault lines in eastern europe

[@dcsymbols4450]

Why does it start in waipukarau?. Also how can you have waves spreading out through a rigid structure?.

[@hamish6109]

Soil and rock during an earthquake is far from rigid

[@sueelliott4793]

Touch wood it never happens for the next few hundred years, hi from Tauranga

[@sarnyboy2133]

“When its long or strong get gone”

[@justsomeyoutubecommentorwi4378]

You are a good person

[@Godfathertoa]

Stay safe whanau and everyone. Prayers go out to you all

[@P51D-Mustang]

The clock is ticking...

[@MNZGA57]

Could this be initiated by the US BOOM ship?

[@lxjoinery]

Well just think. Those deep holes that were drilled into the alpine fault down south-westland. What could have been placed deep into it to set off the rupture? Well that would work.

[@fbiagentmiyakohoshino8223]

magnitude 8 earthquakes are *not* megathrust earthquakes. this only applies to magnitude 9 and higher

[@Lilskox]

chilling

[@kevinsmith467]

I was surprised to discover so much of the tsunami research is flawed. This is in relation to the historical events along the West Coast of the SI. The works of Prof Goff cover articles about the 1870 tsunami which never even happened. That is pure fiction. The research by de Lange and Healy must also be questionable. They also either covered events that never happened or that they grossly exaggerated. Will there be any effort getting put into investigating their claims and correcting our history ?

[@thephaneron3676]

An 8.4 M earthquake would be unusually large and thus unlikely for a single *strike-slip event* (unless it is very complex and propagates along multiple faults such as the 7.8 Kaikoura tremor). Similar to Japan in 2011, a rupture of this magnitude would instead most likely start in the *ocean* north-east of Waipukurau near the south-central segment of the *Hikurangi trench* a couple of hundred kilometers east of Gisborne and the *Hawke's Bay.* Because this subduction megathrust quake (which could range from 8.4-9.0 M) would occur in the ocean, a massive and damaging *tsunami* striking NZ's east coast would pretty much be inevitable.

[@nedyarbnexus9460]

a 6.6 hit Hanmer springs just minutes ago!

[@heathboulter5121]

NedYarbNexus 7.5

[@nedyarbnexus9460]

yeah it kept changing, first it was 7.5 then 6.6 then 6.8 then 6.3 then 7.5 again.

[@hans9254]

and i live right in the middle of it, great.

[@ladystardust5192]

Even if you didn't, you'd feel it, because a magnitude 9 (which is what it's expected to be) is huge, and the whole country would feel it.

[@joyleenpoortier7496]

New Zealand or Japan, Please

[@Tui1x]

This is New Zealand

[@joyfuljoyful6598]

It takes a Japanese to pronounce Waipukurau correctly considering the majority of European NZers struggle to pronounce Maori words period.

[@hudsonquay]

And a few Maori too!

[@joyfuljoyful6598]

@@hudsonquay lol 🤣 you're correct

[@chrisgould101]

Chur da whakapapaz

[@ernawati.er.radar.orari.5235]

Hi

[@shoutoutsforsubs2390]

wow!!!!!!!!!!!

[@nzwotb2525]

I live in Palmerston North I'm stuffed

[@RJ-mk6ep]

NZ WOTB mate you commented twice 5 months apart what are you on 😂😂

[@samanthawells3941]

haha

[@Viagra_risk_PERMANENT_insomnia]

Shock absorbers that you can put in the walls of your house quakeproofyourhome.com/

[@scottyfrognsock2396]

New Zealand has the best pies

[@Lily_Catt-]

Yes, NZ pies are good. Christchurch, Beach Road, North New Brighton, 8083 have good pies 🥧. The store is The Naked Baker

[@AvgeekCarGeek]

Well good bye Hawkes Bay if this happens

[@ianpiper2369]

I'm in welling ton how do you think I feel mat I'm a sub

[@hans9254]

Ian Piper me too im in Johnsonville

[@sirguyfox4762]

I am sorry, but all of the factors are incorrect. Wrong energy directional movements, epicentre placements, sub-lines and expansion zones being the most important. Best to re-calculate using correct historical data, especially sub-fault release data for the last 100 years. There is probably more chance of another volcanic expansion in the Auckland zone, resulting in the entire destruction of Auckland areas ( Bombay to Warkworth ) than this "8.4 Megathrust " Tectonic Plate Movement.That volcano in the Hauraki Golf has only been there for 608 years, a mere micro-second in earths time.

[@sirguyfox4762]

I totally disagree, and for very good reasons. Historic records show undersea volcanic occurrences along the Hikurangu Subduction Zone with venting occurrences forming much of the North Island north of Palmerston North. All volcanos ( including Lake Taupo ) and the volcanic rift up to White Island, then up the Rim of Fire are linked, with more than 150 undersea volcanos being part of recent activity. The Hik Zone is actually a cross-plate incursion into these vents, and recent New Zealand Auckland venting created Rangatoto "Island", which is only 580 years old. It is actually an infant volcano, similar to Krakatoa, and even a small venting caused by subduction movement ( shallow/mid depth earthquakes ) would render Auckland burnt to a crisp. The 47 likewise infant volcanos that greater Auckland has been built on, will actually blow, just the same as Taupo did, as recorded by the Chinese. This is not my opinion, just facts from extensive data collected on repeated tectonic plate construction/movement in the Pacific area going back millions of years. I know of Geologists who will not even visit Auckland, let alone live there.The safest place to be in the North Island, is south of the Bombay Hill, on the East Coast somewhere.Most of the buildings in Napier that were destroyed was due to poor construction materials and no earthquake consideration. The mega quake would drop the Pacific plate sending a Tsunami out over the Pacific, and raise the Australian plate, as in the ChCh and Kaikoura/Seddon quakes. I have absolutely no doubts whatsoever that I would chose a mega quake over volcanic nuclear detonation, anytime.

[@andrewwian4921]

​@@sirguyfox4762let's just hope whatever happens Jacinda Ardern is present so she gets her just dues..

[@Lily_Catt-]

​@@andrewwian4921Now It's Chippy soon to be Chris Lux

[@jeremyu3773]

🤯

[@kirstencg]

I live in Christchurch

[@jackhew93]

Oof, just pray for those in Wellington and Palmerston North if this happens

[@nzwotb2525]

Shit I live in palmerston north

[@jessicacaleno1998]

Same 😅

[@davidnewzealand5353]

when is thi gonna happen I live in Wellington I hope not 2017 cause Im in that year ok everybody wish me luck :)

[@betty8447]

Da whole world is affected hardout? Not just my country New Zealand

[@ladystardust5192]

I'm going to be that classic Kiwi and blame Aussie.

[@tamekkaknuth9612]

Don't make tamekka cry

[@nzwotb2525]

I live in palmerston north

[@wsur]

I'm at the bottom :( Fuck my life.

[@lizchatfield692]

We all be doomed .

[@volcwatcher7563]

we're all going to die

[@ally-mp7cc]

Thé worst is yet to come

[@jesper1306]

Lol this is fake

[@LURADZ]

10 Messi its a simulation duh

[@Tui1x]

It's a simulation, Jesper.

[@JG-fv9bv]

Very interesting thank you , for my seismic analysis and forecasting I always go to "Dutchsinse" .

[@nzwotb2525]

I live in palmerston north