 It's one o'clock on a Monday afternoon, so you must be watching Think Tech Hawaii. After a few weeks' break for teaching, I'm back in the chair. My name's Pete McGinnis-Mark, and I'm your host for Research in Manoa. Every week we come and give you some idea of some of the exciting new earth science research which is being conducted at the University of Hawaii at Manoa, and in particular at the School of Ocean Earth Science and Technology and the Hawaii Institute of Geophysics and Planetology. And speaking of HIGP, my guest today is Dr. James Foster, who is an Associate Researcher within HIGP. And so, James, welcome to the show. Delighted to have you as the first guest of 2018. Yeah, thank you for having me. And you're going to be talking to us about something called marine geodesy. So give us a little bit of an introduction. What is marine geodesy? Marine geodesy is the study of the shape and the change of shape of the marine portion of the earth. So that includes both the change of the sea surface as well as the change of the sea floor. Okay. So we're looking at both the ocean surface and the ocean floor. And I think today we're going to specialize primarily in the ocean floor. Exactly. The ocean floor is almost unexplored on earth. It's, you know, 70% of the earth is covered by oceans and we know very little about what's going on underneath the oceans on the sea floor, particularly compared to even other planets in our solar system. And there are a bunch of processes going on down there, particularly around the edges of the Pacific Ocean and the Pacific Ring of Fire, which most people are familiar with. And most people think of that as being this big ring of volcanoes that surround the Pacific and it's very dramatic eruptions. But the other thing that happens there is that that is where an oceanic plate goes down under another plate and it generates the huge earthquakes that lead to tsunamis that are a big problem for us. And viewers who haven't perhaps become familiar with plate tectonics, this is the ocean floor itself moves past each other or dives one place under another or overrides. Exactly. It's called a subduction zone. Where the two plates are meeting and one of them is forced down. And as those plates get driven past each other, they build up strain and stresses and those are released as the big earthquakes that we all know about. So that sounds pretty important. Would I be correct in saying that the average person in the street, while they don't think about marine joy to see every day, it has some significant implications for their everyday life if they live here in Hawaii? Absolutely. This is an area of the world we know very little about, except that it's the source of the big tsunamis that threaten our coastlines. And we need to understand what's going on down there in much more detail and hopefully be able to predict the likelihood of earthquakes and the threat from tsunamis. And would we include submarine landslides as well in this problem? That's exactly part of the same problem. Submarine landslides, submarine volcanoes, all sorts of processes that we know very little about and have no good understanding of how they might behave in the future. And while you say we have little understanding, are we totally blind or do we know what kind of measurement techniques would be helpful? Well, so what we rely on right now is a combination of seismology. So we look at little earthquakes and they tell us perhaps something that might be going on in terms of the larger processes that lead to the big earthquake. So we have some insight from that. And we have insight from land-based geodetic measurements, mostly through GPS, which I think most people are familiar with. And geodetic measurements is just knowing exactly where you are. Where you are and how you're moving. Relative to what? That's another show I know. That's a whole other show. It's slashingly complex when you need to understand where things are at the centimeter scale. But basically in terms of GPS, what really matters is the center of the earth. That's the GPS satellites. And you mentioned a few centimeters. You're trying to measure changes in the position of something on the ocean floor to within centimeters or an inch or two. Exactly that. Yes. That can't be easy. And it means that we really need to push the existing technologies and numerical analysis techniques right to the edge to get that sort of accuracy. But that's the sort of accuracy we need to be able to help resolve these problems. It sounds very complicated. I know you brought along a diagram to help me as well as the viewers understand. So if we can go to the first slide, this sort of summarizes, I think, some of the issues which you're faced with. So again, you're trying to measure at the centimeter or less than an inch a position on the ocean floor, right? Exactly. So what I'm showing here, this was designed mostly to illustrate one of the techniques we use for looking at vertical motions of the sea floor. But most of these things hold for the horizontal motions. So what this shows is an autonomous surface vehicle, which is called a wave glider. This is a commercial product created by a company that was formed locally here on the Big Island. Okay. And we'll get to the wave glider, I guess, in a few slides. But yeah. And so the way these techniques work generally is you have something on the sea floor that's actually tracking the motion of the sea floor. And then you have something on the sea surface that connects what's happening on the sea floor to the positioning capabilities, typically GPS, on the surface. So in this case, for example, we have the wave glider. We can position that using GPS to centimeter accuracies. And then the wave glider is actually able to send an acoustic ping to the sea floor station. And we can measure the time it takes for that ping to go down to the bottom and come back. And we can use that to estimate how far away that sea floor station is. And through some fairly complicated analysis that takes into account changes of the atmospheric pressure, changes in the sea surface height, changes in the density of the sea column itself. And we can convert that into a measurement of how the sea floor is moving over time. That sounds very complicated. And you mentioned the water column itself, presumably it's changing temperature. So the acoustic signal, isn't that affected by? Horribly. Horribly. Yeah. Yeah. My background actually looks at the similar sort of effect in the atmosphere. I look at how the atmosphere affects the GPS signals, and that makes a significant impact. It changes the apparent length between the GPS satellite and the station on the Earth's surface by two meters. And it's exactly the same problem on the sea floor, but multiplied by an order of magnitude. It really, there are large changes in the sound speed in the ocean column due to changes in the temperature mostly. And salinity. And salinity as well. Yeah. And we have to be able to do something about those in order to be able to retrieve the centimeter accuracies that we need. And that's actually the big analytical, technological trick, is how do you average out, model out, estimate the component of the signal that's due to. And what do you do? Do you come along and say one day you're going to ping this particular part on the ocean floor? Do you have to station keep for weeks or months? The way this is traditionally done is called the GPS acoustic. So that's the technique I just discussed. You have a GPS positioning on the sea surface, and then you do acoustic ranging to the sea floor. And for any sight on the sea floor, you would sit on the sea surface for at least two days, maybe four days, depending on how many times you want to get that measurement in order to average out some of this ocean column noise. So it requires typically used to be a research vessel to sit in the same place for two to four days. And research vessels cost a lot of money to write. Yes, sure. Those of you who don't know, you might be a little shocked to discover that you might be talking about $35,000 to $40,000 a day to run a research vessel. So to just sit it there for two days, four days, to collect one month's signal measurement is a huge investment in time and money. And so my main thrust in this field is to try and find new ways of doing it more affordably so that we can go out. We can make these really important measurements, but we can do them at a cost point that's manageable. And we can start to get the sorts of breadth and range of measurements that we need. OK. And it sounds as if are you an engineer or are you actually only interested in the data or you're a computer modeler or? I'm a scientist. I'm a scientist. I can't call myself an engineer. But one of the fascinating things that's really had me focus on geodesy as a research topic is that you get to be all of those things. You have to be enough of an engineer to understand what the technology can do, what you need to do in order to get the observations you need. I have to work with real engineers to actually build and put these pieces together for me. But that's part of the joy. You need to know what are the science questions that we really need to study and we need to understand better. And you also need to be a good enough data analysis that you can get the information you need out of the data that you record. So it's a broad range of skills that you need to be capable within. But you have a whole team around you that provides the specialist. So let's take a look at some of the kit which you're involved in developing. The next slide should show, I think this is one of, this is the wave glider, right? This is the surface float portion of the wave glider. So I've actually not included a diagram that shows the submarine portion. But it's a very clever but elegant system. So it's actually a two-part system. It has the surface float that we're illustrating here that houses solar panels, batteries, and all of the science and communications equipment that you want to get your data. But the heart of the system is actually the submarine portion, which hangs below it about seven meters. So we're looking at a surfboard, basically. Is it about that size? It is. This is actually a little bit over six feet long. A long board. And it's funny you should mention that. But the original design was created by surface who were retired engineers who wanted to get some long-running ocean measurements. And so they were playing with their surfboards to see what they might be able to build that would allow them to do that. So this floats on the sea surface. This houses the GPS and our science payload. And then hanging below it, there is a submarine portion. And as the waves pick up this float, the submarine portion doesn't move so much. And it has hydrofoils, which as this pulls it up, it drives it forward. And then as the waves let this drop, the weight of the submarine drives it forward again. So the forward motion of this is driven entirely by waves. So you don't need to power it. There's no engine. There's no engine, no motor. So that's the key. That's the little secret that allows us to run for so long is you don't actually have to provide power to keep you going. And how do you control it? It's actually a simple, simple system. It's got a very simple rudder that's just magnetically controlled. And then you have onboard GPS, which tells it where it is at any given time. And you have a control system that sits with your computer. And you plug in some way paths. And you tell it, I want it to go here. And when it gets there, it says, OK, now I need to go here. And so you can program in a complex path and a series of operations. And it'll go. And it can stay out in the ocean for two, three months at a time, collecting data. So it can operate in ocean waters around Hawaii, even though it's like four and a half kilometers depth water. Yep. All it needs is a little bit of wave action in order to keep it moving. Obviously, like anything, if the waves get too big, it can have problems. Do you have to retrieve it to get the data back? Well, we designed the system so that we didn't have to do that. That's typically the case is that you might collect all the data on board. But we actually built a cell phone into ours so that we can have the wave glider come back into cell range, send us all the data, and then go back to wherever it's meant to be recording data. But you can also have it connect to satellite internet. That's more expensive. But if you want the data, and there are plenty of reasons why you might want it rapidly, then you can collect the data that way too. Now you said we. Is that the Royal We? Or is there a team that you represent? As I said, there's a team. The range of skills that you need to pull this sort of project out is beyond one person, certainly beyond me. So I've worked with engineers. Brian Bingham was part of the UH engineering department. One of our colleagues, Todd Erickson, is a marine engineer. So he helped design our version of the wave glider with its science load. And then there are other colleagues at other institutes who have helped drive the whole science of seafloor geodesy, David Chadwell at Scripps Institute of Oceanography is one of those. And we're currently working with Ben Brooks and Todd Erickson has moved to join him at the USGS. So there's a big collaborative group of people. It's a relatively small field. And so we're all working together. But it's initiated here in Hawaii, right? This particular project was an in-house one. And the surfboard type wave glider is Hawaiian design. That's a Hawaiian design. Yeah, a bunch of ex surfers over in the west coast of the big island who wanted to just do some hobby science. And they realized they had a real idea on their hands. And they turned it into a major company now, Liquid Robotics Incorporated that builds and sells the wave glider platform. And I don't need to ask anything really specific. But roughly how much does one of these wave gliders cost? It ranges. The very basic model is about $200,000. So not cheap, but compared to other ways of trying to get these sorts of data, it's actually a very, very affordable way of doing it because you can run it for multiple projects, multiple missions, all the time. Yeah, well, when we come back, I want to quiz you a bit more on some of the hard way. But let me just remind the viewers, you're watching Think Tech Hawaii Research in Mana'a. I'm your host, Pete McGinnis-Marc. And my guest today is Dr. James Foster, who is an associate researcher within the Hawaii Institute Geophysics and Planetology. And we'll be back in a minute. See you then. Hey, aloha, Stanley Energyman here on Think Tech Hawaii, where community matters. This is the place to come to think about all things energy. We talk about energy for the grid, energy for vehicles, energy in transportation, energy in maritime, energy in aviation. We have all kinds of things on our show. But we always focus on hydrogen here in Hawaii, because it's my favorite thing. That's what I like to do. But we talk about things that make a difference here in Hawaii, things that should be a big changer for Hawaii. And we hope that you'll join us every Friday at noon on Stanley Energyman. And take a look with us at new technologies and new thoughts on how we can get clean and green in Hawaii. Aloha. I just walked by and I said, what's happening, guys? They told me they were making music. And welcome back. You're watching Think Tech Hawaii Research in Mana'a. And I'm your host, Pete McGinnis-Marc. My guest today is Dr. James Foster, who's an associate researcher within the Hawaii Institute of Geophysics and Planetology. And we're talking all about marine geodesy. And James, you showed us a little bit about the wave glider before the break. There must be other instruments which are part of this whole package. So I think you brought along another slide, and we'll take a look. This, I believe, is going to be sat on the ocean floor. This triangular thing is what? So yeah, this is one of our seafloor nodes or seafloor sensors. So you're right, the system's two-part system. You have the sea surface portion of the system, and then you have the seafloor portion, which is the bit that's actually connecting you to the motion of the seafloor. So this shows it's a two-part system. There's the tripod. And this is holding the center part, which is the red tube. There's actually the pressure sensor, an acoustic transmitter, and some other instrumentation, and a bunch of batteries all housed in a pressure casing that can survive sitting on the seafloor. There's the yellow square bit around it. That's actually a float so that once it's released, it can come back to the surface and be recovered. So you leave the tripod on the ocean floor? Yeah, and one of the limitations, traditionally, with these sorts of projects is that you send things down. You record data for a couple of years until you've run out of batteries and you bring it back, and then you look and see what did you record. And the problem with that means that you've just got a two-year time window. If nothing interesting happened, you didn't learn very much. So we've designed that particular tripod that has a little mounting plate so we can recover our unit, transponder the expensive portion of the kit, at the sea surface once the batteries are getting low. But we can also go back down with a remotely operated vehicle and replace it once we've put new batteries in so that we can then reacquire that same exact point on the seafloor and get a hold of it. And here's a picture, I guess, that this is the same instrument as it's going to be dropped into the ocean. Right, yeah, so of course we had to demonstrate that all of the bits we'd put together for this project were really going to work. So we went off of the south shore of Oahu and this is running off of a fairly small boat. It doesn't have to be a full research-sized vessel. And this is just dropping it into the seafloor and then it actually ran down there for six months and we sent the wave glider out to talk to it and pick up data and get ranges to it. And then we told the... So we're looking here at the image, the two bits of hardware, the part on the right actually goes down onto the ocean floor, part on the left, the surfboard. That's the wave glider, that stays on the surfboard. And you can see solar panels and things. Exactly, the left part has all of the surface science gear and the broader communications. And then on the right, that was the core bit that was in the tripod and it's been released and has now popped up back to the surface. Okay, okay. So we're just about to pick it up and take it home. Great, I think we've got one more slide and then we'll get into some other discussions. So you've been doing some testing as well, right? That was a real life deployment. How well does it work? It actually works really well. It may be hard to see some of the details on this plot, but this was some of the data that came back from it. It's a comparison of the red data there or the pressure measurements that were recorded on the seafloor and right now it's just really showing the time. We're looking time on the bottom axis in May of 2015. Right, so it's two or three days of continuous data. And where it says pressure going up vertically, that's presumably the same as depth. Yes, so there's a very simple approximate map between depth and pressure. And that's one of the problems is that if the sea height changes, is that due to the tides or something else or is that due to the seafloor having moved? So that's one of the little delicate numerical analysis problems we have to resolve. And presumably you can put several of these sensors down in roughly the same area. So if it's a tide or if it's changes in atmospheric pressure, they would all be responding in sync with each other if they're close. Exactly, no, and that's one of the classical ways of sorting, trying to distinguish these signals. We're exploring ways of trying to do that using the wave glider itself that we can use the wave glider to map the tides directly. And so we can have that mobile surface portion of the system constrain some of the problems that we have without having to throw lots of equipment on the seafloor in the same area where we'd rather have measurements that were more... But this sounds as if it's the confluence of many different disciplines. How did you get into this, James? I mean, it's an evolving field, so we're always interested. How does a researcher actually join this community, or do you invent it? There are actually, there's plenty of scope for inventing these sorts of fields. I have migrated to this area from a fairly different area, actually. And I think there are many different paths that people could come into this sort of discipline from. My background was doing geophysics. I did a degree in geophysics. And geophysics would be studying earthquakes In my case, it could be earthquakes. We had Niels Grubby on the show just before Christmas who's a geophysicist, so that kind of thing. Right, the physics of the earth and earth systems. It's a very, very broad field. You can study good things going on in the atmosphere, in the solar system, you know, within the ocean, within the earth, on the earth's surface. It's very broad, covers a huge range of possibilities. I was interested in volcanoes. I came over to Hawaii to work with the Volcano Observatory. And I had the opportunity to stay on to come to UH and do a PhD here. And I focused there, as I mentioned earlier, on meteorological aspects of GPS. But that actually equipped me with some of the tools that I could then apply to doing these sorts of studies out on the oceans. So if a new student wanted to follow in your footpaths, what kind of subject should she be taking? Well, you could come from the engineering angle. This particular deployment that we were just looking at was actually largely driven by an ocean, an engineering student with Brian Bingham in his robotics lab, Jeffrey Oshiro, who's currently working locally. And so you could come from the engineering angle and you could have enough interest in wanting to understand the science that you could develop your niche in the career that way. You could be a physicist. You could be somebody who's got special mathematical analysis interests that can bring those to help us improve the way we do this. So it sounds, in many instances on this program, sounds like a great background for a student to have. She should be a STEM student, science, technology, engineering, math, that kind of thing where you can... I think we really bring together different disciplines. And I think that would be perhaps one of my take-home pieces of advice to any student is that if you get yourself a strong background in mathematics and physics, you can apply it to a vast array of exciting science. It doesn't have to be... The engineering side is also... And if you can then bring engineering in too, then you can go almost anywhere, do almost anything. It's really... The world is your oyster. It opens up all the doors and it's just down to looking around what's interesting. Where is the current most exciting science happening? Where could I help drive exciting science? All you need is that background and a little bit of creative thinking about how you might apply the tools you have. So it's a completely open field, but you've not only gone and done some tests, we always ask the guests, well, why should we care? And I think the final slides is going to show one of the field experiments you're starting to develop. And this isn't Hawaii. This is, I guess, the Aleutians off the west coast of Alaska. But what are you trying to do there? So this is part of the Pacific ring of fire that we mentioned earlier. And it's one of the subduction zones, those areas where the plates are meeting and the ocean plate, the Pacific plate is going down, believe the Aleutian Ark there. And blue obviously is the ocean and green are the islands and deep blue shows deeper water. Deeper water, exactly right. So you can sort of see the line of the trench where the last bit of the plate that we can see is driving down below the overriding plate. And it's a place of particular interest to Hawaii because this is the Aleutian and Alaska Ark there is where many of the tsunamis that have hit us have come from. And what we need to know to understand what the threat to us is, is how tightly these plates are connected. And these three sites that are listed there are three areas where we think the coupling, the locking between the plates is very different. And yet we can't actually constrain it with the data we have. And it's great because we've had Rhett Butler and Gerard Froyo on previous shows talking about tsunamis. You're actually trying to find places along the Aleutian Ark which could be some of the most risky as far as Hawaii's tsunamis are concerned. Exactly. The source region for the 1946 tsunami is actually just to the west of that portion there. So this is all part of the Pacific ring of fire that threatens Hawaii directly. And we need to understand it better. So it's not really an early warning system in the sense that it's coming in a few hours. It's more, hey, you're building up this tension in the Earth's ocean crust. This is a place where you should start looking and investigating more about the propagation of the tsunami. Exactly. I mean, the end game of understanding this better would be, we think there's a real threat here. We need to put some dedicated resources into monitoring that in real time for the early warning. But that costs a huge amount of money. You want to understand better the system first and then you can decide where you want to focus. And this particular experiment will be happening this year, next year. So yes, our wave glider is just being refitted and getting ready to have its first sea trials over the next month. And then it's due to go on a boat in May and it'll be heading up to Alaska to do all this. And that sounds a great way to end the show because if you're going to be collecting data later this year, you can come back and tell us the results. But James, thank you very much for being on the show. Alas, we've run out of time, but I'd love to have you back some other time and tell us all about the results. I'd be delighted to. Let me remind the viewers that you have been watching think tech Hawaii research in Manoa. I've been your host, Pete McGinnis-Mark. And my guest today has been Dr. James Foster, who is an associate researcher within the Hawaii Institute of Geophysics and Planetology. So we'll be back next week. And I hope you will join us then, one o'clock on next Monday. And we'll see you then. Goodbye.