PubTalk-04/2023: Gravity Never Sleeps - Landslide Science and Risk Reduction

hello and thank you for joining us tonight's USGS public lecture we are happy that you've taken an interest in USGS science my name is Mitch and I will be your host and moderator tonight I have some quick announcements to make before I introduce our speaker next month's public lecture will be on May 25th at 6 PM Pacific time when the USGS water data theme we'll talk about USGS water data and how you can utilize this great resource if you are watching this from a desktop computer you need to turn on closed captioning please look at the bottom right hand corner of the screen for the closed captioning icon it's the one with the two little C's you can also use the stream text captioning please see the stream text link provided in the question and answer window to access that question and answer panel you can click on the question mark icon in the upper right hand corner of the screen at the end of the lecture we will have a q a session and this panel is where you can submit your questions to our speaker and now it's time to introduce you to tonight's speaker joining us tonight is Dr Jonathan Gott en Jonathan is a USGS excuse me U.S geological surveys program coordinator for Landslide hazards and has been with the USGS since graduate school in the mid-1990s prior to taking over the coordinator's position he was a research scientist focused on understanding controls on Landslide initiation he has led teams responding to Landslide disasters both domestically and abroad and those experiences have helped shape his perspective on the role of Science in serving the public good so without further Ado I'm going to pass this over to Jonathan thank you very much Mitch and thanks to everyone for joining this evening I'm going to share my screen with you all let's see if I can make this work great Mitch Amelia does that look okay looks good great thank you so I I really appreciate the opportunity to speak with everyone this evening and um as Mitch said I'm going to talk a little bit about the the landslide hazards program and the work we do at the USGS to reduce the loss losses and risk from landslides and so I've got a kind of a catchy title there gravity never sleeps uh Landslide science and risk reduction hey and so just to begin um to talk a bit a little bit about the kinds of landslides so the pull of gravity on earth materials creates landslides that move in many different ways and there's a schematic diagram there of different types of landslides and they're characterized in the USGS system by the materials that are involved and so a rock fall is the rock that falls so it's the material that's involved and the style that it moves we're going to talk about a few of these in particular because they create uh damage and risk to things we care about so people infrastructure and and other things there are also a range of environmental factors that influence the timing and the size and speed of a landslides in have just got a collection of photographs from around the country highlighting some rainfall induced landslides in the Colorado Front Range and then North Carolina some earthquake induced or a photograph of an earthquake-induced landslide in Northridge California back in 1994 and then a picture of rockfall from Yosemite National Park in 2008 and USGS science has been particularly um useful in understanding the role of of heat thermal stress on rockfall activity we'll talk a little bit more about that here in a moment of course the volcanoes can generate some of the biggest landslides in the world and there's a Lahar that kind of black area in front of Mount St Helens um not when interrupted in 1980 the big eruption but a smaller up into 1983 that kicked out lahars down to the base of the volcano and then we'll focus a little bit more on the talk about um the role of wildfire on debris flows in particular and debris flows are these fast-moving landslides with kind of the consistency of wet concrete and because they can travel fast and far are potentially destructive and the USGS spends it quite a lot of its effort understanding the processes that drive those um I'm going to show this little animation from colleagues at the University of Puerto Rico mayaguez and it's um just a really nice illustration of the different factors that contribute to analyzing including human activity and so that's a great illustration from our colleagues uh at the University of Puerto Rico Mike was and we'll talk a little bit more about um about hurricane Maria and the devastation that it brought through landslides to Puerto Rico but first I want to focus on some of the science that we do at the USGS and we're really conducting um those activities to understand sort of four key questions about landslides and they're all relevant to the hazard and risks that are associated with them so where are landslides likely to occur in the landscape when or under what conditions will they occur in this illustration here or in the middle there's talking about rainfall how big will landslides be how big they are controls how destructive they are in many ways and then how far and how fast they'll travel and so the USGS uses a variety of methods and uh techniques to collect data and conduct studies test hypotheses to close the science gaps to better understand landslides and remote sensing has become an increasingly useful and important tool particularly interferometric synthetic aperture radar and we'll talk a little bit more about that when we come to some discussion on landslides in Alaska obviously mapping of all kinds whether that's field based or from imagery or otherwise has a long history in geology of course and is important to understand where the landsides have occurred in the past what they've impacted and what the geologic and other controls on them we do quite a bit of field monitoring mainly for research purposes so this is monitoring the hydrologic and movement and other conditions um to record that along with Landslide motion can give us a Clues and insight into what controls Landslide initiation and travel in laboratory studies are of course important and the understanding the properties and strengths of materials that are involved in landslides is critical to providing constraints and input data to models whether those are models simulating Landslide initiation Landslide travel or Landslide deposition and so the Landslide hazards program is one of the smaller science programs in the USGS but it received sort of increasing intention in the last several years and importantly in very early 2021 the national Landslide preparedness Act was passed and so that authorizes the department of the interior and the USGS to do a whole variety of things with regards to Landslide and loss reduction and one of those was the delivery of a new National strategy for Landslide loss reduction and that came out in 22 and the graphic on the right sort of describes the overall objective of that strategic plan and it's to assess and coordinate excuse me to assess Landslide hazards and risks coordinate with a wide variety of stakeholders and other users to apply that understanding work with communities to plan for potential for Landslide hazards and then provide the scientists and expertise to respond to Landslide disasters that can affect communities and resources in multiple ways and that graphic at the top it depicts some of the things that landslides can impact so for the balance of this talk we're going to break it out into basically this little graphic here and I'm going to talk about each of the aspects of landslide research technology development and monitoring to create better understanding of past line side activity how that better understanding of land past Landslide activity can be used for long term and medium-term Hazard assessments and outlooks and how short-term Landslide surveillance can provide the information primarily to Partners at the National Weather Service to provide alerts for Landslide events and then once a landslide happens and particularly if there is um human impact the things we care about um we I want to talk about a an instance where the USGS provided technical assistance to Emergency Management folks um responding to a rather tragic Landslide disaster so on the mapping side liadar technology has really revolutionized Landslide mapping and these two images courtesy of Partners at the Washington State Geological Survey is just a fabulous illustration of that so the image on the left hand side is a typical aerial photograph in taken in western Washington along the Cedar River and the thing that stands out there is you can see some roads that Traverse that image and and then River Valley as well that's sort of a break in the trees but beyond that there's some subtle topographic features there that are that are visible but it's nothing like but you can see if you can use the lidar data to strip away the vegetation and beneath that we see evidence of five or six large landslides that have occurred off that escarpment which is a glacial Terrace and have traveled quite far across the valley and so blight art data is really changed the way geologists and others can map landslides and understand where they have occurred in the landscape in the past and so just a little bit about high resolution lidar and Light Art topography it's um a lot of that data collection is done by the USGS 3D elevation program in partnership with a broad range of federal state and other stakeholders that map on the right hand side shows the current status in the United States of lidar data collection and you can see that there are a few non a few gaps there that aren't green and so high resolution topography Across the Nation is pretty close to becoming a reality that is going to enable a some national scale Landslide hazard assessment and other activities that'll be coming in the future and the image on the left hand side is just what do we say lidar data well what is it um it's usually collected with an Airborne platform with a laser scanner that measures the distance and because it measures the distance in many many places on the surface of the Earth it can and that's since penetrate the vegetation and give us those sort of remarkable pictures of the of the bare Earth landscape so that little animation mentioned the 70 000 landslides that were triggered by Hurricane Maria in Puerto Rico in 2017 and the image there on the left is a density map showing those Landslide locations and so the hot colors in the mountainous central part of the island um have had as many as 200 landslides per square kilometer and that was distributed those high intensity landslides are distributed across the central mountainous part of the island and the image on the right hand side is just an example of some of the landslides that were triggered by Hurricane Maria and you can see that the the landscape has almost denuded in places so almost all the vegetation was stripped off so Not only was the island devastated by the winds from Hurricane Maria and the flooding associated with that in the mountainous central part of the island landslides were a big issue and by blocking roads cutting people off from access to basic necessities and damaging the power grid foreign lifelines so the usgis in partnership with the University of Puerto Rico and um other academic folks will use those 70 000 map Landslide locations to create a landslide susceptibility map for the island and that's shown here in this this image with the extremely high Landslide susceptibility category in those Purple colors and very high in the red and high in the orange this is a um a quantitative assessment of the of a landslide Hazard across the island and it's useful for the planning for new infrastructure and for housing and other planning and emergency response activities this type of susceptibility map um is most useful really in its form in its digital form and so there is a web-based map viewer that is available publicly that looks something like this um you can go to the web-based map viewer and zoom in to um neighborhood scales and that's shown in the image blown up there and so the white areas that in that map are um buildings and other infrastructure and the colors there to pick the landslide hazard in the mountains and so this provides a tool that planning entities infrastructure managers emergency managers can use to anticipate and plan for the next hurricane like Maria which is hopefully some long time away the USGS is also working with University of Puerto Rico miguez to monitor the rainfall and hydrologic conditions that generate landslides and so over the last few years we've worked with uprm to establish this network of monitoring and this just shows the locations scattered around the island each of those sites provides information on the current conditions that's telemeter to some web pages and and displayed on some web pages and can be used by lots of in the general public but importantly the National Weather Service so the National Weather Service in San Juan is has these data available to them and so when heavy rainfall is predicted and they can use they use this to include Landslide information in their alerts and warnings and this is uh one of our colleagues here Stephen Hughes doing some maintenance on one of the stations in the mountains of Puerto Rico and on the left hand side is just some of the data that come from those stations the graph on the upper part there is a rainfall Trace so well last week they had about five millimeters of rain which has been quite welcome because when they've been in a drought for some time and then the graphs on the lower part show the the groundwater response and the soil moisture response to that rainfall and we are working to collect these data to identify the conditions both soy moisture and rainfall that are conducive to Landslide activity so a big part of the effort has been to collect the scientific data and conduct the studies to better understand the controls on Landslide Hazard and risk but that information is of little value if it's not available to the people who need it the most and so there was been a Cooperative effort with University of Puerto Rico Mike was the natural Hazard Center at the University of Colorado and the USGS to take this information and bring it to to the communities and so that involves you know Community engagement with Community leaders emergency managers planners and Etc um it has involved a media campaign so the upper right hand image there is a screen capture from WAPA TV where Stephen Hughes um was speaking with ottoman Zone on the right hand side who is a TV meteorologist and a great supporter of scientific education and then we've worked with a bro with quite a number of students um to develop teaching materials the the animation you saw there and other information products that make this available to a variety of of people in the communities down at the K-12 level and all the way up through the graduate level and so really bringing those materials to the to the educational system so that's the Puerto Rico Story and sort of rainfall induced landslides on this and with the main product that we're talking about there being the longer term hazard assessment I'm going to switch gears now to talk about some work in Yosemite National Park where the USGS has been working with the park service to manage some of the risk from rockfall in the valley and so that's uh the image there is from El Capitan in in in September of 2017 where rockfall occurred and that's that sort of dust cloud and that and that scar area there and let me see if I can get my so this is a rockfall that was initiated here and it created this dust cloud here um the the park has quite a lot of issue with rockfall both from a hazard to recreationists so climbers and others as well as threats to infrastructure and this is just a tweet from uh from the park service notifying uh folks that the road was closed back around Christmas time in 2022 from a rock fall so the USGS has been working with the geologists in the in Yosemite National Parks for a number of years and both to understand the controls on rockfall from these big Granite faces and so what are the the meter logical and other conditions that that are associated with those rock wall occurrences and that involves some rather exciting field work um this is Greg stock the park geologist and Brian Collins one of the USGS geologists perched on a on a rock face um near El Capitan and they were installing these instruments here which are basically crack meters they measure the aperture of the of the crack and the flake and you can see that they had they have several installed here and and as well as the the movement of the rock but also the environmental conditions and the the main takeaway from some of their work is that the thermal stress the the in essence the sun incident angle and the temperature really have a a strong influence on the timing and size of rockfall occurrence and and that's just uh just a kind of an example of some of the work that um USGS has been doing to understand the controls on land side occurrence so as a part of this work uh one effort was the identification of a law or the identification and location of rockfall activity in the park over a quite long historical period so being a national park there's been a natural history observations and geologic observations there for a very long time and by collecting these information and identifying the time and size of various rock falls over the years and then combining that information with simulations of rockfall activity which is shown here in this image on the right hand side the USGS and the Park Service who were able to develop a probabilistic hazard assessment for some of the park infrastructure and so this set of images here just gives us a little bit about that risk assessment so in 2014 um the risk assessment was published and what it did was identify and the information was provided to the parks and reforms provided a probabilistic assessment so over a period of time there was a X percentage or X likelihood of a rockfall impacting a given location and so on the right hand side is a series of images from Curry Village and then the upper left so figure a shows a cabin that was smashed by a rock um and figure B shows another one of these fresh Boulders that came down the Park Service knew that they had an issue with um with the hazard there in Curry Village and so they removed cabins um from the area and that image there at the bottom shows the location of a rock that fell in the footprint of a cabin that was removed um had that occurred when people were there the consequences might have been tragic and so this is just an example of the science being used to make planning and management decisions land use management decisions in this case to reduce Landslide risk and loss so now just to talk a little bit more about a shorter term hazard assessment I'm focusing on the effects of wildfire on Landslide occurrence and so the effects of wildfiring communities and infrastructure don't end when the fire is out and that image on the right hand side shows a home that is nearly buried by a debris flow deposit so debris flows being these fast-moving landslides that can travel far and potentially destructive and this is an example of that wildfire has a um an unusual effect on the properties of soil and the erodability and so not only does Wildfire obviously remove all the vegetation or can remove all the vegetation is particularly severe but it also frees up loose material at the surface so creating more erosion and more loose material that can be mobilized in a debris flow and particularly if the fire is very hot and the soil is very hot the ability for water to penetrate the soil is greatly reduced so runoff is much much higher and that image on the right hand side is illustrative of that you can see it's sort of a moonscape where all the vegetation has been removed the loose soil on the surface that has been reeled or eroded away by moderate rainfall and that can when the rainfall is even moderately heavy can create the those destructive debris flows so the USGS produces debris flow Hazard assessments for major wildfires Across the Western United States to answer those questions we were opposed before so where which drainages are most susceptible to post-fired debris flows when so how much rain is it going to take and then how big might the reflows b as they exit the Basin and then we're working towards understanding health bar and and how fast the debris flows or travel which is important for the risk assessment aspects and but that's a that's not something that USGS currently delivers routinely um yet it's still a research product that's at work but the data collection to understand that is ongoing and this is some images from um Montecito California in 2018 which we'll touch on here just in a little more detail and so part of the work is conducted in in sort of extreme environments and so this post event data collection of perishable information that is going to be lost because people need to get their lives back together and clean things up we work we have teams that go out with um Partners typically in state geological surveys to collect that perishable information on the distribution of of Boulders and debris flow deposits and make measurements on the distribution of momentum and this information is important to inform um the various huddles and tools and then as well in the post fire environment the again the monitoring and study to understand the hydrologic control and the initiation of landslides and debris flows is important and this is just some some field measurements that are being made by geologists there in the middle and then an example of one of the monitoring stations to collect information on rainfall soil and moisture conditions and then using video to identify when a debris flow goes past the key takeaway in that graph that's shown on the right hand side is that in burned environments debris flows can be initiated at the very beginning of of a storm with just some high intensity rainfall and that's key to the to the forecasting and other aspects we'll talk about here in a moment so I mentioned that the USGS delivers the post-fired debris flow Hazard assessments and those again are available through a web mapping application and and the image on the left hand side is a screen capture of that web application and on the right hand side is sort of a a prettied up version of one of the hazard assessments where the hot colors the red basins are those that have a high likelihood of debris flow generation for a given design storm in this case it's a 15-minute rainfall intensity of 24 millimeters an hour and this is a this is an example from the Grizzly Creek burn area in central Colorado these are used by um Land Management agencies I mentioned the National Weather Service earlier and others to make decisions about risk management and so this is just a summary figure of what the USGS has done over the last decade or so we've delivered 407 uh assessments or assessments for 407 wildfires that cover about 20 million acres for 63 national forests and 13 different states and 10 national parks um the graph on the right hand side showing burned Acres versus assessed and so there's a trend there of an increasing burned area footprint Across the Western United States and a consequent increase in the acreage that the USGS has assessed part of the increase in the assessed area where the USGS is delivered Hazard assessments is due to a shift from the way we used to produce the hazard assessment as sort of paper reports to that web-based interface which has allowed us to be much more efficient and deliver those Assessments in a timely manner and like the work in Puerto Rico key to this is the communication with communication of the understanding the people who need to know and so this is just an example in Spanish and English of Hazard tips to keep you safe so what to do if you live near a burned area and who to pay attention to and so the key one being to listen for warning signs and pay attention to your local weather service office if they provide flash flood warnings that have debris flow information which look like this next slide here so this is an example of a National Weather Service flood product for um Sierra Foothills so from the um Dixie and North complex fires and so the Weather Service uses those Hazard assessments to compare against forecasted and observed rainfall and then use that to issue alerts watches and warnings for debris flow occurrence this part of their flash flood products and there's the the Box the red box there be prepared to evacuate if told by local officials so the weather service because it has weather forecast offices distributed around the country have very close connections with their local emergency management officials and are the most efficient way for us to get that information to the folks that need it and so I'll just step through um a little bit of how this works with the weather services and using the Thomas fire in Southern California as an example so the Thomas fire started in December 4th in 2017 and then by December 17th it had progressed to the community of Montecito and Montecito is uh is a affluent community in Santa Barbara County and the home to Oprah Winfrey there's a rather famous YouTube video or maybe it's an Instagram post of Oprah Winfrey standing in a debris flow deposit so January 2nd um the USGS released its first hazard assessment for the Thomas fire indicating that indeed the area above Santa Barbara and Carpenteria and in Montecito in particular where there's a very high potential of debris flow occurrence because this is winter season in California the fire was in essence put out by the first storm of the year and so on January 5th the National Weather Service releases a impact assessment or a potential for debris and mud flow and they're they're calling it a significant potential and this is several days before the storm on January 5th on January 8th um a few hours before the storm hits this hits the coast um The Weather Service raises their alert to the highest level to that to what they call Extreme and that prompts the largest evacuation in Santa Barbara County History at that time and then on January 9th about at 2 30 a.m um The Weather Service issues a warning and a few hours later there were debris flows that impacted Montecito and other communities there that's just an illustration of of how this coordination with the Weather Service works so I'm going to jump to a completely different environment now and in sort of a different climatic control so in mountainous Coastal Alaska and in Prince William sound in particular retreating glaciers are leaving uh steep Rock slopes above new water so above new fjords as the glaciers Retreat and in May of 2020 a group of academic scientists who had been assessing um topographic information collected from satellites identified a very large unstable slope at the toe of the berry Glacier near Whittier Alaska and so that map on the right hand upper right hand side shows the location of Whittier and the and the Very arm Landslide and the concern was that if the landslide were to fail rapidly into the water that it would create a devastating tsunami throughout Prince William sound Landslide generated tsunami are some of the most destructive and some of the highest our largest tsunami in recorded in the world and up to several hundred meters in height and so the concern was quite large and so the USGS was asked to understand better understand the risk and develop a in essence a system to provide information again to the Weather Service who has responsibility for tsunami warning as well on what the potential of what this hazard could be and so this is a an oblique aerial image of of the berry arm slide and to just sort of outline here with the laser pointer the unstable slope and this is the berry Glacier here in the Cascade Cascade Glacier coming down here so this is a an extreme and spectacular landscape um and that is a very large Landslide and just another perspective so this is looking down the berry Glacier into the berry arms yard Landslide a is the one I just outlined there with the laser pointer there's also other unstable slopes in the area but this just gives you a sense of the scale and the size and I'm going to show one more image just to again to illustrate that so this is the berry arm Fjord and this is new water so the ice you know not so long ago was down well down the Fjord and this is the unstable slope and you can see the head scarp sort of traced here the head scarf being the upper part where the landslide was pulled away and again the concern there is could this move catastrophically and create a create a very large wave so if we go back to the timing of this so this was spring of 2020 that this was identified by this group of academic scientists and obviously um that was very the very beginning of the global pandemic and so field work and other activities were constrained and difficult to do so the USGS was very fortunate to have um a couple Young post-doctoral Scholars working with us who are Adept in the use of satellite radar interferometry to Monitor and detect Landslide motion and so that remote sensing activities were you know relatively easy to conduct from a distance and and with from the safety of their basements and this is an example of of those results and so what's shown on the left hand side is just the outline of the landslide in an aerial image in the glacier there and then the the middle image in the right image are interferometric interferograms of landslide motion and so I won't go into the details but basically what this can detect is is centimeter scale movement of particularly large Rock slopes and each of those fringes so from one ink color to the other pink color is um is a finite amount of motion and what that does is show that the landslide is indeed moving um in between the acquisition times of those radar images and this was key to helping inform the communities as well as the landowner which is the National Forest Service here and the Coast Guard about the potential for any rapid and catastrophic landside motion so starting in the fall of excuse me starting in the summer of 21 the USGS and its Partners at the Alaska division of geological and geophysical surveys um as well as the Alaska earthquake Center set out on a campaign to install a wide variety of meteorological seismic infrasound and other uh instrumentation throughout the area and this is just some example of the instrumentation and sort of the field work and the locations which are all quite extreme and difficult to access most of this work was done by helicopter and to provide data streams to understand what might control the motion of the landslide the very armland side another effort parallel effort was both to map the landslide act or excuse me the active parts of the landslide and to map the bathymetry the new water that the that below the receding Glacier and so that was done in cooperation with NOAA who has the mission to map the bathymetry with the USGS mapping of the landslide in both the primary objective of the landslide mapping was to identify the size and potential of the moving slopes and so landslides of this size aren't typically a single Rock unit there are multiple pieces that can move independently and that's what the map on the left-hand side is showing the middle map there is the new bathymetric data um in very arm Fjord and on the right hand side are some images of folks doing the rock Mass quality measurements for the mapping part of it and then our colleagues in boats and Noah doing the bathymetric mapping so the result all that information um primarily the mapping information and the and the understanding of the landside motion from the satellite imagery was combined in a a combined Landslide and tsunami model and this was really to provide some constraint on what would be the wave heights in Prince William sound and and importantly what would be the wave heights that arrived in the community of Whittier this map here shows the landslide area here this is the the glacier here this is the new bathymetric information here and listen to the location of Whittier this is with this work was done by Katie Barnhart and others using a USGS model called declaw to that can com that can simulate both Landslide motion and the displacement wave and the series of images on the right is showing the timing the solid fraction of the landslide material and the wave direction importantly um on the lower sets of panels the they come from this really is in an inundation assessment from the community of Whittier so here's the map of state of Alaska and the location of the community of Whittier this is the broad map here with the airport located here in the Whittier Harbor here and the concern was that a wave generated by the landslide would you know over top the infrastructure there and cause quite a lot of damage by doing the work to identify the landslide volume which is about 690 cubic 690 million cubic meters um that if that Landslide were to fail and the simulations show that the wave height you know right there in Barry arm Fjord would be catastrophic they'd be 200 meters high in places for the waves to travel to the community of Whittier it would take about 26 minutes but when they reached the community of Whittier they would only be a meter and a half or two meters high and that was much less than the assessments initially provided by the group of academic scientists so while it still would be a damaging wave in the community of Whittier it's something that can be managed and planned for rather than a catastrophic wave or the the expectation of a catastrophic wave that there really would be very little you could do so that science and information um to again Aid emergency planners and Emergency Management officials and and importantly again communicating that information to the folks that need it so the general public people who recreate in the area and Marine interest importantly and the other communities in Prince William sound and so we work with again the federal partners to make that information available through the forest service that's a forest service web page on the left hand side on the right hand side is a Alaska division a geological and geophysical web page where monthly status updates are provided and then we're in close coordination with the national tsunami warning center in Palmer Alaska to provide them information if there is any change in the landslide motion which there was this past summer and fall on the landslide moved quite a lot so tens of meters in places um and the concern again was would would there be a catastrophic landside failure unfortunately there has not yet been one finally the final example I want to talk about is um after a landslide occurs and so so sort of if when avoidance isn't an option the main effective risk reduction activity that or action that can be taken in a landslide setting is to not be there um but there are times when when that's not possible and so I want to talk a little bit about the technical assistance we provided to um the search rescue and Recovery operation in Oso Washington in March in April 2014. this image is is the an image of the Oso landslide and and down here by the north Florida because it's still aquamic River there was a community of steelhead Haven um 43 people were killed in in the landslide that happened on a sunny Saturday morning and after that there was a week-long effort that started out as search and recovery and then went to a excuse me search and rescue and then switched to a search and Recovery operation to identify the remains of those 43 people um there were hundreds of workers in the Landslide debris field potentially In Harm's Way for weeks during daylight hours and so these are two photographs showing that search operation and on the right hand side is a lidar image of the landslide deposit and this sort of management logo line and so the USGS was able to provide technical assistance to both about where the where the search operations would be most efficient so there was initial effort to search where the homes were the USGS was able to bring some information and expertise available to say that the homes and that their contents were not likely to be where they were but would be pushed to the outer edges of the landslide so make their operations more efficient and then we also conducted um and deployed some temporary monitoring instrumentation to again try to identify the conditions when Landslide motion might be catastrophic and might reach that search operation and so on the left hand side that's an image of a of a spider which is which is a helicopter Deployable instrument package that contains a global positioning system and a geophone that can measure vibration so motion and vibration this is designed for deployment on volcanic active volcanoes and so is well suited for the situation and landslides we also provided a technical team that was on site to to help advise the the search operations who mostly didn't have any experience with with landslides prior to this and then the sort of graph Trace along the bottom is uh what's our Sam which is just a measure of of um seismic noise in essence and it mostly tracks the the excavation operations but you can see the the periods of quiet that are throughout there and that was one of the tools that was useful in assessing what's happening throughout the landslide so in a in a short period of time um working with the state of the geologists from Washington stage Snohomish County and the Washington Department of Transportation um we were able to set up a temporary monitoring system that provided information really to to reduce that short-term risk to the to the search and Recovery operation and this is a map just showing the distribution of the various instruments and other things that were deployed on or near the landslide with again with the idea to identify incipient or active Landslide motion that could travel far enough to reach the search operations which were mostly on the other side of the stilaquamish river and then the graphs there just um some of the information that was provided in a kind of a dashboard setting to the on-site geologist team and then with Direct Communications the Emergency Management folks so with that I'm going to conclude and kind of leave you all again kind of just to summarize that I talked about a number of of USGS activities that lead to these various tools whether those be inventories of past Landslide activity and how that can be used to provide these longer term Hazard assessments and in the case of Yosemite how those Hazard assessments can really be used to support risk-based decision making whether that be by infrastructure managers or other and then you know some the other two examples on this short term surveillance side so how do we work with again land and emergency managers and local communities to provide information about ongoing or potential Landslide activity and I think that the situation in Berry arm is really much this short-term surveillance and which is really based on availability of real-time data and then once a landslide occurs that the USGS does play a role or has played a role in these post-disaster technical assistance so so whether that's advising um search search operations or whether that's advising the uh the emergency managers on risk decision making post fire and with that I will conclude and turn it back over to you Mitch for any questions thank you Jonathan that was great um before we begin with the Q a portion of our lecture uh friendly reminder if you would like to submit a question click on the question mark icon and submit your question we have been monitoring questions that have come in so far and I will go ahead and ask those out loud first we will do our very best to get to all of your questions and first question is from a person who wants to know how are you able to recognize capture the 70 000 plus landslides associated with hurricane Maria were they reported by citizens that is an excellent question and I should have mentioned so most of that mapping of those 70 000 landslides was done from aerial imagery that was acquired by Noah and FEMA right after the hurricane and the and that was done with human interpretation so in this case um mostly done by geology students at the University of Puerto Rico mayaguez who um didn't have school because they didn't the school was closed or the campus was closed for quite a long time after the hurricane and Stephen Hughes our colleague there had enlisted some of his students help on the campus did have light and air conditioning and internet connection and so they did a lot of that work in in sort of right after the after the event mapping from aerial imagery okay thank you um this question comes from uh dick it's a little bit of a different type of question um he's talking about the mining industry produces massive amounts of waste materials generally known as tailings these tailings are then stored in tailing dams it could be more than 300 feet high does the USGS have a program that can calculate the probabilities of a tailing Dam collapse oh that's an excellent question um and I will just say that most uh so in the the short answer is no the usds landslide hazards program does not focus specifically on the tailings issue in part because my understanding at least is those facilities are typically regulated either depending on where they're located by the state or by the by the federal or entities and so we don't typically get involved in those regulatory decisions that being said I know that there is an initiative at the USGS to in essence inventory the existing mine waste primarily for the potential for reprocessing for critical minerals um but I can imagine that that inventory will be useful also to address that type of risk right okay thank you um another question wants to know how how do you determine which slides to study oh I am I really like this question um so I mentioned at the outset I think that the usgs's landslide has this program is one of the smaller programs in the USGS and as such we don't have a national footprint so to speak and so the only um hazard assessment that's done in a in a nationally consistent way is really the post-fired Reflow work and so that is done at the request of state or federal Land Management so Emergency Management folks to produce those assessments so that is that's done in a consistent National way the rest of it's not and so most of the studies are opportunistic in that these are landslides that have either a long history of study so we have some so-called natural Laboratories where where we've done work over over decades or they are brought to our attention because something happens and and that's more often the case is that there is an issue where either it's it's often on public lands um where the the landowner the Emergency Management officials identify they have a problem and and often it's it's after the fact unfortunately so that that's a great question I think going forward one of the things we've outlined in the National strategy is how do we begin um assessing that risk on a more systematic and in essence Equitable way great question yeah um from Wendy wants to know why do wildfires reduce soil permeability well there are some competing theories there um the kind of phenomenological explanation is that the that heat changes the soil properties such that they become hydrophobic in essence the water can't absorb in and that can occur through the volatilization of uh organic material in the soil so that becomes volatilized and then coats the soil particles with a like a waxy coating um the other certainly possible approach is that when soil becomes the heat can in essence reduce the soil moisture to zero and if the soil moisture is reduced to zero and particularly if it persists for a very long time the ability of water to penetrate it it just can't go in the in essence the hydraulic conductivity is so low that the water can't flow through it the those are sort of at the grain scale and almost again the phenomenological skin so what goes on on the broad landscape to create those conditions is is hard to study in and is still kind of an open question um at least to my understanding I will just say that all the work I presented um none of that's mine let's all worked by our team so I'm a scientific manager so it's entirely possible I'm not um up to date on the latest and latest understanding particularly on the soil physics front okay um I won't uh Kent wants to know why is the area in Western Oregon so sparse and lidar data oh is it weather related that's an excellent question and I think can't that that map shows where USGS 3D elevation program lidar have been collected I think there may be other data that are available through entities like open topography that cover some of that but that's a great question and I'd have to uh I'd have to query our 3D elevation program colleagues to get an exact answer might also be Forest Service data too but that's entirely possible although we have gotten better at collecting uh uh land or data over public lands right um from Jeff it seems that most of the work mentioned is Continental where the future looks like a great portion of the future hazards is from Coastal erosion oh excellent question yet so I didn't highlight any of the work on Coastal erosion then the landside hazard program has done some the USGS also has a coastal and Marine hazards and resources program who has done quite a lot of work on the changing Coastline um and they have both on the monitoring side so in essence repeat uh lidar and aerial image surveys of the coastline along the western United States and then they operate a series of coastal erosion models in concert with the National Weather Service the forecast in essence geomorphic change and so um I focus this talk on on the in essence the landslide Hazard stuff that's as you mentioned Continental but there is lots of effort on the coastline that I didn't touch on today okay um another question is what are some risk reduction in mitigation best practices for addressing landslides well in that little animation it showed some of them avoiding building on steep slopes managing drainage um enlist you know following the grading ordinances that are in place in in many municipalities that allow or provide you know instruction on steep slopes so there are a variety of activities that can be undertaken a lot of that falls into the responsibility of of local land use planning and so where we the USGS try to interface is to make sure that those entities have access to the science and mapping and information to to build out those plans appropriately okay okay another question is what instruments do you use in Landslide field investigations for data collection oh and that has evolved tremendously um so you know the back when I was in graduate school a theodolite and nascent GPS and those kinds of instruments were were useful and feel the investigations and now the terrestrial laser scanner so in essence terrestrial lidar is extremely useful we have made an investment recently in some terrestrial radar instrumentation so this is akin to the you know the ability of satellites to measure these fine scale deformations um that that technology is available in a in a terrestrial unit and those are um really found applicability in the high wall mine industry so monitoring High rock walls and we have found that those are extraordinarily valuable for monitoring big rock slopes like that in very arms so the Technologies constantly changing um and the the availability of you know tablets and smartphones and and things like that is really Advanced our ability to collect high resolution and High Fidelity data rapidly okay um like another one from Jeff it seems like the work you describe is observational and predictive do you do any work on quantification of what you would would take to manage and or control or prevent landslides oh that's a great question and you're correct yeah most of it is on the um understanding process in essence the on the prevention side a lot of that really falls to the private sector so there's a you know a massive private sector in the civil engineering realm that has a developed a wide variety of techniques and approaches to the mitigating Landslide occurrence particularly in the Civil Works Arena um and so we don't compete with the private sector in that way and but where we are going is um better understanding where landside risk and that comes back to sort of the question before is like which landslides do we pick the study um in the next several years we expect to have a a national scale I'll call it Landslide risk assessment which probably more like Risk identification so which communities across the country are um most threatened or most in essence most vulnerable and we know sort of anecdotally that that Rural and isolated communities are particularly affected and so it's not just the you know the risk associated with a landslide hitting your home but it's the risk associated with the landslide cutting off your access to basic goods and services or a landslide impeding your ability to get to a hospital things like that and so understanding those connections and that in essence landscape is is where I think the USGS and and play a role and will be doing so in the near term okay and another one that's uh thank you this has been way more informative and entertaining than the NFL draft wow okay I appreciate that that that's pretty good right that's pretty good um I have one from uh then we who's a PhD student from Shanghai South Hong University he says thank you for the Fantastic lecture try GRS is a well-known Landslide analysis software I noticed that there was an update to the software in 2022 but are there any plans to update the manual um I would say that one's best answered if you send me an email and I can do a little research and find out for you my contact information is on that last slide actually yep it's right there on the last slide send me an email I'll uh I'll follow up happy to do so okay um how does the USGS let cities know about the lidar mapping or slides to help with land use decisions so that's a great question and the 3D elevation program has um state level Liaisons who coordinate with organizations in this state and a lot of that is for infrastructure a lot of that works for infrastructure planning the lidar data collection isn't really landslides are just sort of a secondary a secondary use most of that those data are most used for infrastructure planning so cities and other municipalities are likely aware that they exist if they're not um you know we can happy to happy to do so most of our connections to the community level to the municipal level are through the state Geological Survey so so our most of our local interactions work through them we the again the landslide program is quite small and so we don't have staff um in every state by any means and so it's most efficient for the information to reach through our through our state partners and last question um in Brazil we have lots of problems with landslides and reflows especially in the last few years does the USGS have any any interest in studying this kind of problem in other countries like Brazil that's an excellent question and so the USGS partners with the Bureau for humanitarian assistance so that's part of the U.S agency for International Development for both research activities and capacity building in um outside the U.S I don't know of anything immediately immediate work with Brazil although the landslide hazards program has worked with academic Partners in Brazil in the past and so um the short answer is yes we do work abroad um the the long answer is with specifically with Brazil I don't I'm not aware of anything at the moment okay that is our last question so thank you again for your talk tonight Jonathan and for answering all those questions from our audience sure also I want to thank all of you for joining us tonight um this lecture will be available for on-demand viewing in about a week on our website at www.usgs.gov Els

you can also see many of our previous recordings on the website under the multimedia section for videos uh I know there is a we did a we have a have a lecture on post fire debris flows and another one on Yosemite rockfall so you can search The Archives and find those um if you would like to subscribe to be part of our monthly mailing list feel free to send us an email at WMC esic at usgs.gov and we will be happy to add you to the list next month's public lecture will be on Thursday May 25th at 6 PM when the USGS water team will talk about USGS water data and how you can utilize this great resource hope to see you then goodbye

2023-05-04 21:01

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