Multi-hazards

What hazards are in New Zealand

Earthquake, volcano, Tsunamis, Landslides, Floods, Drought, Coastal erosion

What are multi-hazards

1) the selection of multiple major hazards that the country faces, 2) the specific contexts where hazardous events may occur simultaneously, cascadingly or cumulatively over time, and taking into account the potential interrelated effects

What complicates multi-hazard assessments

Hazards may be related to each other, and cumulative (cascading), The impacts of elements at risk can be different for differing hazards and occasionally opposing, The differences between hazard characteristics and therefore the methods used to observe and monitor them, Any of the existing measures of hazard quantification need to be adapted to allow for comparison of multiple hazards

5 Types of multi-hazard

Independent, triggering, change conditions, compound, mutual exclusion

Independent multi-hazard

Hazards that occur independently from each other but have spatial or temporal overlap

Triggering multi-hazard

Implies a primary hazard that triggers a secondary hazard

Change conditions multi-hazard

One hazard alters the probability of another hazard by changing the underlying conditions

Compound multi-hazard

Different hazards that are the result of the same primary event

Mutual exclusion multi-hazard

Two hazards that show a negative dependence

Example of independent multi-hazard

Earthquakes and volcanoes at distance from one-another in an active plate boundary environment

Example of a triggering multi-hazard

Eruption can trigger crustal unrest in proximal areas, leading to earthquakes (e.g. Taupo eruption)

Example of change conditions multi-hazard

Earthquake on one fault can enhance the likelihood of an earthquake on a neighbouring fault

Example of a compound multi-hazard

Earthquake can trigger large landslides and river aggradation/flooding

Example of a mutual exclusion multi-hazard

Drought vs flood

How are multi-hazards modeled

Intensity and frequency thresholds are defined in order to classify the respective hazards into a predefined number of hazard classes (high medium and low), this allows for comparison between hazards

What does developing indices for multi-hazards do

Allows for the comparison of differing parameters, develop indices that are uniquely weighted to reflect the impact of hazards

What types of hazards do these models cover

Only address natural hazards. other models include anthropogenic hazards

What scale do these models cover

Could be local, city, catchment, regional, and global, the larger the scale the more info needed

What focus do these models have

Different resources may be required depending on the focus (different people from different fields may want different info in the model)

What types of multi-hazard models can there be

Quantitative, Semi-quantitative, or qualitative

Characteristics of the Queenstown Lakes District Council

Most rapidly growing region of NZ, rapid pop growth, along with rapid residential, commercial, and industrial growth, Earthquake hazards (strong shaking and fault displacement), Potential for earthquake generated landslides

What is the Queenstown Lakes District Council study aiming to accomplish

A multi-hazard analysis considers the potential occurrence of different natural hazards in the same area of interest