1. Science of Natural Disasters: Tsunamis! And other coastal hazards 21 April 2016 Rebecca Clotts Department of Geology, University of St Thomas Tsunamis Coastal Erosion Sea Level Change

2. Where did the oceans come from? 2

3. http://www.palomar.edu/oceanography/salty_ocean.htm 3 Why are the oceans salty?

4. Wave caused by the vertical displacement of ocean water Requires a Trigger 4 Coastal Hazard: Tsunamis

5. Rapid uplift or subsidence of the sea floor http://www.tsunami.noaa.gov/tsunami_story.html http://www.tsunami.noaa.gov/tsunami_story.html 5 What triggers tsunamis?EARTHQUAKES

6. Lituya Bay, Alaska 6 What triggers tsunamis?LANDSLIDES

7. 7 30.5 million cubic meters of rock fell into ocean

8. 8 Bay water surged to 1790 ft (524 m) above normal

9. 9 What triggers tsunamis?VOLCANOES

10. 10 40 m (140 ft) Tsunami

11. 11 What triggers tsunamis?ASTEROIDS

12. 12 Preliminary evidence of 66 ft high tsunami waves in NYC

13. What happens during a tsunami?

14. Killer Tsunamis Source: Wikipedia

15. Recent & Historic Tsunamis http://nctr.pmel.noaa.gov/database_devel.html 15 https://www.youtube.com/watch?v=_4zKS10oo_Y&feature=youtu.be Most Recent: 2 March 2016 Recent and Historic Tsunamis

16. 16

17. Where will Tsunamis occur?

18. Primary effects of flooding and erosion –Shorten the coastline –Debris erodes both landscape and human structures Secondary effects –Fires –Contaminated water supplies –Disease What are the effects of Tsunamis?

19. Detection and warning –Monitor earthquake zones (seismographs) –Tsunami warning system Tidal gauges to determine sea level changes Buoy sensors to detect tsunami in open ocean (http://nctr.pmel.noaa.gov/Dart/Jpg/DART- II_05x.swf)http://nctr.pmel.noaa.gov/Dart/Jpg/DART- II_05x.swf How is the tsunami hazard minimized? Pacific Tsunami Warning Center: http://ptwc.weather.gov/http://ptwc.weather.gov/

20. How is the tsunami hazard minimized?

21. Structural control –Building codes for susceptible coastline areas Land use –Native vegetation may provide defense –Development of land must be monitored Probability analysis Education How is the tsunami hazard minimized?

22. Tsunami-Ready Status Signs of a Tsunami If you feel an earthquake, leave the beach or low-lying area. If you see the ocean receding, run from beach. A small tsunami in one location may be larger nearby. If you hear the tsunami siren, move to higher ground. Do NOT go down to the beach to watch the tsunami. If you can see it, you are already in danger. How is the tsunami hazard minimized?

23. 23 Coastal Hazard: Coastal Erosion

24. 24

25. 25 Animation: http://www.learnnc.org/lp/multimedia/14706http://www.learnnc.org/lp/multimedia/14706 Movie: https://www.youtube.com/watch?v=U9EhVa4MmEs (2 mins)https://www.youtube.com/watch?v=U9EhVa4MmEs How does Coastal Erosion happen?

26. 26 15 january 2005 17 September 2005 How fast?

27. 27 Where does Coastal Erosion occur?

28. 28 http://www.msstate.edu/dept/geosciences/CT/TIG/WEBSITES/RESEARCH/Gregory_Harris/index.htm How is Coastal Erosion mitigated?

29. 29 How is Coastal Erosion mitigated?

30. 30 Coastal Hazard: Sea Level Change

31. 31 NOAA Sea Levels Trends: http://tidesandcurrents.noaa.gov/sltrends/sltrends.htmlhttp://tidesandcurrents.noaa.gov/sltrends/sltrends.html What is sea level change?RELATIVE

32. 32 Graph from NOAA What is sea level change?GLOBAL

33. 33 What causes sea level change?

34. 34 What causes sea level change?

35. 35 3. Changes in the rate of sea floor spreading What causes sea level change?

36. 36 What causes sea level change?

37. 37

38. How does this apply to YOU?! But… Minnesota has 44,926 miles of shoreline (source MN DNR)

39. 39 What causes sea level change? Minnesota and Coastal Erosion University of Minnesota Extension – Shoreline Education: http://www.extension.umn.edu/environment/shoreland/

40. 40 What causes sea level change? Minnesota and Tsunamis?! Not exactly… In Lake Erie: 1844 - 22 ft seiche killed 78 people, dammed ice blocking Niagara Falls 2008 – Winds created waves up to 16’ and flooded Buffalo NY Seiche!

41. 41 What causes sea level change? Minnesota and Sea Level Change?! Lake Level Data available through the MN DNR at: http://www.dnr.state.mn.us/climate/wat erlevels/lakes/index.html http://www.dnr.state.mn.us/climate/wat erlevels/lakes/index.html http://files.dnr.state.mn.us/waters/area_hydros.pdf The data in this graph originated from the U.S. Army Corps of Engineers-Detroit District No.