EARTHQUAKES EARTHQUAKES Earthquakes are a sudden release of

EARTHQUAKES Earthquakes are a sudden release of vibrations and energy in the Earth’s crust

WHERE ARE EARTHQUAKES LIKELY TO OCCUR? Along plate boundaries Along faults In volcanic regions

$FAULTS o A fault is a fracture in the Earth’s crust that occurs when$

REVERSE FAULTS When 2 blocks are pushed together due to compression One slides up

https: //www. youtube. com/watch? v=4 b 81 n. XSVA 34

NORMAL FAULTS When 2 blocks of rock are pulled apart by tension One slides

https: //www. youtube. com/watch? v=t. JDnf. T 1 pqh. Q

TRANSFORM OR STRIKE SLIP FAULTS Occur as a result of shear stress Scrape past

PARTS OF AN EARTHQUAKE The Focus is the point where an earthquake originates. Waves

HOW DO WE MEASURE EARTHQUAKES? Using seismographs or seismometers Measure the amount of force

EARTHQUAKE WAVES THE VIBRATIONS DURING AN EARTHQUAKE ARE CALLED SEISMIC WAVES Primary Waves- move

TIME TRAVEL CURVES P Waves are always detected first(move faster) With increasing distance there

EARTHQUAKE MAGNITUDE The Richter Scale measures the amount of energy released during an earthquake

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EARTHQUAKES

EARTHQUAKES Earthquakes are a sudden release of vibrations and energy in the Earth’s crust Can happen along any type of plate boundary Can be very small and cause no damage or very large and catastrophic

WHERE ARE EARTHQUAKES LIKELY TO OCCUR? Along plate boundaries Along faults In volcanic regions

$FAULTS o A fault is a fracture in the Earth’s crust that occurs when$

FAULTS o A fault is a fracture in the Earth’s crust that occurs when stress is applied too quickly

REVERSE FAULTS When 2 blocks are pushed together due to compression One slides up relative to the other Can cause tsunamis

https: //www. youtube. com/watch? v=4 b 81 n. XSVA 34

NORMAL FAULTS When 2 blocks of rock are pulled apart by tension One slides down relative to the other

https: //www. youtube. com/watch? v=t. JDnf. T 1 pqh. Q

TRANSFORM OR STRIKE SLIP FAULTS Occur as a result of shear stress Scrape past each other in opposite direction San Andreas Fault (San Francisco)

1992 – 7. 3 MAGNITUDE

PARTS OF AN EARTHQUAKE The Focus is the point where an earthquake originates. Waves travel out from the focus like ripples in a pond The epicenter is the point on Earth’s surface directly above the focus.

Fault line Epicenter Focus

COMPLETE THE STOP AND THINK

HOW DO WE MEASURE EARTHQUAKES? Using seismographs or seismometers Measure the amount of force and the length of shaking Measure the vibrations and shaking of the crust

EARTHQUAKE WAVES THE VIBRATIONS DURING AN EARTHQUAKE ARE CALLED SEISMIC WAVES Primary Waves- move in a push pull motion Can move through solids and liquids The fastest and the first Secondary Waves- move in a side to side motion Can only move through solids Arrive second Surface Waves- from when the s and p waves reach earth’s surface Slowest and last Most destructive

TIME TRAVEL CURVES P Waves are always detected first(move faster) With increasing distance there is a greater difference between the arrival time of P and S waves The difference in arrival time between p and s waves can determine how far away the earthquake is

EARTHQUAKE MAGNITUDE The Richter Scale measures the amount of energy released during an earthquake Scale goes from 0 - 10 The waves generated by a 4 are 10 X larger than the waves generated by a 3 Largest earthquake ever recorded was a 9. 5 in Chile in 1960.