EIIP Virtual Forum Presentation – February 18, 2004
LANDSLIDES
The Natural Hazards Sleeper
Lynn M. Highland
Coordinator, National Landslide Information Center (NLIC)
United States Geological Survey
Avagene Moore, CEM
Moderator, EIIP Coordinator
The following version of the transcript has been edited for easier reading and comprehension. A raw, unedited transcript is available from our archives. See our home page at http://www.emforum.org
[Welcome / Introduction]
Avagene Moore: Welcome to the EIIP Virtual Forum! Amy Sebring, my partner/associate, and I are delighted to see you in our audience today.
Our topic today is "Landslides - The Natural Hazards Sleeper." This is a timely topic in light of recent news about devastating landslides and related problems in southwestern Pennsylvania, Washington state and California. We hope you will find this a most informative discussion.
Now, it is my pleasure to introduce our guest speaker for today's discussion. Lynn M. Highland has been with U. S. Geological Survey since 1978 and became the Coordinator of the National Landslide Information Center in 1995. She has worked extensively on international programs with USGS, the United States landslide inventory, and the coordination of landslide hazard with the emergency response community. She has published extensively on the socio-economic impact of landslides in communities and is currently working on development of a basic handbook for landslide hazard mitigation that will be published in several languages.
Welcome, Lynn! We appreciate your time and effort on behalf of the EIIP Virtual Forum. Lynn, I now turn the floor over to you, please.
[Presentation]
Lynn Highland: Thanks, everyone, for taking time to check into the exciting topic of landslides!
Landslides are commonplace worldwide, with a vast assortment of direct and indirect consequences to world societies. We know landslides mostly through their sudden impacts on human lives and property; for example, when a collapsing hillside destroys buildings or a freeway and tragically disrupts a community. What we seldom perceive are the broad, insidious impacts of landslides throughout multi-state regions; the cumulative direct and indirect impacts on our state and national economies; and the interrelations of landslides to many other natural hazards.
Landslides, including rockfalls, debris flows and a variety of other slope movements cause between 3 and 5 billion dollars in property losses in the United States each year. There are between 25 and 50 deaths caused by landslides in the U.S. each year, with thousands more killed around the world.
The most recent life-loss in the United States was during December 2003 when devastating debris flows on wild-fire-burned areas in southern California occurred. Heavy, winter rainfall loosened mud and debris on steep slopes that had been denuded of vegetation in the wildfires of summer and fall 2003, and killed 17 people in torrents of rapidly moving, deadly mudflows.
Though most landslides occur in our nation's mountainous regions, virtually every state has significant landslide problems. Even relatively flat areas of the U.S. experience devastating bluff collapses along major rivers, damaging property and killing people.
The following link is to the Landslide Overview Map of the Coterminous U. S. that you may wish to take a closer look at later. It shows landslide incidence and susceptibility by region. This page also provides links to download the map in various formats, including ARC INFO export format for use in a GIS hazards analysis.
http://landslides.usgs.gov/html_files/landslides/nationalmap/national.html
This map is to be used for general purposes only, as we always advise that a professional be consulted when making decisions about specific sites, such as building lots. It is sometimes necessary to perform investigative drilling into a hillside or perform soils tests to obtain the best information as to a site's potential landslide hazard.
Rockfall in hiking and camping areas, and along highway cuts cause many deaths each year. Landslides destroy or damage residential and commercial properties and developments as well as agricultural and forestlands, and impair the quality of oceans, rivers and streams. Slope collapse along Highway One on the coast of California has caused fish kills and damage to otter and sea lion populations in wildlife reserve areas in the coastal waters. Sliding silt, rock and debris have negatively impacted the water quality in these ocean waters.
http://landslides.usgs.gov/html_files/landslides/slides/slide21.htm
Bluff collapse and debris flows along Salmon runs in Washington State have devastated pristine salmon spawning areas and travel routes, through contamination of pristine waters by sudden inundations of silt, sand and other debris. When large, landslides often fall into rivers, temporarily, or permanently creating dams which cause blockage of water flows and subsequent flooding upstream, and the cessation of irrigation flow and recreational stream flow, downstream of these dams.
http://landslides.usgs.gov/html_files/landslides/slides/slide3.htm
Many people think of landslides as isolated, local events brought about by special sets of unique conditions, occurring sporadically across the landscape. While this perception is partly true, landslides are more likely to be part of broad, regional earth systems.
Landslides can be activated by earthquakes, widespread rainstorms and snowstorms, hurricanes, wave attacks on coastlines, volcanic eruptions, riverine flooding, or climate change, for example, melting glaciers.
Landslides can move abruptly in a matter of minutes or can sometimes move slowly, causing chronic problems over a period of years. Major earthquakes in hilly and mountainous regions, or heavy rainfall from regional storms typically produce tens of thousands of landslides over broad areas in brief periods of time. Much of the recent development in many of our large metropolitan areas intrudes upon unstable terrain.
Eastern and Midwestern cities such as Cincinnati and Chicago are landslide-prone, despite the popular assumption that landslides are restricted to western areas such as Los Angeles and San Francisco. In addition, widespread development of smaller communities, especially in the intermountain West, creates abundant new exposure to landslide conditions.
Areas that have high precipitation, landslide-prone soils, and steep slopes are the most likely to have landslide problems. Many areas have high potential for landslides, for example the Rocky Mountains, but as rainfall is one of the triggering mechanisms for landslides, the dry climate in that area, keeps landslides to a minimum
In the United States, ground failures and landslide problems are typically dealt with locally, with state transportation departments, county governments, and private property owners paying for the damage. For this reason, exact statistics on the cost of landslide damage are not consolidated, unlike statistics of losses from earthquakes and hurricanes.
Agencies such as the U.S. Geological Society are charged by the U.S. Congress to reduce the effects of geologic hazards and to this end we have a small program of about 15 people who perform basic research on landslide processes and mechanics. Other landslide studies are performed in the academic community, at universities and to some extent, in the private sector, through private geotechnical consulting businesses.
Current USGS projects involve instrumental monitoring of the rates of movement of hillsides, alert and warning system-cooperation with local emergency management agencies, and pilot studies in probabilistic landslide recurrence intervals. We also provide landslide information to a variety of users, an interactive bibliographic database for landslide publications, and we map landslide hazards in areas in which we have cooperators.
Currently, we are evaluating the debris-flow potential for areas burned by wildfires, in several locations - southern California, New Mexico, and Colorado in particular. Slopes behave very differently when subjected to wildfires and the physics and mechanics of potential landslides in this area requires intense analysis and evaluation.
We also issue warnings through the media for areas that we anticipate will have heavy rainfall together with a factor of safety concern, such as a burned surface, or an area that has experienced prior landslide events. Again, we work closely with locals, as to take in to account the unique geographical and meteorological variables in differing locations.
Please view our website at http://geohazards.cr.usgs.gov for a plethora of information on landslides. We have posted our research papers, personnel information, recent landslide events, landslide information for students, an interactive, searchable bibliographic database, and many images that are public domain, and therefore free to download and use. You may also find our fact sheets useful in your public awareness efforts.
One of our premier outreach products for landslide mitigation is a Landslide Hazard Guidebook for planners that will debut sometime this year. This Handbook, written by various landslide experts in cooperation with the American Planning Association (APA), will help urban planners across the U.S. begin planning for hillside development at the zoning and platting level, and will guide them through the process of evaluating communities for landslide hazard potential.
It will contain chapters on types of landslides, a glossary of terms, actual planning case studies, and state-of-the-art mitigation techniques that can be used as a tool for planning recommendations. The handbook will be automatically distributed to those planners having a subscription to APA's series of planning guides on various topics. The rest of the nation's 30,000+ plus planners will be able to purchase the handbook through the American Planning Association. This guide is not limited to planners, and it is our hope that others will be interested in acquiring it also.
I am always available for questions, toll-free, at 1-800-654-4966, by local phone, 303-273-8588, by email, highland at usgs.gov, and via our website. In the meantime, I will be happy to take address your questions and comments this afternoon, and turn the floor back over to our Moderator to start us off.
Avagene Moore: Thank you very much, Lynn. I trust the audience has questions for you.
[Audience Questions & Answers]
Question:
RickTobin: I've read that if you are in a house in an area suspect of land slides you should sleep near a wall next to the hillside. Is that reasonable?
Lynn Highland: Rick, there are variations on that advice - it's better to evacuate, but if you can't, a 2nd story is the best place to be.
Question:
Andre Lee: What land slide types of risks are associated with community planning on land fill areas?
Lynn Highland: There are various ordinances from place to place. The theory is any place can be engineered properly, given enough time and money.
Question:
Jose De La Torre: Are you aware of any study performed in the Caribbean? The potential, especially in Puerto Rico, is very high.
Lynn Highland: Yes, we have an expert now in our Reston office, Matt Larsen, who has published extensively on Puerto Rico.
Question:
Amy Sebring: Lynn, can you tell us a little more about "map cooperators"? Are these local jurisdictions with GIS or universities?
Lynn Highland: Amy, we have our own GIS lab, plus we use data and GIS data from the Defense Department, universities, NASA, and some private entities.
Question:
Jamie Jones: Have there seen any advances in alert and warning specifically for landslides?
Lynn Highland: We have been experimenting with reverse 911, with cell phones notifying Emergency Managers when instruments on landslides indicate movement.
Comment:
Paula Gori: Hello. I am a colleague of Lynn's at USGS and am working with APA on the guidebook. I would like to give you the web site for the guidebook, if you are interested. Go to http://www.planning.org/landslides. Also I have additional information about Puerto Rico. You can write me at pgori at usgs.gov and I will respond. Thanks.
Question:
Isabel McCurdy: Lynn, our province of British Columbia Canada was subjected to the worst wildfires last summer in our history. Would you elaborate more on 'slopes behave very differently when subjected to wildfires'?
Lynn Highland: Yes, the soils change their chemical composition, become what's called hydrophobic, and exacerbate landslide occurrences. There is also no vegetation that would ordinarily affect flow. We have publications on this process on our website.
Question:
William Cumming: Is there any technical merit in distinguishing between seismic related and non-seismic related landslides? Flood related landslides and non-flood related?
Lynn Highland: Just to the extent of their triggering mechanism, which is heavy shaking during earthquakes (plus liquefaction of soils) - there are threshold magnitudes, also. Flood is strictly saturation related.
Question:
Leslie Little: Is there an advance type of warning to enable people to have sufficient time to evacuate, i.e. hours or perhaps a day or more? Also, when evacuating should the people go above the landslide or further inland?
Lynn Highland: We have been able to issue warnings in burn areas that will be experiencing rainfall - for example, during December, 2003, in Southern California. There were evacuations as a result.
Question:
Butch Kinerney: It's well documented in the fire community of the growing threat as more and more homeowners build in the urban-wildland interface. Last summer at the Boulder Hazards Conference we saw the continuing expansion into mountainous areas first-hand. Have there been any recent studies on the growing risk of landslides as suburbs push out into these kinds of areas?
Lynn Highland: One example is our study of the I-70 Urban corridor through the Rocky Mountains. We have historical landslides documented and have looked at the current rate, as the population has increased. Publication is on our Web site.
Question:
Amy Sebring: Lynn, do you have any future or longer term goals or plans for your program?
Lynn Highland: Yes, we would like to get the states to start a uniform inventory system, so that we can look at risk, and we are expanding our wildfire-induced debris-flow studies. We have a 5-year plan that can be viewed as a public document.
Question:
Andre Lee: What assistance is available for homeowners and municipalities when FEMA assistance is not available due to a land slide effects fewer than 18 residences?
Lynn Highland: Homeowners have not had much recourse, except through litigation. There's no insurance, and the causes of landslides can be instigated by one or more occupants of a hillside. It is a grim scene for homeowners. Buyer beware!
Comment:
Art Zeizel: The mudslide coverage under the National Flood Insurance Program, run by FEMA, could provide insurance coverage for mudslides in many instances.
Lynn Highland: The "mudslide insurance" only applies to people who have national flood insurance, so they have to be in a flood plain.
Art Zeizel: No, people only have to be in a community that participates in the NFIP to purchase coverage for mudslides, even if they live on a hillside.
Lynn Highland: Art, I'll contact you about that regulation -- I would like a copy, please. Thanks!
Question:
Avagene Moore: Lynn, if there was one thing you could do or say to make people understand the seriousness of the landslide and mudflow threat, what would that be?
Lynn Highland: I would say that to buyers, "Get your site evaluated." Look at the county and city maps. Again, buyer beware - only a few states have disclosure of hazards during real estate transactions. Colorado and California are two.
Question:
William Cumming: Is there any sort of standardization among geologists, soils engineers, other professions, etc., on distinctions in technical aspects of landslide definitions?
Lynn Highland: Yes, there are many international organizations working on uniform language, practice, and mitigation. Also, the USGS contributes to this uniformization effort.
Question:
Brian Bell: Apart from zoning reviews, it sounds like there are two observable risk factors: deforestation due to fire and real-time rainfall data. Does anyone know if FEMA currently plots these risks in its situation awareness reviews??
Lynn Highland: I don't know about the FEMA question - anyone else?
William Cumming: FEMA in the past has paid money to states for flow-down to local grantees for soil "stabilization" out of the President's disaster relief funds.
Amy Sebring: FEMA has been involved with mapping risk. See the link on our background page to the press release which contains further links. http://www.usgs.gov/public/press/public_affairs/press_releases/pr1826m.html
David Crews: I worked in FEMA info and planning on the recent So Cal fires. The answer is yes the threat areas were GIS mapped and identified. There were areas that were evaluated by USGS at more than a 70% risk after the fires and in the event of a 1.27 rainfall in less than an hour. Lynn, we worked with Sue on a special task force after the southern California fires.
Lynn Highland: David, my colleague, Sue Cannon is working intently on this - her publications are on our website, in their entirety.
Question:
Isabel McCurdy: Lynn, are there mitigation strategies posted on website that could be implemented to prevent landslides?
Lynn Highland: Isabel - we don't post anything general, as there are so many variables at each site - the APA Handbook will have detailed explanations and references for mitigation. We usually leave that to the private sector, such as GeoTech companies.
Art Zeizel: Mitigation strategies and techniques for use by state and Local governments are given in a Guidebook for Landslide Loss- Reduction published by FEMA with the State of Colorado
Comment:
Paula Gori: The maps that David Crews refers to were made following the So Cal fires. If our program at the USGS was larger we would be able to make more of these maps prior to the disasters.
Lynn Highland: Folks, as I was instructed to keep answers concise, I can GREATLY expound on more explanation if you want to contact me later!
Question:
William Cumming: What are the principal points of contact between USGS and DHS on landslide issues? Is it continuing or ad hoc? Corps of Engineers contacts?
Lynn Highland: We have so far worked with FEMA, and I'm unaware if we have worked with DHS on anyone. Paula, do you know?
Paula Gori: We work with FEMA following disasters and also on a group called Natural Disaster Education Coalition with other federal agencies and the Red Cross.
Lynn Highland: William, we have worked with the Corps in Washington State.
Question:
Aart Zeizel: Lynn, how is the past inadequate funding and staffing for landslides faring in the USGS?
Lynn Highland: Art, actually it is pretty good mainly because of our Congressional initiative we have proposed, the landslides in Seattle, and the wildfire problem in Los Alamos and southern California.
Thanks, everyone, for this opportunity. Please contact me if there are more questions!
[Closing]
Avagene Moore: That's all we have time for today. We greatly appreciate your presentation today, Lynn. Very good discussion! Thank you! Please stand by a moment while we make some quick announcements.
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Thanks to everyone for participating today. We appreciate you, the audience!
Before you go, please help me show our appreciation to Lynn for a fine job.
The EIIP Virtual Forum is adjourned!