Measuring and Predicting Earthquakes (Grade 10 NSC Matric Geography): Flashcards
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Practise the cards
10 cards from this deck
Seismograph
Seismograph
Instrument to measure earthquake intensity & locate epicentre
Principle behind seismograph operation
Principle behind seismograph operation
Inertia - heavy weight stays still while ground/surface moves
P waves (Primary waves) characteristics
P waves (Primary waves) characteristics
Fastest waves, arrive first, cause little damage
S waves (Secondary waves) characteristics
S waves (Secondary waves) characteristics
Arrive second, slower than P waves, little damage
L waves (Love waves) characteristics
L waves (Love waves) characteristics
Most destructive, arrive last, travel along Earth's surface
Richter scale
Richter scale
Standard system to measure earthquake intensity/magnitude
Richter scale type
Richter scale type
Logarithmic - each number = 10x more energy than previous
Can earthquakes be accurately predicted?
Can earthquakes be accurately predicted?
No, but early warning systems can provide minutes of notice
Rock behaviour monitoring for earthquakes
Rock behaviour monitoring for earthquakes
Rocks emit varying magnetic frequencies when under stress
Early warning from seismographs
Early warning from seismographs
P & S wave detection gives minutes warning before L waves hit