Earth Science: Phenomena
Volcanoes
Tectonic Plate Movement
Fossils
Earthquakes
A sudden release of energy in the form of seismic waves.
P waves.
S waves.
Surface Waves
P or S waves that travel through the surface.
The most damaging (as their energy is closer to everything on the surface).
Can only travel through solids.
Composite volcanoes.
Shield volcanoes.
Cinder-cone volcanoes.
Can travel through liquids, solids, and gases.
Move in a push/pull motion.
Move in a side to side motion.
Often happens along fault lines.
Can also occur around hot spot volcanoes.
Mold fossils are formed with acids dissolve bone, teeth, or shell, which leaves an imprint in the rock.
Cast Fossils are fossils that form when sand or mud fill a cavity in the rock. The cavity mold the materials, which harden over time into a replica of the original organism.
The age of a fossil can be determined through two processes; radiometric dating and the relative age.
Relative age is the age of the fossil based on the rock layers above and below it. The farther down a fossil is, the old it is. This is stated through the Law of Superposition.
Each organism has a certain amount of carbon in its body.
When an organism dies, the carbon doesn't decay at the same rate as the tissues, fur, or feathers. The carbon slowly decays over the years, becoming nitrogen.
By measuring and comparing the amount of carbon to the amount of nitrogen in a dead organism, or fossil, scientists can create an age range for when the creature may have lived.
Index fossils are fossils that belong to a species that lived in a large radius of land, but died out in a short period of time.
Paleontologists find these fossils especially helpful, as they help to identify the relative age of certain rock layers.
Divergent Boundary
Convergent Boundary
Transform Boundary
Two tectonic plates divide, creating an area of seafloor spreading.
Creates mid-ocean ridges and rift valleys.
Two tectonic plates collide.
Creates trenches, mountains, and some volcanoes.
The movement of tectonic plates is created by convection currents in the mantle. With the movement of the magma underneath the plates, these parts of the crust tend to bump and rub against each other.
Tectonic plates rub against each other, sliding opposite directions.
Creates fault lines.
Lahars
A landslide of mud, water, and volcanic materials down the side of a volcano. As the lahar travels, it picks up more materials and gains size and speed.
Cold lahars are caused by an excess of rain. The rain builds up and starts to roll downhill, carrying volcanic debri with it.
Warm lahars are caused by volcanic heat melting snow and ice. The snow and ice start to slide downhill, picking up volcanic debri and mud.
Shield volcanoes are wide and have a gentle slope.
They generally have less viscous lava; allowing the lava to flow easily to the sides of the volcano. Eruptions are not explosive.
Includes: Mt. Kilauea, Mt. Washington
Steeper slopes.
Created by layers of hardened lava and ash.
Formed by cinders and ash.
Often found on the outskirts of shield and composite volcanoes.
Inflation
The swelling of the sides of a volcano due to magma and gas expanding outwards
Creates new crust, either oceanic or continental.
Steep slope.
Made of alternating layers of hardened volcanic ash and volcanic rock (hardened magma/lava).
Highly viscous lava, and explosive eruptions.
Examples: Mt Fuji, Mt St Helens
Also can be called a stratovolcano.