Geography and Oceanography - Chapter 18 pdf

Today’s Tune Today’s Tune “ “ This is the Sea” This is the Sea” by The Waterboys by The Waterboys Next Midterm Next Midterm Monday, May 16, 2011, 1:00 Monday, May 16, 2011, 1:00  Here in Gilfillan Auditorium, closed book Here in Gilfillan Auditorium, closed book  Same format as Test 1 Same format as Test 1  Bring #2 pencil Bring #2 pencil  Study Guide POSTED on main class web Study Guide POSTED on main class web site: site: http://dusk.geo.orst.edu/oceans/103syl.html http://dusk.geo.orst.edu/oceans/103syl.html Transformation of Wind-Driven Transformation of Wind-Driven Deep-water Waves Deep-water Waves Transformation of Wind-Driven Transformation of Wind-Driven Shallow-water Waves Shallow-water Waves Photography by Clark Little Photography by Clark Little Photography by Clark Little Photography by Clark Little Photography by Clark Little Photography by Clark Little [...]... eruptions, and submarine slumping – open ocean: short heights, long wavelengths (>100 km), and long periods 40 0-5 00 mph!!! – shallow water: their length shortens and their height increases dramatically Global Wave Propagation After 2004 Sumatra Event Titov, V., A.B Rabinovich, H.O Mojfeld, R.E Thomson, and F.I Gonzalez, The global reach of the 26 December 2004 Sumatra tsunami, Science, 309 (5743), 204 5-2 048,... which occur underwater and move along pycnoclines Internal Waves Slower speeds than surface waves because the density difference between water masses is less than between air and water – They occur when water masses slip over one another – They have very long periods and very large heights Advection Along Internal Waves Standing Waves Seas, swell, and surf are progressive waves Standing waves (seiches)…... Hazard Information http://www.coastalatlas.net or http://bit.ly/FG8rz Tsunami from slumping North Carolina Example Driscoll et al., Geology, 28(5):40 7-4 10 Back to Wind-Driven Scenarios: Storm Surges extremely high water levels due to – Low pressure system - big storms persistent onshore winds rise in sea level Hurricanes! (W Atlantic) Cyclones! (W Pacific) Hurricane Katrina, Saturday, Aug 27, 2005 NASA... Oscillate back and forth about a node i.e., a fixed point – Form when winds blow in one direction which causes water to pile up at one end of a basin Node = Fixed Point Antinode = maximum displacement Summary Waves are disturbances that are generated on or beneath the sea surface Progressive waves move along the sea surface The size of surface waves depends on the speed and duration of the wind, and the... affect water to a depth equal to or less than one-half their wavelength A special case is a tsunami, a deepwater wave generated by a submarine disturbance with incredibly long wavelengths, high wave speeds, and very short wave heights, UNTIL they feel the bottom in shallow water! Summary (Cont.) As waves enter shallow water their wavelength shortens and their height increases The most damaging effect . http://dusk.geo.orst.edu/oceans/103syl.html http://dusk.geo.orst.edu/oceans/103syl.html Transformation of Wind-Driven Transformation of Wind-Driven Deep-water Waves Deep-water Waves Transformation of Wind-Driven Transformation of Wind-Driven Shallow-water Waves Shallow-water Waves . periods wavelengths (>100 km), and long periods 40 0-5 00 mph!!! 40 0-5 00 mph!!! – shallow water shallow water : their length shortens and : their length shortens and their height increases. volcanic eruptions, and submarine slumping. eruptions, and submarine slumping. – open ocean open ocean : : short short heights, heights, long long wavelengths (>100 km), and long periods