Earthquake hazards
Ground Rupture
Alaskan pipe after the
Denali quake ruptured
through
Ground rupture from the M8.1
2001 Tibet earthquake
Earthquake hazards (cont.)
Shaking
Wave
amplitude
Wave
frequency
Duration of
shaking
Earthquake hazards (cont)
Liquefaction
Saturated sand
loses strength
upon shaking
1964
Nigata
Japan
Tsunami
Wave wavelength
ocean waves that
can travel vast
distances
2004
Sumatra
earthquake
Sumatra Earthquake tsunami
QuickTime™ and a
Sorenson Video decompressor
are needed to see this picture.
QuickTime™ and a
Video decompressor
are needed to see this picture.
Seismic Hazard of MA
Cape Ann Earthquake 1755
Woodcut illustration depicting damage in Boston from the earthquake
Hazard vs risk
1989 Macquarie Ridge, New Zealand
M 8.3
No losses
1960 Agadir, Morocco
M 5.5
12,000 deaths
Earthquake Risk
Risk = hazard x vulnerability
The amount of damage and numbers of
earthquake related deaths do not correlate
to magnitude of the earthquake.
Products of hazard
assessment
Active fault map
Historical seismicity
Earthquake likelihood
3D models assess seismic
hazard in Los Angeles, CA
SCEC Community Fault Model
Acceptable Risk
Level of acceptable
risk depends on the
structure
Cannot design for
maximum
earthquake with low
probability
Social question
How would you mitigate
damages from….
Ground Rupture
Liquefaction
Ground Shaking
Tsunami
Ground Rupture
Avoid construction
Relocate sensitive facilities
Implement low use facilities
Playing fields
Green space
Portola Valley California
Liquefaction
Recognize liquefaction potential
In-situ remediation
Avoid construction in liquefaction prone
areas
Tsunami mitigation
Early warning system
Broadcast signal to beaches after a major
earthquake anywhere in the ocean basin
Saftey guidelines
Go to high ground
Climb a tree
Ground Shaking
Recognize the degree of probable ground
shaking in the area
Improve construction methods to
accommodate shaking without collapse