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HAZUS: FEMA’S GIS-Based risk assessment tool

Doug Bausch
FEMA Region VIII Denver Federal Center, Bldg. 710
Denver, CO 80225


As part of its efforts to mitigate hazards and protect lives and property from the devastating effects of natural disasters, FEMA aims to provide individuals, businesses, and communities with information and tools to work proactively to mitigate hazards and prevent losses resulting from disasters. One of these tools is HAZUS or Hazards U.S., a natural hazard loss estimation methodology developed by FEMA in partnership with the National Institute of Building Sciences.

Using Geographic Information Systems (GIS) technology, HAZUS allows users to compute estimates of damage and losses that could result from an earthquake. To support FEMA's mitigation and emergency preparedness efforts, HAZUS is being expanded into HAZUS-MH, a multi-hazard methodology with new modules for estimating potential losses from wind and flood (riverine and coastal) hazards.

Hazus Multi-Hazard

HAZUS-MH, to be released in early Spring of 2003, is a nationally applicable standardized methodology and software program that will contain models for estimating potential losses from earthquakes, floods, and hurricanes. HAZUS-MH is developed by the Federal Emergency Management Agency (FEMA) under contract with the National Institute of Building Sciences (NIBS). NIBS maintains committees of wind, flood, earthquake and software experts to provide technical oversight and guidance to HAZUS-MH development. Loss estimates produced by HAZUS-MH will be based on current scientific and engineering knowledge of the effects of hurricanes, floods and earthquakes. Estimating losses is essential to decisionmaking at all levels of government, providing a basis for developing mitigation plans and policies, emergency preparedness, and response and recovery planning.

HAZUS-MH will use state-of-the-art geographic information system software (ArcView) to map and display hazard data, and the results of damage and economic loss estimates for buildings and infrastructure. It will also allow users to estimate the impacts of hurricanes, floods and earthquakes to populations. HAZUS-MH will be fast running to facilitate use in real time to support response and recovery following a natural disaster.

Each hazard model will operate at a Level 1 using national level data sets that are included with the HAZUS methodology, and a Level 2 using national level data modified with local data for more refined results. A Level 3 analysis will allow users to supply their own techniques to study special conditions such as dam breaks and tsunamis. Engineering and other expertise is needed at this level. To support data collection the HAZUS-MH InCAST inventory collection tool was released in 2002 with expanded capabilities for multi-hazard data collection. InCAST assists users with collecting and managing local building data for more refined analyses than are possible with the national level data sets that will come with HAZUS. HAZUS-MH will include an enhanced Building Inventory Tool (BIT) to assist users in collecting local tax assessors data for use in HAZUS-MH.

The HAZUS-MH Hurricane Model will allow users in the Atlantic and Gulf Coast regions of the U.S. to estimate hurricane winds and potential damage and loss to residential, commercial, and industrial buildings. It will also allow users to estimate direct economic loss, post-storm shelter needs, and building and tree debris quantities. The HAZUS-MH Flood Model will be capable of assessing riverine and coastal flooding. It will estimate potential damages to all classes of buildings, essential facilities, transportation lifelines, and utility lifelines, vehicles, and agricultural crops. The model will address building debris generation and shelter requirements. Direct losses will be estimated based on physical damage to structures, contents, and building interiors. The effects of flood warning will be taken into account, as will flow velocity effects. The Flood Information Tool (FIT), released in July 2002, allows users to prepare local flood hazard and other pertinent data for use in the HAZUS-MH Flood Model.

The HAZUS-MH Earthquake Model, an updated version of HAZUS99-SR2, will continue to provide loss estimates of damage and loss to buildings, essential facilities, transportation lifelines, and utility lifelines, and population based on scenario or probabilistic earthquakes. The model will address debris generation, fire-following, casualties and shelter requirements. Direct losses will be estimated based on physical damage to structures, contents, inventory, and building interiors. It also will include the new Advanced Engineering Building Module for single and group building mitigation analysis. The updated earthquake model being released with HAZUS- MH will include:

The HAZUS-MH Earthquake Model, an updated version of HAZUS99-SR2, will continue to provide loss estimates of damage and loss to buildings, essential facilities, transportation lifelines, and utility lifelines, and population based on scenario or probabilistic earthquakes. The model will address debris generation, fire-following, casualties and shelter requirements. Direct losses will be estimated based on physical damage to structures, contents, inventory, and building interiors. It also will include the new Advanced Engineering Building Module for single and group building mitigation analysis. The updated earthquake model being released with HAZUS- MH will include:
  • The new (September 2002) National Hazard Maps
  • Project '02 attenuation functions
  • Updated historical earthquake catalog (magnitude 5 or greater)
  • New Advanced Engineering Building Module for single and group building mitigation analysis
Additionally, HAZUS-MH will be capable of multi-hazard analysis by providing access to the average annualized loss and probabilistic results from the wind, flood and earthquake models and combining them to provide integrated multi-hazard reports and graphs. HAZUS-MH also will contain a third party model integration capability in HAZUS-MH that will provide access and operational capability to a wide range of natural, man-made and technological hazard models (nuclear and conventional blast, radiological, chemical and biological) that will supplement the natural hazard loss estimation capability (earthquake, flood & hurricane) in HAZUS-MH.

HAZUS Loss Estimation Models: Earthquake
  • What is a HAZUS Earthquake Loss Estimate?
  • Why Do I Need to Estimate Earthquake Losses?
  • How Do I Use HAZUS to Prepare for Earthquakes?
  • What Information Do I Need to Provide HAZUS?
  • How Does HAZUS Calculate Losses?
  • What Will a HAZUS Earthquake Loss Estimate Cost?
What is a HAZUS Earthquake Loss Estimate?

damage and human and economic impacts that may result from future earthquakes. These are estimates based on current scientific and engineering knowledge.

The FEMA HAZUS earthquake loss estimation methodology is a software program that uses mathematical formulas and information about building stock, local geology and the location and size of potential earthquakes, economic data, and other information to estimate losses from a potential earthquake. HAZUS is capable of using two separate geographic information systems (MapInfoTM and ArcViewTM) to map and display ground shaking, the pattern of building damage, and demographic information about a community. Once the location and size of a hypothetical earthquake is identified, HAZUS will estimate the violence of the following:
  • ground shaking
  • the number of buildings damaged
  • the number of casualties
  • the amount of damage to transportation systems
  • disruption to the electrical and water utilities
  • the number of people displaced from their homes
  • estimated cost of repairing projected damage and other effects
Why Do I Need to Estimate Earthquake Losses?
An estimate of losses from future earthquakes is essential to preparing for a disaster and facilitating good decision making at the local, regional, state, and national levels of government. A HAZUS estimate of earthquake losses provides vital tools for the following:
  • Land-use planning and facility siting decisions (e.g., a map-based analysis of the potential intensity of ground shaking from a postulated earthquake that identifies those parts of the community that will experience the most violent shaking and the buildings at greatest risk of damage).
  • Prioritization of retrofit or abatement programs (e.g., an estimate of building damage that provides the basis for establishing programs to mitigate or strengthen buildings that may collapse in earthquakes by providing estimates of damages and casualties).
  • Regional, state, and local emergency response and contingency planning (e.g., estimates of casualties and of damage to buildings and utilities).
  • Medical and relief agency preparedness and response (e.g., estimates of casualties and homelessness).
  • Assistance planning (e.g., an estimate of dollar losses that will help the state and federal governments plan for assistance to jurisdictions and disaster victims).
How Do I Use HAZUS to Prepare for Earthquakes?
The first step in preparing for a disaster is estimating its potential impact. Loss estimates can provide the basis for developing mitigation policy, for developing and testing emergency preparedness and response plans, and for planning for post disaster relief and recovery.
  • Before an Earthquake: Mitigating Future Losses

    • Reducing earthquake losses begins before the earthquake. Loss estimates provide public and private sector agencies with a basis for planning, zoning, building codes and development regulations, and policy that would reduce the risk posed by violent ground shaking and ground failure. Loss estimates can also be used to evaluate the cost effectiveness of alternative approaches to strengthening potentially hazardous structures.

  • Before an Earthquake: Preparing to Respond

    • Understanding the scope and complexity of earthquake damage is essential to effective preparedness. HAZUS can forecast damage to buildings, casualties, and disruption of utilities. These estimates can be the basis for developing emergency response plans and for organizing tests and exercises of response capability.

  • "A Guide to Using HAZUS for Mitigation"

    • describes how HAZUS can help your local community, county, region or state identify, develop and implement measures to accomplish effective earthquake hazard risk reduction. Download the Guide

  • After an Earthquake: Speeding Response and Relief

    • A rapid response to a damaging earthquake will reduce loss of life, complications from injuries and secondary damage and loss, and will expedite relief to victims.

    HAZUS can be an important decision support tool during this response period. Immediately after a damaging earthquake, HAZUS can help emergency managers identify the likely damaged areas, provide a rapid estimate of the damage and casualties that occurred and the type and amount of resources that should be deployed to assist the affected area.

    Response and relief agencies can use HAZUS to project damage, loss, and the number of homeless and to estimate the financial and material resources necessary to assist victims. Regional, state, and federal officials can use HAZUS estimates of casualties and injuries to project demand on medical resources. Utilities can use HAZUS estimates and the projected pattern of power and water outages to organize and set priorities for recovery.
What Information Do I Need to Provide HAZUS?
Data requirements for HAZUS will vary with the level of accuracy desired, the data available about the community, and how much can be invested in a loss estimate. There are three estimation levels that can be produced using HAZUS software:
  • When Would I Perform a Level One Analysis?

    • All of the information you will need to produce a preliminary estimate of losses from an earthquake is included in the HAZUS software. This data from national databases included in HAZUS describes in general terms the geology of the region and the building inventory and economic structure of the community. The national data is used to provide a Level One estimate of losses.

  • When Would I Perform a Level Two Analysis?

    • More accurate estimates of losses require more detailed information about the community. To produce a Level Two estimate of losses, detailed information will be required about local geology, an inventory of buildings in the community, and data about utilities and transportation systems. Assistance from geotechnical and structural engineers may be necessary for this analysis.

  • When Would I Perform a Level Three Analysis?

    • The most accurate estimate of loss will require detailed engineering and geotechnical input to customize the methodology to the specific conditions of the community.

    Level One and Level Two studies can typically be carried out by local government emergency services or planning staffs; Level Three estimates require assistance from structural engineers and geologists.
How Does HAZUS Calculate Losses?
HAZUS uses Geographic Information System (GIS) software and scientifically developed algorithms to calculate, map, and display earthquake loss data. Once the size and location (epicenter) of a hypothetical earthquake is selected, the HAZUS software, using a series of mathematical formulas, calculates the violence of ground shaking, the amount of damage, the number of casualties, the number of people displaced by damaged structures, and the disruption and economic losses caused by the earthquake. These formulas describe the relationship between earthquake magnitude, violence of ground shaking, building and utility system damage, cost of repair, and indirect economic impact. HAZUS allows for changing the size and location of the hypothetical earthquake to see the range of damage that may occur to the community.

What Will a HAZUS Earthquake Loss Estimate Cost?
The exact cost of using HAZUS is determined by user needs and the availability of data. The basic components include a computer system, the HAZUS software, MapInfoTM or ArcViewTM software, other data (additional/local), and engineering and technical expertise. The cost of an estimate varies depending on the estimation level (One, Two, or Three) being performed, the availability of inventory data, the computer system available, and the necessity and availability of technical expertise. To run a Level One estimate, all that is required is the computer system described in the section, "Requirements for Running HAZUS", the GIs (MapInfoTM or ArcViewTM) software, and the HAZUS software. The 1999 version of the HAZUS software is currently available at no cost. MapInfoTM or ArcViewTM must be purchased by the user. Level Two and Level Three estimates require both detailed data and engineering and geotechnical expertise. In addition to hardware and software costs, approximately one day of staff time would be necessary to produce a Level One analysis for a community; more time would be
required for deeper levels of analysis.

HAZUS Loss Estimation Models: Wind

HAZUS Wind Loss Estimation
A hurricane Preview Model is being developed for release in 2002 to communities in Atlantic and Gulf Coast regions. This initial version will allow assessment of hurricane winds and computation of basic estimates of potential damage to residential, commercial, and industrial buildings. It will also allow estimating direct economic losses. Development of the full wind model will continue after 2002, to increase the capability of the model to estimate indirect economic losses and impacts to lifelines and to add the capability to assess the effects of extra- tropical cyclones, tornadoes, thunderstorms and hail.

Hurricane Loss Estimation Model
The hazard component of the HAZUS hurricane model will make use of an existing state-of-the-art windfield model, which has been calibrated and validated using full-scale hurricane data. The model incorporates sea surface temperature in the boundary layer analysis, and calculates wind speed as a function of central pressure, translation speed, and surface roughness.


The HAZUS wind model will be an improvement over existing loss estimation models by using a wind hazard-load-damage-loss framework. The model will address wind pressure, wind borne debris, surge and waves, atmospheric pressure change, duration/fatigue, and rain. It will have the following features:
  • A building classification system that depends on the characteristics of the building envelope and building frame.
  • The capability to compute damages based on building classes and the effects of rain, progressive failure.
  • The capability to compute damage to contents and building interior.
  • The capability to estimate tree blowdown and structure debris quantities.
  • Loss estimates will include direct and indirect economic loss, shelter requirements, and casualties.
  • Modules will be included to facilitate future assessment of mitigation, benefitcost, and building code issues.
HAZUS Loss Estimation Models: Flood
The flood loss estimation methodology consists of two basic analytical processes: flood hazard analysis and flood loss estimation analysis. In the hazard analysis module, characteristics such as frequency, discharge, and ground elevation are used to estimate flood depth, flood elevation, and velocity. In the loss estimation module, physical damage and economic loss is calculated based on the results of the hazard analysis. The results are displayed using a series of reports and maps.

Users may perform three levels of analysis using HAZUS Flood. The following describe the information and expertise needed for each level:
  • Level 1

    • All of the information needed to produce a basic estimate of local flood losses will be included as default data, based on national databases and nationally applicable methods.

  • Level 2

    • More accurate estimates will be needed including detailed information on local conditions. Modification of default databases will be required, along with the inclusion of local data and analyses.

  • Level 3

    • Detailed and site-specific input data will be used to create state-of-the-art damage estimates and situation assessment profiles. Level 3 is intended for the expert user.
The HAZUS Flood Module will be distributed to those agencies and organizations likely to have data that can be used in HAZUS. It will be primarily distributed to floodplain management officials, emergency planners, hazard mitigation officers, and National Flood Insurance Program (NFIP) coordinators as a tool to assist in planning, mitigation, and emergency response and recovery activities.

Several communities are also participating in the Flood Information Tool (FIT) Project. The FIT, released in July 2002, was designed to process and convert locally available flood information to data that can be used by the HAZUS Flood Module. The FIT is a system of instructions, tutorials and GIS analysis scripts. When provided with usersupplied inputs (e.g., ground elevations, flood elevations, and floodplain boundary information), the FIT calculates flood depth and elevation for riverine and coastal flood hazards. The FIT is intended to help users perform Level 2 or Level 3 flood hazard analyses. The user is allowed to input various combinations of data in order to customize the analysis, and determine the remaining data from the default values.

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