Original subtitles

NEAR SAN FRANCISCO,

SEISMOLOGISTS ARE BRACING FOR THE NEXT BIG QUAKE,

AND NEW EVIDENCE DEEP UNDERGROUND SUGGESTS

IT COULD BE BIGGER THAN ANYONE IMAGINED.

COULD CALIFORNIA'S FAULT LINES SOON COMBINE FORCES

TO UNLEASH A HISTORIC MEGAQUAKE?

WE'LL SET OFF A SERIES OF SEISMIC EXPLOSIONS TO FIND OUT.

EXPECT A MAJOR EARTHQUAKE ON THIS FAULT.

- REALLY? - THIS IS DEADLY SERIOUS.

AND FURTHER UP THE PACIFIC COAST,

A HOLE SEEMS TO BE DRAINING THE OCEAN.

IS THOR'S WELL A PORTAL TO THE CENTER OF THE EARTH?

I'LL SEND AN R.O.V. INTO THE BELLY OF THE BEAST.

WHOA!

HIDDEN JUST BELOW THE EARTH'S SURFACE,

THERE ARE COUNTLESS UNSOLVED MYSTERIES.

AND, TODAY, WE FINALLY HAVE THE TOOLS TO UNLOCK THEM.

LOOK AT THAT!WHOA.

I THINK THIS IS IT.

I'M ROB NELSON,

A SCIENTIST USING STATE-OF-THE-ART TECHNOLOGY

TO PEEL THE LID OFF OUR PLANET'S HIDDEN DEPTHS.

THE MOMENT OF TRUTH RIGHT HERE.

HOLY MOLY!

THESE ARE THE SECRETS OF THE UNDERGROUND.

Captions by VITAC-- www.vitac.com

CAPTIONS PAID FOR BY DISCOVERY COMMUNICATIONS

JUST NORTH OF SAN FRANCISCO, DEEP BENEATH THE SAN PABLO BAY,

LIES ONE OF NORTH AMERICA'S MOST MISUNDERSTOOD DANGERS,

AN INTERCONNECTED NETWORK OF ACTIVE FAULTS.

FOR DECADES, SCIENTISTS BELIEVED

EACH OF THESE FAULT LINES ACTED INDEPENDENTLY,

BUT NEW EVIDENCE SUGGESTS

THEY COULD ALL TRIGGER AT THE SAME TIME.

IF THIS IS TRUE,

THE NEXT BIG ONE IN THE BAY AREA

COULD BE MUCH BIGGER THAN ANTICIPATED.

FAULT LINES ARE FRACTURES IN THE EARTH'S CRUST

WHERE TWO TECTONIC PLATES MEET.

AND THE MOVEMENT OF THOSE PLATES IN RELATION

TO EACH OTHER IS WHAT CAUSES EARTHQUAKES.

IT SO HAPPENS THAT THE PACIFIC AND NORTH AMERICAN PLATES

INTERSECT ALONG THE ENTIRE WEST COAST OF THE UNITED STATES,

MAKING ONE OF AMERICA'S MOST CROWDED REGIONS

ONE OF ITS MOST SEISMICALLY UNSTABLE.

FORTUNATELY, A LEGION OF SEISMOLOGISTS

ARE NOW ON THE CASE,

AND I'M HEADED OUT THERE TO JOIN THEM--

IN THE HEART OF THE EARTHQUAKE ZONE.

WE'RE IN THE MIDDLE OF SAN PABLO BAY.

WE'RE KIND OF ON THE NORTH END OF THE BAY AREA.

THIS SEEMINGLY PLACID SPOT MIGHT ACTUALLY BE ONE

OF THE MOST SEISMICALLY DANGEROUS PLACES IN AMERICA.

MOST OF US ARE FAMILIAR WITH THE SAN ANDREAS FAULT,

BUT SOME SEISMOLOGISTS BELIEVE

THAT TWO OTHER FAULTS IN THIS AREA,

THE HAYWARD AND RODGERS CREEK,

ARE POTENTIALLY MORE DANGEROUS.

AND BOTH OF THEM RUN DIRECTLY UNDER SAN PABLO BAY.

WHAT YOU CAN SEE IS THAT

THE HAYWARD FAULT ZONE RUNS RIGHT LIKE THIS.

AND YOU'VE GOT THE RODGERS CREEK FAULT ZONE, WHICH RUNS UP HERE.

UNTIL RECENTLY, IT WAS THOUGHT

THE TWO FAULTS ENDED THREE MILES APART.

BUT A RECENT SEISMIC ANALYSIS IS

CHALLENGING THIS ASSUMPTION BY SUGGESTING

THAT FAR BELOW THE SAN PABLO BAY,

THESE TWO FAULTS ARE CONNECTED.

AND IF THAT'S THE CASE, COULD ONE TRIGGER THE OTHER

AND MAGNIFY THE POWER OF THE NEXT BIG QUAKE?

EXPERTS ARE RACING TO FIND OUT.

IT'S ACTUALLY A LITTLE BIT HARD TO BELIEVE

THAT WE COULD HAVE MISSED SOMETHING THIS BIG.

AND IT MAKES ME WONDER, IF WE MISSED THIS,

WHAT ELSE HAVE WE BEEN MISSING?

COULD THE WHOLE WEST COAST BE

A GIANT INTERCONNECTED FAULT SYSTEM?

I'M HERE TO FIND OUT.

TO GET A CLEAR VISUAL OF THESE INTERCONNECTED FAULTS,

I'M MEETING UP WITH BRAD AAGAARD

FROM THE UNITED STATES GEOLOGIC SURVEY, OR USGS.

HIS COMPUTER MODELS CREATE PRECISE EARTHQUAKE SIMULATIONS

WHERE BOTH FAULTS TRIGGER AT ONCE.

SO HERE YOU CAN SEE THE RUPTURE

UNDERNEATH SAN PABLO BAY

PROPAGATING HERE ALONG THE RODGERS CREEK FAULT

AND SIMULTANEOUSLY HERE ALONG THE HAYWARD FAULT.

THE COOLER BLUE COLORS INDICATE LESS INTENSE SHAKING,

WHILE THE WARMER RED COLORS INDICATE MORE INTENSE SHAKING.

WELL, THIS LOOKS REALLY BAD

BECAUSE IT NOT ONLY HITS THIS WHOLE AREA,

IT ALSO HITS THAT WHOLE AREA REALLY BAD.

RIGHT, SO WE WOULD HAVE SEVERE DESTRUCTION

OF ALL INFRASTRUCTURE, POWER, GAS PIPELINES, AND SO FORTH.

THIS IS ONE OF THE WORST CASES FOR THE SAN FRANCISCO BAY AREA

BECAUSE IT REALLY AFFECTS

SUCH A LARGE AMOUNT OF OUR POPULATION.

BUT THIS MIGHT NOT EVEN BE THE WORST NEWS.

IF MULTIPLE OTHER FAULT LINES ARE CONNECTED,

WHAT IS THE LIKELIHOOD OF A BIG EARTHQUAKE

IN THIS REGION IN THE NEXT 30 YEARS?

IT'S ABOUT 72%.

HOLY MOLY!

IF THE CONNECTIONS BETWEEN CALIFORNIA'S FAULT LINES

EXTEND BEYOND JUST THE HAYWARD AND RODGERS CREEK FAULTS,

IT SOUNDS LIKE THE WEST COAST IS IN FOR A HEAP OF TROUBLE.

CHECK THIS OUT.

YOU CAN SEE THE ENTIRE CITY FROM UP HERE.

WHOA!

FROM THIS VANTAGE POINT,

YOU CAN ACTUALLY LOOK OUT ACROSS THE WHOLE BAY AREA.

AND IF YOU LOOK RIGHT DOWN HERE, YOU SEE THAT LITTLE DIP?

THAT'S THE HAYWARD FAULT.

SO A RUPTURE ALONG THIS FAULT

WOULD AFFECT THE HOUSES AND INFRASTRUCTURE UP HERE

AS WELL AS ALONG THE RODGERS CREEK FAULT.

AND IT MULTIPLE FAULTS ARE CONNECTED,

IT COULD MEAN EVEN MORE DEVASTATION.

BUT JUST HOW PLAUSIBLE IS THIS THEORY

ABOUT MULTIPLE CONNECTED FAULTS?

TO FIND OUT, I'M MEETING UP WITH TWO OF THE SEISMOLOGISTS

WHO DISCOVERED THE CONNECTION

BETWEEN THE HAYWARD AND RODGERS CREEK FAULTS,

JANET WATT AND TOM PARSONS.

WHAT HAPPENS WHEN WE KIND OF TAKE A STEP BACK,

AND WE LOOK AT THE WHOLE WEST COAST?

ALL FAULTS MAY BE CONNECTED.

THIS IS A MAP OF THE GEOLOGY OF CALIFORNIA.

YOU CAN SEE THE FAULTS VERY CLEARLY.

IF ALL THESE FAULTS ARE REALLY CONNECTED,

THAT WOULD EFFECTIVELY CREATE AN 800-MILE SUPERFAULT

STRETCHING THE LENGTH AND BREADTH OF CALIFORNIA.

WE THINK A RUPTURE PROPAGATING ALONG HERE

ACTIVELY CAN JUMP AROUND AT LEAST FIVE KILOMETERS

FROM FAULT TO FAULT AS IT'S RUPTURING.

REALLY?

IN THEORY, THE WHOLE WEST COAST

IS AN INTERCONNECTED FAULT SYSTEM,

AND EARTHQUAKES COULD JUMP ACROSS THE WHOLE THING.

WE PAY A PRICE FOR THE TOPOGRAPHY

AND THE BEAUTY OF THE COASTLINE, THAT'S FOR SURE.

THERE ARE EXISTING STUDIES THAT ATTEMPT TO PREDICT

WHAT THE BIG ONE MIGHT LOOK LIKE,

AND EVEN WITHOUT FACTORING IN MULTIPLE FAULTS,

THE PROGNOSIS IS PETRIFYING.

EXPERTS PREDICT THAT A MAGNITUDE-8 EARTHQUAKE

ALONG THE SOUTHERN SAN ANDREAS FAULT ALONE

WOULD RATTLE MOST OF SOUTHERN CALIFORNIA

CONTINUOUSLY FOR MORE THAN 75 SECONDS.

IT WOULD EASILY ECLIPSE

THE NATION'S DEADLIEST TREMOR ON RECORD,

SAN FRANCISCO'S INFAMOUS 1906 EARTHQUAKE,

WHICH CAUSED AN ESTIMATED 3,000 DEATHS.

TODAY, THE BAY AREA'S POPULATION

IS OVER EIGHT TIMES WHAT IT WAS THEN.

WHICH IS WHY IT'S SO CRUCIAL TO FIGURE OUT

HOW THESE FAULTS MAY BE CONNECTED

AND WHAT AREAS ARE MOST LIKELY TO BE OBLITERATED

IF THEY ALL TRIGGER AT ONCE.

SO WHAT IS THIS?

AS IT HAPPENS, A USGS FIELD TEAM

IS ACTIVELY WORKING TO ANSWER THAT QUESTION.

SO I'M JOINING THEM HIGH IN THE HILLS

- NEAR THE HAYWARD FAULT... - IT'S IN THESE TREES.

...SOUTHEAST OF OAKLAND TO TRY SOMETHING

THAT MIGHT SOUND A LITTLE INSANE.

WE'RE GOING TO TRIGGER OUR OWN SET OF MINI EARTHQUAKES

WITH A SERIES OF UNDERGROUND EXPLOSIONS.

WILL WE UNCOVER HIDDEN CONNECTIONS

BETWEEN SOME OF THE WEST COAST'S MOST DANGEROUS FAULTS?

AND LATER, I'LL HEAD TO OREGON

WHERE A STRANGE HOLE CALLED THOR'S WELL

SEEMS TO BE DOING THE IMPOSSIBLE--

DRAINING THE PACIFIC OCEAN.

I'VE NEVER SEEN ANYTHING QUITE LIKE THIS!

WHERE IS ALL THAT WATER GOING?

WHOA!

SHOCKING NEW EVIDENCE

HAS REVEALED THAT TWO OF CALIFORNIA'S

MOST DANGEROUS FAULT LINES

ARE CONNECTED AND COULD TRIGGER SIMULTANEOUSLY.

BUT COULD OTHERS ALSO BE CONNECTED?

TO FIND OUT, I'M TEAMING UP WITH MEMBERS OF THE USGS

TO PLANT SENSORS IN THE GROUND

AS PART OF A SEISMIC IMAGING SURVEY.

ALL RIGHT. LET'S DO IT.

COOL.

WE SET OFF IN THE HILLS OUTSIDE OF OAKLAND

WITH EIGHT SENSORS IN OUR PACKS

AND ONLY A FEW HOURS TO GET THEM ALL BURIED

- BEFORE NIGHTFALL. - THEY'RE OVER HERE.

THE SENSORS WILL MEASURE VIBRATIONS

FROM CONTROLLED DETONATIONS,

WHICH WE'LL SET OFF LATER TONIGHT.

THIS WILL GIVE US A CLEARER PICTURE

OF WHAT'S HAPPENING UNDERGROUND

AND WHETHER THE FAULTS IN THIS AREA ARE INTERCONNECTED.

IT SOUNDS SIMPLE ENOUGH,

BUT THE ROUGH TERRAIN AND THE TRICKY NATURE

OF PINPOINTING WHERE EACH SENSOR

SHOULD BE BURIED LEAVES NO MARGIN FOR ERROR.

SO THESE ARE ALL THE SENSORS.

YEAH.

THERE ARE THREE PRONGS.

EACH OF THE PRONGS IS DETECTING A DIFFERENT VIBRATION.

THESE HAVE VERY ACCURATE CLOCKS INSIDE OF THEM

SO THAT WHEN THEY SET OFF THOSE CHARGES,

THEY KNOW HOW LONG IT TAKES THOSE WAVES

TO TRAVEL THROUGH THE SUBSURFACE AND BACK TO THESE INSTRUMENTS.

SO THEY CAN ACTUALLY DETERMINE

WHAT THINGS LOOK LIKE MILES BENEATH THE SURFACE.

YEAH, EXACTLY.

SO BY TAKING THE DATA FROM ALL OF THESE,

WE'LL BE ABLE TO FIGURE HOW CONNECTED THESE FAULTS ARE.

SHOWED UP TO THE SCENE THIS MORNING

AND PRETTY MUCH EVERYBODY FELT LIKE THERE

WAS A SENSE OF URGENCY GOING ON.

HOPEFULLY, THE MORE WE KNOW ABOUT IT, THE BETTER WE'LL KNOW

WHERE TO SEND FIRST RESPONDERS TO THE AREAS

THAT ARE GOING TO BE HIT WORST.

RIGHT.

WHOA. WE'RE GOING DOWN THROUGH HERE?

THIS IS IT RIGHT HERE.

IT'S IMPORTANT, YEAH, THAT WE MOSTLY COVER THESE UP.

WE'VE GOT THE FIRST SENSOR BURIED.

NOW WE NEED TO REPEAT THE PROCESS SEVEN MORE TIMES.

AND WE'RE QUICKLY RUNNING OUT OF DAYLIGHT.

IT'S GOT TO BE GOOD AND STUCK IN THE GROUND.

IT CAN'T BE MOVING AROUND. A SECURE CONNECTION.

- OH, HERE WE GO. - OH, YEAH.

IT FEELS LIKE WE'RE PUTTING BOMBS IN

BECAUSE WE'RE BEING SO CAREFUL WITH THESE INSTRUMENTS.

THEY'RE NOT BOMBS. THAT'S LATER.

YES.

A TOTAL OF 14 DETONATIONS ARE SCHEDULED

TO TAKE PLACE FROM MIDNIGHT TO 5:00 A.M.

BECAUSE IT'S THE QUIETEST

AND SAFEST TIME TO SET OFF EXPLOSIVES.

THERE WE GO. THERE WE GO.

WE DID IT.

BY DUSK, ALL THE SENSORS ARE IN PLACE.

NOW, I MET WITH THE TEAM LEADERS

TO PREP FOR OUR DETONATIONS.

OKAY, GUYS, THE EXPLOSIVE

IS AN AMMONIA NITRATE DIESEL FUEL BASE.

THIS IS DEADLY SERIOUS.

YOU SET IT OFF IN A CONFINED SPACE,

YOU GUYS GO, SO DO WE.

WE'RE GOING TO BE A LITTLE BIT, YOU KNOW,

INSISTENT ON THINGS

BECAUSE IT'S FOR YOUR SAFETY AS WELL AS OURS.

IF YOU HAVE KIDS, YOU WANT TO GO HOME TO YOUR KIDS.

ALL RIGHT? WE WANT TO GO HOME TO OUR KIDS.

SURE.

SO THAT'S THE MAIN THING RIGHT NOW.

THAT'S GREAT.

LET'S ROLL.

- ALL RIGHT. - OKAY.

THIS IS THE MOMENT OF TRUTH.

IF THIS EXPERIMENT REVEALS MORE FAULT LINES

UNDER THE BAY AREA ARE CONNECTED,

THAT COULD MEAN THE SEISMIC DANGER IN CALIFORNIA

IS BIGGER THAN PREVIOUSLY THOUGHT.

WE HAVE ABOUT 500 SENSORS SPREAD OUT ACROSS THE AREA.

THOSE THINGS WILL PICK UP THE VIBRATIONS,

ALLOW US TO SEE WHAT THESE FAULTS ARE LIKE

AND IF THEY'RE INTERCONNECTED.

SO WE ARE ON TOP OF A BIG HILL OVERLOOKING THE CITY.

RIGHT DOWN THERE IS ONE OF THE CHARGES.

THEY MARK THEM WITH A ROCK.

AND HOW FAR IS IT BURIED DOWN THERE?

MAYBE 20 FEET DOWN TO MAYBE 30 FEET.

FIRST, THE CHARGE CABLE THAT'S BEEN CONNECTED

TO THE EXPLOSIVES IS LAID OUT.

THIS IS GOING TO BE CONNECTED TO AN ELECTRICAL CABLE.

YEAH.

THIS BURNS AT 15,000 FEET PER SECOND.

THREE MILES IN A SECOND.

WHOA.

IF YOU HAVE A WHOLE SERIES OF FAULTS THAT ARE CONNECTED,

THE AREA THAT COULD RUPTURE

DURING A MAJOR EARTHQUAKE IS MUCH WIDER.

- I SEE. - I THINK OF THIS ZONE

AS BEING A SERIES OF FAULTS.

AND THEY ALL LIKELY MERGED TO A THICK ZONE AT DEPTH.

AND IF WE HAVE A BIG EARTHQUAKE, SAY,

ON THE HAYWARD FAULT HERE, THIS ENERGY,

JUST LIKE A TREE, IF IT COMES DOWN ONE BRANCH,

IT'S GOING TO GO BACK UP THE NEXT.

SO IF YOU HAVE AN EARTHQUAKE HERE,

AND YOU THINK THIS FAULT HERE IS DORMANT,

YOU HAVE YOUR HOSPITAL, DAM AND UNIVERSITY

ON TOP OF IT,

IT MAY GET SEVERELY SHAKEN

BECAUSE THAT ENERGY WILL GO DOWN,

IT RADIATES THIS WAY, DOWN,

AND THEN BACK UP AGAIN AND BACK UP AGAIN

- AND BACK UP AGAIN. - WHOA.

WE WANT TO TRY TO UNDERSTAND HOW THEY CONNECT.

OKAY, WE'LL GO THREE MINUTES!

AS SOON AS THEY GET THESE THINGS COVERED UP

AND THE SANDBAGS ON THEM,

WE'RE GOING TO SET OFF THE CHARGE.

IT'S GO TIME.

OKAY, LET'S DO IT.

HOLY MOLY! THAT WAS AWESOME!

THAT WAS A GOOD SHOT.

- RADIAL CRACKS. - GOODNESS, LOOK AT THIS.

IT BLEW ALL THESE CRACK LINES.

THAT LOOKS LIKE A SPIDER WEB.

THE PYROTECHNICS ARE FUN,

BUT WE CAN'T AFFORD TO TAKE OUR EYES OFF THE BALL.

WE HAVE LESS THAN FIVE HOURS

TO SET OFF ALL SEVEN EXPLOSIONS

ACROSS A 10-MILE SURVEY AREA.

SO WITH THE CLOCK TICKING, WE RACE TO OUR NEXT LOCATION.

FIVE SECONDS!

IT WILL TAKE SEVERAL DAYS TO CRUNCH THE DATA WE COLLECTED,

AND I'M ANXIOUS TO SEE WHAT IT REVEALS

BECAUSE IT COULD COMPLETELY CHANGE OUR PERCEPTION

OF THE DANGER LURKING BENEATH CALIFORNIA.

IS ANYONE SAFE FROM THE NEXT MEGAQUAKE?

I'M WITH A TEAM OF GEOLOGISTS

HIGH ABOVE THE BAY AREA

SETTING OFF A SERIES OF EXPLOSIONS

FOR A SEISMIC IMAGING SURVEY.

THAT WAS AWESOME.

SOME SEISMOLOGISTS BELIEVE THE NEXT BIG ONE IS COMING SOON,

AND IT COULD BE FAR BIGGER THAN ANYONE ANTICIPATED.

HOW BIG?

I'M HOPING THE RESULTS OF THIS SURVEY WILL TELL US.

LET'S GO, GUYS.

BUT WHILE THE DATA ROLLS IN ALMOST INSTANTLY,

IT WILL TAKES DAYS TO INTERPRET,

SO I'LL HAVE TO CHECK BACK IN WITH THE TEAM LATER.

NO MATTER WHAT THE RESULTS ARE,

FAULT LINES AND MAGNITUDE ARE ONLY PART OF THE STORY.

NEW TECHNOLOGY IS ALSO REVEALING

WHICH AREAS AROUND THOSE FAULTS

WILL SUFFER THE WORST DAMAGE.

IT'S NO SECRET THAT EARTHQUAKES AND DENSELY POPULATED AREAS

ARE A DEADLY COMBINATION,

AS ANYONE AROUND ON OCTOBER 17, 1989 CAN ATTEST.

A 6.9-MAGNITUDE QUAKE STRUCK A PORTION

OF THE SAN ANDREAS FAULT JUST SOUTH OF SILICON VALLEY.

IT CONTINUED FOR A FULL 15 SECONDS,

CLAIMING 63 LIVES,

INJURING OVER 3,000

AND CAUSING OVER $5 BILLION IN DAMAGE.

THE QUAKE WAS FELT FOR 400 MILES,

FROM LOS ANGELES TO SACRAMENTO.

INTRIGUINGLY, THAT EARTHQUAKE WAS MUCH TOUGHER

ON SOME PARTS OF THE BAY AREA THAN OTHERS.

NEIGHBORHOODS IN WATSONVILLE AND LOS GATOS

WERE VIRTUALLY DESTROYED,

WHILE OTHERS IN NEARBY SAN JOSE EMERGED

RELATIVELY UNSCATHED.

BUT WHY?

AND CAN WE FIGURE OUT WHAT AREAS ARE IN THE MOST DANGER

BEFORE THE NEXT BIG ONE STRIKES?

WHILE I WAIT FOR THE RESULTS OF THE DETONATION TEST,

I'M HEADING TO OAKLAND TO MEET

WITH GEOLOGIST GRETCHEN SCHMAUDER.

SHE HAS A WAY TO TEST THE TOUGHNESS

OF THE GROUND BENEATH OUR FEET.

SOIL MAKES HUGE CONTRIBUTIONS

TO WHAT WE SEE WHEN WE HAVE AN EARTHQUAKE.

MY FIRST THOUGHT IS IF YOU'RE ON HARD GROUND,

AND YOU HAVE THE GROUND SHAKING, YOU'RE GOING TO SHAKE MORE,

WHEREAS IF YOU HAVE SOME SORT OF LOOSE SOIL,

THEN MAYBE IT WOULD BE A BUFFER.

IT'S THE OPPOSITE. THINK OF A BOWL OF JELL-O.

IF YOU SHAKE IT AND YOU WATCH THE TOP OF THE JELL-O,

IT JUST JIGGLES LIKE THIS.

SO IN EARTHQUAKES, IT'S THE SAME THING.

IF YOU HAVE SOFT SEDIMENTS,

LIKE YOU WOULD IN A BOWL OF JELL-O,

YOU'RE GOING TO GET SHAKING THAT'S MUCH WORSE

THAN IF YOU HAD A MORE FIRM FOUNDATION.

SO IN THE EVENT OF A MEGAQUAKE, HOW SAFE IS OAKLAND?

TO FIND OUT IF THE SOIL HERE

IS MORE BEDROCK OR JELL-O,

WE'RE USING A SEISMOGRAPH,

ALONG WITH SEVERAL GEOPHONES PLACES ON THE GROUND.

NOW, EXPLAIN TO ME HOW A SHEAR WAVE TEST LOOKS.

THE SHEAR WAVES REALLY INDICATE

HOW DAMAGING AN EARTHQUAKE IS GOING TO BE.

IN GRANITE, A WAVE WILL MOVE THROUGH REALLY QUICKLY,

MAYBE 2,000 METERS PER SECOND.

OKAY.

BUT IN SAND OR SOFTER MATERIAL,

IT MAY ONLY GO 400 OR 500 METERS A SECOND.

BUT WHAT YOU'RE LOSING IN SPEED,

YOU'RE MAKING UP FOR IN AMPLITUDE,

AND IT'S CREATING MORE SHAKING AND MORE DAMAGE.

EACH OF THE GEOPHONES CAN PICK UP

NOISE TRAVELING THROUGH THE GROUND,

WHICH GRETCHEN CAN ANALYZE

AND TURN INTO A DIAGRAM OF THE SUBSURFACE.

TO CREATE THAT NOISE FOR THE SENSORS,

I'M ABOUT TO SET OFF MY OWN MINIATURE EARTHQUAKE--

WITH A SLEDGEHAMMER.

YOU DO IT THREE TIMES IN A ROW.

SHOULD I SWING IT HARD, OR SHOULD I BE KIND?

I WOULD SWING IT HARD. HAVE FUN.

THE HARDER I GO, THE BETTER.

I THINK SO.

OKAY, HERE GOES.

WHOO!

THAT'S FUN.

- I GOT SOME GOOD NOISE. - YEAH?

- ONE MORE. - ALL RIGHT.

NOW THAT I'VE GOTTEN MY EXERCISE FOR THE DAY,

IT'S TIME TO INTERPRET THE DATA,

AND IT'S NOT GOOD NEWS FOR THIS PART OF OAKLAND.

IT LOOKS LIKE THE SOIL HERE IS TERRIBLE.

YEAH. IT'S PRETTY BAD.

BECAUSE THE WAVES ARE NOT MOVING THROUGH IT FAST AT ALL.

NO, THEY'RE NOT.

IT LOOKS LIKE IT'S BOTH SANDY

AND JUST, LIKE, LOOSE SOIL.

ESSENTIALLY, THIS WILL TAKE YOUR AVERAGE EARTHQUAKE

AND MAKE IT MUCH MORE POWERFUL.

THAT'S EXACTLY RIGHT.

IT AMPLIFIES THE SHAKING

AND CAN REALLY DESTROY STRUCTURES.

A LOT OF THE BAY HERE IS ON THESE LOOSE, SATURATED SOILS,

AND SO IF AN EARTHQUAKE CAME THROUGH,

IT COULD SPELL DISASTER.

THAT'S CORRECT.

BUT THESE 2-D SOUND WAVES DON'T FULLY CAPTURE

THE MAGNITUDE OF THE DANGER HERE.

SO I'M CREATING A SIMPLE 3- D MODEL TO ILLUSTRATE

HOW A MEGAQUAKE ALONG MULTIPLE FAULTS

WOULD AFFECT THE HOUSES BUILT ON TOP OF THIS LOOSE SOIL.

WHAT WE HAVE HERE IS A CONTAINER THAT REPRESENTS THE BAY AREA.

WE HAVE A SKATEBOARD, WHICH CAN DEMONSTRATE

WHAT CAN EARTHQUAKE IS.

WE HAVE WATER, REPRESENTING THE GROUNDWATER IN THE AREA

AND THE SOFT SEDIMENTS OF THE BAY.

THERE'S A LOT OF GROUNDWATER IN THE BAY AREA.

SO AS I'M FILLING THIS UP,

THE WATER IS FILLING IN

IN BETWEEN THE PARTICLES OF SAND.

OKAY. NOW FOR THE HOUSES.

A LOT OF PEOPLE IN THE BAY AREA

BUILD THEIR HOMES ON SOIL JUST LIKE THIS.

BUT ALL OF THOSE HOMES ARE VERY CLOSE TO THE HAYWARD FAULT,

AND IT'S GOING TO BE A HUGE PROBLEM

WHEN THAT FAULT GOES OFF

IN PART BECAUSE SEMISATURATED SOIL LOSES STRENGTH

AND STIFFNESS DURING AN EARTHQUAKE.

WATCH WHAT HAPPENS TO THE HOUSES.

HERE WE GO. EARTHQUAKE'S GOING.

LOOK AT THIS.

THE SOIL THAT WAS ONCE DRY IS TURNING INTO LIQUID.

WHEW, IT IS HARD TO SIMULATE AN EARTHQUAKE.

AS I WAS SHAKING IT,

THE SEDIMENT STARTED MOVING TO THE BOTTOM,

THE HOUSES STARTED SINKING IN THIS LIQUID, AND THEN,

BECAUSE OF THE PRESSURE,

THE WATER STARTED COMING TO THE TOP.

SO THE IDEA OF THESE INTERCONNECTED FAULT LINES

COMBINED WITH THIS PROCESS OF LIQUEFACTION

COULD SPELL DISASTER FOR MILLIONS OF PEOPLE

IN THE BAY AREA WHEN AN EARTHQUAKE COMES.

SO HOW BAD WILL IT BE?

ARE ALL THESE FAULT LINES REALLY CONNECTED?

THE RESULTS FROM OUR DETONATION TEST ARE IN,

AND A LOT IS RIDING ON THEM.

IF WE FIND THAT EVEN MORE FAULTS ARE CONNECTED AT DEPTH,

THAT MEANS THE NEXT BIG ONE COULD BE CATASTROPHIC.

IS THERE A MEGAQUAKE BREWING BENEATH CALIFORNIA?

I'M INVESTIGATING HOW INTERCONNECTED FAULT LINES

AND LOOSE SOIL COULD IMPACT THE MILLIONS

WHO LIVE IN THE BAY AREA

WHEN THE NEXT BIG EARTHQUAKE STRIKES,

AND THE RESULTS FROM OUR SEISMIC IMAGING SURVEY ARE IN.

WILL IT BE GOOD NEWS OR BAD?

I'M NO LONGER ON LOCATION IN CALIFORNIA,

SO I SET UP A VIDEO CALL WITH THE TEAM LEADERS

TO DISCUSS THE RESULTS.

- HEY. - HEY, LUTHER, RUFUS.

- HOW YOU DOING? - IT'S NICE TO SEE YOU.

YEAH, IT'S GOOD TO SEE YOU AGAIN.

SO WHAT DID WE FIND OUT?

WE'RE ONLY PARTWAY THROUGH THE STUDY,

BUT WE'VE FOUND SOME INTERESTING THINGS.

OKAY, YEAH. I'M CURIOUS.

VIRTUALLY ALL THE FAULTS IN THIS ZONE

THAT WE'RE LOOKING IN APPEAR TO MERGE AT DEPTH DOWN BELOW

WHERE THE CURRENT TRACE OF THE HAYWARD FAULT IS.

REALLY?

THAT'S KIND OF THE BIG NEWS HERE.

SO YOU'RE SAYING THAT IT ACTUALLY

IS MAYBE MORE CONNECTED.

BUT WE DON'T KNOW AT THIS POINT

WHETHER THOSE FAULTS ARE ACTIVE OR NOT.

IS THERE ANY PARTICULAR AREA

THAT YOU FOUND MIGHT BE MORE SUSCEPTIBLE?

ONCE WE GET FARTHER INTO THE DATA,

WE HOPE TO BE ABLE TO TELL

WHICH AREAS WOULD BE MOST INTENSELY SHAKEN

AND WHICH AREAS WOULD BE STRONGLY SHAKEN,

BUT LESS SO.

BUT VIRTUALLY EVERYTHING OUT TO THE WEST OF THE HILLS

HERE HAS FAULTS UNDER IT.

AND SO WE'RE PRETTY SURE

THAT THIS THING IS A BIG, WIDE ZONE

THAT SPLAYS AT THE SURFACE,

AND A BIG EVENT IS GOING TO SEND ENERGY UP IT.

YOU NEVER WANT TO SCARE PEOPLE,

BUT A POTENTIAL FOR MORE DAMAGE IS BIGGER THAN YOU HAD THOUGHT.

YES.

YIKES.

WELL, ANY WEST COAST RESIDENTS

LOOKING FOR A GLIMMER OF HOPE IN OUR FINDINGS

IS BOUND TO BE DISAPPOINTED.

BUT HERE IS THE SILVER LINING-- AT LEAST WE'LL HAVE

A BETTER UNDERSTANDING OF WHICH AREAS

WILL BE MOST VULNERABLE WHEN THE BIG ONE STRIKES.

TAKE SAN FRANCISCO, FOR EXAMPLE.

FOREST HILL AND GLEN PARK, YOU'RE ON SOLID GROUND,

SO YOU MIGHT STAND A CHANCE.

MISSION BAY, SOMA, AND THE FINANCIAL DISTRICT,

YOU'RE LIVING ON SOFT, SOUPY SOIL,

SO YOU'D BETTER BRACE YOURSELVES.

THE ONGOING WORK OF THE WORLD-CLASS

SEISMOLOGISTS IN THE REGION

IS HELPING RESIDENTS AND FIRST RESPONDERS

IN THE BAY AREA TO BE BETTER PREPARED,

SO THE NEXT NATURAL DISASTER

DOESN'T HAVE TO BE A COMPLETE CATASTROPHE.

WE CAN'T PREVENT A MEGAQUAKE,

BUT WE CAN AT LEAST BE READY FOR ONE.

AND NOW, I'LL TRAVEL 600 MILES NORTH TO INVESTIGATE

A PERPLEXING NATURAL PHENOMENON

THAT'S BAFFLED LOCALS AND SCIENTISTS FOR YEARS.

IN CENTRAL OREGON, NEAR THE RUGGED

CAPE PERPETUA COAST IS A MYSTIFYING SIGHT--

A GIANT GAPING HOLE THAT ACCORDING TO LEGEND

IS DRAINING THE PACIFIC OCEAN.

BIG ENOUGH TO SWALLOW A BOAT,

THIS SEEMINGLY BOTTOMLESS ABYSS

IS SOMETIMES CALLED THE GATE TO HELL.

MORE COMMONLY, IT'S KNOWN AS THOR'S WELL,

AND THE NAME IS FITTING.

IT CERTAINLY LOOKS AS IF THE NORSE GOD

OF THUNDER SLAMMED DOWN HIS ICONIC HAMMER

IN A FIT OF FURY

AND CREATED THIS RAGING HOLE IN THE BASALT ROCK.

BUT WHAT EXACTLY IS THOR'S WELL?

SOME CLAIM IT'S AN ENDLESS PIT

THAT DROPS TO THE CENTER OF THE EARTH.

OTHERS BELIEVE IT LEADS TO AN ELABORATE

NETWORK OF SUBTERRANEAN CAVES.

THOSE MAY SEEM LIKE OUTLANDISH THEORIES,

BUT AS A MARINE SCIENTIST, I CAN'T HELP BUT BE CURIOUS.

SURPRISINGLY, I COULDN'T FIND

ANY EXISTING RESEARCH ABOUT THOR'S WELL.

IT'S VIRTUALLY UNCHARTED SCIENTIFIC TERRITORY.

SO TODAY, I'M HEADING TO THE OREGON COAST

TO SEE IT FOR MYSELF.

NOW, ACCORDING TO LOCAL LEGEND,

THE WATER CONTINUALLY DRAINS.

I DON'T KNOW IF IT'S AN OPTICAL ILLUSION OR WHAT,

BUT FROM WHAT I CAN TELL, NOBODY REALLY KNOWS

WHERE THE WATER GOES.

AND THAT'S WHAT I WANT TO FIND OUT.

THOR'S WELL IS LOCATED JUST SOUTH

OF THE SMALL COASTAL COMMUNITY OF YACHATS.

THE TOWN'S NAME CAN BE TRACED BACK

TO A LOCAL NATIVE AMERICAN TRIBE

THAT ONCE HUNTED AND GATHERED ON THESE LANDS.

OH-HO!

SO I'M YACHATS, OREGON, RIGHT NOW WHICH,

IN THE SILETZ LANGUAGE,

MEANS "DARK WATER AT THE BASE OF THE MOUNTAIN."

I CAN TOTALLY SEE WHY THEY CALL IT THAT.

RIGHT DOWN THERE IS THOR'S WELL,

A HUGE MYSTERIOUS HOLE IN THE EARTH.

I'M GUESSING ONE OF THE REASONS

THERE HASN'T BEEN A WHOLE LOT OF RESEARCH DONE

ON THIS IS THAT THIS COAST IS REALLY INTENSE.

LOOK AT HOW JAGGED THOSE ROCKS ARE AND THOSE HUGE WAVES,

NOT AN EASY PLACE TO GET TO.

SO I'M GONNA GET A FEEL FOR WHAT'S DRAINING THIS WATER.

I'M WONDERING IF THOR'S WELL

COULD BE SIMILAR TO OTHER UNDERWATER HOLES

I'VE HEARD ABOUT,

LIKE THOSE FOUND IN THE SOUTH PACIFIC

NEAR AUSTRALIA AND THE STUNNING

GREAT BLUE HOLE OFF THE COAST OF BELIZE.

THIS CAVERNOUS, PERFECTLY ROUNDED CHASM MEASURES

ALMOST 1,000 FEET WIDE AND 500 FEET DEEP.

JUST AS IMPRESSIVE IS THE DRAGON HOLE

IN THE SOUTH CHINA SEA.

IT IS BELIEVED TO BE THE WORLD'S DEEPEST OCEANIC HOLE,

PLUNGING DOWN ALMOST 1,000 FEET.

BUT THESE ARE ALL SINKHOLES,

DEEP DEPRESSIONS FOUND IN WARMER WATERS

THAT FORM WHEN LAYERS OF CARBONATE ROCK COLLAPSE.

THOR'S WELL DOESN'T SEEM TO SOUND,

LOOK, OR ACT LIKE A SINKHOLE.

THE ROCKS AND TOPOGRAPHY HERE ARE VERY DIFFERENT.

AND WHILE WATER CONTINUOUSLY GUSHES INTO THIS HOLE,

IT NEVER SEEMS TO FILL UP.

I'VE BEEN ON THE COAST A LOT,

LOOKED AT A LOT OF ROCKY FORMATIONS.

I'VE NEVER SEEN ANYTHING QUITE LIKE THIS.

THIS IS AN IMPRESSIVE HOLE. PROBABLY 15, 20 FEET WIDE.

AROUND THE RIM OF THIS THING,

YOU'VE GOT REALLY RAZOR-SHARP BARNACLES AND MUSSELS.

YOU'RE LOOKING DOWN INTO A PIT

THAT REALLY WOULD SPELL DEATH IF YOU FELL INTO IT.

STARING STRAIGHT DOWN INTO THIS RAGING CAULDRON,

I STILL DON'T UNDERSTAND WHY IT DOESN'T FILL UP.

I'M GOING TO TAKE A LOOK AT IT FROM THE OTHER SIDE,

SEE IF I CAN FIGURE OUT WHERE THE WATER'S GOING.

AT ANY MOMENT A WAVE COULD COME, TAKE YOU OFF THESE ROCKS.

THAT ONE CAME UP.

PBHT.

I CAN TOTALLY UNDERSTAND

WHY PEOPLE MIGHT THINK THAT IT'S DRAINING THE PACIFIC OCEAN.

BUT WHERE DOES THE WATER GO? THAT'S THE BIG QUESTION.

TO FIND OUT, I NEED TO GET A CLOSE-UP VIEW

OF WHAT LIES BENEATH THE WAVES.

SO THIS CABLE'S GOING TO RUN ON THE LAND TO THE COMPUTER.

AND THEN YOU GUYS HAVE GOT ROPES

YOU'RE GOING TO HOOK ONTO EITHER SIDE.

YEP.

SO I BRING IN GEOPHYSICIST TIM BECHTEL

AND TECH ADVISOR GRIFFIN ALBERTI.

THEY'LL HELP ME SEND AN R.O.V.-MOUNTED CAMERA

DIRECTLY INTO THE BELLY OF THOR'S WELL.

I WANT TO SEE WHAT'S UNDERNEATH THE WATER SURFACE.

THE ONLY WAY, REALLY,

TO DO THAT SAFELY IS TO TAKE AN R.O.V. IN.

HOPEFULLY, IT'LL GIVE US A VIEW BACK IN,

SEE IF THERE'S ANY CRACKS, ANY FISSURES,

SOMETHING THAT WE COULDN'T SEE FROM THE SURFACE.

WE'RE GOING TO HAVE THREE LINES,

SO WE OUGHT TO BE ABLE TO CONTROL IT,

KEEP IT FROM GETTING PUSHED INTO THE ROCKS.

MANEUVERING THIS CONTRAPTION INTO THE ROUGH SURF

WILL BE FAR FROM EASY.

THIS COAST IS NOTORIOUS FOR ITS STRONG CURRENTS

AND SUDDEN SWELLS.

WE GOT TO LOWER THIS WHOLE THING DOWN A HOLE,

WHICH IS RISING AND FALLING ABOUT 15 FEET.

I'LL GET BEHIND YOU.

WE'LL PULL IT REAL TIGHT TO LIFT IT AND THEN LOWER IT IN.

WE GOT TO BE REAL CAREFUL.

WE GOT TO MAKE SURE EVERYBODY IS HOLDING THESE WIRES

JUST PERFECTLY SO IT DOESN'T SLAM INTO THE SIDE.

READY? PULL.

OKAY.

LET'S TAKE IT ALL THE WAY DOWN.

OH, THERE WE GO. THERE WE GO.

WE WANT TO LOWER THE R.O.V. AS FAR DOWN AS POSSIBLE TO GATHER

AS MUCH INFORMATION AS WE CAN.

BUT THE MACHINE COULD GET BATTERED

WHEN IT'S SUBMERGED AGAINST THE SURF.

COME ON, DRAIN.

THERE IT GOES! LET'S GO DOWN!

SO WHEN THE WATER LEVEL FALLS, WE SEIZE OUR CHANCE

- KEEP GOING! - YEAH, KEEP GOING.

SHOULD WE TRY TO SPIN IT AROUND?

YES. THAT'S IT.

NICE.

WHOO-HOO-HOO

- YEAH! - BEAUTIFUL.

I THINK WE GOT IT, GUYS.

ALL RIGHT, LET'S WALK IT THIS WAY, GRIFFIN.

ALL RIGHT, SO NOW WE GOT TO PROCESS THIS FOOTAGE,

HOPEFULLY GET SOME INSIGHT FROM IT,

FIGURE OUT WHAT'S GOING ON IN THOR'S WELL.

ARE WE ON THE VERGE OF FINALLY

UNLOCKING THE SECRETS INSIDE THIS MYSTERIOUS CHASM?

OH, MY GOSH. RIGHT THERE, YOU CAN SEE IT.

I'M IN OREGON, INVESTIGATING THOR'S WELL,

THE LEGENDARY ABYSS

THAT SUPPOSEDLY DRAINS THE PACIFIC OCEAN

INTO AN UNKNOWN NETHERWORLD BELOW.

WE'VE JUST LOWERED AN R.O.V.-MOUNTED CAMERA

INTO THE RAGING VOID

IN THE HOPES OF UNCOVERING WHY IT DOESN'T FILL UP

AND WHERE ALL THAT WATER IS GOING.

BUT WHEN WE TRY TO REVIEW THE FOOTAGE,

WE REALIZE THERE'S A PROBLEM.

IT'S KIND OF DIFFICULT TO TELL WHAT'S GOING ON.

BECAUSE OF THE THRASHING WAVES,

IT'S BASICALLY AN INDECIPHERABLE BLUR.

SO, UNFORTUNATELY,

WE'RE NO CLOSER TO UNDERSTANDING

THE INNER WORKINGS OF THOR'S WELL.

I CAN SEE THAT SOLVING THIS PUZZLE WON'T BE EASY.

I'M ALSO STARTING TO UNDERSTAND WHY EVERY LOCAL...

- HOW YOU DOING? - GOOD. YOURSELF?

...SEEMS TO HAVE A THEORY ABOUT THIS CURIOUS CHASM.

- WHAT DO YOU KNOW ABOUT IT? - IT COULD BE A METEOR.

IT COULD BE A SINKHOLE.

NOBODY HAS EVER HAD AN EXPLANATION.

BUT IT REALLY DOES LOOK LIKE IT'S SWALLOWING UP THE OCEAN.

I DON'T REALLY KNOW WHERE THE WATER GOES,

SO IT'S JUST, LIKE, THIS GIANT HOLE IN THE ROCK.

I DON'T KNOW THAT THERE'S ANOTHER PLACE LIKE IT ON EARTH.

IT'S UNBELIEVABLE.

AS FOR ME,

I'M DETERMINED TO UNLOCK THE MYSTERY.

SO, NEXT, I WANT TO GET A DRONE'S-EYE VIEW

OF THE WELL FROM STRAIGHT OVERHEAD.

IF WE CAN'T SEE WHAT'S HAPPENING INSIDE THE WELL,

MAYBE THE SURROUNDING TERRAIN

COULD OFFER A CLUE AS TO WHERE IT LEADS.

JOINING ME AGAIN IS GEOPHYSICIST TIM BECHTEL,

AN EXPERT IN USING 3-D PHOTOGRAMMETRY

TO SURVEY LAND FORMATIONS.

YOU WANT TO GET A LOT OF SHOTS

SO THE COMPUTER CAN SPOT A COMMON OBJECT

FROM PHOTO TO PHOTO, CAN STITCH IT TOGETHER.

FROM 100 FEET ABOVE, A CAMERA MOUNTED ON THE DRONE

IS SNAPPING HUNDREDS OF OVERLAPPING PICTURES

OF THOR'S WELL AND ITS SURROUNDING TERRAIN.

WE WANT TO GET FULL 360-DEGREE COVERAGE

AT SEVERAL DIFFERENT ALTITUDES

WITH A GOOD BIT OF OVERLAP BETWEEN ADJACENT PHOTOS.

SO THERE'S ONLY SO MUCH YOU CAN SEE WITH THE NAKED EYE,

SO WHAT I LIKE ABOUT FLYING THE DRONE UP

IS THAT IT OPENS YOUR EYES

TO SOMETHING THAT YOU HADN'T SEEN BEFORE.

IT'S BEEN SAID THAT THOR'S WELL LEADS DIRECTLY

TO THE CENTER OF THE EARTH,

CHANNELING THE PACIFIC INTO ITS CORE.

BUT TO PUT THAT THEORY IN PERSPECTIVE,

LET'S CONSIDER THE DEEPEST KNOWN CAVE ON THE PLANET,

THE KRUBERA CAVE IN THE REPUBLIC OF GEORGIA.

IT PLUNGES DOWN A TWISTING ROUTE

ALMOST 1 1/2 MILES BENEATH THE SURFACE,

NEARLY AS DEEP AS FIVE EMPIRE STATE BUILDINGS

STACKED TOP TO BOTTOM.

BUT A FAR CRY FROM THE NEARLY

4,000-MILE DEPTH OF EARTH'S CORE.

MAYBE MORE LIKELY IS THE IDEA

THAT THOR'S WELL LEADS TO A NETWORK

OF SUBTERRANEAN LAVA TUBES,

THE NATURAL TUNNELS THAT FORM

WHEN THE OUTER CRUST OF A LAVA FLOW SOLIDIFIES.

MANY OF THESE CAVES, WHICH CAN EXTEND FOR MILES,

ARE FOUND IN THE WESTERN UNITED STATES.

IN FACT, CAPE PERPETUA,

WHICH LIES RIGHT NEXT TO THOR'S WELL,

IS A REMNANT OF A MASSIVE

50-MILLION-YEAR-OLD VOLCANO.

SO COULD THOR'S WELL BE FUNNELING THE PACIFIC

INTO SOME KIND OF INTRICATE UNDERGROUND MAZE?

DO YOU THINK THIS THING ACTUALLY DOES LEAD

INTO SOMETHING A LITTLE BIT BIGGER?

IT'S HARD TO TELL.

THERE'S NO REASON IT WOULDN'T EXTEND FARTHER

BACK UNDER LAND INTO A LARGER TUNNEL.

LET'S GO AHEAD AND LAND THIS AND PROCESS THE DATA.

LET'S DO IT.

WITH THE CAPTURED IMAGES,

WE CAN NOW CREATE A DETAILED MAP

OF THE HOLE'S GEOLOGICAL STRUCTURE.

WHAT WE'RE DOING RIGHT NOW IS TIM IS LOADING UP THE PHOTOS

THAT WE SHOT WITH THE DRONE SO WE CAN CREATE THIS 3-D MAP.

BASICALLY, IT'S STITCHING THEM ALL TOGETHER.

WHAT WE'RE HOPING TO FIND IS WHERE THE WATER GOES,

MAYBE EVEN SOME FISSURES OR CRACKS

THAT WE COULDN'T SEE WITH OUR NAKED EYE.

SO THAT OVER THERE, THAT WOULD BE THE OCEAN.

YEAH, THIS IS THE OCEAN.

WITHIN MINUTES, THE DIGITAL MAP OF THOR'S WELL

AND THE SURROUNDING COAST APPEARS BEFORE US.

WHAT WE CAN SEE RIGHT NOW ON THE SCREEN

IS A 3-D REPRESENTATION OF THE GEOLOGY OF THOR'S WELL.

THE OCEAN IS GOING TO BE THE LOWEST POINT,

SO THAT'S INDICATED IN AN ORANGE COLOR.

AND THEN AS YOU GO UP IN ELEVATION, IT TURNS BLUE.

CAN YOU ZOOM IN ON THAT?

YES, WE CAN.

AT FIRST, THE MODEL FAILS TO REVEAL ANY CLUES.

WE OUGHT TO BE ABLE TO ROTATE THIS

AND SEE WHAT IT LOOKS LIKE.

LET'S SPIN THAT AROUND.

BUT THEN, SOMETHING CATCHES OUR EYE.

OH, WOW.

THERE'S A DARK SPOT RIGHT THERE.

ALONG THE EDGE OF THE CLIFF

THAT FACES OUT TOWARDS THE OCEAN,

WE SPOT A CURIOUS ANOMALY.

THAT LOOKS LIKE AN OPENING.

I THINK YOU'RE RIGHT. SPIN THIS AROUND A LITTLE BIT.

LET ME GET A PERSPECTIVE FOR WHERE WE'RE AT.

STANDING ON LAND, WE CAN'T BE SURE

WHETHER WHAT WE'RE SEEING IS ACTUALLY AN OPENING

SINCE THE CLIFF'S PROTRUDING EDGES BLOCK OUR VIEW.

BUT YOU STILL CAN'T REALLY SEE

WHEN THE WATER LEVEL IS COVERING IT UP.

BUT IF IT IS A HOLE, WHERE EXACTLY DOES IT LEAD?

COULD THIS BE A GATEWAY

THAT LEADS DEEP INTO THE EARTH'S CRUST?

LOWER IT IN!

WITH THE R.O.V., WE'LL HEAD OUT TO SEA IN ONE LAST ATTEMPT

TO FIND OUT.

WHOA!

COULD THIS DISCOVERY BE THE KEY

TO UNLOCKING THE MYSTERY OF THIS ENIGMATIC ABYSS?

THAT'S IT! THAT'S IT RIGHT THERE!

HOLY MOLY.

I'M INVESTIGATING THE MYSTERIOUS VOID KNOWN

AS THOR'S WELL ALONG THE COAST OF CENTRAL OREGON.

SOME BELIEVE THE GIANT HOLE DRAINS THE PACIFIC OCEAN,

LEADING INTO A NETWORK OF VOLCANIC TUNNELS UNDERGROUND.

OR MAYBE, EVEN ALL THE WAY TO THE CENTER OF THE EARTH.

USING 3-D PHOTOGRAMMETRY,

GEOPHYSICIST TIM BECHTEL AND I HAVE UNCOVERED

WHAT COULD BE SOME KIND OF OPENING

ON THE SIDE OF THE WELL.

IF SO, WHERE DOES IT GO?

- HEY, THERE. - HEY.

- IS IT DAVE? - THAT'S ME.

- ROB. - NICE TO MEET YOU, ROB.

THE POTENTIAL HOLE APPEARS TO BE LOCATED

ON THE WALL OF THE WELL THAT FACES OUT TOWARDS THE SEA.

SO WE'LL HEAD OUT INTO THE WATER TO GET A CLOSER LOOK.

IT'S LATE AFTERNOON WHEN WE SET OUT FROM A NEARBY DOCK.

THE PLAN-- USE THE R.O.V.-MOUNTED CAMERA

TO EXPLORE THOR'S WELL FROM THE OCEANSIDE.

I THINK WE COULD SWIM THE R.O.V. RIGHT UP TO IT.

GREAT.

SO WE'RE ABOUT 30 YARDS OFFSHORE RIGHT NOW.

WE ARE RUNNING PARALLEL WITH THE SHORELINE.

WE'VE GOT THOR'S WELL RIGHT THERE.

WE KNOW THIS AREA IS FULL OF VOLCANIC ROCK,

AND I JUST WANT TO SEE IF THERE'S ANYTHING UNUSUAL

IN THE TOPOGRAPHY

OF THE UNDERWATER LANDSCAPE RIGHT DOWN HERE,

ANY CHASMS OR TUNNELS THAT LIE BENEATH.

OKAY, YOU LOWER IT IN. I'LL GET THE CONTROLS.

OKAY, POWER IT ON!

LOWER IT IN!

THERE IT GOES.

I'VE GOT TO GET DOWN LOWER.

WITH THE CAMERA NOW SUBMERGED,

I MONITOR THE VIDEO FEED

AND STEER THE MACHINE TOWARD THOR'S WELL.

SO RIGHT NOW, I'M DRIVING THE R.O.V.

IT'S JUST LIKE PLAYING A VIDEO GAME.

FROM THE SIDE DECK,

THE CAPTAIN WATCHES THE CAMERA LIGHT ON THE R.O.V...

...USING IT TO HELP GUIDE ME

TOWARD THE ROCKY EDGE OF THE WELL.

WHOA!

TWO FEET FROM THE ROCK.

JUST INCH IT IN, INCH IT IN.

OH, RIGHT ON THE ROCK.

I DON'T SEE ANYTHING YET.

WHOA!

OKAY, BACK UP, BACK UP, BACK UP.

THERE WE GO! OH, WE FOUND IT.

WE'RE LOOKING AT WHAT APPEARS TO BE ONE OF THE JAGGED WALLS

OF THOR'S WELL.

RIGHT NOW, I DON'T SEE ANYTHING UNUSUAL.

SOME MARINE LIFE COMES INTO VIEW.

ANEMONES.

OH, WE ARE RIGHT ON THE ANEMONES.

BIG WAVE.

HOLD ON!

OH, MY GOSH. I'M GETTING PULLED AROUND.

BUT WITH THE ROUGH SURF, I'M STRUGGLING TO KEEP

THE R.O.V. STEADY ENOUGH TO GET A CLEAR PICTURE.

WE ARE BATTLING A LOT OF CONDITIONS RIGHT NOW.

THE WAVES ARE JUST THRASHING THIS THING AROUND

AND I CAN'T SEE WHAT'S IN THERE.

WE'RE BATTLING THE LIGHT AT THE MOMENT, AS WELL.

THAT'S THE GROUND.

BUT THEN SOMETHING CATCHES OUR EYE.

THAT'S IT! THAT'S IT RIGHT THERE!

- THERE IT IS. - HOLY MOLY.

I THINK WE MIGHT HAVE FOUND THE ENTRANCE TO THOR'S WELL.

AND IT LOOKS LIKE WE HAVEN'T JUST LOCATED OUR TARGET.

ARE WE IN IT?

ARE WE GETTING SUCKED INTO THE WELL?

IT ALL HAPPENED TO QUICKLY, BUT I REALIZED

WE SOMEHOW MANAGED TO MANEUVER THE R.O.V.

THROUGH THE OPENING...

I THINK WE'RE LITERALLY IN THE HOLE RIGHT NOW.

...AND RIGHT INTO THOR'S WELL.

OH, MY GOSH. LOOK AT THAT.

THIS IS REALLY EXCITING.

BUT I QUICKLY REALIZE

IF OUR R.O.V. COULD GET IN THROUGH THIS HOLE,

THAT MEANS OCEAN WATER COULD GET OUT THROUGH IT, TOO.

AND JUST LIKE THAT, IT APPEARS WE'VE UNLOCKED THE MYSTERY

BEHIND THIS BIZARRE GEOLOGIC WONDER.

THOR'S WELL DOES NOT DRAIN THE PACIFIC

INTO THE CENTER OF THE EARTH,

NOR DOES IT SEEM TO FEED INTO

AN ELABORATE MAZE OF HIDDEN SUBTERRANEAN CAVES.

RATHER, IT'S A CASE OF OCCAM'S RAZOR,

THE SCIENTIFIC PRINCIPLE THAT THE SIMPLEST EXPLANATION

IS SOMETIMES THE BEST.

THOR'S WELL NEVER OVERFLOWS

BECAUSE IT HAS A HOLE UNDERWATER

THAT EMPTIES RIGHT BACK OUT INTO THE SEA.

BUT THAT STILL LEAVES THE QUESTION

OF WHAT EXACTLY IS THOR'S WELL?

NOT FAR FROM HERE ARE SOME GEOLOGICAL STRUCTURES

THAT OFFER A KEY CLUE--

BLOWHOLES, THE OPENING IN SEA CAVES

THROUGH WHICH COLUMNS OF WATER SPEW OUT.

THESE HOLES ARE FORMED WHEN WAVES FLOOD A CAVE

AND CONTINUE TO POUND ITS ROOF.

THE BATTERED AREA THEN ERODES OVER TIME,

CREATING A VERTICAL SHAFT

AND EVENTUALLY A SMALL OPENING AT THE SURFACE.

NOW, WHILE THOR'S WELL LOOKS A LOT LIKE THESE SEA CAVES,

THE HYDROLOGY OF THE TWO BASICALLY BEHAVE

IN OPPOSITE WAYS.

IT DRAINS THE WATER DOWNWARD,

WHILE BLOWHOLES SHOOT IT OUT THE TOP.

THAT'S BECAUSE, UNLIKE IN BLOWHOLES,

THE LARGER OPENING IN THOR'S WELL IS THE TOP ONE.

SO WHEN WAVES SURGE INTO IT AT HIGH TIDE,

THE WATER FLOWS OUT THE BOTTOM BACK INTO THE SEA,

CREATING THE OPTICAL ILLUSION

OF A VOID THAT ENDLESSLY FILLS AND DRAINS.

SO THIS SALTWATER ABYSS ALSO APPEARS TO BE A SEA CAVE,

BUT ONE WITH A ROOF THAT COLLAPSED IN A VERY UNIQUE WAY.

OKAY, I'M GOING TO BACK IT OUT!

I THINK ONE THING PEOPLE DON'T REALIZE IS THERE

IS A LOT THAT SCIENTISTS HAVE NOT DISCOVERED YET,

AND THAT'S WHAT I FIND SO FUN

ABOUT COMING OUT TO PLACES LIKE THIS.

WE'RE ABLE TO TAKE OUR TECHNOLOGY

AND FIGURE OUT WHAT LIES BENEATH.

THOR'S WELL MAY NOT BE A PORTAL TO THE CENTER OF THE EARTH,

BUT IT'S STILL A UNIQUE

AND FASCINATING WONDER IN A WORLD

FULL OF NATURAL SURPRISES.