GEOLOGY 101 Under the Boardwalk: Coastal Geomorphology What to look for while you're on the beach during spring break. J.S. Kite, WVU What Causes Changes in Sea Level? Answer Varies with Time Scale. Long-Term Changes in Sea Level Shape and Volume of Ocean Basins Varies with Sea-Floor Spreading Rates Slow Spreading = Deeper Ocean Basins Fast Spreading = Shallower Ocean Basins & Seas Spill on to Continents Volume of Glacier Ice ~225 ft Higher if All Glaciers Melt ~400 ft Lower at Pleistocene Maximum
Sea Level Variation in Last 700,000 years Long-Term Changes in Sea Level Volume of Glacier Ice Pleistocene Ice Age 400-500 ft Lower Estuaries = Drowned River Valleys: Delaware Bay, Cheaspeake Bay, Pamlico Sound, Albemarle Sounds Eroded During Glacial Low Sea- Level Stands, Drowned During Interglacial High Sea-Level Stands
Chesapeake Bay Bathymetry Susquehanna Paleo-River Last Century: Ocean Warming & Expansion, Glacial Melting Seismic Sea Waves (Tsunami) Short Term Changes in Sea Level Seismic Sea Waves (Tsunami)
Boxing Day Tsunami Animation www.columbia.edu/itc/sipa/nelson/newmediadev/files/2004_indonesia_tsunami.gif Tsunami Animation Sites Indonesia 2004 http://iri.columbia.edu/~lareef/tsunami/#tsunami_animation:_national_institute_of Alaska Simulation http://nctr.pmel.noaa.gov/titov/show/ Tides - Why? Gravity of the Moon and Sun Acting on Ocean Surface 24 Hr 50 Min: 2 Highs, 2 Lows
Tides - Why? Spring Tide = Highest High Tide & Lowest Low Tide Neap Tide = Less Tide Range Why is there a high tide on the earth opposite of the moon? Why is there a high tide on the earth opposite of the moon? Think Bolos
Bolos http://www.flight-toys.com/bola/bola_argentina10.jpg Tides Can Be Enhanced or Reduced by the Shape and Size of a Basin Gulf of Maine, Bay of Fundy Mediterranean Sea The Med - Puny Tides Straits of Gibraltar
Bay of Fundy- Mongo Tides Gulf of Maine-Bay of Fundy Tide Model Copyright 2005 SMAST/ UMASSD View this on line at http://fvcom.smast.umassd.ed u/research_projects/gb/tidal _simulation/gb_tide_curr.gif http://fvcom.smast.umassd.edu/research_projects/gb/tidal_simulation/gb_tide_curr.gif What is Deadliest Day in U.S. History? San Francisco Quake, 1906 ~ 500 Dead? Hurricane Katrina, 2005 1,836 Dead # Johnstown Flood of 1889 ~ 2209 Dead? Pearl Harbor, Dec 7 1941 ~ 2471 Dead # 11 September 2001 ~ 2986 Dead # November 1918 Flu ~ 3000 Every Day Antietam, 17 Sept 1862 3650 Dead (23,000 casualties. NPS: ~ 4000 may have died later) Issac s Storm, 1900: ~ 8000 Dead in Galveston, Texas Alone! # From Wikipedia, the free encyclopedia
Antietam/Sharpsburg 17 Sep 1862 National Park Service Data Casualties in 3 categories: 1) dead; 2) wounded; and 3) missing or captured. Approximate Numbers Union Confederate Total Killed 2,100 1,550 3,650 Wounded 9,550 7,750 17,300 Missing/Captured 750 1,020 1,770 Total 12,400 10,320 22,720 These are the approximate numbers for September 17th, 1862. No one knows the actual number of men who would later die of their wounds or the number of missing who had been killed. If you take a conservative estimate of 20% of the wounded dying of their wounds and 30% of the missing killed, the approximate number of soldiers that died as a result of this battle are 7,640. Storm Surge Wave created by low atmospheric pressure sucking ocean water into center of storm Add pressure map for Hurrican Camille L Powerful Low Pressure System (L) Generates Partial Vacuum that draws water into a large wave (storm surge) 31 October 2000 Upper-Air Weather Map from Environment Canada / d ti /t h id / d l 9 t li d th j t t ht l
Isaac s Storm: The 1900 Galveston Hurricane Galveston Hurricane 1900 Storm Surge Map Tipped House, Galveston, 1900
Debris at Galveston,1900 Debris at Galveston,1900 Galveston, Texas, 1900
Total Destruction at Galveston, Texas, 1900 Lucas Terrace Apartments, BEFORE Galveston Hurricane Lucas Terrace Apartments, AFTER Hurricane
Wind Tides Pamlico & Albemarle sounds, NC Westerlies Blow Water Down Estuaries Wind - Creates Most Ocean Waves Wave Height is Controlled by 1. Wind Velocity 2. Fetch = Distance Water Surface is Subjected to Wind Wind Waves
Waves = Movement of Motion Wind Waves Swash Swash Surf Surf Wave Wave Base Base Breaking Wave in Shallow Water
Swash Beach Terms Surf Breakers Old Berm Berm Wave Erosion-Deposition Wash-Over Refraction Longshore Current Londshore Drift Beach Erosion in the USA
Hurricane Fran 1996 See Changes in Next Slide North Carolina Beach before Hurricane Fran, 1996 See Changes from Last Slide Wash-Over Deposits North Carolina Beach after Hurricane Fran, 1996
Hurricane Fran Damage from Wash-Over Beach Erosion: Third Cape Hatteras Lighthouse, North Carolina Now Relocated in Fourth Different Site Stopped Here 10 March 2009 Wave Refraction
Wave Refraction Longshore Current & Longshore Drift Longshore Current & Longshore Drift LSC
LSD Groins Coastal Structures Coastal Structures: Groins, Ocean City, NJ Plummer et al., 2005, 10 th ed., p. 347 Ocean City NJ USGS Air Photo from Terraserver.com See also Matthew 7:26
Coastal Structures: New Jersey Jetties Plummer et al., 2005, 10 th ed., p. 347 Spit: South Carolina Barrier Islands Historical Changes in a Virginia Barrier Island
Presque Isle, Lake Erie, PA, image courtesy Chris Schaney LSD Baymouth Bar Primary v. Secondary Coasts (Both Examples from California)
Primary Shoreline, Pensacola Florida Secondary Shoreline, Northern California Sandy Primary Shoreline: Albemarle Sound, NC Drowned Roanoke River Valley
Rocky Shoreline: Nova Scotia Primary, relict from Glaciation Headland Erosion Wave Energy Concentrated on Headlands, Dispersed in Bays Wave-Cut Landforms
Wave-Cut Beach, California Idiotic Building Wave-Cut Shoreline, California Oregon Coast Photo by J.S. Kite
High-Energy Rocky Shoreline: Headland Hunter's Brook Beach, Acadia National Park Maine http://www.acadia.net/anp/10oceand.jpg 1997 AcadiaNet Inc., Producers of The Downeast Guide A Tombolo in California Reefs Fringing Volcano Atoll
Eroding Volcanoes with Fringing Reefs Atoll Coastal Landforms Marine Terraces Paleo- Seastack Marine Terrace Wave-Cut Cliff Wave-Cut Bench Active Seastacks