improving usgs input into hazus & other loss estimation tools

U.S. Department of the InteriorU.S. Geological Survey

Improving USGS Input into HAZUS & Other Loss Estimation Tools

Nicolas Luco – Research Structural Engineer

Erdem Karaca – Mendenhall Postdoctoral Researcher

USGS Geologic Hazards Team, Golden, CO

USGS/MAEC Workshop in Memphis, TNOctober 11, 2006

Presentation Topics

1) Improving USGS Input into HAZUSa) USGS-FEMA Plan on Future Opportunities

b) Probabilistic Building Damage & Risk Maps

2) Cost-Benefit Analysis of Earthquake Provisions in Building Codes

3) Prompt Assessment of Global Earthquake for Response (PAGER) – D. Wald & P. Earle

4) An Interactive Web Tool for Quantitative Seismic Risk Assessment of Woodframe Houses (ResRisk-WH)

5) Open-Source Risk Modeling Software ("OpenRisk") – K. Porter & C. Scawthorn

Multi-hazard loss estimation methodology

Earthquake, flood, wind

Default databases

Building inventory, bridge inventory, …

Possible ground motion inputs

Scenario earthquakes, USGS hazard curves, ShakeMaps

Losses

Repair costs, casualties, direct & indirect economic losses

HAZUS - Pros

Integrated earthquake loss estimation methodology

Default databases

Losses for a scenario earthquakes or ground-shaking maps

Various loss measures (repair costs, number of casualties, …)

HAZUS - Cons

Not fully probabilistic (expected scenario/annual losses only)

Computational efficiency (GIS overhead)

Flexibility (not open-source)

Presentation Topics







1) Improving USGS Input into HAZUS

FY06 & FY07 OMB Recommendation:

Improve earthquake risk estimates by integrating the USGS Geologic Hazards Program seismic monitoring with FEMA hazard loss estimation capabilities.

FY06 Milestones (USGS Response):

Establish USGS-FEMA workgroup to develop joint plan for collaboration

Combine USGS National Seismic Hazard Maps with HAZUS methodology to generate probabilistic loss estimates

Produce prototype HAZUS-formatted ShakeMaps for destructive earthquake scenarios to facilitate generating loss estimates for the scenarios

1) Improving USGS Input into HAZUS

USGS-FEMA Plan on Future Opportunities:

Integration of USGS Seismic Monitoring with HAZUS for Earthquake Response

USGS Ground Motion “Plug-In” for HAZUS

Coordination of USGS/FEMA Earthquake Damage Research (“HAZUS-R”)

Joint Earthquake Risk Publications, Maps, and Associated Products

Example: Regional probabilistic loss distributions (i.e., beyond expected losses)

Regional Probabilistic Loss Distributions: Goal

Exceedance probability curves for total losses to a portfolio/region.

Combination of ground motion hazard, building exposure, and building fragilities.

10-4

10-3

10-2

10-1

100

10-6

10-5

10-4

10-3

10-2

10-1

Loss / Total Value

Ann

ual E

xcee

danc

e F

requ

ency

San Francisco Bay Region

Probabilistic Seismic Loss Analysis (PSLA)

PSHA-analogous methodology described in Wesson, Perkins, and Luco (2006): "Direct Calculation of the Probability Distribution for Earthquake Losses to a Portfolio"

Applications to date:

San Francisco Bay Area Residential Woodframe Losses (Luco et al for 2006 AGU Fall Meeting, manuscript in preparation)

Shelby County & Memphis Metro Bridges (Karaca & Luco for 5th National Seismic Conference on Bridges & Highways)

Next applications will couple USGS hazard information with HAZUS exposure data and "revamped" HAZUS fragilities (described later in presentation)

For each individual building of the exposure, the output of PSHA (i.e., a hazard curve for the site) can be coupled with the building fragility to arrive at its “loss curve”:

If the losses for individual buildings were independent, a combined loss curve could be obtained via a simple convolution, e.g., …

But the losses for individual buildings are not independent, since their sites are shaken by the same earthquake events.

Bottom Line: We can’t simply start from the output of PSHA.

Methodology: Motivation

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PSHA OutputFragility“Loss Curve”

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lLPlLlLLPlLLP

indep. were & if ][ 2121 LLllLP ][][ 21 lLPlLP

Recall that Probabilistic Seismic Hazard Analysis (PSHA) conditions on and sums over “all” potential earthquake events:

For a given "event" (defined below), the losses for individual buildings can be considered independent, and hence, e.g., …

Each “event” is defined here by:

(i) M = magnitude of earthquake

(ii) R = location of earthquake & corresponding distances to sites

(iii) inter = measure of average ground motion relative to other

similar earthquake events (i.e., # of inter’s)

Methodology: Extending PSHA

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iEventiEventaGMPaGM ][]|[][

]|[]|[]|[ 2121 EventlLPEventlLPEventlLLP

In summary, an exceedance curve for the sum of losses to all buildings in the exposure can be obtained via the following steps:

1) For each potential event, combine the fragility and site hazard for each building to obtain individual loss curves, i.e., …

2) Convolve the individual conditional loss curves to obtain a combined loss curve for each event, e.g., …

3) Sum (with event weights) the loss curves for each event, e.g., …

Methodology: PSLA Summary

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]|[]|[]|[ 2121 EventlLPEventlLPEventlLLP

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Fragility Hazard

1) Input on USGS Role in Risk Field

FY05 USGS Venture Capital Fund Project

Proposed “National Seismic Risk Maps”

M. Petersen and N. Luco met with …

FM Global AIR Worldwide Corporation RMS (Risk Management Solutions) ABS Consulting (formerly EQE) CGS (California Geological Survey) CEA (California Earthquake Authority) FEMA & NIBS (with D. Applegate)


Stakeholders encouraged …

Research into vulnerabilities and risk analysis, in addition to hazard

Results that they could compare with and/or utilize

Transparent risk calculations for sensitivity studies

Contribution to exposure data (e.g., by USGS Geography)

Evaluations of available vulnerabilities

Analyses for “public” buildings (e.g., homes)


Stakeholders discouraged …

Development of risk modeling software

Risk results that become de facto standard (i.e., do be clear about uncertainties/shortcomings of results)

Competition

Stakeholders willing to cooperate, if not collaborate (similar to response to open-source risk-modeling software)

Presentation Topics







Building Risk Maps

Building risk maps show the mean annual frequencies (MAFs) of exceeding different structural damage states (or losses) for each of the 36 building types in HAZUS designed to 4 different code levels

sa

saSAsaSAdsDSPdsDS |][d|]|[][

(Memphis, TN)

=

Building Risk Maps

Spectral acceleration, PGA, MMI, Inelastic spectral displacement,

Inter-story drift ratio, …

Fragility Curve

P(DS = ds | Sa)

P(DS ≥ ds | Sa)

(Loss | DS = ds)

Vulnerability Curve

P(Loss ≥ loss | Sa)

Example Building Risk Maps

Low Rise Steel Moment Frame Building, Low Code


Slight Damage


Extensive Damage


Low-Code

High-Code

Slight Damage

Building Damage Maps

sa

SA sasafsaSAdsDSPdsDSP d)(]|[][

Building damage maps show the probabilities of different

structural damage states (or losses) for each of the 36 building

types in HAZUS designed to 4 different code levels

Seismic HazardFragility Curve

Example Building Damage Maps: Northridge Eq.

Low Rise Steel Moment Frame Building, Low Code

Example Building Damage Maps

Light Frame Wood Building, Low Code

Presentation Topics







USGS Mendenhall Postdoctoral Project

“Cost-Benefit Analysis of Earthquake Provisions in Building Codes”

In particular, reduction of losses around New Madrid Seismic Zone via adoption of seismic design maps in International Building Code (IBC)

Involves update of HAZUS fragilities to reflect IBC, and to depend on design ground motion

Also involves revamping of HAZUS fragilities for use in “Probabilistic Seismic Loss Analysis” (Wesson, Perkins & Luco, 2006)

Approach: SBC => IBC

Hazard

Fragility/Vulnerability

Inventory

Loss/Risk

Cost?

Reduced Risk?

HAZUS Building Fragilities

DamageState

Definition

CapacitySpectrumMethod

CapacityCurve

Fragility Curve Input:Inelastic Spectral

Displacement

Revamping HAZUS Fragilities

DamageState

Definition

CapacityCurve

Time History

Analysis

Fragility Curve Input:Elastic Spectral

Acceleration


Revamped HAZUS fragilities are:

1) Based on nonlinear dynamic structural analysis rather than Capacity Spectrum Method.

2) Independent of ground motion variability, which is taken care of in hazard computation.

3) Fully probabilistic with variability in ground motion and building response properly accounted for.


Revamped HAZUS fragilities are (continued):

4) In terms of ground motion parameters for which hazard is typically computed, e.g., Sa(0.3s).

5) Available for a large number of structures (all HAZUS building types and code levels).

6) Can be easily combined with seismic hazard information to …

Evaluate seismic risk, e.g. seismic risk maps.

Estimate losses from a scenario event, e.g. seismic damage maps.

Evaluate building design/mitigation options, e.g. SBC vs IBC design.

Approach: SBC => IBC (Current/Future Work)

Cost

Reduced Risk

Presentation Topics







Relevant Other USGS Studies/Products: PAGER

Prompt Assessment of Global Earthquakes for Response

is an automated alarm system being developed to rapidly and accurately assess the severity of damage caused by an earthquake and to provide emergency relief organizations, government agencies, and the media with an estimate of the societal impact from the potential catastrophe.

will distribute alarms via pager, mobile phone, and e-mail that will include a concise estimate of the earthquake’s impact.

will also report the earthquake location, magnitude, and depth, an estimate of the number of people exposed to varying levels of shaking, a description of the region’s vulnerability, and a measure of confidence in the system’s impact assessment.

information will be available within minutes of the determination of the earthquakes location and magnitude

Relevant Other USGS Studies/Products: PAGER

Pager Process

1. Ground ShakingEstimate 2. Population

Data

3. Ground Shaking and Exposure

4. Impact Estimate

Presentation Topics







4) Plan for Residential Risk Web Tool

Ultimate goal: An interactive web tool for quantitative seismic risk assessment of woodframe houses (“ResRisk–WH”)

Phase I plan for FY07 (w/ N. Field & K. Porter)

Java module – Standalone & OpenSHA application

Input: Zip code

Vulnerability relation (dropdown menu)

Output: Loss exceedance probability curve ( including probability of exceeding deductible, expected loss )

Review of IBC Seismic Design Maps

CUREE Small House, Typical QualityCUREE Small House, Braced Cripple WallCUREE Large House, Typical Quality...Wesson et al. Single-Family Home, ShakeMap PGA

Select Vulnerability Relation

Loss Ratio

Loss Exceedance Probability Curve

4) Plan for Residential Risk Web Tool

“Phase II” Plan for Future Work

Supplement available vulnerability relations to adequately represent exposure in Northridge ‘94

Validate/calibrate vulnerability relations using data from Northridge ’94 earthquake

“Phase III” Plan for Future Work

Derive vulnerability relation “on-the-fly” based on user-inputted floor plans

Would result in user-assembled database of vulnerability relations (not tied to an address)

Presentation Topics







5) "OpenRisk"

Like HAZUS, multi-hazard & freeware Unlike HAZUS, an open-source code base R. Murnane (BBSR-RPI) held a workshop in March

of 2005 (www.open-risk.org) K. Porter & C. Scawthorn (SPA) have …

been funded by SCEC to draft initial plan obtained programming support from Russia

A proposal to further "OpenRisk" is pending with USGS NEHRP External Grants Program

USGS development of ResRisk-WH is contributing to OpenRisk code base (Java)

Presentation Topics







HAZUS – Example:

Expected Annual Loss (EAL) using USGS PSHMs

Not a true loss exceedance curve

Area under Curve=

EAL

Example: Earthquake Events & GM’s (Hazard)

San Francisco Bay Region

Characteristic and floating earthquake events from USGS Working Group 2002

4 attenuation relations for ground motions

inter based on Lee &

Anderson (BSSA, 2000)

3 different hazard programs used to compute median and dispersion of ground motion for each earthquake event and building site pair

Example: Buildings & Sites (Exposure)

Residential Woodframe Buildings – Inventory from HAZUS

Aggregated at census tract level

Within each census tract, one site per NEHRP site classification

Components of Risk/Loss Analysis

HAZARD

e.g., National Seismic Hazard Maps, ShakeMaps

EXPOSURE

e.g., HAZUS Inventory Data, USGS Geography

FRAGILITY (or VULNERABILITY)

e.g., HAZUS Fragilities, Wesson et al (2004)

RESILIENCY

e.g., Insurance, Cat. Bonds, Emergency Response

improving usgs input into hazus & other loss estimation tools

Documents

earthquake losses

earthquake risk estimates

usgs hazard curves

usgs hazard information

usgsfema workgroup

hazus methodology

hazus consnot

hazususgsfema plan