EARTHQUAKES-AQA

EARTHQUAKES-AQA

1. MEASURING

   • RICHTER SCALE
     • EACH VALUE ON THE SCALE ALSO REPRESENTS ABOYT 30 TIMES MORE ENERGY RELEASED THAN THE PREVIOUS ONE
     • DOESNT HAVE A UPPER LIMIT AND ITS LOGARITHMIC
     • MEASURES MAGNITUDE
   • MERCALLI SCALE
     • THE SCALE IS BETWEEN 1-12
     • MEASURED USING OBSERVATIONS
     • MEASURES IMPACT OF AN EARTHQUAKE

2. SEISMIC WAVES

   • SURFACE WAVES
     • LOVE WAVES
       • TRAVEL THROUGH SOLIDS ONLY
       • MOVE THE SURFACE SIDE TO SIDE
       • THESE WAVES ALSO CAUSE A LOT OF DAMAGE
         • BY THE SHEARING EFFECT
     • RAYLEIGH
       • CAN TRAVEL THROUGH LIQUIDS AND SOLIDS
       • MOVE THE SURFACE IN A ROLLING MOTION
   • S WAVES
     • TRAVEL THROUGH SOLIDS
     • MOVE AT 90 DEGREES TO THE DIRECTION OF TRAVEL
     • CAUSE A LOT OF DAMAGE BECAUSE OF THEIR SHEARING EFFECT
   • P WAVES
     • TRAVEL THROUGH LIQUIDS AND SOLIDS
     • WAVES PUSH AND PULL THE EARTH IN THE SAME DIRECTION AS THE WAVE IS TRAVELLING
     • TRAVEL FASTER THAN OTHER SEISMIC WAVES

3. EATHQUAKES ARE CAUSED BY THE TENSION THAT BUILDS UP AT ALL THREE PLATE MARGINS

   • WHEN THE PLATE JERK PAST EACH OTHER IT SENDS OUT SEISMIC WAVES
     • SPREAD OUT FROM THE FOCUS
       • DOESNT HAVE TO BE SINGLE POINT COULD BE A FAULT LINE
     • THE EPICENTRE IS TH EPOINT ON THE EARTHSURFACE WHERE THE EARTHQUAKE IS FIRST FELT
   • OTHER POSSIBE CAUSES OF AN EARTHQUAKE
     • REACTIVATION OF OLD FAULT LINE
     • SUBSIDENCE- WHERE THE GROUND SINKS AS A RESULT OF MINING
     • PRESSURE ON SURFACE ROCKS FROM WATER IN LARGE RESERVOIRS

4. SHALLOW FOCUS (0-70KM) CAUSE THE GREATEST DAMAGE

   • ACCOUNT FOR 75% OF ALL EARTHQUAKE ENERGY

5. INDERMEDIATE 70-300KM

6. FOCUS

   • DEEP 300-700KM

7. EFFECTS

   • TSUNAMI
     • ENORMOUS SEA WAVES GENERATED BY DISTURBANCES ON THE SEA FLOOR
     • MOST OFTEN TRIGGERED BY EARTHQUAKES AND SUBMARINE LANDSLIDES
     • MARCH 2011 JAPAN
   • LIQUEFACTION
     • WHEN VIOLENTLY SHAKEN SOILS WITH A HIGH WATER CONTENT LOSE THEIR MECHANICAL STRENGTH AND START TO BEHAVE LIKE A FLUID
     • SAN FRANCISCO
   • LANDSLIDES AND AVALANCHES
     • WHERE SLOPE FAILURE OCCURS AS A RESULT OF GROUND SHAKING

8. PREDICTION

   • SEISMOMETER
     • RECIEVES ARE RECORDS SHOCK WAVES FROM THE EPICENTRE
   • SATELLITE SURVEYING
     • SENSING PLATE MOVEMENT AND MINUTE CHANGES IN THE SURFACE
   • LASER REFLECTION
     • SURVEYING MOVEMENT ACROSS FAULT LINES
   • RADON GAS METER
     • INHERT GAS RADON IS RELEASED FROM MINERALS WHEN THEY ARE CRACKED AS PRESSURE INCREASES DURING THE BUILD UP