DISASTER PREPAREDNESS A KEY ELEMENT OF BECOMING DISASTER RESILIENT

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DISASTER PREPAREDNESSA KEY ELEMENT OF
BECOMING DISASTER RESILIENT
Walter Hays, Global Alliance for Disaster
Reduction, University of North Carolina, USA
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CITY
DATA BASES AND INFORMATION
HAZARDS GROUND SHAKING GROUND FAILURE
SURFACE FAULTING TECTONIC DEFORMATION TSUNAMI RUN
UP AFTERSHOCKS
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A FOCUS ONTHE TECHNIQUE OF DEVELOPING A
DISASTER PLANNING SCENARIO

• EXAMPLES COMPLETED NEXT LECTURE

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PURPOSE Information from disaster scenarios
will facilitate the adoption and implementation
of policies and plans to enable a city to be well
prepared for future events.
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DISASTERS OCCUR WHEN--- A CITYS (COMMUNITYS)
PUBLIC POLICIES LEAVE IT

• UNPREPARED
• FOR THE INEVITABLE NATURAL HAZARDS

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GLOBAL GOALFROM UNPREPARED TO A STATE
OF PREPAREDNESS FOR ALL CITIES AND
ALL NATURAL HAZARDS
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TECHNIQUE
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SUMMARY

• A risk assessment is the probabilistic
  integration of
• The hazard (e.g., earthquakes) and their
  potential disaster agents (ground shaking, etc)
  and
• The exposure, location and vulnerability of
  elements of the citys built environment).

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SUMMARY HAZARD ENVIRONMENT

• The parameters of the hazard environment control
  the primary disaster agents of ground shaking and
  ground failure and the secondary disaster agents
  of surface fault rupture, tsunami wave run up,
  seiche, regional tectonic deformation, and
  aftershocks.

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SUMMARY BUILT ENVIRONMENT

• The built environment is comprised of buildings
  and infrastructure (the exposure, or the elements
  at risk), each having a relative vulnerability to
  a specific potential disaster agent such as
  ground shaking.

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HAZARD MAPSBASED ON A PROBABILISTIC MODEL

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REQUIRED INFORMATION

• Location of active faults.
• Geometry of the faults.
• Regional tectonic setting.
• Spatial and temporal characteristics of
  seismicity

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REQUIRED INFORMATION

• Rate of decay of seismic energy with distance
  from the point of fault rupture.
• Magnitude, other source parameters, and geologic
  structure.

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REQUIRED INFORMATION

• The physical properties of shallow, near-surface
  soils.
• Construction materials of the exposure (buildings
  and infrastructure)

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GROUND SHAKING

• Ground shaking is characterized by two primary
  parameters 1) the acceleration time history, and
  2) its spectral acceleration.
• Each varies as a function of magnitude, distance
  from the fault zone, and the properties of the
  local soil and rock column.

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TIME HISTORY AND SPECTRA
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CONSTRUCTING A PROBABILISTIC EARTHQUAKE HAZARD MAP
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CONSTRUCTING A MAP

• The first step is to choose one of the following
  parameters to map
• Intensity (Typically MMI values)
• Peak ground acceleration (Typically PGA values)
• Spectral acceleration (Typically 0.2 s
  period (short buildings) and/or 1.0 s period
  (tall buildings)

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CONSTRUCTING A MAP

• The second step is to choose an appropriate
  scale for the application and prepare a grid of
  points (e.g., 0.05 degree latitude and longitude)

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CONSTRUCTING A MAP

• The final steps are to add the layers of data,
  such as
• The geographic boundaries and cultural features
  of the community.
• The fault systems.
• The seismicity.
• Seismic attenuation and soil

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EXAMPLE ATTENUATION
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EXAMPLE OF SOIL AMPLIFICATION
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CALCULATIONS

• Perform calculations for an exposure time (e.g.,
  50 or 100 years), and exceedance probability
  (e.g., 2 or 10 ).

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FROM A GROUND SHAKING MAP TO PUBLIC POLICY

• A map format facilitates dialogue on the best
  ways to form public policy for protecting the
  citys essential facilities and critical
  infra-structure, another key element of disaster
  resilience.

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EXPECTED LOSS, VULNERABILTY, AND GROUND SHAKING
MEAN DAMAGE RATIO, OF REPLACEMENT
VALUE
INTENSITY
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POLICY CONSIDERATIONS GROUND SHAKING VARIES
ACROSS USA
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POLICY ENVIRONMENT

• A citys leaders make the decisions on what it
  will do to control and reduce its perceived risks
  (e.g., by adopting and implementing policies such
  as building codes, and lifeline standards to
  protect, and retrofit and rehabilitation to
  sustain).

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RISK MODELING BASED ON HAZUS-MH(OR A
COMPARABLE MODEL)

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RISK ASSESSMENT

• The exposure (e.g., people, and elements of the
  communitys built environment) represent the TYPE
  and EXTENT of loss that is possible.

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RISK ASSESSMENT (Continued)

• The vulnerability (or fragility) of each element
  comprising the exposure affect nature and extent
  of damage and potential for collapse and loss of
  function.

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RISK ASSESSMENT (Continued)

• The location of each element of the exposure in
  relation to the hazard (ground shaking) affects
  the severity of shaking and potential damage.

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RISK ASSESSMENT (continued)

• The uncertainty in parameters that characterize
  the hazard and built environments affect decision
  making.

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EARTHQUAKE DISASTER PLANNING SCENARIOS

• NOTE TECHNIQUE THIS LECTURE RESULTS NEXT
  LECTURE)

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(SAN FRANCISCO BAY AREA) EARTH-QUAKE DISASTER
PLANNING SCENARIO

• WHERE WILL THE EARTHQUAKE OCCUR?
• HOW BIG? HOW CLOSE?
• HOW DEEP? WHEN?
• THE DISASTER AGENTS?
• VULNERABILITIES IN THE BUILT ENVIRONMENT?
• EXPECTED DAMAGE?
• EXPECTED SOCIO-ECONOMIC IMPACTS?

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(LAS ANGELES AREA) EARTHQUAKE DISASTER PLANNING
SCENARIO

• WHERE WILL THE EARTHQUAKE OCCUR?
• HOW BIG? HOW CLOSE?
• HOW DEEP? WHEN?
• THE DISASTER AGENTS?
• VULNERABILITIES IN THE BUILT ENVIRONMENT?
• EXPECTED DAMAGE?
• EXPECTED SOCIO-ECONOMIC IMPACTS?

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(SEATTLE, WA AREA) EARTHQUAKE DISASTER PLANNING
SCENARIO

• WHERE WILL THE EARTHQUAKE OCCUR?
• WHEN?
• HOW BIG? HOW CLOSE?
• THE DISASTER AGENTS?
• VULNERABILITIES IN THE BUILT ENVIRONMENT?
• EXPECTED DAMAGE?
• EXPECTED SOCIO-ECONOMIC IMPACTS?

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(MEMPHIS, TN AREA) EARTHQUAKE DISASTER PLANNING
SCENARIO

• WHERE WILL THE EARTHQUAKE OCCUR?
• HOW BIG? HOW CLOSE?
• HOW DEEP? WHEN?
• THE DISASTER AGENTS?
• VULNERABILITIES IN THE BUILT ENVIRONMENT?
• EXPECTED DAMAGE?
• EXPECTED SOCIO-ECONOMIC IMPACTS?

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(TOKYO, JAPAN AREA) EARTHQUAKE DISASTER
PLANNING SCENARIO

• WHERE WILL THE EARTHQUAKE OCCUR?
• HOW BIG? HOW CLOSE?
• HOW DEEP? WHEN?
• THE DISASTER AGENTS?
• VULNERABILITIES IN THE BUILT ENVIRONMENT?
• EXPECTED DAMAGE?
• EXPECTED SOCIO-ECONOMIC IMPACTS?

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VULNERABILITY OF ELEMENTS

• Note Each element has a unique vulnerability
  (fragility) to earthquake ground shaking as the
  result of flaws that enter during the planning,
  siting, design, construction, use, and
  maintenance of individual buildings and elements
  of infrastructure.

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VULNERABILITY

• An elements vulnerability is related to
  varying designs, ranging from non-engineered
  (e.g., a single-family dwelling) to engineered
  (e.g., a high-rise building).

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VULNERABILITY

• Vulnerability is related to varying ages of
  construction, which also means varying editions
  of the building code and its seismic design
  provisions.

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VULNERABILITY

• Vulnerability is related to varying construction
  materials (e.g., wood, un-reinforced masonry,
  un-reinforced concrete, reinforced concrete,
  light metal, and steel).

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VULNERABILITY

• Vulnerability is related to the design for
  varying service lives (e.g., 30 years for the
  half-life of a class of houses 40 years for a
  class of bridges, etc.).

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VULNERABILITY

• Vulnerability is related to varying
  configurations (i.e., elevations and floor
  plans).
• NOTE The greater the vulner-ability the higher
  the potential for the building to collapse)

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CONFIGURATION VULNERABILITY
LOCATIONS OF POTENTIAL FAILURE
BUILDING ELEVATION
RELATIVE VULERABILITY 1 (Best) to 10
(Worst)
None, if attention given to foundation and non
structural elements. Rocking may crack
foundation and structure.
1-2
Box
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CONFIGURATION VULNERABILITY
LOCATIONS OF POTENTIAL FAILURE
BUILDING ELEVATION
RELATIVE VULERABILITY 1 (Best) to 10
(Worst)
Top heavy, asymmetrical structure may fail at
foundation due to rocking and overturning.
4 - 6
Inverted Pyramid
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CONFIGURATION VULNERABILITY
LOCATIONS OF POTENTIAL FAILURE
BUILDING ELEVATION
RELATIVE VULERABILITY 1 (Best) to 10
(Worst)
CONFIGURATION
Vertical transition in mass, stiffness, and
damping may cause failure at foundation and
transition points at each floor.
2 - 3
Multiple Setbacks
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CONFIGURATION VULNERABILITY
LOCATIONS OF POTENTIAL FAILURE
BUILDING ELEVATION
RELATIVE VULERABILITY 1 (Best) to 10
(Worst)
Asymmetry and horizontal transition in mass,
stiffness and damping may cause failure where
lower and upper structures join.
5 - 6
L- Shaped Building
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CONFIGURATION VULNERABILITY
LOCATIONS OF POTENTIAL FAILURE
BUILDING ELEVATION
RELATIVE VULERABILITY 1 (Best) to 10
(Worst)
Vertical transition and asymmetry may cause
failure where lower part is attached to tower.
3 - 5
Inverted T
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CONFIGURATION VULNERABILITY
LOCATIONS OF POTENTIAL FAILURE
BUILDING ELEVATION
RELATIVE VULERABILITY 1 (Best) to 10
(Worst)
Horizontal and vertical transitions in mass and
stiffness may cause failure on soft side of first
floor rocking and overturning.
6 - 7
Partial Soft Story
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CONFIGURATION VULNERABILITY
LOCATIONS OF POTENTIAL FAILURE
BUILDING ELEVATION
RELATIVE VULERABILITY 1 (Best) to 10
(Worst)
Top heavy asymmetrical structure may fail at
transition point and foundation due to rocking
and overturning.
4 - 5
Overhang
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ANALYSIS OF VULNERABILITY
LOCATIONS OF POTENTIAL FAILURE
BUILDING ELEVATION
RELATIVE VULERABILITY 1 (Best) to 10
(Worst)
Vertical transitions in mass and stiffness may
cause failure on transition points between first
and second floors.
8 - 10
Soft First Floor
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CONFIGURATION VULNERABILITY
LOCATIONS OF POTENTIAL FAILURE
BUILDING ELEVATION
RELATIVE VULERABILITY 1 (Best) to 10
(Worst)
Horizontal and vertical transition in stiffness
and cause failure of individual members.
8 - 9
Theaters and Assembly Halls
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URATION CONFIG VULNERABILITY
LOCATIONS OF POTENTIAL FAILURE
BUILDING ELEVATION
RELATIVE VULERABILITY 1 (Best) to 10
(Worst)
Horizontal and vertical transitions in mass and
stiffness may cause failure at transition points
and possible overturning.
9 - 10
Combination of Soft Story and Overhang
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CONFIGURATION VULNERABILITY
LOCATIONS OF POTENTIAL FAILURE
BUILDING ELEVATION
RELATIVE VULERABILITY 1 (Best) to 10
(Worst)
Horizontal and vertical transition in mass and
stiffness may cause failure columns.
9 - 10
Sports Stadiums
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CONFIGURATION VULNERABILITY
LOCATIONS OF POTENTIAL FAILURE
BUILDING ELEVATION
RELATIVE VULERABILITY 1 (Best) to 10
(Worst)
Horizontal transition in stiffness of soft story
columns may cause failure of columns at
foundation and/or contact points with structure.
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Building on Sloping Ground
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THE GOAL OF EVERY CITY

• WELL PREPARED FOR ALL NATURAL HAZARDS (E.G.,
  FLOODS, SEVERE WINDSTORMS, EARTHQUAKES, ETC.)

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DISASTER PREPAREDNESS IS A 24/7 EFFORT

• KNOW YOUR HAZARDS
• KNOW YOUR CITY
• KNOW WHAT TO DO WHEN
• KNOW HOW TO DO IT WHEM