Geol 108 usc study guide 7 – Flashcards

A phenomenon that cuases fluids, like water and air, to curve as the travel across or above Earth's surface. In the northern Hemisphere storms spin counter-clockwise but in southern hemisphere they spin clockwise. Earth Spins from west to east. Points in equator spin faster than poles. https://www.youtube.com/watch?v=i2mec3vgeaI

Is the energy absorbed or released when a substance changes its physical state. Ex. Latent heat is absorbed upon evaporation, and released upon condensation to liquid (as in clouds). Latent heat is also absorbed when water melts, and released when it freezes. Latent heat, or hidden heat, is heat that is taken up and stored when a substance changes state from a solid to a liquid, from a liquid to a gas, or from a solid directly to a gas. It cannot be measured by a thermometer.

-Latent heat driven -Die down quickly -The weaker the high altitude winds, the stronger the hurricane. -Hurricane centers warmer than surroundings -Air in the center of the eye sinks downward -low pressure in the center of the eye

-Hurricane movement is called Hurricane Propagation. Generally hurricanes are steered by global winds. -In the tropics, where hurricanes form, easterly winds called the trade winds steer a hurricane towards the west. -In the Atlantic basin, storms are carried westwards torwards the carribean sea and the north american coasts.

-A groin is a shoreline structure that is perpendicular to the beach. It is usually made of large boulders, but it can be made of concrete, steel or wood. It is designed to interrupt and trap the longshore flow of sand. -Sand builds up on one side of the groin (updrift accretion) at the expense of the other side (downdrift erosion). If the current direction is constant all year long, a groin "steals" sand that would normally be deposited on the downdrift end of the beach. The amount of sand on the beach stays the same. A groin merely transfers erosion from one place to another further down the beach.

A hurricane would never cross the equator. The Coriolis Force is near zero near the equator, so you don't get the turning needed to spin the air into tight low-pressure centers, so they don't form within 5 or so degrees latitude of the equator.

https://www.youtube.com/watch?v=Rsdxn70pSG4

Formed by winds: Magnitude of waves controlled by: -speed of wind -duration of wind -fetch of wind- the area or distance blown by winds

Human activities promoting sea cliff erosion ◆ Urbanization ◆ Added structures along the edge—pools and patios ◆ Irrigation and other activities Coastal structures interfering with the littoral transport are the most common cause of coastal erosion. Coastal structures interfering with the littoral transport are the most common cause of coastal erosion. The presence of the structure has a series of effects: Trapping of sand on the upstream side of the structure takes sand out of the sediment budget, thus causing shore erosion along adjacent shorelines. Mostly, of course, on the lee side, but large structures may also cause (initial) erosion on the upstream side. Loss of sand to deep water Trapping of sand in entrance channels and outer harbours. The structures, which may cause this type of erosion, are: Groynes and similar structures perpendicular to the shore Ports (see also Port breakwaters and coastal erosion) Inlet jetties at tidal inlets and river mouths detached breakwaters The accumulation and erosion patterns adjacent to coastal structures depend among other things on: The type of coastline, i.e. the wave climate and the orientation of the shoreline The extent of the structure relative to the width of the surf zone The detailed shape of the coastal structure *Human activities result in 15-30% drop in sediment load by rivers to the ocean. Why? -Dams Sediment flux to the ocean has been globally reduced by 30% due to dams.

Hurricanes draw their power from warm, extremely humid air found only over warm oceans. This is because the key energy source is the latent heat that's released when water vapor condenses into cloud droplets and rain. Tropical storms and hurricanes grow best in a deep layer of humid air that supplies plenty of moisture. Disturbances that can grow into hurricanes begin where air is converging and being pushed upward. If the air is unstable, it will continue rising after the initial upward shove. The disturbance will grow only when winds at all levels of the atmosphere from the ocean up to 30,000 feet or higher are blowing at the same speed and from the same direction. Otherwise, the winds can rip apart a growing storm. Hurricanes grow under high pressure areas high above the ocean, which help pump away the rising air, allowing more air to flow into the storm and rise. Text discusses more on what hurricanes need to be born and grow. -warm ocean water leads to evaporation -warm, moisturized air rises -condensation releases latent heat -low pressure sucks in air, increases evaporation

The wave groups generated by storms far out at sea. As the swell enters shallower water, transformations take place that eventually lead to the waves breaking on the shore. waves are unstable when the wave height is greater than about 10 percent (0.1) of the wave length.

Horizontal movement of a large volume of seawater. due to oblique waves due to differences in water tempreature due to differences in water salinity global currents or more local currents

Waves expand energy along the coastline

Decrease in wave length and velocity, but increase in wave height; deep water wave energy translating into wave breakers, pounding the shore.

warmer water rises and cooler water descends.

Wave refraction around headlands Waves reach shallow water sooner in front of headlands. These waves slow down and the wavelength shortens in front of the headlands, but waves in the bays continue at the same speed and wavelength because they have not yet come into the shallow water. Result is that the waves bend (refract) around the headlands http://www.csun.edu/~khurst/ES300/Fritche/300waves.html#III

water particles move in near-circular orbits which decrease in diameter with depth.

water particles actually move forward.

Hurricanes in the Atlantic and Typhoons in the Pacific.

-Latent heat driven -die down quickly on land -the weaker the high alt. winds, the stronger the hurricane -Hurricane centers warmer than surroundings -Air in the center of the sinks downward

Mound of water in center of hurricane being sucked up.

1. moist warm air expands, rises 2-1. cools, condenses, rain falls 2-2. dry air gets compressed while moving north (less area) 3. dense air sinks in sub tropics 4. warmed, dry air spreads at surface

Longshore drift consists of the transportation of sediments (clay, silt, sand and shingle) along a coast at an angle to the shoreline, which is dependent on prevailing wind direction, swash and backwash.[1] This process occurs in the littoral zone, and in or close to the surf zone. The process is also known as littoral drift, longshore current or longshore transport.[1] or longshore beach drift swash pushing sediment onshore in an oblique angle.

Back flow of water and sediments perpendicular to shore by gravity.

Zigzag longshore beach drift

A series of large waves surging to shore, then the rapid backflow of the piled up water in narrow zones.

an effect whereby a mass moving in a rotating system experiences a force (the Coriolis force ) acting perpendicular to the direction of motion and to the axis of rotation. On the earth, the effect tends to deflect moving objects to the right in the northern hemisphere and to the left in the southern and is important in the formation of cyclonic weather systems.

a system of winds rotating inward to an area of low atmospheric pressure, with a counterclockwise (northern hemisphere) or clockwise (southern hemisphere) circulation; a depression.

Beaches are a common feature of a coastline. Beaches are made up of eroded material that has been transported from elsewhere and deposited by the sea. Constructive waves help to build up beaches. The material found on a beach (ie sand or shingle) depends on the geology of the area and wave energy. A cross-section of a beach is called a beach profile. The shingle ridges often found towards the back of a beach are called berms.

A landing stage or small pier at which boats can dock or be moored. A breakwater constructed to protect or defend a harbor, stretch of coast, or riverbank.

Beach groin, barrier to long-shore drift, constructed of large rock blocks or other materials.

Sedimentary budgets are a coastal management tool used to analyze and describe the different sediment inputs (sources) and outputs (sinks) on the coasts, which is used to predict morphological change in any particular coastline over time. Within a coastal environment the rate of change of sediment is dependent on the amount of sediment brought into the system versus the amount of sediment that leaves the system.

a rising of the sea as a result of atmospheric pressure changes and wind associated with a storm.

The quantity of heat absorbed or released by a substance undergoing a change of state, such as ice changing to water or water to steam, at constant temperature and pressure.

The bending of waves (convergence) towards the protruding areas (headlands) and the divergence of waves at the beach or embayment. The longterm effect of greater energy expenditure on protruding areas is differential erosion/beach formation (Summer berm and winter Erosion)

-Wave activity and associated longshore currents in many areas is strongly seasonal -The tides also follow a monthly cycle which is superposed on seasonal and longer time scale wave activity -Sediment input to the coastline also varies on seasonal and longer time scales -Sea cliffs become active or inactive depending on the above factors

National and global problem ● Erosion factors ◆ Constant wave actions ◆ Tropical cyclones, Nor'easters ◆ Tsunamis ◆ Tidal actions ◆ Long-term rise of sea level ◆ Human activities

1-Common structures: Seawalls, groins, breakwaters, and jetties ● Benefits ◆ Improve navigation ◆ Retard erosion, recreational beach expansion ● Problems ◆ Interference with longshore currents, causing unintended adjacent local erosion and deposition 2-Five general principles ● Coastal erosion: A natural process, posing natural hazards as development approaching shore fronts ● Shoreline construction causes changes: Often better for some, worse for others ● Stabilization of the coastal zone: Protecting the interests of few at the expense of the general public ● Engineering structures: Design and consequences ● Structural versus nonstructural alternatives to coastal erosion problems

Sand Budget Inputs - Sediments eroded from backshore cliffs by waves -Sediments eroded from upcurrent beach by longshore drift & current -Sediments brought in by rivers Outputs -Sediments transported to backshore dunes by offshore winds -Sediments transported downcurrent by longshore drift and current -Sediments transported to deep water by tidal currents and waves

Occurs in natural systems where the particles are clastic rocks (sand, gravel, boulders, etc.), mud, or clay; the fluid is air, water, or ice; and the force of gravity acts to move the particles along the sloping surface on which they are resting.

A wall or embankment erected to prevent the sea from encroaching on or eroding an area of land.

-A storm with a violent wind, in particular a tropical cyclone in the Caribbean. -A wind of force 12 on the Beaufort scale (equal to or exceeding 64 knots or 74 mph).