Earthquake
As plates move, large stresses can occur along plate boundaries. Where one plate does not constantly slip past another along their shared plate boundary, elastic strains can be built u. When the elastic stress exceeds the frictional resistance along a pla
Epicenter
a geographic point on earths surface directly above the focus of an earthquake
Hypocenter (focus)
The point along a fault at which slipping initiates an earthquake
P wave (Compression/primary)
alternating periods of compression and expansion, in the direction of wave travel. Like "pressure waves", they are within earths interior and they are the fastest waves, changing both the volume and density of the martial they travel through, they can be
S wave (shear/secondary)
They displace material at right angles to their path of travel, this only changes the shape of the material they travel through. They cannot propagate through gases and liquids, only through solids. Travel at about half the speed of primary waves.
Surface wave
Occuring along the surface of the earth, slow and generally the last to arrive. Cause most seismic damage and is most destructive in a large shallow focus earthquake.
Where do earthquakes occur?
The faults in the lithosphere. They are parts of the lithosphere which break and slide past each other during an earthquake, the actual location of the part of the fault that slips during an earthquake is the focus. It can be from 0 to 700 km deep but are
Long-term forecasting
most likely the response will be the longer the time since the last big quake the sooner the next one will be, they look at the reoccurrence in interval (time required to accumulate the strain that will be released by fault slipping in the future earthqua
Short-term Prediction
using precursors such as swarms of tiny earthquakes and rapid deformation of the ground several hours before the mainshock
Medium-term forecasting
using seismic information off of the surrounding faults to predict earthquakes
Primary Hazards
Tsunami's, earthquakes are dangerous due to the ruptures in the ground surface that occur when faults break the surface, the permanent subsidence and uplift of the ground surface caused by faulting, and the ground shaking caused by seismic waves radiated
Secondary Hazards
landslides and other forms of ground failure that give rise to mass movements of earths materials. Fires ignited by ruptured gas lines or downed electric power lines, firefighting can also be difficult with damage to water mains
Earthquake proof your life
Know your location, many areas near active tectonic boundaries are prone to quakes, and you should avoid areas prone to liquification
Consider construction - consider flexible building designs that can move with the quake and houses that have wood framing
Tsunami
a destructive sea wave ("tidal wave" or "seismic sea waves") generated due to a large earthquake beneath the sea floor or in the coastal area which displaced large amounts of the sea floor (or large submarine landslides) starting large volume waves that a
Liquefaction
in loose, wet, or otherwise unconsolidated solids (landfill/reclaimed tidal flats), the shaking motion caused by an earthquake can transform the ground into liquid-like material
Weathering
the general process by which rocks are broken down at earths surface. Divided into chemical weathering (minerals in a rock are chemically altered or dissolved, weakens a rock and makes more susceptible to physical weathering) and physical weathering (soli
4 Factors that control the rate of weathering
1. properties of the parent rock
2. the climate
3. the absence or presence of foil
4. the length of time rocks are exposed to the atmosphere
Mass Wasting
processes by which weathered and unweathered earth materials move down slope in larger amounts and in large single events
Soil
layers of material, initially created by fragmentation of rock during weathering, that experiences additions of new materials, losses of original materials, and modifications through physical mixing and chemical reactions.
This is all developed from weath
Translocations
lateral and vertical movements of materials within the developing soil (main agent is water)
5 factors that is important to the formation/development of soils
1. Parent Material - the solubility of minerals, the sizes of grains, and the patterns of fragmentation, such as joints and cleavage in the bedrock
2. Climate - temperatures, precipitation levels, and their seasonal patterns of variation
3. Topography - s
Mass Movements
the down slope movements of masses of soil, rock, mud, or other materials under the force of gravity. They are not pulled down slope primarily by the action of an erosional agent, they occur when the force of gravity exceeds the strength of the slope mate
Mass wasting is influenced by 3 primary factors
1. The nature of the slope materials. Slopes may be made up of unconsolidated materials, which are loose and uncemented, or consolidated materials, which are compacted or bound together by mineral cements.
2. The amount of water in the materials. This fac
Strength of materials and affect of water constant
When the ground becomes saturated with water, the planes of weakness within the solid material are lubricated, the friction between particles is lowered, and the particles or larger aggregates can move past one another more easily so that the material may
Creep
the slowest type of unconsolidated mass movement, the gradual downhill movement of soil or other debris. Range from 1 to 10 mm/yr, visuals would be trees, telephone poles and fences start to lean or move slightly down slope.
3 classifications of mass movements
1. the nature of the moving material
2. the velocity of the movement
3. the nature of the movement: whether it is sliding or flowing
Tides
are due to the rotation and gravitational attraction of the moon, earth and sun. This attraction of the earth and moon causes the ocean to bulge toward the moon. The rotation of the two about a common axis creates a bulge on the opposite side of the earth
Ocean Currents
include both surface and deep currents
Surface Currents
Driven by wind direction. It is determined by wind patterns and continent position. Due to the Coriolis Effect, currents in the northern hemisphere are deflected to the right. Those in the southern hemisphere are deflected to the left. Average depth of su
Thermohaline circulation
two major causes of density difference: temperature (hotter is less dense) and salinity (saltier is more dense). Cooling and salty surface currents sink in sub polar areas. They travel along the sea floor, the most important deep water is formed in the No
Upwelling
an important role in nutrient cycling and climate
Waves
a result of wind action (like surface currents). Ocean waves are surface waves not body waves. Water motion is restricted to a depth less than ~1/2 the wavelength. There is no net movement of water as the wave form passes. Even though the wave is moving,
Surf Zone
the area of turbulent water flow
Erosion
not important in ocean systems but can have effects on coastal areas.
Coastal Sediments
Along coasts, sediments are eroded, deposited, and transported. Most of the erosion and much of the transport and deposition occurs in a narrow coastline band.
Thermocline
a thin but distinct layer in a body of fluid in which temperature changes more rapidly with depth. The transition between deep water and surface water
Halocline
subtype of chemocline caused by strong, verticle salinity increase with depth of water
Pyrocline
the layer where the density gradient is greatest within a body of water
Residence Time
how long a chemical species will linger within the ocean
Ocean Mixing Time
1600 years, the amount of time it takes the ocean to mix through surface/deep water circulation
Hydrothermal vent
3 million years, along all mountain chains on divergent boundaries, mixing and reactions with rocks put chemicals in the water (strong influence in the chemistry of sea water)
Chemosynthesis
Similar to photosynthesis, but it works primarily in bacteria/archea and its the process they use in which they utilize chmicals around them (i.e. Iron)
Phytoplankton
coccolithoporida (plants)
Zooplankton
foraminifera (animals)
Effects of rainfall/erosion on topography
Landscapes are shaped by plate tectonic processes, weathering erosion, and resistance to erosion.
Insolation
The amount of solar radiation in a given area (W/m^2) maximized by the equator and minimized by the poles
Coriolis affect
angular momentum of the earth affects the wind patterns
Westerlies
30-60 degrees North and South
Circulation cells
produce trade winds, upper atmosphere belts and westerlies
Ekman spiral/Ekman transport
The idea that a bunch of water moving in a direction based on the wind will drag lower water along with it but in a circular motion
gyre
circular process of moving winds
El Nino
normally trade winds blow E to W in the equatorial Pacific. This piles up vast amount of warm water near Australia. Occasionally these trade winds diminish, and the warm water that was piled up in the Western Pacific moves to the Eastern Pacific (off the
The carbon cycles
the continual movement of carbon between different components of the earth system.
Ocean Acidification
a process in which carbon dioxide from the atmosphere dissolves into the ocean and reacts with seawater to form carbonic acid, increasing the oceans acidity
Cabon cycles 4 main reservoirs
the atmosphere, the oceans (including marine organisms) the land surface (including plants and soils), and the deeper lithosphere
calcium corbonate in the water
calcium can react with carbonate which forms calcium carbonate. this can then precipitate as carbon sediment. the amount of calcium that remains dissolve in seawater thus depends on the availability of carbonate ions, which in turn depends on the influx o
seawater composition
its the product of a number of geological and biological processes. Chlorine is in high concentration because of low demand. Iron is in extremely low concentration because of the high demand. Calcium is in a mid point of concentration because of the high
residence time
the balance between the amount of the dissolved elements that are removed from seawater, and the supply of these elements to seawater.
Wind at equator
little surface wind, the air rises forming clouds and rain as it cools
trade winds
blow from the east. the cooled air sinks, warms up, absorbs moisture, and yilds clear skies
Westerlies
come from the west. called the temperate zones