 Let me introduce today's speaker, we're very lucky to have Tom Whitley, who's come down from Sonoma State, where he is in the Department of Anthropology and Director of the Anthropological Studies Center. He says he grew up around Germany and Netherlands on a military basis, but did his BA in Washington and then an MA in PhD at the University of Pittsburgh. His area of interest is the beaver gene, or the use of digital technologies to understand past, present, and future environments. He sees himself as working the boundary between academic archaeology and CRM. He has published quite widely on topics around this general theme in journals even well known to me, like Journal of Archaeological Science and the Journal of Archaeological Method and Theory. Others, because I don't work in this area, series that are obscure to me, but seem to be focused on specifically this topic and his expertise. Today he's going to talk about some of his ongoing research where he's going to touch on no fewer than three different continents. And his talk is entitled Visualizing the Complexity of Past and Future Shoreline and Near Shore Environments Over Time. Examples from Australia, Vietnam, and California. So I'll turn things over to Tom. Thanks. So what I want to do today is I'll give you a brief overview of some of the last four or five years I've been working in digital photorealistic 3D modeling of past and future environments. And I wanted to highlight three major projects that I've been working on and give you some examples. There's quite a few slides, so I'll move through some of them pretty quickly. There are some videos in there as well that some animations that can take a while. So the first project I want to talk about is the Murajuga project. This is a Joe McDonald and Peter Vess project in Northwestern Australia. And I got involved with this back in 2015. And part of my job was modeling the changing shoreline over time in this part of Northwestern Australia. So I was dealing with a combined topographic, bathymetric database from Geosciences Australia. And the resolution on this database is fairly poor in a lot of ways, in the bathymetry particularly, when you get into the shallow water areas. So one of the things I had to do, I created a paleo hydrology model to create what former stream channels would have been like before the ocean was there. And we're looking at a time frame of about 125,000 years ago until today. So I had several different model sea level curves and I had to average between them and figure out where sea level was. And then what we wanted to do was model sea level change against this bathymetry and topography. The only problem is that the topographic distinction when you get less than about 14 or 15 meters below sea level, the Geosciences Australia, they just interpolated between that sea level depth and the shoreline. And it's completely misleading. So I had to take the small boat hydrographic data and then digitize all this environment and get a better bathymetry for that area to deal with. So that's the first issue that I'm dealing with. Second issue is Holocene sediments, which I don't get into in this particular model, but I'll get into later ones. Then I'm looking at relative climatic indicators. I was looking at changes in warmth and changes in moisture and dune building and reef building in this area. So all of this kind of combined allowed me to have a broad environmental data set that dealt with shoreline changes and also environmental changes. So I went to this program called Terogen. Terogen is a 3D modeling software and they use it for big scale movies like Star Wars and all of these things. They use it to create realistic background green screen environments that look like real world situations. But the nice thing about Terogen is you can take existing datasets, GIS datasets, import them into the model and manipulate them in the modeling, create past environments or future environments in the modern topography. And you can use things like density of different plant species and all this kind of stuff to simulate what are essentially realistic environments. So this is a mountain environment with pine trees and all that. Completely simulated in Terogen with atmospheres and clouds and all that. That's a tropical one there. So with Terogen one of the things you have to bear in mind is in ArcGIS or in any other form of GIS when you're dealing with digital terrain you're talking about the distances between data points and in this case we're dealing with 30 meter data points. So every point has an elevation value and when you're interpolating that in three dimensional modeling it creates this smooth surface. What Terogen does is it creates a 3D fractal interpolation of that. So it takes fractals and creates a rough terrain and you can set the variation in that. So in all of these modeling situations I don't have the variation set any more than the difference between any two points. Anything in between can't be more than one and a half times that difference. So it's not massively different. It's just interpolating a rough surface between them and it makes it more realistic. When you get to things like modeling the ocean it creates a transparent surface in which you can put things like this white shark model 3D object which I put under there. So this is a simulation of Dolphin Island in Morajuga and there's no vegetation on that island at all but it looks very realistic compared to the photograph from the same area. When you get on the ground level then you're dealing with things like plants, rocks, shells, sand. I've got three different sand layers in here. I've got a water surface. I've got three or four different kinds of rocks. I have Terrabralia shell. I have mangrove plants. These are four or five different versions of mangroves. So you can get very realistic on the ground kind of environment. And depending on where you have the camera looking from is how much photorealism you put into it. So in this case we wanted to look at a... Okay, so this is an animation taken from about 200 kilometers above the Earth and we're looking down at that same region. This original animation was from 125,000 years ago until today but this one is just showing the last 50,000 years. That's the Morajuga region over there and this Barrow Island over here. And what you see is the shoreline going in and out based on those sea level curves. And the changes in coloration are reflecting about 23 or 24 different plant communities that I have distributed around the landscape using fractalization on top of that hydrology surface to simulate forest patterns and things like that. So this is showing the last four or five, six thousand years until today. So when you take individual frames from this time frame you can see, which is kind of hard to see in this light, but you have a snapshot of 50,000 years ago when it's pretty wet and heavily forested. About 20,000 years ago it was very dry and grasslands. 10,000 years ago the shoreline is coming in very rapidly. There's no reef building at that time and you have a lot of erosion going on. 8,000 years ago the islandization is starting to form here in the Morajuga area. About 4,000 years ago it's almost the same as today. So that was looking at the satellite view and the transition over time and what was really interesting for the archaeologists is understanding where sites might have been located at different times in the past. Now I did some slight modifications with geomorphology on that one, but that was kind of an early one and it's using essentially the modern bathymetry, even though I've modified it a little bit with a more higher resolution version. When we look at some ground level views I set up three cameras, one here, one there and one there in different places around this region. And I created ground level visualizations for each of these locations and looking in those directions as landscapes for these different time frames. So this is the shoreline in modern Barrow Island at 50,000 years ago. It would have been this open eucalyptus forest with a lot of understory plants. Offshore from Rosemary Island we have a denser, a little bit more dense eucalyptus forest. It still is pretty wet at this time. The ridge line on the Burup Peninsula, we're looking at forested areas pretty far off in the distance. When we get to 20,000 years ago it's a lot drier. At the top it's a grassland environment. There's a skeleton of a thylacine over on the right that I inserted as well. This is a rocky area offshore of Rosemary Island and the Burup Peninsula you can see the rocks exposed here. These rocks on Merigiga are about 2 billion years old. When you get to about 8,000 years ago it's a little bit wetter, not quite as wet as it was 50,000 years ago. But you start to see a much more dense, a bunch grass kind of environment with these white eucalyptus and offshore from Rosemary Island. The shoreline is only about 2 kilometers from here at this time and you start seeing these dunes. Today there's a lot of dunes in Western Australia that are very similar to this. When you get to the ridge line of Burup Peninsula it's starting to look a little bit more like it does today. Here's the same views from 4,000 years ago. You can see the shoreline is coming in at the top. Offshore from Rosemary Island it's already inundated but it's still pretty shallow and you have this mangrove forest which is growing there. A little bit drier on the ridge lines you can see some of the highly numerous rock art that's on the Murajuga rocks. This is actually a photo of a real piece of rock art that I just pasted onto that rock. When you look at, this is about 200 years ago so we're looking at there's a sailing ship in the distance on that one but this is approximately where the shoreline is today on Barrow Island. Offshore on Rosemary Island it's about 2 to 3 kilometers offshore. You have a sea turtle floating there and in the Burup Peninsula you start to see this encroachment of the mangroves in the distance. So for the Western Australian Museum they asked me to put together 3D immersive environments of this. So right now this is just a video of me clicking through the 5 time periods from that center camera from Offshore on Rosemary Island. So that was 50,000 years ago, this is 20,000 years ago and these are full 360 fully immersive still pictures but these could be made into animations as well and you can make them 3 virtual reality kinds of visualizations. So that's essentially where I kind of finished up with the Murajuga project there's a shoal of fish there. It would be nice if I made them moving but they're just static in this view. Maybe easy to catch there. And there's the sea turtle. So that's what it looks like today. The next project I was going to talk about is some excavations we did in April of this year. This is the Vietnam Maritime Archaeology Project. We excavated a site called Dong Choy. This is on Quang Lan Island in Vietnam and this is a Neolithic cemetery about 5,000 to 3,000 years ago and we were doing test excavations and it was a GPR project too so we were doing GPR where we could at this site. The 3D modeling time range that I'm going to show you pictures of is about 10,000 years ago too today. So this was a great project to work on. It's just outside of Ha Long Bay so it was beautiful to get there. We had great food, great people, nice cows. Did some GPR in some really nice temple areas. But this is the location. This is the Van Don District in Quang Ninh province. Ha Long City is here. This is Ha Long Bay that's by Tu Long Bay and Quang Lan Island is this long, narrow one right on the outside. So the data set I used for this is a bathymetry and topography of the Gulf of Tonkin and it's pretty much on the same level as the Australian data set where you have very good topographic data. It's 30 meters or less. But when you get to the bathymetric data really the best bathymetry you can get is every 90 meters or so and a lot of that is pretty coarse and when you get into the shallow waters you don't have a lot of information on what's Holocene sediments and what's Pleistocene sediments so modeling where the shoreline actually was is pretty complex. So here in this image the darker blue is 10 meters. 10 meters or more below sea level, modern sea level the middle blue is between 4 to 10 meters and then the lighter blue is 0 to 4 meters of depth. So when you get into Ha Long Bay it's saying everything is 0 to 4 meters but there's a lot more deep bathymetry in there it's just we don't have a lot of detail on it. On Quan Lan Island itself the Dong Choy site is in red and the hatched white areas are stabilized Holocene dune deposits. So with this site I was really concerned about modeling what the environment was like for the site over a long period of time in this kind of very unstable dune situation. What we were finding at the site was a lot of ceramics. We had literally millions of ceramics that came out of two test pits. These two test pits are 2 by 2 meters and those are photogrammetry 3D models of the test pits during excavation. So what we had was the red line is one of the test pits and the blue line is the other one and this is the depth on the side which you can't read but what it's showing is that there's a lot of deflation in the site. The dunes have been, they've had blowouts and all of the ceramics have collapsed into layers that are only about 10 to 15 centimeters thick and they're essentially a ceramic pavement. It was almost nothing but ceramics coming out of there and there's no faunal material, there's no domestic material there's some fragmentary human bones in these deflated areas and portions of the site are less deflated. On the blue line, for example, there's less deflation going on in the center portion of the site and these are similar kinds of vessels that we think were being placed on this site over several thousand years. And when we look at an aerial image, this was a drone aerial image that we took, the GPR grids that I did up in this area really show that in fact these are the test units we were doing. This one is highly deflated, this one is moderately deflated. When we get into GPR grid 3, 2, 3 and 4 we can see that grid 2, it looks like there's much less deflation going on and this is an area that was recently cleared of mature forests. So we think that where the mature forest is in this quadrant of the site it's been stabilized more for a longer period of time and there's probably less deflation going on. When you look at GPR grid 3 you can see how all of those layers have been compressed. So I started recreating this environment about 10,000 years ago. This sea level is 38 meters below a modern sea level. The red circle is where the site is. In this environment I've estimated about 10 to 12 meters of Holocene sediment and I've taken it out of the model. So in pterogen I can create a displacement surface which eliminates all of that. It simulates a surface where it hasn't been deposited yet. So around 8,000 years ago the sea level is coming in. It's about 10 meters below modern sea level and as the sediments are coming in the sediments are being added with the shoreline itself or with the ocean here and it's essentially created a bay an embayment in here and possibly some islands or something. By around 7,000 years ago there's this very strong offshore wind which is creating these long linear dunes and saltation is causing the creation of dunes in the back beach areas and at this time the site is probably on this kind of knoll of sand dune. The site hasn't been created yet but it's still a couple thousand years before that. So 5,000 years ago about the same timeframe they may have started building or putting these ceremonial burial urns in the site the dunes are stabilizing vegetation is stabilized the ones in the interior the only active ones are kind of along the shoreline and it's a wetter environment vegetation is taken over and it's kind of holding the dunes down. By around 3,000 years ago it's gotten drier, vegetation is dropping off and the dunes are starting to erode so in this model the dunes that I had coming in they're now being eroded in the pterogen model and also some of the early rice fields were starting to crop up 3,000 years ago too so by about 1,000 years ago we have village development, village formation and one of the peaks of rice production so the lighter green areas are rice fields and these rice fields are actually modeled in the aerial photography by around 20 years ago the rice fields there's no longer any rice planting on the island it's pretty salted in now they stopped planting rice almost 50 years ago that was another peak production timeframe and now all of these rice fields are just abandoned kind of marshy deposits in some places but sand mining is coming in and it's starting to encroach in this area and also the villages populations are much larger on this part of the island this is an aerial image from 5 years ago so they cut a highway through here in 2011 and it's because of one of the archaeologists who stopped they got a flat tire in their car and they found some of the ceramics alongside the road that's why the site was actually identified in 2016 so today it's also a modern cemetery so it's had this continuity of 5,000 years of being used as a cemetery possibly with abandonment in between but this 3D model kind of helps us visualize the difference between what the terrain was 10,000 years ago and what it is today so the third project I was going to talk about is one where we had a grant from the National Center for Preservation Technology and Training to look at 3D modeling at the Point Rays Peninsula we finished this up last year and what we looked at was 20,000 years 18,000 years ago into the past and 2,000 years into the future and so we're focused mostly on Point Rays national seashore but also the region around it a 3D visualization looking out from Chimney Rock and I set this about 100 years ago because I didn't put the lighthouse in this one but there's about 15, 16 different plant species in the foreground and all of the vegetation layers are taken from the Park Service's GIS database so it takes that and it builds on it so we're doing this fractal interpolation so one of the things to think about in this area is unlike Australia and Vietnam we have really, really good bathymetry probably some of the best in the world in San Francisco Bay and we have bathymetric LiDAR data up to 2 to 3 miles offshore once you get farther than that you're interpolating a little bit of more coarse bathymetric data but what I was concerned about was can we identify what the Holocene sediments are and what the thicknesses of them are in this area and when we look at past attempts to model the shoreline change in California over time people are using modern bathymetry and we have to get away from that because it's not modern bathymetry we want to know it's Pleistocene bathymetry so San Francisco Bay has some really good data on the thicknesses of the Bay Mud, the Holocene Mud and soils data on the topographic areas also we have some pretty good data on thicknesses of Holocene sediments there as well I put those together and then the offshore sediments the models mostly indicate that Holocene sediments go up to about 60 meters deep or so on the continental shelf once you get off the continental shelf you get up to 500 or more meters of Holocene sediment but the first thing I did was model all of that in the GIS and then subtract it from the modern bathymetry to create what the Pleistocene bathymetry might have been like additionally I had to create a Pleistocene terrain model for the existing topography and this is the modern terrain over on the right on the left we had to model all of that cliff face erosion that's occurred since sea level pretty much stabilized around 5000 years ago or so all of that eroded shoreline had to be modeled back in so we digitized all of that estimating about how much is about a kilometer or more of sea cliff has eroded since about 7 or 8000 years ago so that was all put back into the model so we're using this Pleistocene bathymetry and Pleistocene topography for modeling different things in the point rays area one of the things we wanted to look at was connectivity and mobility so we looked at, I did a caloric model moving across this environment north to south, south to north, east to west to east from corner to corner back and forth and then add all this up and average it and you get this relative ease of travel or connectivity value for every pixel in your model so the brown areas are easy to travel across the blue areas are harder to travel across this is the Pleistocene model so the shoreline the ocean is way out here it's not on this square area and the one on the right is the modern area or the modern terrain so the shoreline or the ocean is the bluest area there where it's harder to travel across the ocean not that it's hard to row a boat but you have to expend all the energy to build the boat and the number of people are rowing it and all that as well it's easier to walk across the orange terrain so when we take that into consideration we can do things like lease cost paths and these are lease cost paths from the Petaluma River watershed to the shoreline so these are paths we would expect people during the Pleistocene or the early Holocene to have taken through this terrain and in the later Holocene these are the paths we would expect people to take and when you clip that to the modern maps of Point Reyes then you would see that if you're looking for the older sites you'd expect them to be more within the reddish the brown, orangish areas and less in the blue and the more recent sites you'd expect them to be the same over here so you have these potential components which can be added to a predictive model and used to help predict where you might encounter sites or where they might be in danger so one of the first animations we did was looking at the whole region from 18,000 years ago with a cooler, wetter climate up to 2,000 years into the future and so every frame in this animation is 100 years and you see the shoreline coming in as the shoreline comes in the Holocene sediments are added as it grows and they're only added below the actual ocean topography so it's not being added where it hasn't inundated yet and the climate is changing with the green and brown, when it's brown it's drier and these colors, again this is using like 32 or something different vegetation layers you can see San Francisco Bay building up there and it's showing the sea level depth and also the plus or minus degrees centigrade versus today and so you can see San Francisco Bay gets pretty large then there's a time period starting around 6,000 years ago where it starts getting drier and you have less sediment going into the bay or it starts getting wetter so you have more sediment going into the bay and it starts decreasing in size so when we think about the growth of San Francisco Bay it's not this linear sort of it just gets bigger and bigger until it hits modern it actually gets bigger and then it gets smaller again and then it gets bigger again depending on the kind of processes that are going on and this is the creation of the San Francisco sand dunes on the peninsula there as well so this is about when we get to the modern time frame I've got just gray coming in representing urban areas and then we have shoreline or sea level rising and when we get to about 2,000 years from now this is pretty conservative I only have an 8 meter sea level rise on this and point rays has turned into an archipelago here and that also includes erosion of the cliff line which you can't really see at that smaller scale so this is the model of San Francisco Bay just shown obliquely looking from the south towards the north so this is at 14,000 years ago you can see it's starting to get a little bit warmer the greens are getting a little bit brighter green a little bit more yellow in there by 11,000, 10,000 years ago there's the shoreline coming in and this only goes up until today so this doesn't go into the future I have another one that goes into the future though it gets bigger and then it gets smaller again and then it gets bigger again so it's only the last couple of frames where urbanization is kind of taken off so when we look at some of the future this is the point rays peninsula eroding from today until 2,000 years from now so if you're able to stand in the same place looking at this peninsula for 2,000 years this is what you're going to see and this is San Francisco Bay areas being inundated in pink as they come in so this is from today until about 400 years from now possibly so big areas are going to be gone so the thing to bear in mind with this is in Terrigin I use different erosion models and the erosion models can be very similar even over the same time frame or be very different even over the same time frame so this is looking on South Beach a point raised today with a modern topography I've taken out everything except one vegetation layer just to keep it sort of fairly consistent this is the same erosion model applied for 200 years in both situations and you have sand as being eroded or sediment as being eroded off of the uplands and into the ocean but there's two different transport mechanisms this is a weak one and that's a strong one so depending on how much shore long shore current you have moving sand away it can make a very different environment in this case you actually have the extension of beaches going out and then in that situation you have a retraction of beaches so there's still a lot of complexity involved in all of these hydrodynamic forces and the thing that's good about Terrigin is you can experiment with different techniques of visualizing this so this on the right is showing the eroded the black areas and the depositional areas which are blue to green on this 200 year erosion surface so you can see where things are actually moving more in this case I've just thrown a bunch of virtual measuring rods on that environment so you can see in any particular location where sediment is building up or where it's being subtracted so the ground level visualizations I set a camera offshore looking toward point rays the cliff face where the lighthouse is and set this one at 18,000 years ago and so you have things like blackberry in the foreground you have a variety of Douglas fir and sick of spruce and other trees that were in this area at the time with the right grasses and everything there's about 10 or 12 different plant species scattered around in this environment here's the same location at 10,000 years ago so the forest is retreating, the shoreline is moving in you're getting this open grassland here and things like stream channels eroding down to the ocean by around 7,000 years ago you have active erosion of the cliff faces here and collapse of trees into the ocean for example in the thinning of the Douglas fir forest so that it's a little bit drier by 3,000 years ago the shorelines moved back quite a bit and you start getting these larger cliff faces that we see at point rays now here's what that same view looks like today or about 100 years ago because the lighthouse is like right here and this is about 2,000 years from now so that would be a little island in that archipelago so that's just the very remnants of that big formation that we know as point rays and just for fun we also modeled around Marin County we looked at some of the population areas and modeled currently the new climate forecast models are projecting as much as 8 feet of sea level rise 600 years and a loss of 8% of the forested habitat so we did these visualizations this is Sausalito today and this is 2119 where the color code shows from red to purple 1 foot, 2 foot, 3 foot, 4 foot, 5 foot, 6 foot inundation so everything that's colored would be inundated so some of the shoreline of Sausalito would be gone not too bad there this is Corda Madera, that's going to be gone that includes the highway which goes across it so within the next 100 years we're going to have to solve that issue about how are people going to, is it going to be a bridge going across that area or what this is San Rafael a lot of industrial area is going to get completely inundated this is Terralinda so that's fairly rural in general right now this is Navado, Navado is going to be a little peninsula sticking out over there so if you have a house in Navado, or buy a house over there not down in the flat areas this is Point Ray station so currently you can look out and see the little Point Ray station and you see Tamales Bay there and the stream going into it Tamales Bay is going to be a lot larger and that stream is going to be a lot higher as well conversely when you look at Drake's Bay for example there's actually really not a whole lot of effects going on over there there's some inundation but it's mostly archaeological sites which are going to be affected there and natural habitat of course and that's Stinson Beach it's also mostly areas that are still fairly low right now that would be affected so ultimately that's a quick overview of the geospatial research and 3D modeling that I've been doing lately within the last few years and the main emphasis on this is that the Earth's surface is not static we can't use modern topography to measure this we have to build in these dynamic geomorphological models into how we can measure where terrain actually was in the past and where it's likely to be in the future those models of inundation in Marin County they're still using the modern terrain so what you have to consider is that over the next 100 years as the first foot erodes it's going to be a different terrain model for the second foot and for the third foot and the fourth so it's actually going to be kind of exponential it's not going to be as simple as I made it there so it's something that we still have to take into consideration that we can use for a lot of the modeling that we do if you have any questions you can send me an email or we still have a few minutes here before we talk about those remind people that next Wednesday we'll have Doug Bailey from San Francisco State who has a Bailey and Topic art slash archeology colon a space beyond explanation dash the ineligible project so next week anyway now I'll turn back to Tom who will entertain questions that people need to filter out filter go ahead yeah there are some of these animations available online for like showing in the classroom yeah I have a bunch of them on a YouTube channel that I have what's the name of that channel? it's just under my name search on my name you can find it and there's about 15 or 20 different animations there awesome, thank you it was very impressive and I wanted to ask you besides the Star Warsy software collecting the environmental data you talk about the geometry if you're not right on the sea just doing topography how much of this do you have to model and how much did you sort of get from modelers where did those models of the terrain come from? yeah it's mostly me modeling it and like for all of these for everything you see with the bathymetry it's fairly straightforward all the climatic information it's about 40 or 50 different references that I have to pull together all this different information wetter dryer moisture dryer plant species and I can tell you it's pretty hard it's pretty hard to find a lot of these especially when you start getting into the Vietnam data because a lot of it's in Vietnamese and I have to rely on Vietnamese colleagues to put it together or other sources luckily we did have well I'm asking you that because I'm working with a modeler from Mexico on modeling sort of central Mexico with a little bit of Florida that kind of swash to look at environments that are appropriate for certain plant species so that we can try and plot the wild taxa of capsicum and where they would be growing through time we did 20,000, 10,000 and he did then 4,000 today and I want that 8,000 in the model because that's when I think people are going to be really engaging with those plants and he just keeps saying he can't do it he doesn't have so I'm asking you where do you get these data that why can this modeler not well I'm also fudging a bit too because when you look at the vegetation models I'm using pre-existing 3D models from gaming sites or people who trade 3D models and for example the blackberry in the Point Rays one that's Himalayan blackberry that's in there but I know it's supposed to be California blackberry but you can't really tell the difference between the two in the model or if I can actually change it so I think the difference visually is on both sides of the leaf are green on California blackberry where it's a lighter color and Himalayan huckleberry I can actually go in and change those colors so I can modify an existing model to be one that I want it to be I had to do all of it and there's a point where I have to cut off and just say I'm guessing for some of this because some of it you can't really tell from the visualization so yeah Nico you mentioned that 6,000 years ago the sea level of the bay was sort of filled with the less water today yeah that may have been starting around 6,000 years ago I don't remember off the top of my head exactly where it was but around 4,000 years ago I think it was the driest it was pre-historically but implications for shell mound formation along the bay yeah maybe they were elongated or people might have pursued the water they wanted to get yeah possibly may as possible because when you're looking at the formation of the bay you also have to think about alright so where's the fresh water coming in where's the salt water coming in and where is it mixing so and where is it rocky and where is it sandy so those are going to be huge factors in determining which shellfish species are where and where those shorelines are and how fast they're moving because as they're coming in especially in the last 10,000 to 5,000 years ago shoreline is moving really fast so you get this erosion of shoreline especially in that Australia model it's very flat so you have single seasons where people might have gone to the shoreline they come back the next year they've lost more than 150 meters of shoreline in some places so in some situations it's moving so fast it's not amenable to shellfish it's the same thing with a reef building when the sea level is rising more than I think it's like an inch and a half or a centimeter and a half every 10 years or something the coral doesn't get enough sunlight to build up so the reefs aren't building so it's not until it slows down so we have to take all of that into consideration and build that into the model I know some of the reefs aren't showing up in the animations but it's something to bear in mind when we're talking about where the archaeological sites are going to be I'm curious to see in your point rays modeling forest density seemed about 5,000 years ago to 2,000 years ago how do you decide that's reading a lot of the literature saying these are the species that are there these species tend to be yeah and the density there's there's a few sources where they talk about the density of the forest during those timeframes and how it probably cleared out but it doesn't take into consideration Native American fire management systems that's that's something that we did not include in this model but we'd like to do that we're I'm writing a grant to do this same thing at the Channel Islands and also in the Mojave Mojave Desert Area recreating these environments and but at some place like point rays that fire management system is really important and I talked about it in my California prehistory class but it's not included in this model but it's something that you can include because you can you can have variations and say this is the density I want for this animation and this is the density I want for this one and see how they're different I just ran it that one way Have you ever played with vegetation feedbacks to erosion or moisture dynamics that would be really complicated but it seems that you're very well set up to explore that yeah that's something in Terrigin I have an erosion model that I can play with a lot of parameters but feedback from vegetation is not one of them so it's a little bit too simplistic and there's other ways you can add in displacements or things like that that may reflect that but it's something that I don't really have enough background in to be able to do it but it's something that would be really useful for people who do want to model that that's it okay okay well let's thank you