Waves and Beaches Movement of air (disturbing force) across the ocean causes waves to form Splash waves can be generated by coastal landslides or icebergs calving Seismic sea waves or Tsunamis can be formed by underwater avalanches, volcanic eruptions, or fault slippage Tides are a vast, low, predictable wave created by the sun and moon and spin of the earth Waves can also be created by ships creating a wake

Wave Properties Ocean waves are Orbital waves which involves components of both longitudinal and transverse waves Also known as body waves because energy is transferred through a body of matter Crest- high part of the wave Trough- low part of the wave Still water level- half way between crest and trough

Wave Properties cont. Wave Height- measured top of crest to bottom of trough Wave Length- measured crest to crest or trough to trough Wave period- time it takes one wavelength to pass a point, typical between 6 and 16 sec. Frequency- number of crests passing a fixed point per unit of time

Water Properties cont. Waves break when steepness exceeds 1:7 ratio, a wave 7 meters long can only be 1 meter high or it breaks, near shore or open ocean, Wave Base- Point at which the circular orbital motion dies out with depth ( surge ) usually ½ wavelength Floating oil rigs, Bridges are designed so that most of their mass is below the wave base

Wave Properties cont. Energy in a wave determined by: Wind speed- mph or kph Fetch- distance wind blows, 100s-1000s of miles Duration- time wind blows,hours- days 10% of the waves in a fully developed sea will be twice the average height Swell- waves moved out of the storm area move faster than the wind, steepness decreases become long crested waves, travel great distances

Wave Properties cont. The circular orbit in a wave is slower in the bottom half or trough than the top crest half so a floating object does not return to its exact spot, moves slightly forward (Wave Drift ) Deep water waves are faster than shallow water waves which drag on the ocean bottom and slow down The longer the wavelength the faster the wave

Breaking Waves Waves entering shallow water drag their base on the bottom and slow, waves move closer and wavelength decreases, wave height increases When the front bottom of the wave touches the ocean bottom and stops, the Back part of the wave runs up over the front increasing height and falls foreward Spilling Breakers- slower waves from dragging on bottom Plunging Breakers-fast waves going from deep to shallow water suddenly

PIPELINE

MAVERICKS

RINCON California Wave diffraction

Reflection of Waves off the Sea wall

Newport Beach Inlet

The Wedge

The Wedge

The wedge

The Wedge

Rogue Waves Massive solitary waves can occur when normal ocean waves are not large In a 6.5 ft sea a 65 ft wave may appear 1 wave in 23 twice average height 1 in 1175 will be 3 times average 1 in 300,000 will be 4 times average Probably caused by constructive wave interference, 2 or more waves combining 10 large ships lost every year, 1000 total yearly

USS Bennington

Hurricane Damage USS Bennington

USS Bennington

USS Ramapo

Bayou Renaissance Man, Algulhas Current

Bayou Renaissance Man

Norwegian Dream

Rogue Wave in Mediterrean

Algulhas Current Rogue Waves Heading south along East coast of Africa, encountered multiple large waves

Algulhas Current Rogue Waves

Life Boat

Giant Waves Tsunamis are created by Fault movement of the Earths crust with vertical displacement Tsunami wavelength can exceed 125 miles and can move across open ocean at 435 mph Wave height in open water may be 1.6 feet but when they reach shallow water the wave piles up Wave appears as a surge of water up onto the land but does not form a huge breaking wave on the beach

Lituya Bay Alaska 1740 Ft Splash wave

Lituya Bay Alaska

Lituya Bay Alaska

Tsunami

Tsunami

Tsunami

Krakatoa Volcanic Eruption

Giant Waves Tsunami crated by the explosion of a volcanic island in the Sunda Straight between Sumatra and Java A wave 116 ft high drowned over 1000 villages and killing 36,000 people 3 large waves followed the first colossal wave

Krakatoa Tsunami 30 meters

Light House, Scotch Cap Alaska

Light House, Scotch Cap Alaska

Light House After Tsunami

Tsunami, Scotch Cap, Alaska Earth Quake measuring 7.3 occurred off Aleutian Islands Light house with foundation 46 ft above sea level was destroyed Top of the cliff 103 feet above sea level was damaged Wave estimated to be 118 ft high Also hit Hilo Hawaii 1850 miles away with a 55 ft high wave, 25 million in damage

Hurricane Storm Surges

Hurricane Sandy Storm Surge

Hurricane Camile 24 Ft Storm Surge

Ship Hull Markings

Ship Hull Markings

Coast Guard Rescue Boat

Break Walls with Jacks

Break walls

Break wall, Maldives

Break wall, England

Redondo Harbor Break wall, Calif

Break Wall after storm