seismic early warning systems in japan & mexico ... conference...japanese earthquake early...
TRANSCRIPT
SEISMIC EARLY WARNING SYSTEMS IN JAPAN & MEXICO:
EXPECTATIONS AND REALITY
FRANNIE EDWARDS, MUP, PHD, CEM
DEPUTY DIRECTOR,
NATIONAL TRANSPORTATION SAFETY & SECURITY CENTER
MINETA TRANSPORTATION INSTITUTE
SAN JOSE STATE UNIVERSITY
MARCH 11, 2011TODAY IS 7TH ANNIVERSARY OF JAPAN’S TRIPLE DISASTER
Population notification
in Tokyo
• TV
• Cell phones
• Computer screen
DIFFERENTIAL TRAVEL TIME OF P WAVE (6 KM/SECOND
& S WAVE (3 KM/SECOND) :BASIS OF SEWS
0
50
100
150
200
250
300
350
400
immediate 10 seconds 30 seconds 60 seconds
S Wave P Wavw
JAPANESE EARTHQUAKE EARLY WARNING SYSTEM
• Major fault is 200 miles off the
eastern coast
• Based on travel time of P wave,
which is 1.5 times S wave
• Wayside system stops Shinkansen
• Coastal system notifies public by
computer screen, cell phone, media
• 2011 provided 2 minutes’ warning
to Tokyo
MEXICO’S EARTHQUAKE EARLY WARNING SYSTEM
Sept. 7, 2017 8.1 earthquake off Mexico’s
Pacific Coast
525 km from Mexico City = 86 seconds’
warning
MEXICO CITY EARTHQUAKE 9/19/17:DID THE SYSTEM FAIL?
•7.1 Earthquake under
Mexico City – no warning =
“blind zone”
•Not enough distance from
the rupture to create time
differential
•60 more sensors could have
given 10 seconds’ warning
CALIFORNIA EARTHQUAKE EARLY WARNING
• California’s ShakeAlert
system is being pilot
tested
• Real time experience in
Napa Earthquake,
8/24/2014, 6.0 M
• 16 km blind zone
SINGLE SITE SYSTEM IN PALM SPRINGS- LOCAL ALARM
On site sensor triggers alarm to warn buses to pull over.
At airport opens fire station door, audible alarm in case firemen are sleeping.
CHALLENGE OF PUBLIC EDUCATION
•What do we want people to
do when they hear the
earthquake alarm?
• Mexico – run outside
• Japan – duck and cover
• US – drop, cover and hold
• Driven by building codes and
construction methods
• How do we get people to
comply? Continuing challenge!
