L2: Foundations for hazard and risk assessment Flashcards
What are the 3 components of risk assessment?
- risk identification
- risk analysis
- risk evaluation
What factors determine the modelling approach?
- hazard type
- purpose of assessment
- scale of analysis
- data and model availability
What are the main components of hazard analysis?
- frequency/magnitude relationship
- initiation process
- travel or transmission of hazard
What is another name for a statistical hazard model?
Empirical or black box
What method is used by statistical hazard models?
derive statistical relationship between observed hazard drivers and resulting hazard event. Hazard can be modelled by using statistical relationship to transform inputs to outputs
What data do statistical hazard models use?
observed hazard events with associated triggers and system properties
What assumptions do statistical hazard models make?
repeatability and stationarity of system (past is key to the future). only applicable in similar settings
What is another name for a physically-based hazard model?
deterministic, grey or white box
What is the method used by physically-based models
hazard processes explicitly represented by physics-based equations solved using numerical modelling (FE)
What data do physically-based hazard models use?
measured physical parameters of the system
What assumptions do physically based models make?
model and input data describe the physical system
What is the reality of physically based models?
environmental systems can never be fully defined. many models use mix of measured and empirical inputs GREY BOX
What is a qualitative model?
info evaluated and analysed verbally: based on judgement and logic
What is a quantitative model?
info recorded, analysed and evaluated using numerical scales
What is a heuristic model?
use subjective expert knowledge to describe hazard system. often encode it in form of semi-quantitative decision rules to be applied in computational models
What are stochastic and probabilistic models?
input parameter values sampled from their probability distributions, and the model is run multiple times with these different input values to represent the full parameter space and account for the effects of uncertainty
What are spatially distributed (map-based) models?
implemented in Geographical Information Systems (GIS)
What is aleatory uncertainty?
uncertainty with stationary statistical characteristics. may be structured (bias, autocorrelation, long-term persistence) but can be reduced to a stationary random distribution
What is epistemic uncertainty?
uncertainty arising from lack of knowledge of system and a lack of data
What are the 3 types of epistemic uncertainty?
- System dynamics - L.O.K. of model structure and parameters
- Forcing and response data - L.O.K. how to interpret data
- Disinformation - Data known to be wrong
What is semantic/linguistic uncertainty?
uncertainty about what statements or quantities actually mean
What is ontological uncertainty?
uncertainty associated with different belief systems e.g. assumptions
Name 4 physics-based landslide hazard assessment models
Analytical
Dynamic LEM
Analysis of Continua
Discrete Element Models
Name 4 risk modelling frameworks
Quantitative Risk Analysis (QRA)
Event tree analysis
Risk matricies (or Consequence-Frequency Matricies, CFM)
Indicator-based approaches
