1. GEO/OC 103 Exploring the Deep …. Today’s Tune “ Sink to the Bottom” Fountains of Wayne

2. Labs Start Next Week  Read through labs ahead of time  See your sections and TAs on the web –dusk.geo.orst.edu/oceans/103labs.html

3. Shape of the Seafloor

4. Techniques of Bathymetry - 1  Challenger expedition (1872-1876) -1st systematic bathymetric survey –ocean floor NOT flat - significant topographic relief  German ship Meteor (1920’s) - 1st echosounding survey –sounds travels through water much better –velocity = distance/time –SONAR (Sound Navigation and Ranging)

5. Bathymetry - 2  WWII - U.S. Navy further developed SONAR technology –knowledge of the enemy –knowledge of the ocean  1950’s - 1960’s - single, focused high- frequency, short wavelength sound beam –“wide-beam” bathymetry –sound beam spreads out as it reaches bottom –range of depths - fuzzy estimate

6. single, focused high-frequency, short wavelength sound beam

7. Bathymetry - 3  1970’s - revolution in bathymetric mapping with multibeam bathymetry  multiple, focused, high-frequency, short wavelength sound beams –“narrow-beam” or “multibeam” bathymetry –sound beam stays narrow and focused all the way to the bottom –depths much more precise –e.g., Sea Beam has 16 beams, Sea Beam 2000 has 121, Simrad EM120 has 191

8. multiple, focused, high-frequency, short wavelength sound beams A Gigabyte of data a day A Gigabyte of data an hour

9. multiple, focused, high-frequency, short wavelength sound beams Multibeam Movies courtesy of NOAA

10. Bottom Coverage & Data Density by Survey Method LeadlineSingle Beam Multibeam 1-2 K soundings per survey 500 - 750 K soundings per survey 400,000 – 1,000,000 K soundings per survey Image courtesy of NOAA & UNH

19. Shallow Water Multibeam

20. Shallow Water Multibeam (cont.)

21. Initial Tutuila Surveys

24. Tutuila Surveys

25. Fagatele Bay National Marine Sanctuary

26. FBNMS Benthic Terrain

27. Entire Eastern Samoa

28. Goldfinger et al., OSU Active Tectonics & Seafloor Mapping Lab Oregon Department of Fish & Wildlife Need for Mapping Oregon Territorial Seafloor Siletz Bay Need for Mapping Oregon Territorial Seafloor Siletz Bay

29. Applications for Mapping Tsunami Runup Models - Evacuation Planning Habitat Restoration Shoreline Change Analysis Analyzing Storm Impacts - Coastal Erosion Fisheries Management Commercial Fishing Marine Reserve Design Emergency Response, Impact Assessment Port Security Maps and VisualizationsNavigation Products, Services Wave EnergyOil Spill Response, Tracking Coastal tourism, recreationMANY others

30. “Fine Scale” Mapping  on the order of tens of meters to meters  features the size of a can of beer!

31. Image courtesy of Dan Fornari, Woods Hole Oceanographic Institution Study Area

32. HURL Sub & ROV surveys Ka‘imikai-o-Kanaloa Pisces IV or V RCV-150 HURL = Hawaii Undersea Research Lab ROV= remotely-operated vehicle *Launch iTunesU

33. Sonar Also Used as...  a “catscan” of oceans to see water structure ABOVE seafloor  an “x-ray” of seafloor to see structure BENEATH seafloor –seismic reflection & seismic refraction –low frequency, long-wavelength sound  sidescan sonar to get pictures of seafloor in addition to depth –backscatter strength as opposed to traveltime

34. Sidescan Sonar Image courtesy of USGS Woods Hole

35. DSL-120 Vehicle Image courtesy of USGS Woods Hole Image courtesy of WHOI Deep Submergence Lab and Dr.Dan Fornari

37. Sidescan Sonar Sidescan Movies courtesy of NOAA

41. Resolution  with multibeam bathymetry can see things on seafloor the size of this room –swath width of 6 km or 3.7 miles  good, high-resolution maps possible only since 1980’s  other instruments needed to see things smaller than size of room –remotely-operated vehicles (ROVs) –submersibles

43. Seafloor Features: Continental Margins  continental shelf - extends from shore to a point marked by great increase in slope  continental slope - steep slope beyond the continental shelf break  slopes often cut by submarine canyons –turbidity currents - dense flows of sediment- laden water –deepsea fans  continental rise  abyssal plain - extensive, flat

45. Seafloor Features: Deep Ocean  seamounts - underwater volcanoes 500 m to 1000 m high –flat-topped ones are called guyots –volcanic features (buoyed up by hot rock, lava)  abyssal hills - features around 200 m high –pervasive on seafloor –volcanic AND tectonic in origin - still debated

47. USS San Francisco crashed into 2-km tall uncharted seamount Los Angeles class nuclear submarine ran aground enroute from Guam to Brisbane, Australia - 8 January, 2005 One sailor killed, 115 injured 30-hour trip back to Guam, crew managed to keep the sub from sinking Courtesy of Dave Sandwell, Scripps Institution of Oceanography

48. Seafloor Features: Deep Ocean  Plate Boundaries –Ridges (Rises), Trenches, Transform Faults, Fracture Zones