AIR Worldwide Expands Suite of Catastrophe Models for Australia

Catastrophe risk modeling firm AIR Worldwide (AIR) has expanded its suite of catastrophe models for Australia with the release of the industry’s first probabilistic bushfire model and updated tropical cyclone and earthquake models.

The AIR Bushfire Model for Australia captures the effects of bushfires on insured properties in the Australian mainland and Tasmania. To determine the occurrence and severity of wildfires, the model considers fire ignition frequency and location, available fuels (vegetation), weather (seasonal conditions and wind characteristics), topography (the ground surface features that can affect winds) and fire suppression efforts.

“Bushfires in Australia are the natural product of the continent-wide aridity, frequent periods of drought, high temperatures, parched vegetation, and the recurrent strong, steady winds that are characteristic of the country,” said Dr. Jayanta Guin, senior vice president of research and modeling at AIR Worldwide. “Many populated areas in Australia have conditions that are ideal for feeding fires, and Australia has suffered significant losses from such events — including the 2009 Black Saturday bushfires, which caused insured losses of more than AUD $1.3 billion.”

The AIR Bushfire Model for Australia generates demonstrably realistic scenarios of loss. It filters the roughly 10,000 continent-wide ignitions that occur in Australia every year down to the dozen or so that are likely to cause property loss — in line with the historical average. It includes a large and robust event set of simulated fires in the locations where they are most likely to occur and explicitly models the tendency of fires to occur in clusters. In addition, the model accounts for the seasonality of bushfires in Australia by region. To provide accurate vulnerability assessment, the model supports a wide range of construction types commonly found in Australia.

AIR also made significant updates to all components of its tropical cyclone and earthquake models for Australia. In addition to a wide range of enhancements to the hazard components, both models now account for regional differences in construction practices, as well as building code evolution and enforcement. Both models also support property and business interruption losses to complex industrial facilities.

The AIR Tropical Cyclone Model for Australia estimates losses separately for wind, storm surge, and precipitation-induced flooding. Other highlights include:

• a new 10,000-year stochastic catalog containing more than 116,000 simulated storms ranging from tropical low to Category 5 on Australia’s Bureau of Meteorology intensity scale

• a new, dynamic flood module for capturing precipitation-induced flooding

• a new storm surge module for capturing sea level rise along the coast caused by onshore winds of a cyclone

• new high resolution (1 km) land use/land cover data (near the coast) to estimate the local roughness of, and turbulence generated by, land and water surfaces

• updated damage functions that support a greatly expanded set of construction types, occupancy classes and lines of business, including pleasure boats and yachts (The damage functions have been validated based on loss experience data and findings from recent AIR post-disaster surveys.)

Highlights of the updated AIR Earthquake Model for Australia include:

• a new, optimized 10,000-year catalog that incorporates the latest science and research on the earthquake hazard in Australia, including a novel approach for utilizing information on neotectonic faulting to estimate earthquake risk in this seismically stable region.

• a new liquefaction module covering major urban areas that have high liquefaction potential

• a new nationwide high-resolution (1 km) soil classification map (0.5 km in regions of higher exposure) to better account for the potential amplification and attenuation of seismic waves caused by soil type

• Australia-specific ground motion prediction equations that assess the regional differences in seismic risk

Source: AIR Worldwide