CHAPTER 11 SECTION 2
FEATURES OF EARTHQUAKES
SEISMIC WAVES
 EARTHQUAKE WAVES THAT TRAVEL THROUGH EARTH
 ENERGY IS RELEASED WHEN ROCKS PASS THEIR ELASTIC LIMIT.
 ENERGY IS RELEASED AT THE FOCUS
KINDS OF WAVES
 PRIMARY WAVE-MOVE BACK AND FORTH IN THE DIRECTION WAVE
TRAVELS. FASTEST WAVE
 SECONDARY WAVE-SECOND FASTEST, PARTICLES MOVE AT RIGHT
ANGLES IN THE DIRECTION WAVE TRAVELS
 SURFACE WAVES-SLOWEST BUT MOST DESTRUCTIVE WAVE, MOVES
PARTICALS IN ALL DIRECTIONS. OCCUR WHEN WAVE REACHES
SURFACE. CAUSE MOST DAMAGE AT THE EPICENTER
LOCATING AN EPICENTER
 NEED AT LEAST THREE SEISMOGRAPH STATIONS TO FIND AN
EPICENTER
MEASURING SEISMIC WAVES
 SEISMOGRAPH RECORDS THE ENERGY RELEASED ON A DRUM OF
PAPER
SEISMOGRAPH STATIONS
 FROM AN EARTHQUAKE, PRIMARY WAVES ARRIVE FIRST,
SECONDARY WAVES SECOND AND SURFACE WAVES LAST
BASIC STRUCTURE OF EARTH
 SOLID CORE, LIQUID OUTER CORE, FLUIDY LOWER MANTLE,
THICKER, GOOEY UPPER MANTLE, AND CRUST ON THE SURFACE
 MANTLE IS LARGEST LAYER
 CRUST CAN BE 60 KM THICK IN SOME MTN. AREA AND ONLY 5 KM
THICK ON THE OCEAN BOTTOM
MAPPING EARTH’S INTERNAL STRUCTURE
 THEY STUDY THE WAY THE WAVES TRAVEL THROUGH THE PLANET.
THIS TELLS THEM IF IT IS A LIQUID OR A SOLID