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TRIANGULATION:
- Obtain data from 3 different seismological stations.
- Determine the difference in the arrival time of S and P waves recorded from each of the seismological stations.
- Determine the distance of the epicenter from the station.
- Use the triangulation to locate the center.
PLATE TECTONICS:
'Plate tectonics' is a theory which suggests that the Earth's crust is made up of plates that interact in various ways, thus producing earthquakes, volcanic eruptions, and other geological features. Plates are rigid sections of the lithosphere that move as a unit.
DIFFERENT KINDS OF CRUST:
● continental crust: thicker but less dense ● oceanic crust: thinner but denser
MAJOR PLATES:
North American Pacific South American Antarctica Indo-Australian Eurasian African
MINOR PLATES:
Scotia Nazca Indian Philippine Sea Arabian Caribbean Juan de Fuca Cocos
BASIS OF IDENTIFYING TECTONIC PLATES:
- Distribution of earthquake epicenter.
- Location of volcanoes
- Formation of mountain ranges
TYPES OF PLATES:
CONVERGENT: plates that move towards each other/collide differently the two plates are oceanic plates. DIVERGENT: plates that move away from each other
TRANSFORMATIVE: plates that slide against each other
CONVERGENT (OCEANIC AND OCEANIC):
Geological events: subduction, earthquake, volcanic eruptions, tsunami Geological features: volcanoes/volcanic arcs, islands/archipelago/island arcs, trenches
When two oceanic plates converge they go through "subduction
CONVERGENT (OCEANIC AND CONTINENTAL):
Geological events: subduction, earthquake, volcanic eruptions Geological features: volcanoes/volcanic arcs, trenches
CONVERGENT (CONTINENTAL AND CONTINENTAL):
Geological events: earthquakes, faulting Geological features: mountain ranges
DIVERGENT:
Rift Valleys - a break in the Earth's surface Ridges - mountains which originate as a result of a folding
TRANSFORM:
lots of earthquakes but no subduction, volcanoes, and rift valleys can occur in any type of boundary
LAYERS OF THE EARTH:
● CRUST - outer layer/part of the Earth. It is made up of oxygen, silicon, aluminum, iron, magnesium, sodium, potassium and calcium. ● MANTLE - beneath the crust and it is the largest layer of Earth's interior. The major elements that take up the mantle are oxygen, silicon, and magnesium. ● CORE - the innermost layer of the Earth, it has two parts: inner and outer. The inner core mostly consists of iron and nickel. It's solid due to intense pressure that prevents the iron from melting,meanwhile the outer core is liquid. ● LITHOSPHERE - the outermost layer of the Earth. It is mostly rocky and rigid. It is made up of silicon, iron and magnesium.
SEISMIC WAVES:
They are mechanical waves travelling through the Earth generated by a slip of the plates.
TYPES OF SEISMIC WAVES:
BODY WAVES - a type of wave that travels through the Earth. They have a higher frequency than surface waves. SURFACE WAVES - a slower and lowered frequency compared to body waves. They pass both longitudinal and transverse.
