SEVEN
SEVEN OR
SEVEN OR GREATER, SIMILAR TO THE EARTHQUAKE IN SOUTHERN
CALIFORNIA BUT HERE IT WOULD
BE UNDER A POPULATED AREA.
AND THAT IS NOT THE ONLY
MYSTERY.
MYSTERY.
MYSTERY. >> Reporter: LAST JULY WE
FOLLOWED A CREW FROM THE U.S.
GEOLOGICAL SURVEY INTO THE
SOUTHWEST PART OF THE STATE.
THEIR JOB TO DETECT
DIFFERENCES IN GRAVITY TO
BETTER LOCATE THE FAULT AS
DIFFERENT ROCK FORMATIONS HAVE
SLIGHTLY MORE GRAVITATIONAL
PULL THAN OTHERS.
SINCE THE 1950S THE SHAPE OF
THE MOUNTAINS HERE PROVIDED
CLUES A FAULT WAS OUT THERE
BUT IT IS NOT A FAULT WE KNOW
MUCH ABOUT.
MUCH ABOUT. SOMETIMES IT TAKES AN
EARTHQUAKE FOR A FAULT TO SHOW
UP.
UP.
UP. >>
UP. >> WHAT IT LOOKS LIKE HAPPENED
IS THE EARTHQUAKES HAVE SHOWN
HOW THERE ARE A BUNCH OF
CONNECTED FAULTS THAT IS NOT
SHOWING UP IN THE MAPPING
PRIOR TO THIS.
>> Reporter: AS MUCH AS WE
THOUGHT SCIENTIST KNEW ABOUT
SOUTHERN CALIFORNIA, THEY
DIDN'T KNOW EVERYTHING.
>> I HAVE BEEN OVER THE WHOLE
REGION, EVEN TO THE SOUTH.
>> HE STUDIED FAULTS IN THE
AREA AROUND RIDGECREST,
CALIFORNIA.
CALIFORNIA. THERE ARE KNOWN FAULTS UNDER
THE ORANGES AND BLUES AND THE
REDS.
REDS.
REDS. >>
REDS. >> THESE ARE ALL MINOR ACTORS
IN THE -- IN THE GEOLOGIC
STORY GOING ON.
>> Reporter: CAPABLE OF A
SMALL MAGNITUDE FIVE, NOT A
MAGNITUDE 7.1.
MAGNITUDE 7.1. ONLY A SMALL CHUNK OF ONE OF
THE PREVIOUSLY KNOWN FAULT
LINES ENDED UP UNDER THE
YELLOW DASH LINE THAT WAS
FRIDAY'S EARTHQUAKE.
FRIDAY'S EARTHQUAKE. >> THAT IS THE WAY THE MAPPING
WORK.
WORK.
WORK. COMPARED TO A COUPLE DECADES
AGO WE KNOW A GREAT DEAL MORE.
>> Reporter: EVEN THE FAULTS
WE KNOW SOMETHING ABOUT LIKE
THE SEATTLE FAULT AS SEEN IN
THIS IMAGE, DON'T TELL US
EVERYTHING.
EVERYTHING. THE U.S. GEOLOGICAL SURVEY
LOOKING TO 72 THE FAULTS
EXTEND THROUGH THE MOUNTAINS
INTO EASTERN WASHINGTON
THROUGH TRENCHING TO SEE WHERE
THE DIRT AND ROCKS DON'T LINE
UP.
UP.
UP. SUGGESTING OLDER EARTHQUAKES.
EVEN A TINY EARTHQUAKE CAN
TELL US WHAT OUR OWN EYES
CAN'T.
CAN'T.
CAN'T. >>
CAN'T. >> WE TRACK ANDLOCATE
EARTHQUAKES DOWN TO TINY
MAGNITUDE, WAY BELOW WHAT
PEOPLE FEEL.
PEOPLE FEEL. MEASURING ONE AND BELOW.
NO ONE WILL FEEL THOSE
EARTHQUAKES BUT THEY HELP US
POTENTIALLY MAP OUT THE AREAS
OF ACTIVITY THAT COULD
ULTIMATELY LEAD TO LARGER
EARTHQUAKES.
EARTHQUAKES. >> I THINK IT IS HIGHLY
POSSIBLE THAT WE COULD HAVE
BIGGER EARTHQUAKES HERE THAN
OUR CURRENT FAULT MAPS TELL
US.
US.
US. >>
US. >> Reporter: FROM CALIFORNIA,
THAT FAULT MAP DIDN'T EVEN
SHOW UP.
SHOW UP.
SHOW UP. WHICH IS WHY DETECTION IS MORE
DIFFICULT HERE IN WASHINGTON,
NOT JUST BECAUSE OF ALL THE
TREES AND WATER LIKE PUGET
SOUND, BUT THE GLACIERS
SCRAPED AWAY MUCH OF THE
EVIDENCE OF THE OLDER FAULT
HISTORY.
HISTORY.
HISTORY. >> LOT OF PEOPLE ARE TALKING
ABOUT CALIFORNIA'S BIG ONE.
BUT WE HAVE A BIG ONE COMING
--
--
-- >>
-- >> DIFFERENT KIND OF AN
ANIMAL.
ANIMAL.
ANIMAL. OUR BIG ONE IS THE BIG FAULT
OFF THE COAST, WHERE THE OCEAN
FLOOR IS BEING PUSHED UNDER
THE WEST COAST.
THAT DOESN'T EXHIBIT IN
CALIFORNIA.
CALIFORNIA. THAT IS CAPABLE OF A MAGNITUDE
9. NOBODY WANTS TO MESS WITH
THE FAULT.
THE FAULT. THOSE ARE CAPABLE OF HIGH
SIXES AND A MAGNITUDE SEVEN
AND BECAUSE WE DON'T KNOW LONG
IT IS WE DON'T KNOW THE FULL
CAPABILITY OF THAT.
UNLIKE THIS AREA IN
CALIFORNIA, WHICH IS REMOTE,
SMALL TOWNS, CONSIDER WHERE