THE BAY BRIDGE STRUCTURAL
INTEGRITY REMAINS IN PLACE AND
NOT AFFECTED SIGNIFICANTLY FROM
THE EARTHQUAKE.
WE HAVE MICHAEL ON THE PHONE
WITH US RIGHT NOW.
HE IS A PROFESSOR OF EARTH AND
PLANETARY SCIENCES AT UC-DAVIS.
THANK YOU FOR JOINING US.
AS YOU HAVE BEEN WATCHING THE
COVERAGE, YOU KNOW IT WAS A 6.0
QUAKE THAT HIT
AT 3:20 THIS
MORNING.
WHAT IS YOUR INITIAL ASSESSMENT?
THIS IS AN AREA WHERE THERE
HAS BEEN A LOT OF INTEREST IN
BECAUSE WE DON'T UNDERSTANDING
THE FAULTING THE RUNS THROUGH
NAPA VALLEY TOO WELL.
[INDISCERNIBLE]
PEOPLE ARE GOING OUT THERE RIGHT
NOW TO TRY TO MEASURE THE
SURFACE RUPTURE, THE DAMAGE TO
THE ROADS THERE, BEFORE IT
DISAPPEARS.
THE ROAD CREWS ARE ALREADY OUT
THERE FIXING IT.
MICHAEL, WHAT DO THEY LOOK
FOR IN TERMS OF -- OBVIOUSLY
THERE ARE GOING TO BE CREWS
LOOKING AT ALL KINDS OF DAMAGE.
THEY ARE LOOKING AT IT FROM A
VERY DIFFERENT PERSPECTIVE THAN
THE ENGINEERS WHO ARE OUT THERE.
WHAT ARE THE
TEAMS WERE
SPECIFICALLY LOOKING AT THE
EARTHQUAKE SCIENCE, WHAT DO THEY
LOOK FOR?
THERE ARE A COUPLE OF
STUDENTS OUT THERE RIGHT NOW
SENDING ME PICTURES.
THEY ARE MEASURING HOW MUCH
DISPLACEMENT OCCURRED, AND THE
LOCATIONS OF WHERE THE FAULT IS.
WE DON'T KNOW THIS AREA ALL THAT
WELL IN TERMS OF WHAT RUNS
THROUGH IT.
YOU MENTIONED THE
FAULT.
THIS TOOK PLACE AT THE WEST NAPA
FAULT.
AS WE UNDERSTAND, IT IS NEAR THE
FRANKLIN FAULT, WHICH HAS BEEN
INACTIVE FOR 1.6 MILLION YEARS.
IT IS IN AN AREA BETWEEN THE
WEST NAPA FAULT AND SOMETHING
CALLED THE CARNEROS FAULT.
I SAW THE
POSTINGS ABOUT A
FRANKLIN FAULT AND I HAVE NOT
GOTTEN TO LOOK AT THE MATH YET.
WHAT THE MAVS TELL YOU IS IT HAS
BEEN ACTIVE WITHIN THE LAST 1.6
MILLION YEARS.
IT IS ACTIVE
IN WHAT WE CALL
GEOLOGICALLY RECENT TIME BUT WE
DON'T HAVE MORE INFORMATION.
IT IS SOMETHING TO BE MINDFUL
OF.
MICHAEL, WE WANT TO BRING IN
EILEEN JAVORA.
TALKING ABOUT THE DEPTH
OF
EARTHQUAKES, THIS ONE WAS ABOUT
SIX AND A HALF MILES DEEP OR
SO
INTO THE EARTH.
TALK ABOUT DEEPER EARTHQUAKES
VERSUS SHALLOW EARTHQUAKES AND
HOW MUCH WE FEEL HERE ON THE
EARTH'S SURFACE AND HOW MUCH
DAMAGE WE CAN SEE.
WAS THIS A FAIRLY SHALLOW
EARTHQUAKE WE EXPERIENCED IN
NAPA?
IT IS TYPICAL FOR COASTAL
CALIFORNIA.
IT IS FAIRLY SHALLOW OVERALL.
WHEN THEY ARE SHALLOW, THERE
FELL MORE SHARPLY.
-- THEY ARE FELT MORE SHARPLY.
IT'S NOT ABNORMAL.
THIS IS A STANDARD EARTHQUAKE
IN TERMS OF DEPTH.
TYPICALLY, WHEN ARE THE MOST
AFTERSHOCKS FELT AS WE GO
FORWARD HERE?
THE USGS IS GETTING THE WORD OUT
IN THE NEXT SEVEN DAYS WE COULD
STILL FEEL SOME NOTABLE
AFTERSHOCKS.
YES.
THERE WILL BE A LOT IN THE
NEXT
FEW DAYS, GRADUALLY TAPERING
OFF.
THEY ARE ONE OF THE FEW THINGS
ABOUT EARTHQUAKES THAT ARE
SOMEWHAT PREDICTABLE.
IT TAPERS AT A PRETTY REGULAR
PACE.
THE USGS IS POSTING WHAT THEY
KNOW.
FROM A CHANCE
PERSPECTIVE,
THERE'S ALWAYS THE POSSIBILITY
OF AN AFTERSHOCK THAT IS BIGGER
THAN THE MAIN ONE.
THAT IS SOMETHING TO BE
CONCERNED ABOUT.
THE EPICENTER OF THIS
EARTHQUAKE WAS LOCATED IN SAN
PABLO BAY.
IT RADIATED OUT ALONG THE FAULT
THERE.
WILLY'S AFTERSHOCKS BE CENTERED
RIGHT IN THE SAME LOCATION --
WILL THESE AFTERSHOCKS BE
CENTERED RIGHT IN THE SAME
LOCATION, OR COULD IT HAPPEN
ANYWHERE ELSE ON THE FAULT LINE?
WHAT THE AFTERSHOCKS APPEAR
TO SHOW IS THAT THE FAULT IS A
NORTHWESTERLY LINE.
THEY TEND TO LINE UP ALONG THE
PART THAT RUPTURED.
AFTERSHOCKS ARE LINING UP TO THE
NORTH OF WHERE THE EPICENTER
WAS.
THAT INDICATES THE RUPTURE
PROPAGATED TOWARDS NAPA, AND
MAYBE HALTED SOMEWHERE WITHIN
THE CITY OF NAPA OR TO THE
SOUTH.
THAT IS PART OF GOING OUT THERE
LOOKING FOR THE EVIDENCE THAT
THE SURFACE RUPTURE TELLS US.
ARE YOU SURPRISED TO SEE HOW
MANY CRACKS WE ARE SEEING IN THE
EARTH ALONG THE ROADWAYS?
EVEN OUT TOWARDS
VINEYARDS, HOW
MANY CRACKS WE ARE SEEING IN THE
EARTH AROUND NAPA.
THAT IS KIND OF WHAT WE
EXPECT FROM AN EARTHQUAKE OF
THIS SIZE.
IT IS BIG ENOUGH TO PRODUCE
SURFACE RUPTURE ALONG THE FAULT.
THOSE CRACKS ARE THE MOTION OF
ONE SIDE OF THE FAULT TO THE
OTHER.
IT IS ABOUT FIVE OR 10 INCHES,
WHICH IS NOT HUGE BUT NOT
UNEXPECTED FOR AN EARTHQUAKE OF
THIS SIZE.
YOU SAID YOU HAD STUDENTS OUT
THERE.
YOU HAD TO BE ASSESSING WHAT IS
HAPPENING THIS MORNING IN NAPA
CARD -- NAPA.
HOW DO YOU USE THIS INFORMATION
GOING FORWARD?
ONE WAY WE USE IT
IS WE
REALLY DON'T KNOW VERY WELL
WHERE THE FAULTS ARE IN THE NAPA
VALLEY.
IT IS ONE OF THE LESSER-KNOWN
REGIONS OF NORTHERN CALIFORNIA.
IT HAS BEEN SETTLED FOR SO LONG,
THERE'S NOT A LOT OF ACCESS FOR
DETAILED MAPPING.
IN NORTHERN CALIFORNIA,
SPECIFICALLY THE BAY AREA, HOW
MANY FAULT LINES ARE WE TALKING?
WE KNOW ABOUT THE SAN ANDREAS
FAULT.
BUT YOU'RE SEEING -- SAYING
MAY
BE THE DETAILS OF THE FAULT
LINES BY SCIENTISTS IS NOT KNOWN
THAT WELL.
IS THIS A TREND, THIS FAULT LINE
IS WAKING UP NOW?
THERE'S NO ANSWER TO THE HOW
MANY FAULT LINES QUESTION.
WE KNOW THERE ARE THE MAJOR
SYSTEMS.
THERE IS SAN ANDREAS.
THERE ARE A SERIES OF THEM TO
THE EAST.
IT HAS BONE -- HAS BEEN LONG
SUSPECTED THAT ONE OF THE AREAS,
NAPA VALLEY, THERE IS NOT A LOT
OF INFORMATION ON THE GROUND.
IT
HELPS DELINEATE WHERE THE
PORTION OF THE FAULT THAT DID
RUPTURE EXISTS BY MAPPING OUT
THAT SURFACE RUPTURE AND CAN
HELP US UNDERSTAND HOW IT LINKS
TO FAULTS THE DID NOT RUPTURE TO
THE NORTH AND THE SOUTH.
IT HELPS INFORM FUTURE HAZARD
PREDICTIONS.
INTERESTING.
MICHAEL OSKIN FROM UC DAVIS.
EARTH AND PLANETARY SCIENCES
DEPARTMENT.
WONDERFUL TO TALK TO HIM, TO
GET
THAT PERSPECTIVE.
IT'S AMAZING HOW LITTLE WE KNOW