Download CHAPTER 12 VOLCANOES

CHAPTER 12 VOLCANOES
SECTION 1
VOLCANOES AND EARTH’S PLATES
 KILAUEA IS WORLD’S MOST ACTIVE VOLCANO
 ICELAND IS FAMOUS FOR ACTIVE VOLCANOES.
EFFECTS OF ERRUPTIONS
 AFFECT LIVES AND PROPERTY
 ASH CAN BLOCK ROADS, COLLAPSE BUILDINGS AND CAUSE LUNG
DISEASE
 SOME VOLCANIC DEBRIS CAN MAKE A PYROCLASTIC FLOW,
BURNING EVERYTHING IN ITS PATH
HUMAN AND ENVIRONMENTAL IMPACTS
 SULFURIC ACID MIXES WITH WATER VAPOR AND FORMS ACID RAIN,
WHICH CAN KILL VEGETATION AND POLLUTE LAKES AND STREAMS
HOW DO VOLCANOES FORM
 HEAT AND PRESSURE CAUSE ROCKS TO MELT
 LESS DENSE MAGMA IS FORCED TO SURFACE
 AFTER THOUSANDS OR MILLIONS OF YEARS, LAVA REACHES
SURFACE AND OOZES OUT OF VENTS, MAKING CONE SHAPED MTN.
WHERE DO VOLCANOES OCCUR?
DIVERGENT BOUNDARIES
 ICELAND IS ON TOP OF THE MID-ATLANTIC RIDGE
 PLATES SEPARATE FORMING VOLCANOES FROM SEAFLOOR
SPREADING
CONVERGENT BOUNDARIES
 PLATES COLLIDE FORMING SUBDUCTION ZONE
 PLATE MELTS, MAGMA MIXES WITH STEAM, GETS PRESSURIZE AND
EXPLODES VIOLENTLY
HOT SPOTS
 VOLCANIC ISLANDS THAT FORM IN MIDDLE OF PLATE
 MANTLE AND CRUST ARE VERY HOT, MAGMA FLOWS TO SURFACE
FORMING HOT SPOT
 CREATES A CHAIN OF VOLCANOES
THE HAWAIIAN ISLANDS
 ISLANDS ARE BEING MOVED WITH PLATE CREATING NEW VOLCANO
WHERE PREVIOUS ONE WAS
 THESE ISLANDS FORMED OVER PAST 5 MILLION YEARS