MOUNT ST HELENS | ||
INTRODUCTION - TYPES OF VOLCANOES | ||
VOLCANOES MADE OF 'RUNNY' LAVA - HAWAII | ||
VOLCANOES MADE OF 'RUNNY' LAVA - GALAPAGOS | ||
![]() VOLCANOES MADE OF EXPLODED SOLIDS (TEPHRA) | ||
VOLCANOES - MADE OF LAVA AND SOLIDS | ||
INTRODUCTION - TYPES OF MATERIALS | ||
![]() RUNNY LAVA | ||
RUNNY LAVA | ||
PASTY LAVA | ||
![]() ASH | ||
![]() LAPILLI | ||
![]() BOMBS AND BLOCKS | ||
![]() WELDED ASH (IGNIMBRITE) | ||
THE MAY 18, 1980 CATASTROPHIC ERUPTION OF MT. ST. HELENS | ||
![]() BEFORE | ||
![]() AFTER | ||
SETTING, PREVIOUS HISTORY, PRECURSOR EVENTS | ||
THE CASCADE RANGE | ||
![]() AFTER 123 YEARS QUIET, MARCH 20 QUAKES. ONE WEEK LATER, PHREATIC EXPLOSIONS | ||
![]() MAGMA RISE WITHIN MT -> 450' BULGE BY MAY 17. | ||
THE CATASTROPHIC EVENTS OF MAY 18, 1980 | ||
![]() 8:32 AM: M= 5.1 QUAKE; GIANT LANDSLIDE, MAJOR PUMICE AND ASH ERUPTION. 1300 FEET OF PEAK COLLAPSED OR BLEW OUTWARD, DEBRIS AVALANCHE, LAHARS | ||
FOUR SEQUENTIAL LANDSLIDE IMAGES: | ||
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LANDSLIDE DEPOSITS | ||
![]() DEBRIS AVALANCHE DEPOSITS | ||
PYROCLASTIC FLOW | ||
NINE HOUR VIGOROUS ASH PLUME ERUPTION. | ||
![]() ASH DEPOSITS | ||
![]() VOLCANIC ASH | ||
CLEANING UP. | ||
MAP OF ASH DISTRIBUTION | ||
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![]() EFFECT OF LATERAL BLAST | ||
FOREST DESTRUCTION - BEFORE | ||
![]() FOREST DESTRUCTION - AFTER | ||
MUD FLOWS (LAHARS) | ||
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![]() CRATER GLACIER - SOURCE OF WATER FOR LAHAR | ||
LAHAR | ||
HOUSE ENGULFED BY LAHAR | ||
MAILBOX ENGULFED BY LAHAR | ||
![]() LAHAR - DEPTH OF MUD | ||
![]() PYROCLASTIC FLOW | ||
![]() PUMICE BLOCKS AT EDGE OF PYROCLASTIC FLOW | ||
SUBSEQUENT EVENTS | ||
![]() FIVE MORE EXPLOSIVE ERUPTIONS IN 1980 | ||
![]() 1982 ERUPTION FOLLOWED BY LAHAR | ||
![]() DOME GROWTH AND DRAINAGE DEVELOPMENT | ||
![]() DOME GROWTH | ||
HAZARD ABATEMENT | ||
ON THE SCALE OF THINGS | ||
MONITORING NETWORKS | ||
![]() MEASURING DOME GROWTH | ||
![]() ESTABLISHING SEISMIC STATION NEAR DOME | ||
![]() COLLECTING GAS SAMPLES | ||
![]() MEASURING CRACKS IN CRATER FLOOR | ||
![]() REMOTE MONITORING STATIONS | ||
![]() LAKES DAMMED BY DEBRIS FLOW | ||
![]() FLOOD GAGES TO WARN OF DAM FAILURE | ||
![]() OUTLET CHANNELS | ||
![]() RIVER CHANNEL SEDIMENTATION | ||
![]() DREDGING | ||
![]() SEDIMENT RETENTION DAM | ||
![]() LIFE RETURNS | ||
EVENTS OF OCTOBER, 2004 | ||
![]() VISITOR OBSERVATION PLATFORM | ||
![]() DOME UPLIFT | ||
![]() PHREATIC EXPLOSIONS FROM DOME | ||
![]() CRATER ASH ERUPTION | ||
![]() ASH FALL ON CRATER FLOOR | ||
![]() DEBRIS FLOW CLOGS RIVER CHANNEL | ||
WHAT'S GOING ON? | ||
BEFORE | ||
AFTER | ||
![]() ARCHITECTURE, PROCESS AND MATERIALS | ||
SUBDUCTION ZONE | ||
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ERUPTIVE MECHANISMS | ||
![]() SUMMARY OF EVENTS |