Speaker 1: Yoda.
Speaker 2: I'm Chelsea Daniels and this is a summer special of
Speaker 2: the front page the NSID Herald's daily news podcast. Major
Speaker 2: earthquakes may not be a regular occurrence in New Zealand,
Speaker 2: but the threat of them is always often in the
Speaker 2: back of our minds. With a major fault line running
Speaker 2: through the middle of the country, you only have to
Speaker 2: look at the events in christ Church and Kaikalder to
Speaker 2: know the risk they pose.
Speaker 1: In May, new modeling.
Speaker 2: Was published that highlighted the impact a catastrophic quake could
Speaker 2: have on this country, including the threat of tsunamis and
Speaker 2: how prepared we are for such an event. We spoke
Speaker 2: with doctors Bill Fryer and Matt Gerstenberger from GNS Science
Speaker 2: to dig into the latest research on our seismic threats.
Speaker 2: To Bill fry this week, you were on a panel
Speaker 2: at the Nature Challenge Symposium talking about the Hikui subduction zone.
Speaker 2: Can you start by explaining what this zone actually means
Speaker 2: in Layman's terms?
Speaker 3: Yeah, sure, quite simply, it's just New Zealand's biggest fault.
Speaker 3: It's the place where the Pacific and Australian plates collide
Speaker 3: about five centimeters per year and it hosts some of
Speaker 3: our largest earthquakes, So.
Speaker 2: We often hear of certain fault lines being overdue for
Speaker 2: a quake.
Speaker 1: Is that the case here?
Speaker 3: Yeah, maybe I'll hand that question over to Matt Leader
Speaker 3: of our new National Seismic Hazard Model.
Speaker 4: Yeah. So what we do is we look at how
Speaker 4: often earthquakes have occurred on big or on any fault
Speaker 4: really in the past, and we have different models of
Speaker 4: how we understand what that means about the future. So
Speaker 4: we can look at roughly the inter event times between
Speaker 4: earthquakes in the past and get an idea of when
Speaker 4: it is likely to occur in the future. It's pretty
Speaker 4: hard to say if something's actually overdue. We generally have
Speaker 4: a range of time when an earthquake might occur within.
Speaker 2: Is there any way of actually telling when a quake
Speaker 2: could happen or is it really just luck.
Speaker 3: Of the drawl.
Speaker 4: So when we do the National Seismic Hazard Model, this
Speaker 4: is a model that we use to give probabilistic estimates
Speaker 4: of shaking that we might see in the next fifty
Speaker 4: e one hundred years in New Zealand. When we do that,
Speaker 4: we look at kin the whole range of possible earthquakes
Speaker 4: that could occur in New Zealand. So we're looking at
Speaker 4: all the faults that we know about plus earthquakes that
Speaker 4: could occur in different places, and that gives us probabilities
Speaker 4: or likelihoods that shaking might occur in a particular location.
Speaker 4: But yeah, we cannot predict earthquakes, so we cannot say
Speaker 4: it's going to occur within the next ten days, but
Speaker 4: we know pretty well where they're more likely and where
Speaker 4: they're less likely to occur.
Speaker 3: Yeah, can I add onto that mat The work that
Speaker 3: we presentage at the recent symposium was the result of
Speaker 3: a National Science Challenge program of work that allowed us
Speaker 3: to build up on some of the great computational numbers
Speaker 3: that the National Science Hazard Model has given us and
Speaker 3: try to explore the way these earthquakes would look when
Speaker 3: they do happen. So try to understand the types of
Speaker 3: differences in earthquakes, not just the rates, but also but
Speaker 3: that might say about the impacts to New Zealand and
Speaker 3: the people living, certainly on our coastlines.
Speaker 1: And it's really important for planning as well.
Speaker 2: I guess the research that I saw regarding the Hikarangi
Speaker 2: subduction zone planners actually use a kind of worst case
Speaker 2: scenario right, and that's often what we see in the
Speaker 2: news and media.
Speaker 5: The biggest earthquake that could possibly happen along the Hikarngi
Speaker 5: is around magnitude possibly a nine, but they think maybe
Speaker 5: more like eight point seven or so, which is very large,
Speaker 5: and they only probably happen every thousand years or so.
Speaker 2: What is the purpose of saying, Look, if a nine
Speaker 2: point one quite hit this fault line, tens of thousands
Speaker 2: of people would die, this many people will be displaced.
Speaker 1: What's the purpose of doing that? Do you think?
Speaker 3: Perhaps the real utility and trying to come up with
Speaker 3: scenarios that might be similar to what New Zealand will
Speaker 3: experience in the future is opportunity to test our response systems,
Speaker 3: to say, if this happens, what would we do and
Speaker 3: how could we improve that process? How could we improve
Speaker 3: what we do to try to limit the damage to
Speaker 3: New Zealand, to try to improve how we respond as
Speaker 3: a nation to it. So by understanding how likely these
Speaker 3: things are, what they might look like when they happen,
Speaker 3: and then using that information to forecast impacts, we can
Speaker 3: test those systems that can improve our outcomes if it
Speaker 3: does happen in our lifetimes.
Speaker 4: The other thing we can do with that type of information,
Speaker 4: particularly when we start to look across different types of
Speaker 4: earthquakes that can occur, is we can then look at
Speaker 4: long term planning, so we can move towards what we
Speaker 4: would call risk based planning, so you look at the
Speaker 4: potential earthquakes that could occur, the impacts that those could have,
Speaker 4: and that allows kind of long term planning for things
Speaker 4: related to building code and different urban planning type settings.
Speaker 2: Generally speaking, how active are our fault lines at the moment?
Speaker 2: I know over twenty twenty two, twenty twenty three, for instance,
Speaker 2: there was a series of mini quakes under Lake Topor
Speaker 2: a magnitude five point six earthquake that struck Topaul last
Speaker 2: night was felt by thousands of people across the country.
Speaker 1: It was horrendous.
Speaker 5: Yeah. Yeah, I was flying in bed and not hold
Speaker 5: bed and up and down and move absolutely skied.
Speaker 3: Yeah, it's the biggest fun I felt.
Speaker 1: Does that speak to a wider issue here?
Speaker 4: We know through kind of to the last two hundred years,
Speaker 4: there's quieter times and there's more active times in terms
Speaker 4: of the number of earthquakes that we may get over
Speaker 4: a series of decades. You could say, and starting in
Speaker 4: two thousand and three, it's certainly been a more active
Speaker 4: time in terms of earthquakes that we've had in the country.
Speaker 4: We can't say when that's going to end, and maybe
Speaker 4: that things are starting to quiet down now or maybe
Speaker 4: that we continue to stay in this active period. And
Speaker 4: that's really the reason that we do this research in
Speaker 4: this type of planning, and so we can understand the
Speaker 4: potential for what could occur much better and then pass
Speaker 4: that information on so that that can be included in
Speaker 4: the tas that are being made.
Speaker 3: Can I add man, One thing we can say unequivocally
Speaker 3: from looking at the last twenty years of activity in
Speaker 3: New Zealand is New Zealand always has the potential for
Speaker 3: a big earthquake and tsunami, and we need to be
Speaker 3: prepared for that. There's never going to be a situation
Speaker 3: where we go through time where we say, Okay, all
Speaker 3: the earthquakes are done, I'm finished with that, move on
Speaker 3: to something else. And it's this realization that leads us
Speaker 3: to do things like I just explained, testing the response systems,
Speaker 3: or to even develop new tools to help us respond
Speaker 3: things like tsunami early warning, being able to look at waves,
Speaker 3: monitor tsunami waves before they arrive to our shores, or
Speaker 3: being able to forecast the extent of strong ground motion,
Speaker 3: the amount of damaging shaking we might get after these
Speaker 3: earthquakes happen in the minutes to hours after they do,
Speaker 3: so we can try to triage their recoveries and engineers
Speaker 3: where they need to go to start looking at buildings
Speaker 3: and rescue crews where they need to go to start
Speaker 3: dealing with the aftermath of the big events.
Speaker 2: So, Matt, you mentioned over the last few years you've
Speaker 2: been working on the National Seismic Hazard Model. What are
Speaker 2: some of the risks posed by a major earthquake in
Speaker 2: New Zealand, like if the Hiccodangi fault raptioned, for example.
Speaker 4: Yeah, well, very related to what Bill just said. We
Speaker 4: know that there can be earthquakes anywhere in the country,
Speaker 4: so we do have the potential for strong shaking everywhere.
Speaker 4: There are certain areas that are more likely to have
Speaker 4: larger earthquakes, and certainly the Hikarangi subduction zone is one
Speaker 4: of the dominant ones that really controls what we would
Speaker 4: call the hazard.
Speaker 3: So we talk about two things.
Speaker 4: We talk about the earthquake hazard and that is kind
Speaker 4: of the potential for shaking. And then when we talk
Speaker 4: about the risk, that's really the impact for society, and
Speaker 4: the National Sizemic Hazard Model really focuses then on the
Speaker 4: potential for the shaking that gets then passed on to
Speaker 4: the other information. There are many active faults around the
Speaker 4: country that have potential for strong shaking.
Speaker 3: Yeah. Can I add, Matt that one significant outcome of
Speaker 3: our national science challenges their resilience to Nature's challenge, is
Speaker 3: that we developed a framework in which we can use
Speaker 3: what we know about the faults in New Zealand and
Speaker 3: what we understand about the physics of how earthquakes actually
Speaker 3: happen to simulate hundreds of thousands of years of possible
Speaker 3: earthquakes in New Zealand. This work has led us to
Speaker 3: understand just a little bit better what might happen in
Speaker 3: a big Hickadonki earthquake. And what we've seen from this
Speaker 3: is that quite commonly when you get the very largest earthquakes,
Speaker 3: when you think about a magnitude eight plus earthquake that
Speaker 3: we might have on the subduction interface, we quite commonly
Speaker 3: have associated activity or triggering of crustal faults. Some of
Speaker 3: the smaller faults that are very close to that plate interface,
Speaker 3: and this interaction or communication between the faults that really
Speaker 3: has given us a bit better idea about what might
Speaker 3: happen and how we need to prepare for that. You
Speaker 3: can well imagine it like happened in twenty sixteen in
Speaker 3: the kai Quota earthquake. Before the tsunami hit our coasts,
Speaker 3: there was a tsunami generated. We had over a meter
Speaker 3: of uplift of some of the coastlines. Some of the
Speaker 3: coastlines actually rose by over a meter before that wave hits,
Speaker 3: So you can imagine that the tsunami impact when it
Speaker 3: does hit, it's going to be different than if that
Speaker 3: coastline hadn't risen. We started looking for the same type
Speaker 3: of behavior in the Hikarongi. So if we get a
Speaker 3: very large earthquake there in the future, are we going
Speaker 3: to get the coastline going up? Are we going to
Speaker 3: get it going down? If so, by how much and
Speaker 3: how is that going to change the impacts will get
Speaker 3: from that big earthquake.
Speaker 2: Bil, Just to add to our sense of panic, you've
Speaker 2: actually been working on a tsunami hazard work as well.
Speaker 1: Hey, so what more can you tell us about that.
Speaker 3: Yeah, Well, first of all, I can tell you, don't panic. Prepare.
Speaker 3: That's the best thing we can do. The more we
Speaker 3: understand about these hazards, the more we can prepare for
Speaker 3: them and make them something that we can live with,
Speaker 3: coexist with in a smart way. Through the nationale. It's
Speaker 3: challenge work that I was talking about, and the understanding
Speaker 3: that these complicated earthquakes have an impact on the tsunami hazard.
Speaker 3: We recognize that now is as good a time as
Speaker 3: ever to try to start putting together all the information
Speaker 3: we have, making self consistent tsunami hazard maps that we
Speaker 3: can then carry into inundation, inundations just the flooding we
Speaker 3: might see from the tsunami itself. And we understand that
Speaker 3: when you're very close to the tsunami source. So when
Speaker 3: you've got a situation like in New Zealand where the
Speaker 3: megathrust fault is right at us, where the Hikonogy subduction
Speaker 3: zone is right at us, we know that small scale differences, heterogeneities,
Speaker 3: or things that make one eight point zero earthquake look
Speaker 3: like a different earthquake than another eight point zero earthquake,
Speaker 3: those things matter for the tsunami inundation. So now we
Speaker 3: have the opportunity, really for the first time, to provide
Speaker 3: a realistic hazard map for tsunami inundation that would somehow
Speaker 3: complement the really globally leading world of the national size
Speaker 3: Macacert model.
Speaker 2: And on the Herald podcast tell you why I've Forgotten History?
Speaker 2: We heard a lot in that about the dangers of
Speaker 2: that lack of preparation.
Speaker 6: The question is if and when that happens again, will
Speaker 6: it be just a completely overwhelming act of God, or
Speaker 6: will it be an act of God that actually, if
Speaker 6: we're UPSPECD a bit we could have prevented.
Speaker 2: Are either of you worried about the level of investment
Speaker 2: as a country we're putting in towards limiting the impact
Speaker 2: of natural disasters, because we're still hearing stories from Wellington,
Speaker 2: for instance, about earthquake prone buildings nearly eight years after
Speaker 2: the Cauculda earthquake.
Speaker 3: Yeah, maybe maybe, Matt. I answered that first, then hand
Speaker 3: over to you. I'm a scientist, not an economist. When
Speaker 3: I show up at my office each day and I
Speaker 3: get very passionate about trying to do science that improves
Speaker 3: the human condition, the politicians and the funding system of it.
Speaker 3: That's someone else's issue for me, So it's something that
Speaker 3: I rarely spend time thinking about because I have very
Speaker 3: little influence on how it's going to play out.
Speaker 4: Yeah, I think I would agree with Bill on that.
Speaker 4: But I do think it's important that there are societal
Speaker 4: discussions to have about this, that New Zealand needs to
Speaker 4: think about what it considers important and how it wants
Speaker 4: to address various things related to natural hazards. And I
Speaker 4: think it's good that discussions are happening, and I hope
Speaker 4: those continue to happen.
Speaker 2: Well, the fact of the matter is that if one
Speaker 2: of these natural disasters actually did happen, and the first
Speaker 2: question would be.
Speaker 1: Well, how do we plan for it?
Speaker 2: Right, And this is what we're talking about here, This
Speaker 2: is how we plan for something catastrophic.
Speaker 4: Yeah, So it's important that we continue to do the
Speaker 4: work like both Bill and I are talking about, so
Speaker 4: we have the best information that we can about what
Speaker 4: could occur. So when we those decisions do get made
Speaker 4: in the planning, that they're based on the best science
Speaker 4: that is really available for that and that can be
Speaker 4: brought into the wider picture about what the risk tolerance
Speaker 4: is for the country.
Speaker 1: As experts in this area.
Speaker 2: How worried are you both about what we've been talking
Speaker 2: about today.
Speaker 3: About the likelihood of a large Hikarangi earthquake. I'm not
Speaker 3: worried at all. I feel a keen sense of urgency
Speaker 3: to do as much science as we can to improve
Speaker 3: how we make it through that big event. But as
Speaker 3: far as a day to day fear, it's not something
Speaker 3: I have. We live here, We enjoy this beautiful country.
Speaker 3: The reason the country is so beautiful is because of
Speaker 3: these natural processes. It's just something that we need to
Speaker 3: prepare for, do the best we can to make sure
Speaker 3: that our planning processes are in place. We've got our
Speaker 3: house in order for when it does happen.
Speaker 4: Yeah, I think Bill said it very well. I would
Speaker 4: agree with that. It's not something I worry about on
Speaker 4: a daily basis. It's something I'm certainly aware of living
Speaker 4: here and seeing the impact it has on the landscape,
Speaker 4: and looking at earthquakes around the country, around the world, sorry,
Speaker 4: and see an impact that those can have. But it's
Speaker 4: something I think about really in terms of planning and
Speaker 4: how do we prepare for this, How do we help
Speaker 4: the country to prepare for that.
Speaker 2: You're both experts in your field, and like you said,
Speaker 2: go to work every day, keen to get stuck into
Speaker 2: the science. What is something that you're working on or
Speaker 2: you've read or seen in regards to this issue in
Speaker 2: New Zealand that really tickles your fancy.
Speaker 4: I'd say for me, it's really how do we model
Speaker 4: the entire Earth as a system. So in the past
Speaker 4: that hasn't really been done. There's been little individual pieces
Speaker 4: of say that you could call the earthquake process that's
Speaker 4: been looked at it on its own. And where we're
Speaker 4: heading now, both with the work that I've been leading
Speaker 4: and the Bill's been leading, is that we're really looking
Speaker 4: at how New Zealand, and not just New Zealand on
Speaker 4: its own, but in all the surrounding how that Earth
Speaker 4: behaves together, how the different faults interact, and how that
Speaker 4: changes the whole earthquake process. And that I find that
Speaker 4: particularly fascinating and it has big implifications for implication, sorry
Speaker 4: for improving how we model these sorts of things.
Speaker 3: Yeah, let me follow in on that too. What's really
Speaker 3: getting me excited these days is the desire and the
Speaker 3: possibility I believe now for the first time ever, because
Speaker 3: of advances in our physical knowledge, advances in computational infrastructure,
Speaker 3: advances in AI. I think we're now really for the
Speaker 3: first time able to start looking truly at the multi
Speaker 3: peril problem. So not only thinking about earthquakes, not only
Speaker 3: think about earthquakes and tsunamis, but also earthquakes, tsunamis, landslides,
Speaker 3: and even coastal processes like storm surge and like the
Speaker 3: effects of climate change, all within a self consistent model.
Speaker 3: I think that's what the future is going to look like.
Speaker 3: And certainly we need to make sure that the earthquake
Speaker 3: and tsunami fields follows with advances to allow us to
Speaker 3: jump in on these large scale models, these large scale
Speaker 3: realizations that we can make to put everything together, put
Speaker 3: all of our hazards together, so we can somehow function
Speaker 3: in a future that we know is going to be
Speaker 3: drastically affected by climate change.
Speaker 4: Yeah, and I think those being on with that, and
Speaker 4: the more that we can look at these things in
Speaker 4: a coordinated fashion, have the decisions being made in a
Speaker 4: coordinated fashion, That's how we're going to get the most
Speaker 4: benefit for New Zealand.
Speaker 7: In the end, Bill, thanks for joining us. That's it
Speaker 7: for this episode of the Front Page. You can read
Speaker 7: more about today's stories and extensive news coverage at enzidherld
Speaker 7: dot co dot nz. The Front Page is produced by
Speaker 7: Ethan Sills and sound engineer Patti Fox.
Speaker 2: I'm Chelsea Daniels. Subscribe to the Front Page on iHeartRadio
Speaker 2: or wherever you get your podcasts.