1. PerilAUS II - Relative Risk Ratings for Postcodes and CRESTA/ICA Zones
Part 1: Methodology Part 2: CD-ROM

2. Background PerilAUS I CD-ROM (released in October 1999)
Most comprehensive collection of natural perils data
Searchable database with geo-spatial mapping software
9 perils
5,000 events and 10,000 affected locations
PerilAUS II CD-ROM (release in January 2001)
Relative Risk Ratings (RRR)
2,573 postcodes
49 CRESTA/ICA Zones
PerilAUS I historical data + additional natural hazards potential
Main concern: Damage to buildings
Approach: Multi-Criteria Evaluation (MCE)-GIS

3. Geographical scales
Global
States
ICA
zones
Balaclava Road
Individual dwellings
Postcodes
Street blocks
RRR of PerilAUS II deal with two geographical scales: ICA zones and Postcodes

4. Part 1 - Methodology (PerilAUS II)
Historical data from PerilAUS I
Potential hazards
data
Step 1
Step 2
Step 3
Damage index
Future perspective
Normalisation of scales for each peril
Global weighting
Peril-by-peril
(W1, W2, …, W9)
Normalisation of scales for each peril
Combination (historical)
Combination
(potential)
Final RRR

5. Step 1: Historical data from PerilAUS I (e.g. earthquake)
Earthquake MM intensity scale for 1448 affected locations
Number of affected locations:
Bushfire: 941
Earthquake: 1448
Flood: 990
Gust: 1763
Hail: 2984
Landslide: 278
Tornado: 712
T. Cyclone: 877
Tsunami: 74
Total: 10067

6. Affected locations are overlaid with postcode boundaries
For each peril,
at a postcode level:
 The number of affected locations;
 Magnitude or intensity;
 Frequency.

7. Potential hazards data (e.g. bushfire)
Six base maps:
Bushfire
Earthquake
Gust
Hail
T. Cyclone
Tsunami
Derivative maps: buffering zones of historical affected locations:
Flood
Landslide
Tornado
Bushfire Potential
Source: Johnson et al., (1995). Natural Hazards:
their Potential in the Pacific Southwest.

8. Potential regions are overlaid with postcode boundaries
Medium
Low
Potential magnitude for the green postcode =
Areal averaging
(“Low”, “Medium”)
Nine potential maps are converted into raster images with the same scale and same coordinate system:
Size: 2250 pixels (W-E)  2000 pixels (N-S)
Resolution: 2 km
Low
Medium

9. Step 2: Normalisation Conversion: linguistic terms  fuzzy sets  crisp values
A numerical approximation system by Chen, S.J. and Hwang, C.L. (1992) with 8 conversion scales. 7th scale contains 9 linguistic terms (left).
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0 X
Very low
Very high
High-V. high
V. low-low
Low
Medium
High
Low-medium
Medium-high
e.g., Bushfire potential with 5 scales

10. Weighting
Weighting is to express the relative importance between 9 perils, in terms of damage to buildings (historical and potential)
Four sub-factors were assessed using Analytical Hierarchy Process (AHP). The final relative weight for each peril uses their average.

11. Step 3: Combinations
Weighted Linear Combination (WLC)-GIS was used, with five advantages (for details, refer to the PerilAUS II report)
(1) Historical component:
(2) Potential component:
(3) RRR = 30%  (Historical) + 70%  (Potential)
Finally, a series of composite maps and spreadsheets at a postcode level and at a CRESTA/ICA zone level are produced.

12. Results
e.g.
RRR at an ICA Zone level

13. RRR spreadsheet at a postcode level
Results (contd.)
RRR spreadsheet at a postcode level
RRR are comparable and serve as “risk meters”, allowing arithmetic calculations.
(1) Peril-by-peril (horizontally):
Which peril is the most significant? Sub-total risk ratings for perils selected
(2) Postcode-by-postcode (vertically):
individually (9 perils) and collectively
minimum, maximum, average values for easy comparisons
Relative standings (taking the right-hand column “Total” as example, go next slide)

14. Distribution of RRR “Total” at a postcode level:
Results (contd.)
Distribution of RRR “Total” at a postcode level:
For the Postcode 800, 98.9% of all 2,573 postcodes have RRR less than 119.3; or only 1.1% of all postcodes have RRR larger than In this way, a RRR relative standing spreadsheet can be produced (go next page).
e.g (Postcode 800, Darwin)
98.9%

15. New RRR relative standing spreadsheet at a postcode level
Results (contd.)
(previous) RRR spreadsheet at a postcode level
New RRR relative standing spreadsheet at a postcode level

16. Results (contd.)
Based on the calculated RRR, while the first three most damaging perils remain the same, RRR values for hails and tornadoes are higher than those from the previous 100 years.
Tropical
Cyclone
Flood
Bushfire
Gust
Hail
Quake
Tornado
Landslide
Tsunami

17. Part 2: PerilAUS II CD-ROM includes:
Spreadsheets (4):
RRR at a postcode level (70 pages)
Relative standing of RRR at a postcode level (70 pages)
RRR at a CRESTA/ICA zone level
Relative standing of RRR at a CRESTA/ICA zone level
Input maps (18):
Historical maps (9)
Potential maps (9)
Output composite maps (6):
Historical composite map at a postcode level
Potential composite map at a postcode level
Final RRR map at a postcode level
Historical composite map at a CRESTA/ICA zone level
Potential composite map at a CRESTA/ICA zone level
Final RRR map at a CRESTA/ICA zone level
Report

18. PerilAUS II CD-ROM
Spreadsheets are provided in .pdf, Excel 97, Access 97 formats
Report and maps are provided in .pdf and Word 97 formats
- printable, editable, easy data manipulation and conversions

19. Spreadsheets - PerilAUS II CD-ROM
East to browse and locate a postcode using left-pane indexes
Summary given at bottom of each page facilitates comparisons

20. Maps - PerilAUS II CD-ROM
East to browse and locate a map using left-pane indexes

21. Report - RRR of PerilAUS II
Detailed methodology and procedures of the RRR development are given in a report

22. Natural Hazards Research Centre
Thank you for viewing the PerilAUS II Demo.
To place an order or for more information, please contact:
Natural Hazards Research Centre
Telephone:
Fax: