Killer Landslides
1. March 22, 2014 near the town of Oso, Washington, many homes were covered by a square mile of mud 15 to ______feet deep.
2. Landslides occur commonly all over the earth. In one 7 month period there were 222 large landslides worldwide that killed nearly ______.
3. The raw slope left behind after a landslide is called a ______.
4. A technique using laser-based altimetry or ______can see old landslide scars. This technique shows that in the area of Oso there have been many large landslides in the past. This area is truly unstable.
5. The old slides can be dated by ______analysis using pieces of wood buried by slide. A large slide was dated at 5300 years ago. Since 1933 aerial and satellite photos show that the recent slide had slid many time before 2014,
6. ______helped searchers refocus the search downslope from where the houses were to where they were carried which is called the distal end of the landslide.
7. What was surprising is the 600 foot slope slid for nearly a ______, many times further than this slope had slid before at least in recent times.
8. Studies indicate that the slide can quickly trigger a second often larger slide as happen in Oso, and a few weeks later this same double slide occurred in ______where many rescuers were killed.
9. The lower layer of the Oso slide is composed of ______lake material that is a mixture of silt and clay. Above that was glacial ______which was more cohesive and slid as blocks. The Oso area had the wettest march in history, nearly 2 feet of rain.
10. The ground at Oso underwent liquefaction which is usually associated with ______., but it known that this can happen during slides, especially if there is a lot of ______in slope material.
11. The young lady, name Summer, that was trapped in her car on the highway was found 5 days after the slide. She hadnʼt suffocated but had died of percussion trauma due to ______waves hitting her car