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MEASURING TECTONIC EVENTS - Coggle Diagram
MEASURING TECTONIC EVENTS
VOLCANIC EXPOSIVITY INDEX (VEI)
● Measures the relative explosiveness of a volcanic eruption.
● Based on the height of ejected material and duration of eruption.
● Scale goes from 0-8 and is logarithmic (increase of 1 on the scale indicated a 10 times more powerful eruption).
MODIFIED MERCALLI SCALE
● Measures the destructiveness of an earthquake.
● It is a relative scale as people would feel different amounts of shaking in different places.
● It subjective as based on if people wake up, if furniture moves, how much damaged structures receive.
● The scale varies from I to XII I = Generally not felt by detected on seismographs XII = Nearly total destruction
● It doesn’t consider economic, social and environmental impacts.
MOMENT MAGNITIRE SCALE
Moment Magnitude Scale
● Measures the amount of energy released in earthquake.
● Scale from 0-9.
● It's a simple measure, so environmental or social impacts must be inferred.
RICKTER SCALE
● Like the VEI its scale is logarithmic.
● Must infer social or environmental impacts, which can be misleading. The highest Richter scale earthquake readings won't necessarily be the worst disasters
● Most widely used scale, as it's absolute
● Measures the amplitude of the waves produces during an earthquake