PerilAUS II - Relative Risk Ratingsfor Postcodes and CRESTA/ICA Zones

Part 1: Methodology Part 2: CD-ROM

BackgroundBackground

• PerilAUS I CD-ROM (released in October 1999)– Most comprehensive collection of natural perils data 1900-1999

– 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

Geographical scalesGeographical scales

States ICA zones

Postcodes

Balaclava Road

Individual dwellings Street blocks

RRR of PerilAUS II deal with two geographical scales: ICA zones and Postcodes

Global

Part 1 - Methodology (PerilAUS II)Part 1 - Methodology (PerilAUS II)

Damage index

Fu

ture

p

ers

pec

tiv

e

Global weightingPeril-by-peril

(W1, W2, …, W9)

Historical data from PerilAUS I

Potential hazards data

Normalisation of scales for each

peril

Normalisation of scales for each

peril

Combination (historical)

Combination(potential)

Final RRRFinal RRR

Step 1

Step 2

Step 3

Step 1: Historical data from PerilAUS I (e.g. earthquake)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

Affected locations are overlaid with postcode boundariesAffected locations are overlaid with postcode boundaries

Affected locations within a postcode

Medium

Low

High

Very high

For each peril,

at a postcode level:

The number of affected locations;

Magnitude or intensity;

Frequency.

Potential hazards data (e.g. bushfire)Potential hazards data (e.g. bushfire)

LowModerateHighVery highExtreme

Source: Johnson et al., (1995). Natural Hazards:

their Potential in the Pacific Southwest.

Six base maps:

BushfireEarthquakeGustHailT. CycloneTsunami

Derivative maps: buffering zones of historical affected locations:

Flood

Landslide

Tornado

Bushfire Potential

Potential regions are overlaid with postcode boundariesPotential regions are overlaid with postcode boundaries

Low

Postcode

Medium

Postcode

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

LowMedium

Step 2: Normalisation Conversion: linguistic terms fuzzy sets crisp values

Step 2: Normalisation Conversion: linguistic terms fuzzy sets crisp values

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0X

0.1

0.2

0.3

0.4

0.7

0.8

0.5

0.6

0.9

1.0

Very low Very high

High-V. high

V. low-low

Low Medium High

Low-medium Medium-highA numerical approximation system by Chen, S.J. and Hwang, C.L. (1992) with 8 conversion scales. 7th scale contains 9 linguistic terms (left).

Linguistic terms Fuzzy sets Crisp values

Very low [0, 0, 0.2] 0.0833

Very low – low [0, 0, 0.1, 0.3] 0.125

Low [0, 0.2, 0.4] 0.25

Low - medium [0.2, 0.35, 0.5] 0.37

Medium [0.3, 0.5, 0.7] 0.50

Medium -high [0.5, 0.65, 0.8] 0.63

High [0.6, 0.8, 1] 0.75

High – very high [0.7, 0.9, 1, 1] 0.875

Very high [0.8, 1, 1] 0.9167

e.g., Bushfire potential with 5 scales

Potential scaleLow

Moderate

High

Very high

Extreme

Linguistic terms Fuzzy sets Crisp valuesVery low – low [0, 0, 0.1, 0.3] 0.125

Low – medium [0.2, 0.35, 0.5] 0.37

Medium [0.3, 0.5, 0.7] 0.50

High [0.6, 0.8, 1] 0.75

Very high [0.8, 1, 1] 0.9167

WeightingWeighting

Weighting is to express the relative importance between 9 perils, in terms of damage to buildings (historical and potential)

0%

5%

10%

15%

20%

25%

30%

35%

T. Cyclone Flood Bushfire Gust Hail Earthquake Tornado Landslide Tsunami

Re

lati

ve

we

igh

t

% HE (from PerilAUS I) Building damageArea affected Nationwide importance

Four sub-factors were assessed using Analytical Hierarchy Process (AHP). The final relative weight for each peril uses their average.

Four sub-factors were assessed using Analytical Hierarchy Process (AHP). The final relative weight for each peril uses their average.

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.

Step 3: CombinationsStep 3: Combinations

H r w fj j jj

n

1

P r wj jj

n

1

ResultsResults

RRR at an ICA Zone level

Historical (30%) + Potential (70%)(49 zones, 15 levels)

0.14 to 0.18 (6)0.18 to 0.19 (4)0.19 to 0.2 (3)0.2 to 0.21 (1)0.21 to 0.22 (2)0.22 to 0.26 (6)0.27 to 0.28 (2)0.28 to 0.29 (2)0.29 to 0.3 (1)0.3 to 0.31 (1)0.31 to 0.33 (5)0.33 to 0.34 (5)0.34 to 0.35 (2)0.35 to 0.43 (9)

e.g.

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)

Results (contd.)Results (contd.)

Postcode Reference Bushfire Earthquake Flood Gust Hail Landslide Tornado T. Cyclone Tsunami Total

800 Darwin 0.0 7.9 15.3 11.1 9.6 0.0 11.4 62.6 1.4 119.3

2026 Bondi Beach 0.0 7.7 0.0 10.4 20.3 0.0 11.7 0.0 0.7 50.9

2072 Gordon 0.0 7.3 9.4 10.4 17.4 1.0 9.8 0.0 0.0 55.5

2077 Hornsby 32.5 7.3 0.0 10.2 18.5 0.4 9.8 0.0 0.0 78.6

2084 Terry Hills 34.5 6.8 0.0 11.6 19.5 0.2 9.5 0.0 0.0 82.1

2135 Strathfield 0.0 7.3 33.1 9.8 18.0 0.0 10.1 0.0 0.0 78.3

2140 Homebush 0.0 7.8 7.1 7.6 18.5 0.0 11.2 0.0 0.0 52.1

2150 Parramatta 0.0 7.3 42.7 10.3 22.1 0.0 12.3 0.0 0.0 94.7

… …

MIN 0 1.7 0 1.4 4.8 0 0 0 0 16.1

MAX 52 15.6 53 19.6 34.2 6.5 17.1 100 1.5 162.7

AVG 15.7 5.0 16.3 4.8 11.9 1.4 8.4 26.5 0.2 54.8

Distribution of RRR “Total” at a postcode level:Results (contd.)Results (contd.)

0

20

40

60

80

100

120

140

160

180

200

16 24 32 40 48 56 64 72 80 88 96 104

112

120

128

136

144

152

160

"Total" for a postode

Th

e n

um

be

r o

f p

os

tco

de

s

0%

20%

40%

60%

80%

100%

120%

e.g. 119.3 (Postcode 800, Darwin)

98.9%

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 119.3. In this way, a RRR relative standing spreadsheet can be produced (go next page).

Results (contd.)Results (contd.)

New RRR relative standing spreadsheet at a postcode level

PC Reference Bushfire Earthquake Flood Gust Hail Landslide Tornado T. Cyclone Tsunami Total

800 Darwin 0 93.5 84.2 98.4 9.7 0 96.2 99.1 99.8 98.9

2026 Bondi Beach 0 91.9 0 97.5 97.0 0 97.7 0 96.2 53.8

2072 Gordon 0 80.2 77.7 94.4 88.8 90.3 73.4 0 0 62.1

2077 Hornsby 95.4 80.2 0 94.0 93.0 86.1 72.5 0 0 86.1

2084 Terry Hills 96.3 58.7 0 98.7 95.3 84.4 63.9 0 0 88.6

2135 Strathfield 0 80.2 93.6 93.1 90.4 0 84.1 0 0 86.0

2140 Homebush 0 93.1 75.2 89.0 93.1 0 92.9 0 0 56.3

2150 Parramatta 0 80.2 97.9 94.2 98.7 0 98.8 0 0 94.1

… …

(previous) RRR spreadsheet at a postcode level

Postcode Reference Bushfire Earthquake Flood Gust Hail Landslide Tornado T. Cyclone Tsunami Total

800 Darwin 0.0 7.9 15.3 11.1 9.6 0.0 11.4 62.6 1.4 119.3

… …

MIN 0 1.7 0 1.4 4.8 0 0 0 0 16.1

MAX 52 15.6 53 19.6 34.2 6.5 17.1 100 1.5 162.7

AVG 15.7 5.0 16.3 4.8 11.9 1.4 8.4 26.5 0.2 54.8

0%

5%

10%

15%

20%

25%

30%

35%

% o

f to

tal b

uild

ing

da

ma

ge

RRR average nationwide Historical (1900-1999)

TropicalCyclone

Flood Bushfire Gust Hail Quake Tornado Landslide Tsunami

Results (contd.)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.

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.

Part 2: PerilAUS II CD-ROM includes: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

PerilAUS II CD-ROMPerilAUS 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

Spreadsheets - PerilAUS II CD-ROMSpreadsheets - PerilAUS II CD-ROM

East to browse and locate a postcode using left-pane indexes

East to browse and locate a postcode using left-pane indexes

Summary given at bottom of each page facilitates comparisons

Summary given at bottom of each page facilitates comparisons

Maps - PerilAUS II CD-ROMMaps - PerilAUS II CD-ROM

East to browse and locate a map using left-pane indexes

East to browse and locate a map using left-pane indexes

Report - RRR of PerilAUS IIReport - RRR of PerilAUS II

Detailed methodology and procedures of the RRR development are given in a report

Detailed methodology and procedures of the RRR development are given in a report

Thank you for viewing the PerilAUS II Demo.

To place an order or for more information, please contact:

Natural Hazards Research CentreTelephone: +61-2-9850 9683

Fax: +61-2-9850 9394Email: nhrc@ocs1.ocs.mq.edu.au