1 hazard mapping and modeling session 6: modeling earthquake hazards
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HAZARD MAPPING AND MODELING
SESSION 6: MODELING EARTHQUAKE HAZARDS
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OBJECTIVE 1
Clarify the nature of earthquakes as a hazard and
their impacts
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An earthquake is a natural event associated with
movements on a global scale of tectonic plates and the
rupture of faults on a regional scale as a result of that
movement.
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SEISMICITY SEISMICITY
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Schematic Diagram of the Schematic Diagram of the Earthquake Fault RuptureEarthquake Fault RuptureSchematic Diagram of the Schematic Diagram of the Earthquake Fault RuptureEarthquake Fault Rupture
NORTHNORTHNORTHNORTHWESTWESTWESTWEST
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Schematic Diagram of the Schematic Diagram of the Earthquake MechanismEarthquake Mechanism
Schematic Diagram of the Schematic Diagram of the Earthquake MechanismEarthquake Mechanism
NORTHNORTHNORTHNORTHWESTWESTWESTWEST
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CYCLONESCYCLONES
DROUGHTDROUGHT
WILDFIRESWILDFIRES
VOLCANIC ERUPTIONSVOLCANIC ERUPTIONS
LANDSLIDESLANDSLIDES
TSUNAMISTSUNAMIS
LANDSLIDESLANDSLIDES
EARTHQUAKESEARTHQUAKESHURRICANESHURRICANES FLOODSFLOODS
NATURAL HAZARDSNATURAL HAZARDS
ATMOSPHERICATMOSPHERICATMOSPHERICATMOSPHERIC GEOLOGICGEOLOGICGEOLOGICGEOLOGIC HYDROLOGICHYDROLOGICHYDROLOGICHYDROLOGIC
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FLOODS VS EARTHQUAKES
• Floods are the most frequent and most costly natural hazard on an annual basis in the United States, occurring in every state and territory and causing an average of $5 billion damage each year (Schildgen, 1999),
• However, a single earthquake (e.g., the 1994 Northridge, California quake, has the potential for causing greater economic loss within a minute than floods do for an entire year.
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EARTHQUAKES, LIKE FLOODS, ARE A NATIONAL PROBLEM
• 44 of the 50 states are at high to very high risk from earthquakes with nearly 200 million households and tens of trillions in property at risk. (FEMA 1997).
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EARTHQUAKES
• The moderate, large, and great earthquakes (i.e., magnitudes of 6 or greater) generate potential disaster agents that pose the greatest threat to society.
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FLOODS VS EARTHQUAKES
• In the United States, earthquakes cause fewer fatalities than floods. On the average, fatalities from earthquakes are only about one-third of the 160 fatalities that floods cause annually (Schildgen, 1999; FEMA 1999).
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FLOODS VS EARTHQUAKES
• Prediction and early warning systems are not yet reliable for earthquakes
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FLOODS VS EARTHQUAKES
• Disaster mitigation measures (i.e., building codes, construction materials, and retrofit and strengthening) and preparedness measures (e.g., earthquake hazard maps and disaster planning scenarios) are significant factors in keeping the death toll for earthquakes low relative to that for floods in the United States.
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CLASS ACTIVITY
1.Examine informative documents on seismicity and probabilistic maps of the ground shaking hazard to be downloaded from the USGS Web site
2. http://earthquake.usgs.gov/hazmaps
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CLASS ACTIVITY
• Identify the significant historic earthquakes that have impacted your area of the United States.
• Were you aware of these historic earthquake events?
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CLASS ACTIVITY
• Describe the notable earthquakes that have impacted the Northeastern Coast, Southeastern Coast, Gulf Coast, or Western Coast of the United States?
• How do they differ?
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CLASS ACTIVITY
• Which coasts are most likely to experience tsunami wave run up?
• Least prone?• Why?
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CLASS DISCUSSION
• What is an earthquake and what factors influence the generation of earthquakes and their societal impacts?
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CLASS DISCUSSION
• What explanation do you have for the fewer numbers of earthquake fatalities in the United States as compared with fatalities in other countries?
•
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OBJECTIVE 3
Explain how an earthquake is measured
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MAGNITUDE- A MEASURE OF THE SIZE OF AN EARTHQUAKEMAGNITUDE- A MEASURE OF
THE SIZE OF AN EARTHQUAKE
• Magnitude is based on instrumental measurements devised in the 1930’s by the late Charles F. Richter.
• Magnitude is based on instrumental measurements devised in the 1930’s by the late Charles F. Richter.
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MAGNITUDE- A MEASURE OF THE SIZE OF AN EARTHQUAKEMAGNITUDE- A MEASURE OF
THE SIZE OF AN EARTHQUAKE
• Magnitude is based on values derived from a global network of standardized instruments.
• Magnitude is based on values derived from a global network of standardized instruments.
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MAGNITUDE- A MEASURE OF THE SIZE OF AN EARTHQUAKEMAGNITUDE- A MEASURE OF
THE SIZE OF AN EARTHQUAKE
• The procedure for assigning a value of magnitude provides a standardized way to compare the size of one earthquake with another anywhere in the world.
• The procedure for assigning a value of magnitude provides a standardized way to compare the size of one earthquake with another anywhere in the world.
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MOMENT MAGNITUDE – A BETTER MEASURE
MOMENT MAGNITUDE – A BETTER MEASURE
• The moment magnitude scale was devised in the 1980’s as an extension of the Richter scale.
• The moment magnitude scale was devised in the 1980’s as an extension of the Richter scale.
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MOMENT MAGNITUDE –A BETTER MEASURE
MOMENT MAGNITUDE –A BETTER MEASURE
Moment magnitude enables scientists to characterize the great earthquakes (M > 8) more accurately.
Moment magnitude enables scientists to characterize the great earthquakes (M > 8) more accurately.
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THE LARGEST EARTHQUAKESTHE LARGEST EARTHQUAKES
• The three largest earthquakes of the 20th and 21st centuries were assigned moment magnitudes: a) 9.5 Chile earthquake of 1960, b) the 9.3 Great Sumatra Earthquake of December 2004, and c) the 9.2 Alaska earthquake of 1964.
• The three largest earthquakes of the 20th and 21st centuries were assigned moment magnitudes: a) 9.5 Chile earthquake of 1960, b) the 9.3 Great Sumatra Earthquake of December 2004, and c) the 9.2 Alaska earthquake of 1964.
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INTENSITY: A MEASURE OF THE DAMAGE STATE
• Intensity is a subjective measure of the state-of-damage of a building at a site, ranging from:
• 1) No damage• 2) Slight damage• 3) Moderate damage• 4) Severe damage• 5) Collapse
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INTENSITY: A MEASURE OF THE DAMAGE STATE
• The value of intensity assigned to a damaged building is determined on the basis of observations, not instrumental measurements, of the nature and spatial distribution of the damage
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INTENSITY MAP OF NEW MADRID EARTHQUAKESINTENSITY MAP OF NEW MADRID EARTHQUAKES
• This map shows the range of MMI intensity values expected in future earthquakes in the New Madrid Seismic Zone.
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INTENSITY MAP OF NEW MADRID EARTHQUAKESINTENSITY MAP OF NEW MADRID EARTHQUAKES
• Intensity VI denotes the threshold of liquefaction.
• Intensity VII denotes the threshold for architectural damage.
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INTENSITY MAP OF NEW MADRID EARTHQUAKESINTENSITY MAP OF NEW MADRID EARTHQUAKES
• Intensity VII denotes the threshold of structural damage.
• Intensity IX - XI denotes levels of severe damage.
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INTENSITIES OF IX TO XI
The Kocaeli(Turkey) Earthquakeof 17 August 1999
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FREQUENCY OF OCCURRENCE
• The chance of a earthquake occurring at a specific location in a given interval of time can be estimated by plotting a graph of the number, N, of earthquakes known to have occurred within an area versus their magnitude, M, and determining empirically how often earthquakes of a particular size.
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EARTHQUAKE HAZARD ASSESSMENTEARTHQUAKE HAZARD ASSESSMENT
ATTENUATION
SESMIC SOURCES RECURRENCE
PROBABILITY
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CLASS ACTIVITY
1.Go to the USGS Web site http://earthquake.usgs.gov/hazmaps
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CLASS ACTIVITY
• 1. Select the longitudes and latitudes bounding the area where you are located in the United States and download a USGS probabilistic ground shaking map for this area.
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CLASS ACTIVITY
2. Develop the data for determining the magnitude and intensity distribution of past earthquakes within a 300 mile radius from your area.
3. Is it easier to estimate the frequency of earthquakes per century or per year? Why?
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National Earthquake Hazards Reduction Act (Public Law 95-124)
• Established in 1977, Public Law 95-124 provided a comprehensive basis for implementing seismic safety policy on mitigation, preparedness, emergency response, and recovery and reconstruction in the United States.
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National Earthquake Hazards Reduction Act (Public Law 95-124)
• The law calls for strategic actions to save lives and protect property and infrastructure, including:
• Research into the basic causes and mechanisms of earthquakes.
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National Earthquake Hazards Reduction Act (Public Law 95-124)
• The law calls for strategic actions to save lives and protect property and infrastructure, including:
• Development of methods to predict the time, place, magnitude, and probability of future earthquakes.
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National Earthquake Hazards Reduction Act (Public Law 95-124)
• The law calls for strategic actions to save lives and protect property and infrastructure, including:
• Development of information and guidelines for zoning land use in light of seismic risk in all parts of the United States and preparation of seismic risk analyses useful for emergency planning and community preparedness.
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National Earthquake Hazards Reduction Act (Public Law 95-124)
• The law calls for strategic actions to save lives and protect property and infrastructure, including:
• Undertaking studies of foreign experience with all aspects of earthquakes.
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National Earthquake Hazards Reduction Act (Public Law 95-124)
• The law calls for strategic actions to save lives and protect property and infrastructure, including:
• Development of ways for state, county, local and regional governments to use existing and developing knowledge about the regional and local variations of seismic risk in making their land-use decisions.
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National Earthquake Hazards Reduction Act (Public Law 95-124)
• The law calls for strategic actions to save lives and protect property and infrastructure, including:
• Development of tools for seismic hazard and risk assessments, including seismic zonation.
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National Earthquake Hazards Reduction Program (NEHRP)
• Public Law 95-124, as amended, is the legal mandate for the National Earthquake Hazards Reduction Program (NEHRP).
• NEHRP is an integrated national program of basic and applied research on the hazard, built, and policy environments and corresponding applications.
•
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NEHRP LEADERSHIP
• Federal Emergency Management Agency (FEMA), the lead agency, provided coordination until 2004.
• National Institute of Standards and Technology (NIST) replaced FEMA as lead agency in 2004.
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NEHRP LEADERSHIP
• United States Geological Survey (USGS) makes maps, conducts monitoring and basic research, and supports applied research in universities.
• National Science Foundation (NSF) supports basic research in universities.
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NEHRP BUDGET
The annual budget for NEHRP is about $ 100 million.
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NEHRP Post-earthquake Studies (Public Law 101-614 )
• Since 1990, an explicit national mandate has existed for NEHRP to conduct interdisciplinary postearthquake studies of damaging national and notable international earthquakes.
• The goal is to use each damaging event as a laboratory to learn.
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CLASS ACTIVITY
1.Go to the USGS Web site http://earthquake.usgs.gov/hazmaps
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CLASS DISCUSSSION
1. Download a national probabilistic ground shaking map.
2. Identify the date when the map was prepared.
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CLASS DISCUSSSION
3. Describe the physical parameter that is mapped.
4. What is the exposure time?
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CLASS DISCUSSSION
5. What is the probability of exceedance?
6. Do you believe that the map accurately reflects the nature of earthquakes in your area?
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CLASS DISCUSSSION
7. Has there been any residential, commercial or industrial development that might change earthquake risks?
8. Has there been any major construction of infrastructure that might change risks?
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OBJECTIVE 5
Provide examples of models used in examining the risk from
earthquakes in the National Earthquake Hazards Reduction
Program
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GROUND SHAKING HAZARD
• Ground shaking is characterized by two primary parameters, each varying as a function of magnitude, distance from the fault zone, and the properties of the local soil and rock: 1) acceleration time history, and 2) spectral acceleration.
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MAP FORMAT
• The map format can be either probabilistic (PHSA) (PREFERRED), or deterministic (DHSA).
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CONSTRUCTING A PROBABILISTIC CONSTRUCTING A PROBABILISTIC EARTHQUAKE HAZARD MAPEARTHQUAKE HAZARD MAP
ATTENUATION
SESMIC SOURCES RECURRENCE
PROBABILITY
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CONSTRUCTING A PHSA 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 and/or 1.0 s period values)
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CONSTRUCTING A PHSA 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 PHSA MAP
• The third step is to add the layers of data, such as:
• The geographic boundaries and cultural features of the community.
• The fault systems.
• The seismicity.
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SEISMICITY SEISMICITY
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CLASS DISCUSSSION
1. Explain the importance of assessing and insuring to distribute the earthquake risk in your community
2. Describe the steps that would be required for all businesses in your community to be self-insured.
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OBJECTIVE 6
Explain the basic elements of earthquake
insurance
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INSURANCE
• The business of insurance, including life and health insurance, plays a major financial role in our society, making up about 15 percent of the national gross domestic product.
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INSURANCE
• In the United States, there are over 3,000 insurance companies, most of which focus on a specific market or line such as auto, title insurance, health, or life.
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LAW OF LARGE NUMBERS
• The insurance industry exists because of the “Law of large numbers.”
• This law means that the average loss insurers will pay in claims will converge very quickly to a predictable number with low uncertainty as the number of claims increases.
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INSURANCE
• Reinsurance companies help to spread the risk.
• Reinsurance is the process by which one insurance company insures another insurance company as a strategy for controlling capacity.
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CLASS DISCUSSSION
1. Explain the importance of assessing and insuring to distribute the earthquake risk in your community
2. Describe the steps that would be required for all businesses in your community to be self-insured.
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OBJECTIVE 7
Explain the elements of risk.
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HAZARDSHAZARDSHAZARDSHAZARDS
ELEMENTS OF RISKELEMENTS OF RISKELEMENTS OF RISKELEMENTS OF RISK
EXPOSUREEXPOSUREEXPOSUREEXPOSURE
VULNERABILITYVULNERABILITYVULNERABILITYVULNERABILITY LOCATIONLOCATIONLOCATIONLOCATION
RISKRISKRISKRISK
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RISK ASSESSMENT
• Risk assessment for earthquakes involves the probabilistic integration of interlinked parameters into a comprehensive risk 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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BUILDING ELEMENTS
• Note: Each element has a unique vulnerability (fragility) function and a dominant period of vibration..
• Single family dwellings.
• Multiple family dwellings
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BUILDING ELEMENTS
• Note: Each element has a unique vulnerability (fragility) function and a dominant period of vibration..
• Low-rise office and commercial buildings .
• High-rise office and commercial buildings.
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BUILDING ELEMENTS
• Note: Each element has a unique vulnerability (fragility) function and a dominant period of vibration..
• Industrial facilities and factories.
• Government office buildings and related facilities (including embassies).
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BUILDING ELEMENTS
• Note: Each element has a unique vulnerability (fragility) function and a dominant period of vibration..
• Schools, colleges, and universities.
• Hospitals.
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BUILDING ELEMENTS
• Note: Each element has a unique vulnerability (fragility) function and a dominant period of vibration..
• Historic buildings, monuments, museums, and other national treasures.
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BUILDING ELEMENTS
• Note: Each element has a unique vulnerability (fragility) function and a dominant period of vibration..
• Police and fire stations.
• Hotels and resorts.
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BUILDING ELEMENTS
• Note: Each element has a unique vulnerability (fragility) function and a dominant period of vibration..
• Shopping malls.• Sports arenas and stadiums. • Parking structures.
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INFRASTRUCTURE ELEMENTS
• Note: Each element has a unique vulnerability (fragility) function and a dominant period of vibration..
• Highways - The largest element of every community’s infrastructure inventory.
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INFRASTRUCTURE ELEMENTS
• Note: Each element has a unique vulnerability (fragility) function and a dominant period of vibration..
• Bridges.
• Utility systems (i.e., gas electricity, water, wastewater, and telephone).
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INFRASTRUCTURE ELEMENTS
• Note: Each element has a unique vulnerability (fragility) function and a dominant period of vibration..
• Telecommunication systems.
• Waterways, ports, and harbors.
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INFRASTRUCTURE ELEMENTS
• Note: Each element has a unique vulnerability (fragility) function and a dominant period of vibration..
• Dams and levees.• Fossil fuel and nuclear power
plants.
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INFRASTRUCTURE ELEMENTS
• Note: Each element has a unique vulnerability (fragility) function and a dominant period of vibration..
• Airports and related facilities. • Storage tanks for water and
hazardous materials.
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VILNERABILITY OF ELEMENTS
• Note: Each element has a unique vulnerability (fragility) function..
• An element’s vulnerability (fragility) to earthquake ground shaking is 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 element’s 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
• Varying ages of construction, which also means varying editions of the building code.
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VULNERABILITY
• Varying construction materials (e.g., wood, unreinforced masonry, unreinforced concrete, reinforced concrete, light metal, and steel).
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VULNERABILITY
• Varying service lives (e.g., 30 years for the half-life of a class of buildings).
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VULNERABILITY
• Varying usage functions (e.g., the functions represented by single family dwellings, multiple family dwellings, high-rise buildings, government centers, commercial buildings, industrial facilities, schools, hospitals, and places of public assembly).
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VULNERABILITY
• Varying levels of public and private use, which varies with the time of day, holidays, and seasons of the year.
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VULNERABILITY
• Varying configurations (i.e., elevations and floor plans).
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RISK REDUCTION
• Reliable risk assessments are essential for good decision making on local, regional, state, and national levels to reduce the risk towards more acceptable levels
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RISK REDUCTION
• The community can control and reduce its perceived risks by implementing public policies such as insurance, building codes, lifeline standards, and retrofit and rehabilitation.
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OBJECTIVE 8
Clarify the capabilities and levels of analysis of the HAZUS-MH
Earthquake Program
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HAZUS – EARTHQUAKE
• The HAZUS-MH Earthquake Program is a comprehensive, state-of-the-art, loss estimation methodology that was established in the early 1900’s as the standard for earthquake loss estimation by governments in earthquake-prone regions of the United States.
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HAZUS – EARTHQUAKE
• More than 137 earthquake and software professionals contributed to the development of the program through working groups, oversight groups, pilot studies in Boston, MA and Portland, OR, and calibration studies combining unprecedented data and experience.
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HAZUS – EARTHQUAKE
• Loss estimation for earthquakes involves the probabilistic integration of interlinked parameters of the community’s hazard and built environments into a comprehensive risk model.
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HAZUS – EARTHQUAKE INTERDISCIPLINARY TEAM
• The community at risk should form a team comprised of:
1. Geologist (s), from state geological survey
2. Seismologist (s), from university
3. Structural engineer (s)
4. Geotechnical engineer (s)
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HAZUS – EARTHQUAKE INTERDISCIPLINARY TEAM
5. Economist (s) – finance officers
6. Sociologist(s)
7. Emergency planner(s), from state office of emergency services
8. Public works personnel
9. Loss estimation users.
10. Local business leader
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