3.1 Definitions:
3.1.1 See Terminology E631.
3.1.2 For definition of terms related to the seismic risks of individual properties, see ASTM E2026 and E2557. Selected terms are included in this standard.
3.1.3 For definition of terms related to building construction, ASCE 7 and ASCE 41 provide additional resources for understanding terminology and language related to seismic performance of buildings.
3.1.4 For definition of other terms and additional detailed information related to seismic events and structural design, see the reference documents (Section 2) as well as the references at the end of this document.
3.2 Definitions of Terms Specific to This Standard—This section provides definitions of concepts and terms specific to this guide. The concepts and terms are an integral part of this guide and are critical to an understanding of this guide and its use
3.2.1 acceleration, n–the rate of change of velocity as a function of time. Acceleration may change the speed or direction of an object. Commonly expressed as a fraction or percentage of the acceleration due to gravity (g), wherein g = 32.2 feet per second per second.
3.2.2 active earthquake fault, n–an earthquake fault with evidence of displacement during the Holocene epoch, typically about the last 11,000 years. Faults with evidence of displacement during the Pleistocene may be considered potentially active.
3.2.3 adjacency risk, n–risk posed by adjacent structures to the subject building, from pounding, from collapse of the neighboring structure or falling debris
3.2.4 aggregate loss curve, n–see risk curve or exceedance probability curve
3.2.5 allocation models, n–financial models to distribute consequences among stakeholders
3.2.6 average annual(ized) loss (AAL), n–the loss per annum due to hazards, calculated from a probabilistic loss contribution of all events. The expected annual loss is the expectation of the probability distribution of loss per annum, and under certain assumptions may be calculated as the probability-weighted average-of loss due to all possible hazard events.
3.2.6.1 Discussion–The expected annual loss is the expectation of the probability distribution of loss per annum and under certain assumptions may be calculated as the probability weighted average of loss due to all possible hazard events.
3.2.7 building code, n–a collection of laws (regulations, ordinances, or statutory requirements) applicable to buildings, adopted by governmental (legislative) authority and administered with the primary intent of protecting public health, safety, and welfare.
3.2.8 building contents, n–elements contained within the building that are not defined as building systems.
3.2.8.1 Discussion–Examples include tenant-installed equipment, storage racks, material handling systems, shelving, stored inventories, furniture, fixtures, office machines, computer equipment, filing cabinets, and personal property.
3.2.9 building systems, n–all physical systems that comprise a building and its services.
3.2.9.1 Discussion–This includes architectural, structural, mechanical, plumbing, electrical, fire life-safety, vertical transportation and security systems. Not included in building systems are those contained within a building and defined as building contents.
3.2.10 business interruption, n–a period of interruption to normal business operations that can potentially or materially cause a loss to the owner/operator of that business.
3.2.10.1 Discussion–The loss may be partial or total for the period under consideration. Business interruption is expressed in days/weeks/months of downtime for a building as a whole and the loss estimated using the cost per unit time for the interruption.
3.2.11 catastrophe model, n–a computer-based model that assesses the impact of natural catastrophes, estimates physical damage to property, contents and occupants, and assigns probabilities to the range of possible outcomes, to estimate financial loss and other consequences from such perils as earthquakes, hurricanes, or floods.
3.2.12 catastrophe model provider, n–a vendor or consultant who creates and maintains a software system for the analysis of earthquake risks, and provides the software, or access to the software to the engineering service provider for seismic risk analysis of the user’s real estate portfolio.
3.2.13 correlation, n–the tendency or likelihood of the behavior of one element to be influenced by the known behavior of another element, e.g., geographic correlation of risks; spatial correlation of ground motion.
3.2.14 damage or repair cost, n–cost required to restore the building to its pre-earthquake condition, allowing for salvage and demolition.
3.2.14.1 Discussion–The value includes hard costs of construction as well as soft costs for design, site supervision, management, etc. (See also replacement cost.)
3.2.15 damage ratio, n–ratio of the damage or repair cost divided by the replacement cost.
3.2.15.1 Discussion–sometimes called 'damage factor'
3.2.16 deductible, n–(Insurance) The amount of loss above which an insurance payment is due to the insured.
3.2.17 deficiency, n–conspicuous defect(s) in the building or significant deferred maintenance items of a building and its components or equipment.
3.2.17.1 Discussion–Conditions resulting from the lack of routine maintenance, miscellaneous repairs, operating maintenance, etc. are not considered a deficiency.
3.2.18 demand surge, n–a sudden and usually temporary increase in the cost of materials, services, and labor due to the increased demand for them following a catastrophe. [ASB, Actuarial Standard of Practice 39, 2000].
3.2.19 design basis earthquake (DBE), n–the site ground motion intensity (e.g., PGA, SA) with a 10% probability of exceedance in 50 years, equivalent to a 475-year return period for exceedance, or a 0.2103% annual probability of occurrence.
3.2.19.1 Discussion–The design basis earthquake ground motions are associated with any earthquake that has the specified site ground motion value; often there are several earthquakes with different magnitudes and causative faults that yield equivalent site peak ground motions.
3.2.20 deterministic, adj–a method of engineering and decision-making evaluation based solely on the selection of one or at most a few hazards events used as scenarios. For instance, an historical earthquake may be taken as a scenario to see what would happen if that earthquake recurred. Deterministic methods are typically based on source models and intensity propagation methods that exclude random effects.
3.2.20.1 Discussion–This contrasts with probabilistic approaches, which attempt to consider the full range of hazards or scenarios, and include random (aleatory) effects.
3.2.21 direct loss, n–(Insurance) The portions of the ground-up loss retained by the insurer are losses above the deductible and below the limit of liability. Also called the gross loss (to the insurer).
3.2.22 distribution function, n–the probability distribution for a random variable.
3.2.22.1 Discussion–The random variable may include such things as loss, ground motion, or other consequence of earthquake occurrence.
3.2.23 diversification, n–a strategy to reduce the volatility of risk by limiting the exposure to correlated events producing a loss.
3.2.23.1 Discussion–In portfolio seismic risk, diversification may aim to geographically distribute the property exposure to avoid multiple high losses in a single earthquake. Other forms of diversification may seek to avoid common seismic vulnerabilities or defects, such as nonductile concrete moment frames or unreinforced masonry.
3.2.24 due diligence, n–the assessment of the condition of a property for the purposes of identifying conditions or characteristics of the property, including potentially dangerous conditions, that may be important to determining the appropriateness of the property for financial or real estate transactions.
3.2.24.1 Discussion–The extent of due diligence exercised on behalf of a User is usually proportional to the User’s tolerance for uncertainty, the purpose of seismic risk assessment, the resources and time available to the Provider to conduct the site visit and research.
3.2.25 duration, n–The time interval in earthquake ground shaking during which motion exceeds a given threshold.
3.2.26 earthquake, n–a sudden motion or trembling in the earth caused by the abrupt release of gradually accumulated strain in the earth's crust.
3.2.27 earthquake sprinkler leakage loss (EQSL), n–damage, typically to contents and nonstructural items, resulting from leakage from charged fire-water sprinklers due to damage in earthquakes.
3.2.28 empirical model, n–a predictive model, relating a number of relevant, quantifiable input parameters to a measurable outcome parameter. Such models may be based on judgement (heuristic) or may be tested against data (statistical). Examples include ground motion models (GMM) such as those used in the U.S. Geological Survey’s National Seismic Hazard Mapping Project, and building damage models (e.g., HAZUS®™).
3.2.29 event set, n–a set of (earthquake) simulations, each with a spatial distribution of ground shaking and annual frequency of occurrence, intended to represent the complete ensemble of future earthquakes for the defined region(s), used for the evaluation of earthquake damage to spatially-distributed real estate properties.
3.2.30 exceedance probability curve, n–a plot of the severity of loss or other consequence as a function of annual exceedance probability. See also risk curve
3.2.31 expected loss, n–the mean value of loss [$] from a statistical distribution of loss
3.2.32 expected value, n–of a random variable, the average or mean of the distribution function._
3.2.32.1 Discussion–The expected value is determined as the sum (or integral) of all the values that can occur multiplied by the probability of their occurrence. (Compare: median value.)
3.2.33 exposure, n–the quantity and value of the properties or infrastructure, and the number of occupants at risk from earthquake hazards.
3.2.34 exposure period, n–the period of time over which a facility or population at risk is subjected to a hazard.
3.2.35 fault zone, n–area within a prescribed distance from any of the surface traces of an active fault.
3.2.35.1 Discussion–Within California, the fault zones are determined by the California Geological Survey under the Earthquake Special Studies Zones Act for active and potentially active earthquake faults that have been identified by the state or other governmental bodies.
3.2.36 fire-following earthquake, n–(Insurance) a collateral hazard from earthquake, adding to damage from shaking and soil failures
3.2.37 fragility, n–the relationship to estimate damage from an engineering demand parameter such a ground acceleration, floor acceleration or interstory drift
3.2.38 frequency, n–in the context of risk analysis, this refers to how often an event or outcome will occur, given a specified exposure period. For example, annual frequency is the number of events per year.
3.2.39 geographic correlation index (GCI), n–an index intended to indicate the relative severity of the risk contribution from a particular building or site on the aggregate losses of a geographically distributed portfolio of buildings or other values at risk from earthquake hazards.
3.2.39.1 Discussion–See [Graf & Lee, Proceedings of 7NCEE, 2002]. This is useful in identifying the buildings or sites contributing most to catastrophic portfolio risks, so those sites or buildings can be targeted for further investigation or risk mitigation.
3.2.40 gross loss, n–(Insurance) The portions of the ground-up loss retained by the insurer are losses above the deductible and below the limit of liability. Also called the gross loss (to the insurer).
3.2.40.1 Discussion–Gross loss may refer to (1) gross of policy terms (i.e. before deductibles and limits) or (2) gross of reinsurance (but after deductibles and limits).
3.2.41 ground failure, n–a general reference to fault rupture, liquefaction, landsliding, and lateral spreading that can occur during an earthquake or other land movement causes.
3.2.42 ground motion model (GMM), n–an empirical model relating the intensity of ground shaking to earthquake magnitude, distance from causative fault to site, and other factors
3.2.43 ground-up loss (GU), n–(Insurance) the total financial loss considered by an earthquake insurance policy, prior to allocation through the application of deductibles and limit of liability.
3.2.43.1 Discussion–The portions of the ground-up loss retained by the insured are losses below deductible and loss in excess of the limit of liability. The portion paid by the insurer (also called direct loss or gross insurer loss) is the loss above the deductible, but below the limit of liability.
3.2.44 hazard, n–a natural physical manifestation of the earthquake peril, such as ground shaking, soil liquefaction, surface fault rupture, landslide or other ground failures, tsunami, seiche. These hazards can cause damage to man-made structures.
3.2.44.1 Discussion–This is an event or physical condition that has the potential to cause fatalities, injuries, property damage, infrastructure damage, agricultural loss, damage to the environment, interruption of business, or other types of harm or loss.
3.2.45 independent reviewer, n–technically qualified individual or organization that has not been engaged in the design or modifications of the building(s), and is not in any way affiliated with the Provider.
3.2.45.1 Discussion–The concept may also be represented by the phrases “independent technical reviewer,” or “independent peer reviewer”.
3.2.46 insured loss, n–losses to be paid by an insurer under an insurance policy. Typical earthquake policies for buildings specify a deductible, given as a fraction of the building's insured value, and a limit of liability. See also: Ground-up Loss; Gross or Direct Insurer Loss
3.2.47 intensity measure (IM), n–a measure of ground motion severity, such as peak ground acceleration, peak ground velocity, or spectral response acceleration at a particular period, etc.
3.2.47.1 Discussion–Intensity measures that can be directly recorded by instruments (acceleration) or derived from instrumental recordings (spectral acceleration) are generally more useful in engineering applications than those based on human observations (e.g., MMI).
3.2.48 interdependency, n–a condition wherein the function of the building is dependent on another building, on utilities, or on other critical elements in a supply chain.
3.2.48.1 Discussion–Other critical elements include transportation and may include a customer, vendor (for example, supplier of materials), contractor (supplier of services), staff (for example, supplier of staff), information (for example, data processing for accounting or distribution), etc.
3.2.49 landslide, n–(1) ground motion; the rapid downslope movement of soil or rock material, or both, often lubricated by ground water, over a basal shear zone; and (2) geological, stationary material deposited in the past by the rapid downslope movement of soil or rock material, or both.
3.2.50 lateral load-resisting system, n–the elements of the building system that resist the seismic forces applied to the building. This includes vertical, horizontal, and torsional response of elements and systems.
3.2.51 lender loss, n–the financial risk to a lender from damage to a property or properties that secure a mortgage in an earthquake, should the owner choose to default.
3.2.51.1 Discussion–This may occur when the cost to make earthquake repairs exceeds the owner's equity in the property or properties (owner equity is found as the market value minus mortgage balance for the property). Owner-retained earthquake insurance may reduce repair costs paid by the owner, reducing the probability of default or guaranteeing the repayment of the loan. An owner may choose to continue to pay on a damaged property in order to preserve reputation or credit rating, or in anticipation of future property value growth. Additionally, a lender may forbear on a foreclosure for various reasons, such as a decline in market values.
3.2.52 limit of liability, n–(Insurance) The maximum payment amount which an insured may receive for a covered loss.
3.2.53 logic tree, n–a method to evaluate the outcomes from multiple admissible scientific models. Each branch of the logic tree considers mutually exclusive, scientifically admissible method, and the branches are intended to represent the full span of admissible solutions. A numerical weight may be assigned to each branch, with the weights summing to 1.0. Also called solution trees.
3.2.54 magnitude of earthquake (M, Mw), n–a measure of the size of an earthquake.
3.2.54.1 Discussion–Various magnitude scales have been developed and applied (e.g., local magnitude, body wave magnitude, surface wave magnitude). Currently, the moment magnitude scale (M or Mw) provides the best quantification of the size of the event in terms of energy released, and is the preferred term used by the U.S. Geological Survey for large earthquakes.
3.2.55 maximum capable earthquake (MCE), n–earthquake that can occur within the region that produces the largest average ground motion at the site of interest.
3.2.55.1 Discussion–This is NOT the same as the ASCE 7 definition of MCE, which is a ground motion with a 2,475-year return period or 150% of the median ground motion in a design basis earthquake, which ever is the lesser. The concept of MCE for purposes of the guide does not include a return period value.
3.2.56 median value, n–value that divides the distribution function into equal parts, such that the value of the random variable has an equal probability of being above or below the reference value. (Compare expected value.)
3.2.57 mitigation, n–sustained action taken to reduce or eliminate long-term costs and risks to people and property from hazards and their effects. Mitigation distinguishes actions that have a long-term impact from those that are more closely associated with preparedness for, immediate response to, and short-term recovery from a specific event.
3.2.58 model, n–a representation of a physical system or process intended to enhance our ability to understand, predict, or control its behavior
3.2.59 Modified Mercalli Intensity (MMI), n–qualitative description of the local effects of the earthquake at a site.
3.2.59.1 Discussion–Normally, it is given as a Roman numeral, from I to XII, to emphasize its qualitative, not quantitative, nature. A single earthquake can have many different MMI intensities assigned over the region in which the earthquake is felt. MMI does not specify a specific ground motions, but a range of peak horizontal ground motion are assigned to a given MMI value. Use of MMI to characterize ground motions for use in the seismic risk assessment of buildings should be done with caution because the damage level predicted is associated with a very wide range of earthquake ground motions, not a specific earthquake ground motion.
3.2.60 Monte-Carlo simulation, n–a statistical method that relies on repeated random sampling of the statistical distributions of input variables to obtain a numerical estimate of the probability distribution of the output variable. Monte Carlo methods avoid errors produced by closed-form solutions that assume the shape of the output variable.
3.2.61 mortgage-backed securities, n–a type of asset-backed security or collateralized investment vehicle that is secured by a mortgage or collection of mortgages. The loans are packaged together and sold in the financial markets, with the proceeds from mortgage payments used to repay the security.
3.2.61.1 Discussion–Examples include commercial mortgage-back securities (CMBS) and residential mortgage-back securities (RMBS)
3.2.62 non-structural components, n–components of a building system that are not part of the vertical or lateral-load resisting structural systems nor are defined as building con- tents.
3.2.63 observations, n–the relevant information or measurements, or combination thereof, documented during the site visit survey.
3.2.64 obvious, adj–readily accessible and can be seen easily by the independent reviewer without the aid of any instrument or device and understood by the Provider as a result of a walk-through survey.
3.2.65 occupant, n–of a building, a group or organization, or a part thereof, or an individual or individuals, that is or will be occupying space in a particular facility.
3.2.65.1 Discussion–Persons who are authorized to be present only temporarily, or in special circumstances such as those permitted to pass through during an emergency, are visitors.
3.2.66 offsite factor, n–a source of loss or business interruption resulting from damage or system failure outside of the property boundaries of the real estate properties in the portfolio, such as from disruption to the utilities and lifelines serving the sites in the portfolio.
3.2.67 original construction documents, n–documents used in the initial construction phase and any subsequent modification(s) of building(s) for which the seismic risk assessment is prepared.
3.2.67.1 Discussion–Generally as-built plans are the preferred form of construction documents.
3.2.68 other earthquake hazards, n–i.e., other than strong ground shaking. Other earthquake hazards include, but are not limited to, soil liquefaction; ground deformation including subsidence, rupture, differential settlement, landsliding, slumping, etc; and, hazards from off-site response to the earthquake including flooding from dam or dike failure, tsunami, or seiche.
3.2.69 owner, n–the entity or individual holding the deed to the building, or their designated representative. An agent or contractor may be considered an owner in some circumstances.
3.2.70 P-delta effect, n–the secondary effect of column axial loads and lateral deflections on the shears and moments in various components of a building.
3.2.71 peak ground acceleration (PGA), n–the maximum acceleration at a site caused by an earthquake ground motion. PGA is most often given as the maximum of the two orthogonal horizontal components and is usually expressed as a fraction of gravitational acceleration, g, 32.17 ft/s2 (9.81 m/s2).
3.2.72 portfolio, n–within the context of typical building seismic risk studies, this refers to a geographically-distributed set of facilities or other values-at-risk.
3.2.73 potentially active earthquake fault, n–an earthquake fault that shows evidence of surface displacement during the Quaternary period (approximately the last two million years).
3.2.74 probabilistic ground motion, n–earthquake ground motions for the building site that are determined from an evaluation of the seismic exposure for the site for a given time period and are represented by a probability distribution function. Where appropriate, the ground motion assessment process should reflect conditional probabilities of the temporal dependence of earthquakes on specific seismic features, where they are known.
3.2.75 probable loss (PL), n–earthquake loss to the building systems that has a specified probability of being exceeded in a given time period, or an earthquake loss that has a specified return period for exceedance.
3.2.75.1 Discussion–This value is meant to reflect in a statistically consistent computational manner all of the uncertainties that can impact damage, including when and where earthquakes occur and with what magnitude, attenuations of ground motion to the site, local site effects and performance of the building systems in this ground motion. The PL is expressed in terms of the damage ratio and is generally limited to earthquake loss associated with the earthquake ground-shaking hazard, but may include losses from other earthquake hazards as prescribed by a User. Dollar values can be determined by multiplying the damage ratio by the replacement cost estimate for the building. Where seismic analysis of discounted present value is to be performed then annual PL, mean and standard deviation are appropriate damageability measures for use in such application.
3.2.76 probable maximum loss (PML), n–term historically used to characterize building damageability in earthquakes. See ASTM E 2026.
3.2.76.1 Discussion–PML has had a number of very different explicit and implicit definitions. The concepts of probable loss (PL) and scenario loss (SL) are used in this guide to characterize the earthquake losses of buildings or groups of buildings. When a Provider uses the term PML, it should be defined in terms of SL or PL as defined herein.
3.2.77 provider, n–person or organization that conducts the site visit and prepares a report on the seismic risk of a building or group of buildings.
3.2.78 replacement cost, n–cost required to construct an entirely new building of the same size, envelope, configuration and character as the referenced building, assuming a virgin site.
3.2.78.1 Discussion–Replacement cost includes costs for construction, including building materials and labor; design; site supervision; management; etc.
3.2.79 retrofit scheme, n–preliminary suggestion(s) of modifications or additions to the building intended to correct, mitigate, or repair a physical deficiency that will improve the seismic performance of the building so that it is acceptable to the User.
3.2.80 return period, n–(of a random variable) this is the average period of time between recurrence of consequences equalling or exceeding a given level. It is the inverse of the annual probability that the value is equaled or exceeded.
3.2.80.1 Discussion–Return period is not the time period between occurrences of the value, but is the long-term average of the random times between occurrences. Often, return period is incorrectly interpreted to mean that if the value was realized in 1994, and the return period is 100 years, then the next occurrence will be in 2094. For example, earthquake occurrences usually are considered as Poisson-distributed random variables, that is, variables where the probability is near constant from year to year, and the probability of an occurrence this year is independent of what happened last year. For a Poisson random variable, the probability that the value will be equaled or exceeded in its return period term is 63%.
3.2.81 risk curve, n–a plot of the severity of loss or other consequence as a function of annual exceedance probability or average return period
3.2.82 robust simulation, n–a method to evaluate the outcomes and the dispersion of outcomes from multiple admissible scientific models, preserving the coherency of the model chains (e.g., as depicted in a logic tree). Robust simulation adapts Monte Carlo simulation using equiprobable events in diachronic simulations, and is applicable to numerous mega-risks resulting from natural and human-generated hazards.
3.2.82.1 Discussion–See Taylor, C.E., Robust Simulation for Mega Risks, Springer, 2015
3.2.83 scenario expected loss (SEL), n–expected value of the scenario loss for the specified ground motion of the earthquake scenario selected.
3.2.84 scenario loss (SL), n–earthquake damage loss expectation to building systems and site improvements and where User-prescribed, building contents and/or related business interruption loss, associated with specified earthquake events on specific fault(s) affecting the building.
3.2.84.1 Discussion–SL values are expressed in terms of the damage ratio or damage cost/repair cost in present day dollars. The SL is generally limited to earthquake loss associated with the earthquake ground-shaking hazard, but may include losses from other earthquake hazards, as prescribed by a User.
3.2.85 scenario upper loss (SUL), n–scenario loss that has a 10% percent probability of exceedance due to the specified ground motion of the scenario considered.
3.2.86 secondary modifiers, n–building-specific structural characteristics considered in commercial seismic risk models to account for structural condition, vertical and plan irregularities, pounding with adjacent structures, etc. and their impacts and improve prediction of building damage, life-safety and loss-of-use.
3.2.87 site class, n–a classification of the propensity of a site to amplify ground shaking, based on soil profile or Vs30. Site Class A = hard rock, B = rock, C = soft rock or very firm soil, D = firm soil, E = soft soil and F = soils susceptible to failure in earthquake. ref: ASCE 7; ASCE 41
3.2.88 site visit, n–visual reconnaissance of the site and physical property by the Provider to gather information on the physical property for the purposes of preparing seismic risk assessment.
3.2.87.1 Discussion–The Provider is not expected to use or provide scaffolding, ladders, magnifying lenses, etc. in undertaking the visual reconnaissance of the building systems and components during the site visit. This definition implies that such a visit is preliminary, not in-depth, and typically done without the aid of exploratory probing, removal of materials, or testing. It is literally the Provider’s visual survey of the building(s) and site improvements.
3.2.89 soil liquefaction, n–the transformation of loose, saturated, sandy soil materials into a fluid-like state.
3.2.89.1 Discussion–Damage from soil liquefaction results primarily from horizontal and vertical displacements of the ground. This movement of the land surface can damage buildings and buried utility lines such as gas mains, water lines and sewers, particularly at their connection to the building. Extreme tilting or settlement of the building can occur if soil liquefaction occurs underneath the building foundations.
3.2.90 soil profile, n–the vertical arrangement of soil horizons down to the parent material or to bedrock. Under current building codes (e.g., International Building Code) and FEMA NEHRP guidelines, the soil profile may be categorized by average shear wave velocity in the upper 30m of sediments for the purpose of estimating amplification of ground motions with respect to those occurring on rock.
3.2.91 spectral acceleration (SA or Sa), n–the maximum acceleration of an elastic spring-mass system with 5% critical damping to a specified (ground) shaking time history, typically given in units of [g]
3.2.92 stakeholder, n–one of the parties who may suffer damage, loss or injury from an earthquake event
3.2.93 statistically consistent manner, n–following the mathematical rules and concepts of probability and statistics.
3.2.94 structural component, n–component that is a part of a building’s lateral and/or vertical load-resisting system.
3.2.95 system model, n–a mathematical model intended to represent the behavior of a system. System models may be depicted by nodes and links. In portfolio seismic risk analysis, nodes may represent geographically distributed real estate properties and links may represent product, data or revenue flows between the properties.
3.2.96 tsunami, n–long water waves that are generated impulsively by tectonic displacements of the sea floor associated with earthquakes.
3.2.96.1 Discussion–Tsunamis also may be caused by eruption of a submarine volcano, submerged landslides, rock falls into the ocean, and underwater nuclear explosions. Tectonic displacements with a substantial vertical (dip-slip) component are more likely to cause tsunamis than are strike-slip displacements. Wave heights associated with tsunamis in deep water generally are small; however, as the wave fronts approach coastlines where there is shallow water, the wave heights increase and will run up onto the land. Tsunami run-up can cause loss of life and substantial property damage.
3.2.97 uncertainty, n–degree of random behavior represented by an applicable probability distribution and associated parameters.
3.2.98 uncertainty tolerance level, n–amount of uncertainty in financial exposure that a User is willing to accept resulting from the cost to remedy earthquake damage not identified by an seismic risk assessment.
3.2.98.1 Discussion–This can be influenced by such factors as initial acquisition cost or equity contribution, mortgage underwriting considerations, specific terms of the equity position, projected term of the hold, etc.
3.2.99 user, n–individual or organization that retains the Provider to prepare a seismic risk assessment.
3.2.100 valuation, n–the process of assessing or assigning financial value to an asset or process
3.2.101 vulnerability, n–the susceptibility of a building, equipment item or component to damage or loss from a specific hazard. See also fragility.
3.2.102 weak story, n–story in a building that is expected to deform significantly more than any story above it under a given lateral loading. Such weak stories can occur at any level in a building, except the top story.