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  • woodse
    started a topic looking for landslides

    looking for landslides

    I am working on a lab using worldwind to look at mass wasting events and would like to find more examples of landlsides especialy in areas of how resolution imagery. The ones I have right now are

    North of Pacifica 37.66862N and -122.48512W Landslides at junction of San andres fault with the Pacific Ocean

    South of Pacifica (Devils slide) 37.57437 N and -122.50761W

    North side of Mount Diablo 37.9734 N and -121.87782 W (slumps)

    Himalaya 28.30825N 95.70420E (slides)

    Philippians 15.99569N 121.18103E (mudlflows related to Mt. Pinatubo)

    Thistle Creek Utah 39.99959N -111.49816W

    Groves Creek 38.43039N -78.39095W (mudlisde)

    Gros Ventra Slide 43.634N -110.55309W


    I would like to make a large list and post it on worldwind central and my own web-page. I am also interested in making location lists for other geologic features in the future.

  • withak
    replied
    re: Lake Sarez, here are the high points of my notes from the talk last week:

    Vital stats:
    - The dam was formed by a landslide caused by an earthquake in 1911, magnitude approximately 7.4
    - It is ~5km long along the crest, ~4 km wide, and 600 m high
    - The dam currently impounds ~17 km^3 of water
    - It currently leaks from a point about 400m up from the downstream toe (about 200m down from the top), this leakage forms a medium-sized to large river
    - Despite the leak, the lake fills faster than it empties and has been filling since 1911. It is currently rising at a rate of 20-30 cm per year, but this rate is slowing because the reservoir gets wider as it gets higher.
    - The river and erosion from the leakage is not a risk to the stability of the dam
    - The leaks are stable and do not appear to be eroding soil from inside the dam
    - There is currently 20-50 meter of freeboard (the height of the dam above the water level), it is estimated that it will be hundreds of years before the dam overtops naturally

    Risk mitigation:
    - Funding from the Swiss government, administered by the World Bank (Swiss government is the largest source of foreign aid in the region)
    - There are 18 villages in the immediate river valley, and countless cities in both Tajikistan and Afghanistan between the dam and the ocean
    - The failure of the dam would cause the largest flood in history, and probably the largest in pre-history as well.

    Major risks:
    - landslide into lake could cause a sietch (a tsunami in a lake) that could overtop the dam
    - the dam itself could have a landslide the damages it
    - an earthquake could damage the dam
    - natural erosion/overtopping could damage the dam

    - Of these, a landslide into the lake is the most serious
    - There is very little geologic info, the only soil boring was done by the USSR in the 1980s to investigate an ongoing landslide behind the dam (see attached diagram). The boring stopped at 200 m because they used all of the well casing they brought with them. There are no borings of the material making up the dam itself.
    - The location is very remote, it is a 20km hike (no roads) from the nearest village to the dam site. That village is at the end of a constantly eroding/landsliding jeep trail, approximately one week of driving from the nearest city.
    - The slide investigated by the 1980s Soviet soil boring is on the right bank upstream from the dam. The size of this slide is unknown; the 200m boring was not deep enough to reach the slip surface.
    - This landslide is the greatest risk to the dam, it is estimated that it would cause a wave 19-40m high in the lake that would run up 50-100m higher when it reached the dam.

    - There is currently a manned monitoring station near the dam with many sensors to detect earthquakes, rainfall large waves, increased streamflow downstream, etc. This monitoring station can set off sirens via satellite at locations downstream of the dam if it detects a problem.
    - The nearby villages have evacuation plans and trails made leading to high ground.

    - Main way to reduce the risk is to lower the lake level
    - Possible schemes:
    - divert the river upstream of the lake so it stops filling
    - drill bypass tunnels around the dam to lower lake level
    - Estimated costs for these projects range from $121 million to $300 million, of which $100 million is from only transportation costs to get construction equipment out to the remote location

    - In Sept 2006 another area of leaks opened up in a different location from the old leaks, these also appear to be stable and not an immediate risk to the dam.
    - The increased river flow from these new leaks triggered a small landslide downstream of the dam which formed its own small lake before eroding away and causing another larger flood downstream.

    Last edited by withak; 02-12-2007, 09:57 PM.

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  • patmurris
    replied
    Look for "La Clapiere landslide" in the french maritime alps... 44.2520/6.9428. I've seen it move over the last three decades and found some photo archives to make an interactive animation.
    Last edited by patmurris; 02-03-2007, 10:22 AM.

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  • Guest's Avatar
    Guest replied
    possible landslide

    looking at JPL OnEarth pseudo color data worldwind://goto/world=Earth&lat=37.70843&lon=73.03309&al t=13932&dir=153.3

    this looks more like a massive landslide but i am no expert

    Leave a comment:


  • withak
    replied
    Another interesting one that was just pointed out to me:

    Lake Sarez in Tajikistan



    This lake was created after an earthquake in 1911 caused a large landslide to form a natural dam 550m high (called Usoi Dam, the largest in the world) blocking the Murgab River. The scarp left behind by the slide is the lighter-colored area at the northwest end of the lake in this image. The slide is ~5km wide.

    I'm going to a talk next week on work that is being done to stabilize the natural dam. There are a number of populated areas downstream and the failure of a 550m-high dam during an earthquake would be disastrous.

    Leave a comment:


  • woodse
    replied
    The Vaoint Slide in Italy is spectacular in the VE imagery, Thanks Wthak!

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  • woodse
    replied
    Thanks.
    I took a look at the ON-earth data for the area as well and the changes are quite extreme. It could be fun for the students to look at the ON earth data identify areras at risk for landslides and mud flows and see how they compare to the 2006 event.

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  • withak
    replied
    http://unosat.web.cern.ch/unosat/asp...ee.asp?pid=832

    Plenty of landslides in that map.

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  • woodse
    replied
    Found some Lahars in think, around Merapi in Indonesia. The ones to the south of the volcanoe or more interesting to me as they seem to come out of vegitated areas.

    worldwind://goto/world=Earth&lat=-7.6234&lon=110.4849& view=0.3

    this will put you in the center of one of them. THere apears to be a much larger barren area in 1990 than in 2000, So my guess if largest Lahar occured sometime shortly before 1990 and the area is recovering or only small lahars have come down since.

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  • Efrain
    replied
    Quick clay

    What about quick clay landslides in Scandinavia? They are quite common there.

    You have examples like Rissa in Norway
    worldwind://goto/world=Earth&lat=63....33333&view=0.3

    or Verdal also in Norway
    worldwind://goto/world=Earth&lat=63....33333&view=0.3

    or Baastad in Sweden
    worldwind://goto/world=Earth&lat=56....33333&view=0.3

    Though I'm afraid you won't see too much using NLT! However you can find lots of info and some videos on the net. Take a look at http://www.ngi.no/English/default.as...DA8646C5EF13ED

    Efrain

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  • withak
    replied
    Wind could also cause features that look like they came from moving water.

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  • 5of0
    replied
    No one knows for sure, I think they're rockfalls/slides, after Valles Marineris was originally formed. My science club did a big project on it, and it's interesting to see that the debris at the bottom cover up evidence in the bottom of possible water - Valles Marineris leads to the lowest parts of Mars (oceans?), suggesting it was formed by water rushing down to the ocean. And there are definite evidences (streamlined islands) of there being water rushing by at some point. So some could be caused by the water rushing through the canyon so many years ago. Mars is a whole nother can of worms.

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  • woodse
    replied
    Thanks for the locations
    I checked out Vaiont and it shows up very well. It is also a good example of the usefullness of On-earth as it is clearly easier to see on it than the other data sources. I definetly hope to put this one in the lab.
    The mars slides are interesting. Part of the lab is having the students distinguishing different types of mass wasting features and a key factor in classifying mass wasting features is amount of water, and i assume water is not a major component of the Valles Marinaris Slides? Would they be considered rockfalls?

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  • withak
    replied
    Mass wasting will show up a lot better on the moon and mars than on earth because earth has all that pesky rain that keeps erasing geology from the surface.

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  • 5of0
    replied
    I don't know the nature of your study, but the edges of Valles Marineris on Mars are full of mass wasting.
    If it fits, the mass wasting on Mars is probably more massive (no pun intended) than that on earth, because of the sheer size of Valles Marineris.
    ou can, of course, google a lot of info on it:
    http://hirise.seti.org/epo/masswasting_theme.htm
    ^^Has good general info on wasting, as well as good info on Mars, too.

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