(MUSIC)
JOAN CARTAN-HANSEN: HI, I'M JOAN
CARTAN-HANSEN.
AND WELCOME TO SCIENCE TREK: THE
WEB SHOW .
AND WELCOME TO CRATERS OF THE
MOON NATIONAL MONUMENT.
AS RECENTLY AS 2,000 YEARS AGO
THIS PLACE WAS ALIVE WITH ACTIVE
VOLCANOS.
JOINING US ARE TWO SCIENTISTS AT
BOISE STATE UNIVERSITY JEFF
JOHNSON AND BRITTANY BRAND.
THANK YOU BOTH FOR JOINING US.
BRITTANY BRAND: IT'S GREAT TO BE
HERE.
JEFF JOHNSON: THANKS FOR THE
OPPORTUNITY.
CARTAN-HANSEN: OKAY.
LET'S GO TO YOUR QUESTIONS.
(MUSIC)
COLLINS: MY NAME IS COLLINS, AND
I GO TO CYNTHIA MANN ELEMENTARY
SCHOOL.
AND MY QUESTION IS DO VOLCANOES
ERUPT BECAUSE OF EARTHQUAKES?
JOHNSON: SO VOLCANOES AND
EARTHQUAKES LIVE SIDE BY SIDE.
VOLCANOES WHEN THEY ARE GETTING
READY TO ERUPT ALWAYS PRODUCE
LITTLE EARTHQUAKES; SOMETIMES
MEDIUMSIZED EARTHQUAKES.
AND THIS IS A GOOD THING FOR
PEOPLE WHO ARE INTERESTED IN
TRYING TO FORECAST VOLCANIC
ERUPTIONS, BECAUSE A VOLCANO
THAT'S BECOMING RESTLESS WILL
START TO SHAKE THE GROUND AS THE
ROCK IS BROKEN AND THE MAGMA IS
COMING TOWARDS THE SURFACE.
DENNIS: HI, MY NAME IS DENNIS.
I GO TO A.J.
WINTERS ELEMENTARY.
AND MY QUESTION IS WHAT CAUSES A
VOLCANO TO ERUPT?
BRAND: A VOLCANO WILL ERUPT WHEN
MOLTEN MAGMA MAKES ITS WAY TO
THE SURFACE.
NOW, MAGMA IS WHAT WE CALL
"MOLTEN ROCK" WHEN IT'S INSIDE
THE GROUND; AND "LAVA" IS WHAT
WE CALL IT WHEN IT ERUPTS
OUTSIDE OF THE VOLCANO AND ONTO
THE GROUND.
MAGMA IS LIQUID, AND IT'S MOVING
UP THROUGH ROCK, WHICH MEANS
IT'S LESS DENSE, THIS LIQUID
MAGMA IS LESS DENSE THAN THE
SURROUNDING ROCK.
WHEN YOU HAVE SOMETHING THAT'S
LESS DENSE THAN WHAT'S AROUND
IT, IT'S GOING TO RISE TOWARDS
THE SURFACE, KIND OF LIKE A
HOTAIR BALLOON RISING THROUGH
COLD AIR.
IN THE CASE OF MAGMA, WHEN IT
MAKES ITS WAY TO THE SURFACE
IT'S GOING TO START TO PUSH ON
PUSH ON THE CRUST, AND THE
PRESSURE INSIDE OF THAT MAGMA
BODY WILL EVENTUALLY EXCEED THE
PRESSURE OF THE ROCK HOLDING IT
IN AND BREAK THROUGH TO ERUPT AT
A VOLCANO.
IT'S KIND OF LIKE FILLING UP A
WATER BALLOON A LITTLE BIT TOO
FULL AND THE WATER BALLOON
BURSTING.
THE SAME KIND OF PROCESS WITH
MAGMA ERUPTING ONTO THE SURFACE
AS LAVA.
QUINN: HI, MY NAME IS QUINN, AND
I GO TO GATEWAY ELEMENTARY.
I WAS JUST WONDERING WHAT ARE
THE KEY REASONS WHY SOME
VOLCANOES STRONGLY AFFECT GLOBAL
CLIMATE AND SOME DON'T?
JOHNSON: SO THERE ARE TWO
INGREDIENTS THAT ARE NECESSARY
FOR A VOLCANO AND ITS ERUPTION
TO AFFECT CLIMATE GLOBALLY.
FIRST OF ALL, YOU NEED A BIG
ERUPTION; YOU NEED TO SEND
MATERIAL UP INTO THE
STRATOSPHERE, WHICH IS MORE THAN
6 MILES ABOVE SEA LEVEL.
SECONDLY, YOU NEED TO ERUPT
SULFUR GAS IN LARGE QUANTITIES
SO THAT THAT SULFUR GAS REACTS
WITH THE ATMOSPHERE AND CREATES
SULFATE PARTICLES, WHICH
EFFECTIVELY BLOCK SUNLIGHT FROM
REACHING THE EARTH.
CORTNEY: HI, MY NAME IS CORTNEY,
AND I GO TO CYNTHIA MANN
ELEMENTARY SCHOOL.
AND MY QUESTION IS HOW LONG DOES
IT TAKE UNTIL LAVA TURNS INTO
ROCK?
BRAND: WELL, IT REALLY DEPENDS.
ONE THING TO KEEP IN MIND IS
THAT WHEN LAVA ERUPTS ONTO THE
SURFACE IT'S SO HOT THAT JUST
INTERACTING WITH THE COOL AIR
AROUND IT, THE SURFACE WILL COOL
VERY QUICKLY MAYBE WITHIN
MINUTES IT WILL FORM A CRUST
THAT'S SOLID ENOUGH THAT YOU
COULD ACTUALLY WALK ON IT, BUT
IT MIGHT MELT YOUR BOOTS BECAUSE
THERE'S STILL A LOT OF MOLTEN
STUFF JUST UNDERNEATH THAT
CRUST, WHICH IS GOING TO TAKE
LONGER TO COOL.
SO LAVA FLOWS IN HAWAII, FOR
EXAMPLE, THE CRUST WILL COOL
VERY QUICKLY, WITHIN MINUTES OF
FLOWING ACROSS THE SURFACE, BUT
THE CENTER MOLTEN PART CAN BE
MOLTEN FOR QUITE A BIT LONGER.
IN ANOTHER CASE, SOMETIMES
VOLCANOES CAN GENERATE LAVA
LAKES.
AND THIS IS WHERE LAVA WILL
ACTUALLY ERUPT OUT OF A VENT AND
FILL IN THE CRATER OF A VOLCANO.
IN THIS CASE, IF THE VOLCANO IS
SHUT OFF AND THE LAVA IS SHUT
OFF, THE CENTER OF THAT LAVA
LAKE WILL TAKE A VERY LONG TIME
TO COOL.
SO A GOOD EXAMPLE OF THIS IS THE
KILAUEA IKI ERUPTION IN HAWAII,
WHICH WAS JUST A FLANK VENT FROM
KILAUEA.
IN THIS ERUPTION THERE WAS A
LAVA LAKE THAT WAS 150 FEET
THICK.
THE CRUST COOLED IMMEDIATELY.
THERE WERE VOLCANOLOGISTS
WALKING ACROSS IT AND DRILLING
DOWN TO TAP INTO THE LAVA AND
GET SAMPLES.
IT TOOK MORE THAN 30 YEARS FOR
THAT LAVA INSIDE KILAUEA IKI'S
LAVA LAKE TO COOL.
ELSA: MY NAME IS ELSA, AND I GO
TO LONGFELLOW ELEMENTARY.
AND MY QUESTION IS WHAT IS THE
BIGGEST ERUPTION EVER RECORDED?
JOHNSON: ONE OF THE BIGGEST
HISTORICAL ERUPTIONS THAT HAS
OCCURRED DURING IN RECENT TIMES
HAS BEEN THE ERUPTION OF TAMBORA
VOLCANO IN INDONESIA, WHICH
ERUPTED IN 1815 AND RELEASED 165
CUBIC KILOMETERS OF MAGMA.
HOW MUCH IS THAT?
WELL, THAT WAS ABOUT 160 TIMES
THE SIZE OF MOUNT ST. HELEN'S
ERUPTION.
THIS ERUPTED IN 1815, AND IT
CAUSED LOTS OF LOSS OF LIFE.
IT CHANGED THE CLIMATE OF THE
PLANET, AND IT GENERATED OR
PRODUCED A GIANT HOLE IN THE
GROUND CALLED A CALDERA.
TONY: HI, MY NAME IS TONY.
AND I GO TO WHITE PINE
ELEMENTARY.
AND MY QUESTION IS WHICH VOLCANO
IS MOST DANGEROUS, THE CINDER
CONE, COMPOSITE VOLCANO, OR A
SHIELD VOLCANO?
BRAND: WHAT MAKES A VOLCANO
DANGEROUS ISN'T NECESSARILY THE
TYPE OF VOLCANO IT IS OR WHETHER
OR NOT IT'S GOING TO HAVE A LAVA
FLOW ERUPTION OR AN EXPLOSIVE
ERUPTION THAT FORMS ASH.
WHAT MAKES A VOLCANO DANGEROUS
IS WHEN THERE ARE PEOPLE LIVING
IN THE PATH OF POTENTIAL
VOLCANIC HAZARDS.
SO, FOR EXAMPLE, THE MOST
DANGEROUS VOLCANO IN THE UNITED
STATES IS MOUNT RAINIER.
AND THAT'S BECAUSE THERE ARE
HUNDREDS OF THOUSANDS OF PEOPLE
LIVING ALONG THE FLANKS AND
DOWNSTREAM FROM MOUNT RAINIER.
ANOTHER VERY DANGEROUS VOLCANO,
WORLDWIDE, IS MOUNT VESUVIUS, IN
ITALY.
MOUNT VESUVIUS IS FAMOUS FOR ITS
79 AD ERUPTION WHICH TOOK OUT
THE TOWNS OF HERCULANEUM AND
POMPEII.
THERE ARE CURRENTLY MORE THAN
500,000 PEOPLE LIVING IN THAT
ZONE.
SO THOSE ARE CLEARLY VERY
DANGEROUS, THESE STRATOVOLCANOES
THAT ARE FAMOUS FOR PRODUCING
VERY EXPLOSIVE ERUPTIONS WHERE
ASH CANNOT ONLY GO UP INTO THE
SKY BUT CAN COLLAPSE BACK DOWN
TO FORM THESE GROUNDHUGGING
CLOUDS OF ASH, GAS, AND ROCK
THAT BURY LANDSCAPES.
BUT A SHIELD VOLCANO OR A CINDER
CONE COULD BE EQUALLY AS
DANGEROUS IF THERE ARE PEOPLE IN
THE PATH OF THE LAVA.
SO, REALLY, IT DEPENDS ON
WHETHER NOT WHETHER OR NOT A
VOLCANO IS GOING TO ERUPT, BUT
WHETHER OR NOT THERE ARE PEOPLE
LIVING IN A ZONE THAT OVERLAPS
WITH THE VOLCANIC HAZARDS WHEN
THE VOLCANO ERUPTS.
CARTAN-HANSEN: I'M SORRY, WE'VE
RUN OUT OF TIME.
MY THANKS TO JEFF AND BRITTANY
FOR ANSWERING QUESTIONS.
BRAND: THANK YOU FOR HAVING US.
JOHNSON: YEAH.
AND THANKS FOR THE GREAT
QUESTIONS.
CARTAN-HANSEN: AND THANKS, TOO,
TO THE FOLKS AT BOISE STATE
UNIVERSITY AND THE FOLKS HERE AT
CRATERS OF THE MOON NATIONAL
MONUMENT FOR HOSTING US.
IF YOU WANT TO LEARN MORE, CHECK
OUT THE VOLCANOES AREA ON THE
SCIENCE TREK WEBSITE.
YOU'LL FIND FACTS, LINKS, GAMES,
OUR VOLCANOES BROADCAST SHOW,
AND LOTS MORE.
AND EVERY WEEK CHECK OUT MY BLOG
FOR THE LATEST SCIENCE NEWS FOR
KIDS.
ALL AT IDAHOPTV.ORG.
THANKS FOR JOINING US FOR
SCIENCE TREK: THE WEB SHOW .