2004 indian ocean tsunami: 10 years on - aon...

Risk. Reinsurance. Human Resources.

Aon BenfieldAnalytics | Impact Forecasting

2004 Indian Ocean Tsunami: 10 Years OnJanuary 2015

Table of Contents

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Event Recap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Impacts of the Tsunami on Infrastructure . . . . . . . . . . . . . . . . . . . . . . . . . 9

Tsunami characteristics and sources in Indian Ocean . . . . . . . . . . . . . . 20

Indian Ocean tsunami warning systems . . . . . . . . . . . . . . . . . . . . . . . . . 24

Preparedness and communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Aon Benfield’s tsunami modeling initiatives . . . . . . . . . . . . . . . . . . . . . 35

Tsunami insurance coverage in Asia Pacific . . . . . . . . . . . . . . . . . . . . . . 41

Closing Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Appendix 1 . Indian Ocean tsunami observations between 1900 and 2014 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Appendix 2 . Useful Internet Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Appendix 3 . Availability of tsunami insurance cover in Asia Pacific region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Appendix 4 . Remnants and Reminders of 2004 Indian Ocean tsunami . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Aon Benfield 3

Preface

The 2004 Indian Ocean earthquake and tsunami (also called

the Boxing Day tsunami) was a devastating catastrophe that

caused extensive loss of life and damage. The people of the

affected territories experienced immense suffering due to the

event. Since then, there has been an enormous amount of

research carried out on the catastrophe and a large volume

of literature published on the subject. This publication marks

the completion of a decade following the event and aims

to reflect upon the event and the subsequent changes in

several aspects regarding the peril, over the past ten years.

The document is organized into seven chapters. The first

chapter, titled ‘Event Recap’, provides some background

on how the event was triggered and provides a brief

commentary on the losses experienced as a result of the

disaster. The second chapter is an invited commentary

by Professor Iaon Nistor and Professor Tad Murthy,

internationally renowned experts on tsunami risk. The

chapter explores the impact of the tsunami on the

infrastructure present in the region at the time of the event,

based on the characteristics of the tsunami and general field

observations after the event. The third chapter explores the

sources and features of tsunamis in the Indian Ocean region.

The scale of damage due to the tsunami had not been

experienced before and the people of the affected regions

were not suitably prepared regarding the event. The

unsuspecting communities, therefore, endured massive

losses. Countries like India and Indonesia, which were

affected by the tsunami, established institutions and warning

systems following the event that could advise the at-risk

communities of impending tsunamis. Chapter four briefly

summarizes these warning systems. The changes in the

preparedness towards similar events and the communication

systems in place are discussed in the fifth chapter.

The sixth chapter looks at the tsunami risk from an insurance

industry perspective, while the seventh chapter briefly

discusses Impact Forecasting’s approach to tsunami

modeling, through case studies from Japan and Chile.

Related appendices and references are included.

years. Figure 1: Tsunami wave monument in Banda Aceh, Indonesia.

Source: Impact Forecasting

4 2004 Indian Ocean Tsunami: 10 Years On

Event Recap

On December 26, 2004, a megathrust earthquake was

registered off the coast of Sumatra, Indonesia, which

generated a huge tsunami that spread across the Indian

Ocean, killing and injuring hundreds of thousands of

people and causing devastating damage. There is still

no consensus as to the total number of people who

perished as a result of the disaster – most estimates

suggest a figure of around 230,000. The earthquake

of magnitude Mw9.1 (USGS) struck at 07:58 local time

(00:58 UTC) with an epicenter 250 kilometers (155

miles) south-southeast of Banda Aceh, Indonesia.

Figure 2: Tectonic base map of the Sumatra subduction zone showing major faults and the location of main shock. The annual speed and direction of plate movement is also indicated.

Source: http://walrus.wr.usgs.gov/tsunami/sumatraEQ/tectonic.html

http://walrus.wr.usgs.gov/tsunami/sumatraEQ/tectonic.html

Aon Benfield 5

The earthquake, the third largest ever recorded

instrumentally and the largest known tremor to have struck

the Indonesian archipelago occurred as a result of thrust-

faulting at the interface of the Indo-Australian tectonic plate

and the Burma tectonic plate. Figure 2 shows the tectonic

base map of the Sumatra subduction zone showing major

faults and the location of the main shock. From the epicenter,

the fault-rupture propagated northwestward for 500

kilometers (310 miles) towards the southern Andaman and

Nicobar Islands. (Some models suggest that the

fault-rupture may have propagated as far as 1,200 kilometers

(745 miles) from the epicenter.) The width of the rupture

zone was approximately 150 kilometers (95 miles), and

the maximum displacement on the fault plane was about

20 meters (65 feet). The depth of the earthquake was

only 30 kilometers (18.6 miles). The shallow depth

combined with the substantial movement on the fault

plane meant that the sea-floor overlying the thrust

fault was uplifted by several meters. It was this sea-

floor uplift that triggered the catastrophic tsunami.

The sudden vertical rise of the sea-floor due to the earthquake

displaced an enormous volume of water triggering the

tsunami. The wave immediately spread out in all directions

from the earthquake epicenter, taking just 15 minutes to

reach the western coast of Sumatra. About 7 hours later,

the wave had traversed the Indian Ocean and had come

ashore in eastern Africa. In total, the tsunami affected the

coasts of 14 countries around the rim of the Indian Ocean:

Bangladesh, India, Indonesia, Kenya, Madagascar, Malaysia,

Maldives, Myanmar, Seychelles, Somalia, Sri Lanka, Tanzania,

Thailand, and Yemen. The vast majority of the fatalities

and damage were a result of the tsunami rather than being

directly caused by the earthquake. Post-event analysis

uncovered evidence that runup height reached as high as 49

meters (160 feet) as it came ashore near Banda Aceh (Figure

4b) and travelled as far as 5 kilometers (3.1 miles) inland.

In Thailand, runup heights of up to 10.6 meters (35 feet)

were observed (source: National Geophysical Data Center,

NOAA). Wherever the tsunami came ashore, buildings,

structures, vegetation, and vehicles were destroyed.

Figure 3a: 2004 Indian Ocean tsunami runup heights.

Source: http://www.ngdc.noaa.gov/hazard/img/indian_ocean_runups.png)

http://www.ngdc.noaa.gov/hazard/img/indian_ocean_runups.png)


Figure 5: Boat on the roof, Gampong Lampulo, Banda Aceh; 56 people survived from the disaster by taking shelter in the boat.

Figure 4b: Maximum runup height of 48.86 m was noticed in Rhitting, near Banda Aceh.

Economic Losses and Fatalities

The most devastating effects of the tsunami were observed

in Indonesia, particularly in Banda Aceh Province, where

almost 170,000 lives were lost. Total economic losses reached

USD4.5 billion (2004). In Sri Lanka, the death toll reached

almost 35,500 and economic losses totaled USD1.5 billion

(2004). In Thailand, the number of lives lost reached almost

8,500 and economic losses were USD2.2 billion (2004)

[Ref: Asian Disaster Prepared Center]. The combined cost

of damage caused by the tsunami across the 14 affected

countries was USD14 billion. To cite one example of the

magnitude of the damage, a fishing boat (length: 25 meters

(82 feet), width: 5.5 meters (18 feet), and weight: 20 tonnes)

was carried several kilometers inland onto the roof of a house

(Figure 5) in Lampulo village, Banda Aceh, Indonesia.

Source: Prof. Tomoya Shibayama, Waseda University, Japan


Aon Benfield 7

The high number of fatalities caused by the tsunami has

been attributed by many to be due to two main factors:

firstly, the large number of coastal communities around

the perimeter of the Indian Ocean on low-lying ground;

and, secondly, the lack of a tsunami warning system.

Given the short amount of time it took the tsunami to

strike the Banda Aceh coast, it is unlikely that a tsunami

warning system would have been deployed in time to

prevent many of the fatalities there. However, had a

warning system been deployed in Sri Lanka and India, it

would have given the population there almost 3 hours

to prepare and evacuate from low-lying areas, and in

all likelihood, would have prevented many thousands

of deaths. Over 16,000 people were estimated to have

been killed in India and runup height above 5 meters (17

feet) was noticed at Nagapattinam in Tamil Nadu state.

Insured Losses

There were a wide range of insured loss estimates

from different sources following the event, a significant

component of which were attributed to losses in the

life insurance, personal accident and property lines

of business. The insured losses were estimated to be

approximately USD3 billion (2004). The tsunami did

not have a significant impact on major city centers

or concentrations of infrastructure in the affected

territories. Most of the property destroyed was in the

regions with low insurance penetration. Losses were

also dispersed widely over many countries. Many

properties including residential structures, motor, cargo,

industrial plants, tourist sites and resort hotels were

destroyed or severely damaged during the event.

Figure 6: Tsunami monument at Lhoknga beach, one of the severely affected sites in Indonesia.



Insurance penetration in the affected areas was generally

low, particularly with regard to residential properties and

small businesses. The countries impacted by the tsunami

were characterized by a large number of small localized

insurance companies who spread their risk primarily

through national and regionally based reinsurance

companies, generally by proportional reinsurance.

Historically the insurance companies and national

reinsurance companies also ceded a significant amount

of risk by proportional reinsurance to the international

reinsurance market. Following the events of 9/11 and

Typhoon Nari which hit Taiwan in September 2001, event

limitations were introduced in 2002 to South Korean

and Taiwanese proportional treaties for catastrophic

peril loss recoveries. In subsequent years Philippines

and Indonesia also introduced such event limitations for

catastrophic loss recovery from proportional treaties.

Also catastrophic peril losses were excluded from

Taiwanese surplus treaties. As a result of the adoption of

these non-proportional restrictions on to proportional

treaties, proportional reinsurance capacity became scarce

and uneconomically viable resulting in many insurers

opting to reinsure their catastrophic perils via non-

proportional treaties. This significantly reduced the risk

to the international reinsurers. Although the estimated

total insured loss is large, for individual companies,

and even national reinsurers, the losses were probably

generally not large relative to their retentions. As a

consequence, the estimated total insured loss would

have been borne by the tens of local, national and

regional insurance and reinsurance companies, for some

of whom it may have been a significant loss, but for very

few of whom it would have been a disastrous event.

Another characteristic feature of the regions impacted

by the tsunami event was the significant concentration

of international tourist resorts, especially in Thailand,

Sri Lanka and the Maldives. These were probably

largely insured offshore, so will have impacted on

international insurers. However, they were reasonably

well spread among a number of insurers, probably

roughly in proportion to the size of the insurers.

Figure 7: Affected tourist sites in Thailand.

Courtesy: Dr. Poh Poh Wong

Aon Benfield 9

Impacts of the Tsunami on Infrastructure

Introduction

A team of Canadian engineers conducted a reconnaissance

visit to Thailand and Indonesia3. The visit focused on urban

areas with engineered constructions, closest to the epicenter.

Rawai Beach, Kata Noi Beach, Kata Beach, Patong Beach,

Nai Thon Beach and Kamala Beach on the Thai island of

Phuket were visited first, followed by Phi-Phi island, about

48 km south east of Phuket and the coastal town of Khao

Lak about 100 km north of Phuket. Two locations were

visited in Indonesia; the city of Medan located north-east

of the island of Sumatra and Banda Aceh, the capital of

Indonesia’s Aceh Province at the northern tip of Sumatra.

There was no damage observed in Medan, though the

earthquake was felt significantly, causing limited damage to

building contents and creating fear among the residents.

Banda Aceh, with a population of about 300,000 suffered

extensive seismic damage. The city of Meulaboh, with a

population of about 40,000 along the west coast of Sumatra

reportedly also suffered seismic damage, but could not be

visited because of difficulties in transportation. Figure 8

shows the areas where site investigations were carried out.

1 Dr. Ioan Nistor is an Associate Professor of Hydraulic and Coastal Engineering, Department of Civil Engineering, University of Ottawa, Ottawa, Canada. He is a coastal and hydraulic engineer researching hazards associated with extreme hydrodynamic loading on infrastructure (tsunami impact on infrastructure, extreme wave and flood forces on structures, dam failure phenomena, etc.) and he is currently the Chair of the Maritime and Coastal Division of International Association for Hydro-Environment Engineering and Research (IAHR). He is also a voting member of the new ASCE7 Subcommittee for the elaboration of New Design Guidelines for Tsunami-Resistant Buildings.

2 Dr. Tad Murty is an Adjunct Professor, Department of Civil Engineering, University of Ottawa, Ottawa, Canada. He is also the Vice-President, International Tsunami Society, Honolulu and Editor, Natural Hazards (published by Springer in the Netherlands). He retired as a Senior Research Scientist, Canadian Oceanographic service, Director of Australian National Tidal Facility, Prof of Earth Sciences, Flinders University, Adelaide, Australia. He obtained his PhD from the University of Chicago, USA.

3 The visit took place in January 2005 in Thailand and Indonesia and was under the auspices of the Canadian Earthquake Engineering Association. A report was issued as follows: Saatcioglu, M., Ghobarah, A., Nistor, I. (2005). The 26 December 2004 Sumatra earthquake and tsunami, Final Report prepared for Canadian Assoc. of Earthquake Engineering, Ottawa, Canada, 27 p

* The views expressed in this chapter are those of the authors and do not necessarily represent the views of Aon Benfield.

Dr. Ioan Nistor1 and Dr. Tad Murthy2

(a) Phuket, Thailand (b) Khao Lak, Thailand (c) Banda Aceh, Sumatra, Indonesia

Figure 8: Locations visited in Thailand and Indonesia.

Sources: Geocities, Khao Lak Promotions and Mapsoftworld


General Field Observations

Damage along southern Phuket beaches was limited to

coastal erosion and partial failures of non-engineered

reinforced concrete and timber frame structures along

the coast. The runup height was measured to be

approximately 6meters (20 feet) from the sea in Kata

Beach, damaging low-rise buildings, including roof tiles,

as illustrated in Figure 9. The most populated beach

town along the west coast of Phuket was Patong Beach,

which suffered extensive damage to low-rise buildings.

The water mark on buildings was measured to vary

between 4-6meters (13-20 feet) above sea level. The

building inventory in Patong Beach consisted of a large

number of non-engineered one to two story reinforced

concrete and timber frame shops and hotels. There

were also a number of multistory engineered reinforced

concrete hotels. Extensive damage to masonry infill walls

was observed. Limited damage occurred in reinforced

concrete structural elements, though significant damage

was seen in timber structural elements. Most of the

entire shopping district of Patong Beach was destroyed

within an area extending approximately two kilometers

inland from the shore as illustrated in Figure 10.

Figure 9: Damage to single story non-engineered buildings in Kata Beach.

Figure 10: Observed damage in Patong Beach.

Nai Thon Beach, further north of Patong Beach on

the island of Phuket, suffered extensive structural

and non-structural damage to reinforced concrete

frame buildings. The water depth was in excess of

10 meters (33 feet), especially in areas between

the shore and the nearby hilly terrains, and led

to significant water run-ups. Figure 11 illustrates

the structural damage observed in this area.

Aon Benfield 11

An area that was heavily affected by the tsunami is Khao

Lak Beach, about 100 kilometers (62 miles) north of

Phuket. The maximum water depth was measured to

be in excess of 10 meters (33 feet), causing extensive

structural damage. The failure of first-story masonry

infill walls and structural collapse of low-rise reinforced

concrete frame buildings are shown in Figure 12. Many

resort hotels were completely destroyed. Some multistory

reinforced concrete hotels survived the tsunami pressure,

with damage limited to the first-story infill walls.

Figure 11: Structural damage in Nai Thon Beach due to tsunami waves.

Figure 12: Structural and nonstructural damage in Khao Lak Beach.

Further north of Khao Lak Beach is the harbor. This

area was also hard hit by the tsunami, destroying the

harbor and floating boats inland. The town near the

harbor was devastated as shown in Figure 13.

Figure 13: Damage to Khao Lak harbor town.

Phi Phi Island is a small island located about 48 kilometers

(30 miles) south east of Phuket. The topography of

the island is such that east and west sides are entirely

covered with steep hills, with a low lying area between

the two, where most of the island’s inhabitants live. This

area is only a few meters above sea level and was hit

by the tsunami from both sides. Most structures on the

island were destroyed, with the exception of a few well-

built reinforced concrete frame buildings, a steel frame

building and some non-engineered construction. Many

of the one- and two-story non-engineered reinforced

concrete and timber frame buildings of the island

collapsed entirely due to tsunami wave pressures. Figure

14 illustrates the extent of damage on the island.


Banda Aceh, Indonesia, was a city with a population of

about 300,000 inhabitants before the tsunami. It was

subjected to damaging forces of not only the tsunami but

also the earthquake. The majority of casualties were in this

city. Coastal areas were entirely swept away by tsunami

waves, leaving piles of timber as the remains of building

infrastructure. A large number of non-engineered reinforced

concrete buildings suffered structural damage, especially in

their first floor columns. Multi-story engineered reinforced

concrete government buildings suffered earthquake

damage due to poor seismic design and detailing practices.

A large number of mosques survived the disaster, though

they also suffered damage to masonry walls. Figures 15 and

16 illustrate the extent of damage observed in Banda Aceh.

Figure 14: Phi Phi Island, Thailand.

Figure 15: Tsunami damage in Banda Aceh, Indonesia.

Figure 16: Earthquake damage in Banda Aceh, Indonesia.

Aon Benfield 13

Effects of tsunami inundation

Tsunami waves imposed dynamic water pressures on

coastal structures as well as buildings and bridges near the

coastline, inducing serious damage to the entire surrounding

infrastructure located up to approximately 4 kilometers

(2.5 miles) inland. The resulting impulsive pressures of

breaking waves and hydro-dynamic pressures associated

with water velocity inflicted partial and full collapses of non-

structural and structural elements. The damage observed

in Thailand was almost entirely due to water pressures

that varied from impulsive pressures of breaking waves at

the shore, to reduced dynamic pressures inland as water

velocity decreased due to surface friction. There was some

impact loading generated by the floating debris, though

this was most pronounced in Banda Aceh, where large

objects were observed to have impacted on structures.

Performance of timber construction

In both Thailand and Indonesia, coastal towns had a large

number of low-rise timber frame buildings. These buildings

had timber columns and beams, supporting timber joist

floor systems. The roofs either had light corrugated iron

coverage or clay roofing tiles. Figure 17 illustrates the

framing system used and the types of damage observed.

Figure 17: Damage to timber frame buildings in Phi Phi Island, Thailand.


Performance of unreinforced masonry walls

The majority of buildings in Thailand and Indonesia

had frames infilled with unreinforced masonry walls.

The masonry units used were consistently of the same

type, with 50 millimeters (2 inches) in thickness. Both

hollow clay bricks and concrete masonry blocks of

the same thickness were used (Figure 18). These walls

suffered punching shear failures due to the tsunami wave

pressure, applied perpendicular to the wall plane. These

resulted in large holes in walls, sometimes removing

the masonry almost entirely. The remaining walls

around the frames did not show any sign of diagonal

tension cracks, contrary to expectations, unless the

failure was caused by seismic excitations, which was

limited to Banda Aceh only. Figure 19 shows the type

of punching failures observed in masonry infill walls.

Figure 18: Clay brick and concrete masonry block units with 50 mm thickness.

(a) Kamala Beach (b) Khao Lak Beach (c) Banda Aceh

Figure 19: Punching failure of masonry infill walls caused by tsunami wave pressure.

Aon Benfield 15

(a) Khao Lak Beach (b) Phi Phi Island (c) Banda Aceh

Performance of non-engineered reinforced concrete buildings

The majority of one- to two-story low-rise buildings

were constructed using cast-in-situ concrete, without

much evidence of engineering design. The columns were

of very small cross-section (about 200 millimeters (8

inches) square), containing 4 smooth or deformed corner

bars with 8 millimeter (0.3 inch) diameter, resulting in

approximately 0.5% reinforcement ratio. Their flexural

capacity was computed to be significantly below the

moments imposed by tsunami waves and slightly below

the moments imposed by hydrostatic pressure. Figure 20

illustrates column failures in non-engineered reinforced

concrete frame buildings due to the tsunami wave pressure.

Observations on column behavior indicated that many

failures occurred at mid-height, especially in Banda Aceh.

This was attributed to the effects of debris impact, over and

above the tsunami wave pressure. Indeed, floating building

remains, as well as floating large objects like fishing boats

and cars impacted on the columns, causing column failures

near their mid-heights. This is illustrated in Figure 21.

Figure 20: Column failures in non-engineered reinforced concrete construction.

Figure 21: Column failures due to debris impact in Banda Aceh.

Performance of engineered reinforced concrete buildings

There were many low- to mid-rise reinforced concrete

frame buildings which appeared to have been

engineered in the visited areas of Thailand and Indonesia.

These buildings survived the tsunami pressure without

structural damage, though they suffered damage

to non-structural elements, especially the first story

masonry walls. Figure 22 shows reinforced concrete

hotel buildings in Thailand that survived the tsunami

without any sign of structural damage, although

nearby non-engineered buildings were either partially

or fully collapsed. There were some exceptions to

this observation in Nai Thon Beach, where water

runup affected slender reinforced concrete columns

of a shopping center, causing a partial collapse.


A common precast slab system that was used in Thailand

consisted of prefabricated reinforced concrete strips,

supported by cast-in-place beams. These strips had 50

millimeter (2 inch) thickness, 300 millimeter (12 inch)

width and 2.0 meters (79 inches) length, reinforced with

4-6 millimeter (0.1-0.2 inch) diameter smooth wires,

equally spaced in the center of the section. Figure 23

shows the specifics of the slab system. Because of lack of

proper connection to the supporting beams, these strips

lifted up due to water pressure, causing slab failures. One

good example was a shopping center in Patong Beach

on Phuket Island, Thailand, where the lower level below

grade was filled up with water, lifting and destroying the

first floor slab panels, as illustrated in Figure 23. A similar

type of slab failure was also observed in the concrete dock

of the Kao Lak Harbor, as shown in Figure 24, though the

strips used in the harbor dock were slightly thicker.

Figure 24: Failure of Kao Lak Harbor dock.

Figure 23: Failure of precast slab strips in Patong Beach.

(a) Hotel on Phi Phi Island (b) Hotel on Phi Phi Island (c) Hotel in Nai Thon

Figure 22: Engineered concrete buildings survived tsunami forces without structural damage.

Aon Benfield 17

Damage to lifelines

There was extensive damage to bridges in the Aceh

province of Indonesia caused by tsunami wave forces,

collapsing many and jeopardizing relief efforts. Figure

25 shows a two-span steel truss bridge in western Banda

Aceh that failed and displaced approximately 50 meters

(164 feet) from its piers and abutments which were not

damaged. The Indonesian army constructed a Bailey

bridge on the same supports to maintain access to the

nearby cement plant. Similarly, in eastern Banda Aceh

a two-lane, multi-span reinforced concrete bridge was

swept off its piers, as illustrated in Figure 25(a). Two of

the bridge piers were also destroyed while the others

remained in place. Another multi-span, reinforced concrete

bridge, over the same river further away from the ocean,

survived the tsunami wave pressure as shown in Figure

26(b). This bridge is likely to be of the same type as that

collapsed (shown in Figure 26(a)), judging by the spans

and the piers, though this point could not be confirmed.

Figure 25: The failure of steel truss bridge in eastern Banda Aceh.

(a) Bridge, completely swept off by tsunami

Figure 26: Multi-span reinforced concrete bridges in eastern Banda Aceh.

(b) Bridge that survived the tsunami


The transportation system in Banda Aceh was completely

paralyzed by the tsunami. Main arteries as well as small

streets were massively blocked by debris, jeopardizing

response and relief efforts. Foreign aid crews put in a

substantial effort to clean and open streets that had

been covered by the debris of collapsed buildings

and destroyed trees. Access to urban areas was lost, in

particular the 150 kilometer (93 mile) coastal road to

Meulaboh was washed away and bridges on the way lost

their superstructure due to the tsunami wave pressure.

The storm drainage system in Banda Aceh, as well as in

Medan, Indonesia consists of concrete open channels

located along main streets. These channels are sometimes

covered with prefabricated concrete slabs, especially

in populated regions. This drainage system suffered

extensive damage in Banda Aceh. Cover slabs were broken

and displaced and the channels were blocked by mud and

debris, further contributing to flooding. A major part of

the clean-up operation was to clean the drainage channels

to make them functional again, as illustrated in Figure 27.

Figure 27: Open channel drainage system in Banda Aceh.

Water supply in Banda Aceh was disrupted due to the failure

of water mains. A number of main pipelines were broken as

they were attached to bridges to cross the rivers that pass

through the city. These pipes were damaged either by the

floating debris or collapsed bridge components. Figure

28 illustrates damaged pipelines attached to bridges.

Figure 28: Damage to pipeline attached to bridges in Banda Aceh.

Aon Benfield 19

Conclusions from the field-trip

The following conclusions can be drawn from the

reconnaissance visit conducted in Thailand and Indonesia

to assess engineering significance of the December 26,

2004 Indian Ocean tsunami and earthquake disaster,

with lessons learned and re-learned, as stated below:

• Lateralforcesgeneratedbytsunamiwavepressurecan

be orders of magnitude higher than typical design wind

pressures, generating out of plane forces high enough

to damage unreinforced masonry walls within the

tsunami height. The observations indicated widespread

failure of masonry infill walls within the first story level

of most frame buildings. These failures were often in

the form of large circular holes in the masonry walls.

• Whiletherelativelevelofforceswillchangefromone

building to another, depending on the characteristics

of the building, the type of exterior enclosure,

proximity to shoreline, topography of the region and

other seismic and tsunami characteristics, tsunami

generated base shear in buildings can be at a level

that is comparable to seismic induced base shears.

• Non-engineeredlow-risereinforcedconcreteframe

buildings, with small size structural elements, are

vulnerable to partial or full collapse due to lateral

tsunami pressures. Columns of such buildings are

further vulnerable to impact forces generated by

floating debris caused by tsunami, often leading to

flexural failures of columns within their mid-heights.

• Engineeredreinforcedconcreteframesoftenappearto

have sufficient strength against tsunami forces. There was

very little damage observed in structural components

of engineered concrete buildings. Often, nonstructural

elements failed before the effects of tsunami pressure

reached a critical level for structural components of such

buildings, relieving pressure on structural elements.

There was one steel frame building investigated, which

survived the tsunami pressure without any sign of distress.

• Prefabricatedreinforcedconcreteslabstrips,commonly

used in the area, suffered from uplift forces caused

by hydrostatic pressures. Lack of proper anchorage

to the supporting beams was blamed for the failure

of these slab systems.

• Bridgeinfrastructurewasdevastatedbytsunamiforces.

Many bridges were swept away from their supports,

disabling the transportation network.

• Storagetanksshouldbewellanchoredtotheir

foundations to resist tsunami pressures. Many steel

storage tanks, as well as other unanchored structures

floated away long distances due to the uplift pressure

generated by tsunami.

• Lighttimberframebuildingsareextremelyvulnerableto

tsunami wave pressures. Many residential districts with

timber residential buildings in Banda Aceh were

entirely wiped out by tsunami waves.


General Characteristics of tsunami

Tsunamis (Japanese: “harbor wave”) are giant waves

due to the sudden displacement of a large volume of

the water in the sea or in the lake. These displacements

are most often caused by earthquakes; other caused

of tsunamis include submarine and coastal landslides,

volcanic eruptions or meteoric impacts.

Devastating tsunamis have been historically generated on

faults which are located offshore or inland at small distance

from shore. Tsunamis can be generated when the sea floor

abruptly deforms and vertically displaces the overlying water.

Tsunamis often occur following under-sea earthquakes, due

to the destabilization of the water above the deformed area.

Tsunamis are also generated by volcanic eruptions and under-

sea and coastal landslides. (Ref: Nayak S., Kumar S.T. (2008)

Addressing the Risk of Tsunami in the Indian Ocean,

Journal of South East Asia Disaster Studies).

The energy released from a tsunami is constant, which

is the function of wave speed and wave height. Tsunami

waves form only a small hump on the open sea, barely

noticeable and harmless, which generally travels at a

very high speed of 500-1,000 kph (310-620 mph).

As the wave travels towards the shore (shallower water) the

speed decreases and in order to conserve the energy the

wave height increases. Distant-tsunamis or tele-tsunamis (or

far-field tsunamis) are those that travel a long distance and

strike far from the original source, whereas local-tsunamis

(or near-field tsunamis) affect regions close to the source.

Tsunami characteristics and sources in Indian Ocean

Source: http://walrus.wr.usgs.gov/tsunami/sumatraEQ/seismo.html

Figure 29: The figure shows local tsunami intensity (a function of maximum tsunami runup) plotted against the moment magnitude of the earthquake (Mw) for a number of tsunamis that occurred in the past century. The size of the 2004 Sumatra local tsunami is consistent with the size of tsunamis generated by other earthquakes of similar magnitude. It is also clear that this is one of the largest earthquakes to have been recorded.

Aon Benfield 21

Tsunami characteristics are highly influenced by

earthquake parameters such as seismic moment, source

mechanism and hypo central depth. The seismic moment

represents the energy released by the earthquake

which indicates the magnitude of the earthquake.

Major tsunamis have been invariably the result of larger

earthquakes. The earthquake mechanism is defined by

the orientation of the fault and direction of fault slip.

Earthquakes which have larger vertical fault movement

(dip-slip events) are more effective in triggering

tsunamis compared to earthquakes which have larger

horizontal fault movement (strike-slip events). Also,

shallower hypocentral earthquakes are more capable of

triggering tsunamis compared to deeper earthquakes.

Figure 30: Location of the origin of tsunamis in Indian Ocean between 1900 and 2014.

Tsunamigenic earthquake sources in the Indian Ocean

When compared to Pacific Ocean tsunamis, those in the

Indian Ocean occur less often. However, a large number

of countries are vulnerable, including (in alphabetical

order) Australia, Bangladesh, India, Indonesia, Iran,

Kenya, Madagascar, Malaysia, Maldives, Mauritius,

Myanmar, Oman, Pakistan, Reunion Island (France),

Seychelles, Somalia, South Africa, Sri Lanka, Thailand.

(Ref: Department of Ocean Development, Integrated

Coastal and Marine Area Management, Project Directorate,

Chennai, India (2005) Preliminary Assessment of Impact

of Tsunami in Selected Coastal Areas of India).

(source: NOAA)


Figure 31: Areas prone to Tsunami in and around Indonesia.

Destructive tsunamis largely originate from earthquakes

that occur along the following principal tectonic sources.

In the western part of Indian Ocean, the Makran coast

is an east-west subduction zone running from the Strait

of Hormuz to the Ornach-Nal Fault in Pakistan. The best

known historical tsunami in the region was generated by

the great earthquake of November 28, 1945 off Pakistan’s

Makran Coast (Balochistan) in the Northern Arabian Sea.

The destructive tsunami killed more than 4,000 people

in Southern Pakistan but also caused great loss of life

and devastation along the coasts of Western India, Iran,

Oman and possibly elsewhere. Further south on the

western side the Indian tectonic plate is bounded by the

Central Indian and Carlsberg mid-ocean ridges, a region

of shallow seismicity. To the east, the Sunda Arc extends

over 5,600 kilometers (3,480 miles) between the Andaman

Islands to the northwest and the Banda Arc to the east,

resulting from convergence between the Indo-Australian

plate and Southeast Asia. The Sunda Arc consists of three

primary segments; the Sumatra segment, the Sunda Strait

Segment and the Java Segment. These locations represent

the area of greatest seismic exposure, with earthquake

magnitudes of 8 or higher on the Richter scale - as the 26

December 2004 proved. Among these tectonic features,

the Makran and Sunda Arc subduction zones are the

primary tsunamigenic sources in the Indian Ocean.

A tsunami catalogue for last 100 years is given in Appendix 1

indicating that several major events were generated in the

Indian Ocean. The runup heights range between few

centimeters and several meters with the maximum 49 meters

(160 feet) resulting from the 2004 Indian Ocean tsunami

event. The same data are illustrated in Figure 29 which

shows evidence for highest activity in the Sunda Arc

subduction region, especially the islands of Indonesia

and Andaman Islands.

Source: InaTEWS

Aon Benfield 23

Tsunami Hazard Assessment

The hazard parameter of interest from a tsunami is

typically runup height which is a measurement of the

maximum height of the water that the tsunami pushed

onshore above a reference sea level. The goal of the

hazard assessment is to determine the runup height of a

tsunami striking an area. Traditionally, tsunami hazards

have been assessed deterministically using the concept of

a maximum credible event or worst-case scenario. There

is, however, no single accepted way of determining this

scenario. In some cases, the physically largest earthquake

is used to assess the tsunami hazard at a coastal site,

whereas in other approaches, the largest historical event

is defined as the worst-case scenario. The methods

require specifying all relevant tsunami sources that may

affect the site, performing time demanding numerical

hydrodynamic modeling for each source, and aggregating

the results to form the hazard curve which expresses the

frequency of occurrence as a function of the runup height.

The geographical extent of Indian Ocean is smaller

compared to the Pacific Ocean and therefore the tsunami

reaches the coast earlier in Indian Ocean. To capture

the scenarios in a more realistic fashion, it is critical that

the models should use good quality bathymetry and

coastal bathymetry data.


UNESCO’s Intergovernmental Oceanographic Committee

(IOC) coordinated and established the Intergovernmental

Coordination Group for the Indian Ocean Tsunami Warning

and Mitigation System (ICG/IOTWS) in 2005. It became

fully operational in 2011 in twenty eight countries that

form the Intergovernmental Coordination Group (ICG).

The aim of the system is to provide information regarding

approaching tsunami waves. The system works by detecting

tsunamigenic earthquakes more quickly and precisely than

was possible before as several new seismograph stations have

been added to the pre-existing network. It then confirms if

a tsunami wave has been generated and issues appropriate

warnings. While there were only a few real-time seismometers

prior to 2004, there are now several countries in the region

which operate real-time seismic networks (Figure 32).

Many Indian Ocean countries now have established National

Tsunami Warning Centers that are capable of receiving and

distributing tsunami advisories. Australia, India, and Indonesia

act as Regional Tsunami Service Providers (RTSP) under the

IOTWS and are the primary source of tsunami advisories for

the basin. The following sections discuss the tsunami warning

systems developed in India and Indonesia since the event.

Indian National Centre for Ocean Information Services (INCOIS)

In response to the 2004 Indian Ocean tsunami event,

the Indian government, via the Ministry of Earth

Sciences, established the Indian Tsunami Early Warning

System. It is based at and operated by Indian National

Center for Ocean Information Services (INCOIS),

Hyderabad (operational set-up is shown in Figure

33). The main objective of the Indian Tsunami Early

Warning Centre is to detect, locate, and determine the

magnitude of potentially tsunamigenic earthquakes

occurring in the Indian Ocean Basin, and subsequently

issue warnings regarding any potential event.

The National Tsunami Early Warning Centre at INCOIS has

been operational since October 2007 (Ref: Addressing

the Risk of Tsunami in the Indian Ocean: Shailesh Nayak

and T. Srinivasa Kumar) and has been issuing tsunami

advisories for all under-sea earthquakes of ≥ 6.5-magnitude.

Information regarding earthquakes is received from a

network of 17 broadband seismic monitoring stations

and more than 300 international stations. A database of

all possible earthquake scenarios for the Indian Ocean is

used to identify the regions at risk at the time of event.

Significant changes in sea level are monitored at the

time of occurrence of tsunamigenic earthquakes.

Indian Ocean tsunami warning systems

Figure 32: Seismic Network in Indian Ocean, 2004 (left) and 2014 (right).

Source: Intergovernmental Oceanographic Commission

Aon Benfield 25

The change in sea level needs to be measured close to the

fault zone with high accuracy. The Indian Tsunami Early

Warning Centre’s sea level network comprises 7 tsunami

buoys (5 in Bay of Bengal & 2 in North Arabian Sea) and tide

gauge stations at 21 locations. The location of the ocean

buoys and tide gauges is shown in Figure 34. Near-real time

data is also received from international stations as well as

Indian Meteorological Department (Ref: Indian Tsunami

Warning System by Shailesh Nayak and T. Srinivasa Kumar).

Necessary software for real-time reception, display and

archiving of tide gauge data has also been developed.


Figure 33: Operational set-up at INCOIS office, Hyderabad, India.


Figure 34: Map showing the network of seismic stations, tsunami buoys and tidal gauges surrounding India.

Source: INCOIS

In addition to real time monitoring of the natural

phenomena, INCOIS also uses modeling software in order

to assess the possibility of a tsunami after an earthquake.

Further modeling software is also being developed in

order to better determine the possibility of tsunami.

INCOIS and its subsidiaries collect information regarding

seismic events in real time, study the possibility of a tsunami

after a seismic event and disseminate warnings to both

emergency centers and the general public. Timely tsunami

advisories (Warning/ Alerts/ Watches) are disseminated

to the vulnerable communities following a Standard

Operating Procedure (SOP), shown in Figure 35, by means

of various available communication methods like global

telecommunication systems, fax, phone, SMS and others.

The center, along with other such warning centers in the

region also provides regular training and conducts drills

Aon Benfield 27

Figure 35: Standard Operating Procedure (SOP) of Indian Tsunami Early Warning Centre (source: INCOIS)Source: INCOIS

to study the preparedness of the systems in place. India

is a Regional Tsunami Service Provider and also issues

warnings and advice to surrounding countries in the

Indian Ocean which could be affected by a tsunami.

There are still challenges in modeling, estimation of

tsunami wave heights and dissemination of information to

remote regions, among others. However, the systems in

place are much improved now, when compared to 2004;

improvements have been made in seismic monitoring

networks, sea level monitoring, tsunami modeling,

standard operating procedures, international network

development and capacity building. Improvements are

happening in the development of denser seismic networks,

modeling and visualization software, utilization of satellite

networks for faster dissemination of information and

the integration of storm surge forecasting system.

Figure 35: Standard Operating Procedure (SOP) of Indian Tsunami Early Warning Centre.


Indonesia Tsunami Early Warning System (InaTEWS)

The Indonesian Tsunami Early Warning System (InaTEWS)

is the official tsunami early warning system in Indonesia.

It was set up with a mandate to produce tsunami

warning within 5 minutes of an earthquake occurring

(Ref: Development of Indonesia Tsunami Early Warning

System towards Regional Tsunami Watch Provider by P.J

Prih Hajadi, Fauzi) and was officially launched on 11th

November 2008. Parts of Indonesia are located at the

convergence zone between the Indo-Australian tectonic

plate and the Eurasian plate. This subduction area is

prone to severe earthquakes and hence, also tsunamis.

Therefore, Indonesia is well placed to host a tsunami

warning system. To help achieve this purpose, a series

of broadband seismograph stations, accelerographs,

tide gauges and GPS stations have been installed at

tsunami and earthquake prone regions in Indonesia.


Figure 36: Operational set-up of InaTEWS at Jakarta, Indonesia.

Aon Benfield 29

Source: InaTEWS

The operational component is denoted by agencies like the

BMKG (Meteorological, Climatological and Geophysical

Agency), Indonesian Geospatial Information Agency

(Badan Informasi Geospasial, BIG) and BPPT (Agency for

the assessment and application of technology). These

departments are primarily involved in monitoring the

situation, processing and analyzing information, and

issuing and disseminating warnings in case of an event.

Earthquake monitoring is performed via a network

of seismographs (163 broadband stations), and 259

accelerographs, while land deformation is assessed by

30 GPS stations. Sea level is monitored by DART–buoys

(Deep-ocean Assessment and Reporting of Tsunamis)

and tide gauges (113 stations). The information from the

different monitoring stations and networks is transmitted

to a central monitoring center via satellite communication.

Figure 37: Network of seismic stations in and around Indonesia.


Source: InaTEWS

Source: InaTEWS

Figure 38: Network of tsunami sirens in Indonesia.

Figure 39: CCTV monitoring at InaTEWS office.

Aon Benfield 31

The mitigation and emergency response is undertaken

by BNPB (Indonesia’s National Disaster Relief Agency)

and other government and private agencies (such as

local governments at provincial, district and municipal

levels, national and local television and radio stations,

the Indonesian military, the National Indonesian

Police, communities at risk, cellular service providers,

managers of hotels/tourist sites) which can respond

appropriately after an event and keep the public aware

and prepared at other times. Satellite communications

are useful here as well. Once it is confirmed that a

tsunami has been generated, other devices of mass

communication, such as sirens (Figure 38), are deployed

to inform a large number of people about the danger

and warning them to relocate to higher ground.

The capacity building component comprises of LIPI

(Indonesian Institute of Sciences) and ITB (Bandung

Institute of Technology) which assist in research and

development and in building human and other resources

to tackle the tsunami risk in the region. Based on

previous tsunamis and their characteristics, tsunami

modeling is also pursued at these institutions.

In addition to being an effort at a multi-institutional

level, InaTEWS has been developed with assistance

at the multi-national level. InaTEWS is also a regional

tsunami watch provider and provides warnings

to other nations in the ASEAN region.

Other Countries: It is to be noted that several countries

in the region operate their own tsunami warning systems:

like the National Disaster Warning Centre in Thailand,

Malaysia Meteorological Services in Malaysia and

Department of Meteorology and Hydrology in Myanmar.


Preparedness and communication

Given the very short warning lead time, preparedness

is key to mitigating the losses from a tsunami event. As

such, creating public awareness about the appropriate

response (such as following the instructions/signs,

reaching higher grounds and tsunami shelters etc.)

and education about the peril is essential.

Prior to 2004, there was no real-time earthquake monitoring

in Indian Ocean; but now, several countries operate real-

time seismic networks and are capable of estimating the

event parameters within 10 minutes of the occurrence.

Establishment of monitoring and warning systems in different

territories and coordination activities among different

agencies in disseminating the information stands out as a

marked improvement from the past. Television, radio, phone,

fax, email, SMS, etc. are all now used to issue warnings and

advisories to the general public and communities at risk.


Figure 40: Tsunami evacuation sign and escape building in Banda Aceh.

Aon Benfield 33

The first real test of the system was when a Mw8.6

earthquake struck to the southwest of Banda Aceh in

April 2012. The RTSPs in India, Indonesia and Australia

issued the warnings within a few minutes of the

occurrence of the event. Ultimately no tsunami was

generated by the quake but it provided an opportunity

to assess the effectiveness of the system and identify

areas where improvements were still required.

More recently, a mock test of the system was undertaken

in September 2014 when the three RTSPs issued warnings

based on computer-simulated earthquake and tsunami

scenarios. 24 countries took part in the exercise with

many countries undertaking public evacuation exercises.

The test was designed to assess the effectiveness of

communication flows between the agencies involved,

country readiness, and the efficiency of emergency

procedures. Preliminary results from the exercise suggest

that, ten years on from the event that inspired the

development of the basin-wide tsunami warning system,

the region is now much better prepared for such incidents.

Some challenges in tsunami risk management include

issuing quick and accurate warnings to regions near the

source, maintenance of expensive equipment and the

improvement in public response to the warnings. For

example, when an earthquake of Mw8.5 occurred near

Aceh in 2012, people did not approach higher elevations or

evacuation buildings but instead they ran farther inland. This

highlights the need for creating further safety awareness,

active community participation and the effective last

mile connectivity for warning dissemination. The recent

“Indian Ocean Wave 14” tsunami simulation exercises

involving 24 nations in the region during September 2014

and the evacuation drill in Banda Aceh on 26th October

2014 (Figure 42) are positive steps in this direction.

Courtesy: Dr. Poh Poh Wong

Figure 41: Tsunami evacuation route map, warning tower, height marker and shelter in Thailand.



Figure 42: A poster announcement of tsunami evacuation drill on 26th October, 2014 at Banda Aceh.

Aon Benfield 35

Due to the low insurance penetration in the regions

affected by 2004 Indian Ocean tsunami, the insured losses

were relatively low. However, the recent devastating

tsunami events such as 2010 Maule in Chile and 2011

Tohoku in Japan caused significant industry losses

leading to a need to understand and quantify the risk

from this secondary peril, in particular in the APAC

region as the exposures continue to grow rapidly.

Impact Forecasting, Aon Benfield’s catastrophe model

development center of excellence, has developed

tsunami models for Japan and Chile, and implemented

them on its proprietary loss calculation platform

ELEMENTS. Impact Forecasting recently collaborated

with Deltares (one of the research partners of Aon

Benfield) on different tsunami risk assessment projects.

The following paragraphs discuss some of the tsunami

risk assessment initiatives undertaken by Aon Benfield.

1. Japan tsunami scenario model

The Japan tsunami scenario model is based on

information gathered from scientific publications

and the Japanese Government Cabinet office. The

model has been developed in-house but evaluated

together with local academics from Japan. The

following scenario events are available for analyses:

List of events.

Event ID Event name Magnitude (Mw) Source

1 Kanto 1923 8.0 Kobayashi and Koketsu 2005

2 1703 Genroku-Kanto 8.2 Shishikura et al 2005

3 Tohoku 9.1 IISEE

4 – 15 Nankai 9.0 Government Cabinet’s office 2012

Aon Benfield’s tsunami modeling initiatives


Figure 43: 2011 Tohoku event slip distribution tsunami.

Source model (IISEE)

Aon Benfield 37

2. Chile Tsunami probabilistic and scenario model

Impact Forecasting’s Chile earthquake and tsunami model is

the first model on the market that includes both probabilistic

and scenario tsunami components as the secondary peril

to the earthquake component (Ref: A Probabilistic model

for Chile: Rara V et al, 2014). The tsunami probabilistic

event set contains 3,700 events and the historical includes

1960 Mw9.5 Valdivia and 5 variations of 2010 Mw8.8

Maule event. The tsunami hazard is defined in terms

of inundation depth and velocity. Wave propagation

and inland inundation (flooding) is modelled using 2-D

hydraulic software Delft3D (Deltares). An original set of

tsunami damage curves is developed for general and

detailed construction and occupancy classes reflecting

the particularities of the Chilean construction practice.

Source: GEER team report, SRTM, Impact Forecasting

Figure 44: Validation of the simulated and observed tsunami extent for 2010 Maule event in Talcahuano.


3. Jakarta tsunami scenario

As part of the Jakarta Coastal Defence Strategy (JCDS,

Deltares 2009-2012) a tsunami model was developed by

Deltares for Jakarta based on the worst case hypothetical

tsunamigenic earthquake along the Sunda Strait. Figure

45 shows the inundation depths generated using

the hypothetical scenario. Aon Benfield will examine

further to implement a scenario on ELEMENTS.

Source: Deltares; background imagery: Google Earth

Figure 45: Screenshot showing the simulated inundation depths using a hypothetical worst case scenario for Jakarta.

4. Hong Kong and PRD Tsunami study

Aon Benfield engaged an external agency to investigate the

probabilistic tsunami hazard for Hong Kong and the Pearl

River Delta region caused by earthquake sources around the

South China Sea. As shown in Figures 46 and 47, the Manila

Trench is determined as the dominant tsunami source in the

South China Sea for Hong Kong and Shenzen while sources

from the Indonesian archipelago were also considered.

Aon Benfield 39

Figure 46: Source and magnitude disaggregation map of Hong Kong, 475 average return period; the northern section of Manila Trench poses the most significant risk to Hong Kong.

Figure 47: Source and magnitude disaggregation map of Shenzhen, 475 average return period; the southern section of the Manila trench has greater impact while Hong Kong islands provide sheltering effect.


5. 2004 Indian Ocean Tsunami Event

The inundated areas from 2004 Indian Ocean

tsunami are available on ImpactOnDemand, Aon

Benfield’s proprietary mapping visualization platform.

An overview of the exposure within the affected

areas can be obtained using this information.

Commentary from Impact Forecasting

“The December 2004 Indian Ocean tsunami provided a catastrophic reminder that South East Asia is far from being immune to tsunamis. The region traversed by almost one-third of the world’s subduction zones, capable of producing the world’s largest earth-quakes and tsunamis, requires systematic and continuous understanding and quantification of the tsunami risk. A lot of research has been done based on this event and the next steps in tsunami modeling should include the use of high resolution and detailed input data (bathymetry, topography, land use) and state-of-the-art software for 2D hydraulic modeling, should understand and quantify better the building contents vulnerability and business interruption and of course should have in-depth consideration of the market needs. Now, ten years after this catastrophic event, in these new economic conditions, we are committed to work with our clients to examine such need and to define our model development strategy accordingly.”

Dr. Goran Trendafiloski, Head of Earthquake Model Development, Impact Forecasting

Sources: USGS, Pacific Disaster Center, NOAA, ReliefWeb and Aon Benfield

Figure 48: Inundated areas (in blue) in Banda Aceh, Indonesia from 2004 Indian Ocean Tsunami as visualized in ImpactOnDemand.

Aon Benfield 41

Tsunami insurance coverage in Asia Pacific

One aspect of tsunamis that make them different to other

insured hazards is the potential for wide geographical extent

of their impact, as well as their impact on a wide range of

insurance classes. With some exceptions, insurance cover

for losses resulting from tsunamis appears to be widely

available. A summary of the general availability of insurance

cover for tsunami losses from insurance companies in

select territories in Asia Pacific is given in Appendix 3.

Catastrophe Reinsurance

Reinsurance for catastrophe losses arising from tsunamis

appears to be fully available without any significant

exclusions. However in line with normal practice, reinsurance

only covers tsunami losses if the primary insurance company

includes it in their policy terms, since a reinsurance

contract is subject to the policy conditions used by the

primary company being followed in the event of losses.

Property Insurance

In most Asian countries indemnity is usually provided for

tsunami losses under named perils policies in association

with either earthquake or flood cover, depending on the

country, or covered under an all risk policy in the case

of larger commercial and industrial businesses. In Asian

countries it is most commonly associated with flood

cover; however in Malaysia and Indonesia, it is clubbed

with earthquake coverage. The relatively low levels of

insurance losses in the 2004 Indian Ocean tsunami was

primarily due to the low penetration of insurance cover

generally in the areas affected and even lower levels of

extensions to earthquake, flood and other major perils.

While most residential property insurance policies in the

region exclude tsunami cover, most standard commercial

and industrial policies cover it. A common proviso indicating

that should the damage be ‘caused by or arising out of an

earthquake or seismological disturbance’ may be the cause of

contention in the event of losses from earthquake-generated

tsunami, with insurers arguing that the proximate cause is the

tsunami and not the earthquake or seismological disturbance.

However by excluding ‘tidal wave’, the old colloquial term

for tsunami, but including the phrase ‘or seismological

disturbance’, which many would interpret as including

tsunamis, some insurance companies may find themselves

liable for earthquake-generated tsunami losses even if this is

not their intention. Special policies for larger commercial and

industrial business often do not have the seawater exclusion.


Closing Remarks

Revisiting and learning from the devastating event can

offer opportunities to reduce vulnerabilities and risks. The

destruction caused by the 2004 Indian Ocean tsunami

underlined the under-preparedness of the region in the

event of such massive disaster. There was no organized

approach to alert communities across the Indian Ocean

that a calamitous wave was approaching their coasts.

However, after a decade, several countries in the region

are now equipped with the scientific know-how and

instruments to forewarn the public in case of a possible

disaster and are better prepared to face such events.

But, as ever, challenges like effective maintenance of the

warning systems which requires continuous funding,

information dissemination to all the vulnerable groups,

disaster response and infrastructure resilience remain.

There has been a substantial amount of work from research

and academic institutions to understand more about

the tsunami peril in recent years. Various institutions

[e.g. TDMRC (Tsunami and Disaster Mitigation Research

Centre, Banda Aceh)] have been specifically set up to

study and explore potential ways to mitigate the risk

from tsunamis. It is now generally known that tsunamis

are not as rare as they were formerly perceived to be.

The insurance industry can play a vital role in rebuilding

after such catastrophic events. The insured losses were

relatively small when compared to the large economic

losses during the 2004 Indian Ocean tsunami and

rebuilding has largely depended on external funding

and aid; however, as the insurance penetration rates

continue to grow in the region, one could expect more

resilience against economic disruptions arising from such

events which would alleviate the loss burden. In this

milieu, the insurance industry, via better risk assessment

approaches, development of suitable products and risk

transfer mechanisms can support loss mitigation and

economic recovery following such natural disasters.

Aon Benfield 43

Year Magnitude Country Name Latitude Longitude Runup Height

1908 7.5 INDONESIA SW. SUMATRA -2 100 1.4

1917 6.6 INDONESIA BALI SEA -7 116 2

1921 7.5 INDONESIA JAVA -11 111 0.1

1930 6 INDONESIA SOUTH OF JAVA -5.6 105.3 1.5

1930 6.5 INDONESIA SOUTH OF JAVA -9.3 114.3 0.1

1931 7.4 INDONESIA SW. SUMATRA -5 102.7 1

1941 7.6 INDIA ANDAMAN SEA, E. COAST INDIA 12.5 92.5 1.5

1945 8 PAKISTAN MAKRAN COAST 24.5 63 17


1977 8 INDONESIA SUNDA ISLANDS -11.1 118.4 15

1982 5.4 INDONESIA JAVA TRENCH 4.3 97.7 0.1

1982 6.6 INDONESIA SUMBAWA ISLAND -9.2 118.4 0.1

1983 7.7 UK TERRITORY CHAGOS ARCHIPELAGO REGION -6.8 72.1 1.5

1985 6.2 INDONESIA BALI ISLAND -9.2 114.1 2

1987 6.6 INDONESIA TIMOR SEA -8.2 124.1 0.1

1992 7.8 INDONESIA FLORES SEA -8.4 121.8 26.2



1994 6.1 INDONESIA SOUTH OF JAVA -10.3 113.3 3

1995 6.9 INDONESIA TIMOR SEA -8.4 125 4

2000 7.9 AUSTRALIA SOUTH INDIAN OCEAN -13.8 97.4 0.3

2004 9.1 INDONESIA OFF W. COAST OF SUMATRA 3.3 95.8 50.9

2005 8.7 INDONESIA INDONESIA 2 97.1 4.2

2005 6.7 INDONESIA KEPULAUAN MENTAWAI -1.6 99.6 0.4


2007 8.4 INDONESIA SUMATRA -4.4 101.3 5

2008 6.5 INDONESIA SUMATRA -2.4 99.9 0.12

2009 7.5 INDIA ANDAMAN ISLANDS 14.1 92.8 0.01



2010 7.8 INDONESIA SUMATRA 2.3 97.1 0.44

2010 7.5 INDIA LITTLE NICOBAR ISLAND 7.8 91.9 0.03


(Source: NOAA)

Appendix 1. Indian Ocean tsunami observations between 1900 and 2014


Appendix 2. Useful Internet Links

Web Link Information on Tsunamis and 2004 Indian Ocean Tsunami

http://www.pmel.noaa.gov/tsunami/sumatra20041226.html

US NOAA web site containing extensive links to reports and studies on 2004 Indian Ocean tsunami

http://www.drs.dpri.kyoto-u.ac.jp/sumatra/index-e.html

Extensive links to reports and studies of 2004 Indian Ocean tsunami and general information on tsunamis

http://www.tsunami2004.net/tsunami-2004-facts/

Website contains information about 2004 Indian Ocean tsunami

Tsunami Databases

http://www.ngdc.noaa.gov/hazard/tsu_db.shtml

World-wide historical database of tsunami events maintained by the national Geophysical

Data centre of NOAA, the US government meteorological organization.

http://tsun.sscc.ru/On_line_Cat.htm

Historical tsunami database compiled by Institute of Computational and Mathematical Geophysics,

Novosibirsh, Russia. Includes 1490 Pacific Ocean events dating from 47BC, 260 Atlantic Ocean events dating

from 60BC, and 548 Mediterranean Sea events dating from 1628BC – but no Indian Ocean events.

Tsunami Warning Centers

http://www.bom.gov.au/tsunami/about/jatwc.shtml

The Joint Australian Tsunami Warning Centre (JATWC) is operated by the Bureau

of Meteorology (Bureau) and Geoscience Australia (GA).

http://www.tsunami.incois.gov.in/ITEWS/HomePage.do

Indian National Centre for Ocean Information Sciences (INCOIS) based in Hyderabad, India

https://inatews.bmkg.go.id/new/

Indonesia Tsunami Early Warning System, Jakarta, Indonesia

Others – General

http://www.nerc-bas.ac.uk/tsunami-risks/

Information on tsunami occurrences and risk

http://walrus.wr.usgs.gov/tsunami/

US Geological Survey tsunami site.

http://www.tsunami.noaa.gov/

US NOAA tsunami site. Extensive information on nature of tsunamis, studies of different tsunamis, and emergency response.

http://itic.ioc-unesco.org/index.php

Web site of the International Tsunami Information Centre (ITIC) established by the International Oceanic Commission (IOC)

http://nctr.pmel.noaa.gov/model.html

Information on tsunami modeling and research from NOAA Center for Tsunami Research

http://www.ioc-tsunami.org/index.php?option=com_content&view=article&id=8&Itemid=13&lang=en

Link to Indian Ocean page of Intergovernmental Oceanographic Commission (IOC)

http://ioc.unesco.org/itsu/

Aon Benfield 45

Web site of the International Co-ordination Group for the Tsunami Warning System in the Pacific

http://iotic.ioc-unesco.org/

Indian Ocean Tsunami Information Centre located in UNESCO office at Jakarta, Indonesia;

established by The Intergovernmental Oceanographic Commission (IOC) of UNESCO

http://www.itc.nl/library/tsunami.asp

Website of ITC, Netherlands to publications and websites containing information on tsunamis

http://www.earthobservatory.sg/

Earth Observatory of Singapore; an institution with research focus on the geohazards in and around Southeast Asia

Others – Indian Ocean Tsunami

http://walrus.wr.usgs.gov/tsunami/indianocean.html

US Geological Survey studies and reports on 2004 Indian Ocean Tsunami

http://en.wikipedia.org/wiki/2004_Indian_Ocean_earthquake

Wikipedia encyclopedia report.


Appendix 3. Availability of tsunami insurance cover in Asia Pacific region

Country Domestic property policies

Not Covered

Standard Cover

Earthquake Extension

Flood Extension

Comments

Bangladesh X Policy excludes loss caused as a

direct result of earthquake.

China X Tsunami is a standard exclusion in all

domestic policies but it can be covered

by Tsunami Extension with sub-limit

around 80% of sum insured.

India X Earthquake Extension covers Tsunami losses.

Indonesia X Not covered under Indonesian Fire

standard policy. Will be covered

under the EQ Pool scheme.

Korea X Exclusion under local standard policies.

Malaysia X Earthquake Extension covers Tsunami losses;

extension requires additional premium.

Maldives X Earthquake Extension covers Tsunami losses.

Philippines X By specific exclusion, but cover

may be re-purchased.

Sri Lanka X Earthquake Extension covers Tsunami losses.

Taiwan X Definition of Flood is including surge and

therefore presumed to be covered.

Thailand X Earthquake Extension covers Tsunami losses.

Vietnam X X Extension possible using the Flood and

Earthquake extensions. Earthquake

extensions are rarely used.

Japan X Earthquake Extension covers Tsunami losses.

Australia X Provides explicit coverage for:

Earthquake, Tsunami that happens as

a result of an earthquake, Landslide or

subsidence that happens immediately

as a result of an earthquake.

New Zealand X Covered by combination of national

government earthquake insurance

scheme (EQC) and private sector

While an attempt has been made to provide a general overview of tsunami insurance coverage in different territories

via the following tables, there might a few exceptions (or deviations from) to the information outlined below.

Aon Benfield 47

Country Small & medium commercial & industrial property

Not Covered

Standard Cover


Flood Extension

Comments

Bangladesh X Not covered but Earthquake Extension has

recently been extended to cover tsunami,

landslip, volcanic eruption etc. and can be

purchased for an additional premium.





India X1 X2 1. Standard cover under an all risk policy.

2. Earthquake Extension covers tsunami

losses in a Fire & Allied Perils policy.

Indonesia X Will be covered under the EQ Pool scheme.

Korea X Standard Cover under an All Risk

policy (Korean Package Policy).

Malaysia X Earthquake Extension covers tsunami losses.

Maldives X Earthquake Extension covers tsunami losses.



Sri Lanka X1 X2 1. Standard cover under an All Risk policy.



Taiwan X Definition of flood is including surge and

therefore presumed to be covered.

Thailand X1 X2 1. Standard cover under an All Risk policy.



Vietnam X1 X2 X2 1. Standard cover under an All Risk

policy. 2. Extension possible using

the flood and earthquake extensions.

Earthquake extensions are rarely used.

Japan X Tsunami is covered by flood extension.

Australia X Tsunami coverage is provided

alongside the EQ peril

New Zealand X Tsunami coverage is provided

alongside the EQ peril


Country Large commercial & industrial property (including ISR)

Not Covered

Standard Cover


Flood Extension

Comments

Bangladesh X Not covered but Earthquake Extension has

recently been extended to cover tsunami,

landslip, volcanic eruption etc. and can be

purchased for an additional premium.





India X1 X2 1. Standard cover under an All Risk policy.



Indonesia X Will be covered under the EQ Pool scheme.

Korea X Standard cover under an All Risk

policy (Korean Package Policy).

Malaysia X Earthquake Extension covers tsunami losses.

Maldives X Earthquake Extension covers tsunami losses.



Sri Lanka X1 X2 1. Standard cover under an All Risk policy.



Taiwan X Covered under All Risk policy.

Thailand X1 X2 1. Standard cover under an All Risk policy.



Vietnam X1 X2 X2 1. Standard cover under an All Risk

policy. 2. Extension possible using

the flood and earthquake extensions.

Earthquake extensions are rarely used.

Japan X Tsunami is covered by flood extension.

Australia X ISR

New Zealand X

Aon Benfield 49

Country Motor

Not Covered

Standard Cover


Flood Extension

Comments

Bangladesh X Policy does not exclude tsunami.

Presumed to be covered.

China X Policy does not exclude tsunami.


India X

Indonesia X Tsunami and earthquake are covered

under Act of God extension.

Korea X

Malaysia X X Both earthquake and flood extensions

cover tsunami losses; extension

requires additional premium.

Maldives X



Sri Lanka X

Taiwan X X Earthquake and flood extension are

included under the same extension.

Thailand X

Vietnam X

Japan X Some policies cover tsunami as indemnity

and some cover it as expense.

Australia X

New Zealand X


Country Workers’ Compensation

Not Covered

Standard Cover


Flood Extension

Comments





India X

Indonesia X

Korea X It appears to be absolute exclusion

under local standard policies.

Malaysia X Policy does not exclude tsunami.


Maldives X

Philippines X

Sri Lanka X

Taiwan X Policy does not exclude tsunami.


Thailand X Policy does not exclude tsunami.


Vietnam X

Japan X Presumed to be covered.

Australia X

New Zealand X

Aon Benfield 51

Country Medical (Accidental injury or death)

Not Covered

Standard Cover


Flood Extension

Comments





India X

Indonesia X Policy does not exclude tsunami.


Korea X

Malaysia X Policy does not exclude tsunami.


Maldives X

Philippines X

Sri Lanka X

Taiwan X

Thailand X Policy does not exclude tsunami.


Vietnam X

Japan X Medical policies do not cover but “natural

perils extension” covers tsunami.

Australia X

New Zealand X


Appendix 4. Remnants and Reminders of 2004 Indian Ocean tsunami

Figure 50: Recent (Oct 2014) views of Lampuk (left) and Lhoknga (right) beaches, Indonesia which were affected during the event.

Figure 49: Top: ‘Aceh Thanks to the World’ monument at Blang Padang in Banda Aceh; it is a symbol of gratitude to the support extended after the disaster. Down: Tsunami museum at Banda Aceh (left picture); the museum houses many photos and videos related to the event including the names of the victims (picture on the right).



Aon Benfield 53

Figure 51: Snapshots of the disaster: - PLTD Apung 1, an electrical generator ship weighing 2600 tons was moved 2 to 3 km inland during the event (left) and a wrecked helicopter from the catastrophe (right).

Figure 52: Left: - Battered Mercedes, beachfront road, Patong, Thailand. Right: - Flood damage to an electricity generating unit in a substation on Maafushi Island, Maldives. Both connections and wiring were damaged due to inadequate insulation.


Source: Dr. Dale Dominey-HowesSource: Aon Benfield



Figure 53: One of the tsunami sirens installed at Banda Aceh, Indonesia.

Aon Benfield 55

References

[1] Asian Disaster Prepared Center, http://cmsdata.iucn.org/downloads/social_and_

economic_impact_of_december_2004_tsunami_apdc.pdf

[2] Department of Ocean Development (2005) Preliminary Assessment of Impact of Tsunami in

Selected Coastal Areas of India compiled by Department of Ocean Development, Integrated

Coastal and Marine Area Management, Project Directorate, Chennai, India.

[3] Geocities, www.geocities.com

[4] Haque C. E., Nirupama N., Murty T. S., (2006) Nature itself does not cause a

disaster, In Natural Hazards & Disaster Mitigation pp 79:103

[5] Harjadi P.J.P., Fauzi (2009): Development of Indonesia Tsunami Early Warning System

(InaTEWS) toward Regional Tsunami Watch Provider (RTWP). - In: (Ed.), -DEWS-Midterm-

Conference 2009, DEWS Midterm Conference 2009 (Potsdam 2009), p. 10-10.

[6] Harjadi P.J.P., Fuazi, (2010) InaTEWS Concept and Implementation, from Agency

for Meteorology Climatology and Geophysics, Jakarta, Indonesia

[7] Mapsoftworld, www.mapsoftworld.com

[8] National Geophysical Data Center, http://www.ngdc.noaa.gov/hazard/tsu.shtml

[9] National Science Foundation, http://www.nsf.gov/news/news_summ.jsp?cntn_id=104179

[10] Nayak S., Kumar S.T. (2008) Addressing the Risk of Tsunami in the Indian Ocean, J South Asia Disaster Stud. 1(1): 45-57

[11] Nayak S., and Kumar S.T. (2008) Indian Tsunami Warning System, In: International Archives of Photogrammetry,

Remote Sensing and Spatial Information Sciences. Part B4, Beijing, XXXVII. pp 1501-1506

[12] Rara V., Arango C., Puncochar P., Trendafiloski G., Ewing Ch., Vatvani D., Chandler A. (2014) A Probabilistic

model for Chile, 11th International Conference on Hydroinformatics, New York City, USA, August 2014

[13] U.S. Geological Survey, http://www.usgs.gov/


Acknowledgements

We would like to thank Mr. Nicolas Arcos (NOAA), Prof Russell Blong, Dr. Patrick Daley, Dr. Dale Dominey-

Howes, Mr. Shubharoop Ghosh, Mr. Ibnu Mundzir, Prof Tad Murty, Prof Ioan Nistor, Dr Mochammed Riyadi

(InaTEWS), Dr. T. Srinivas Kumar (INCOIS), Ms. M V Sunanda (INCOIS), Dr. George Walker, Dr. Poh Poh Wong

and the staff members at the following organizations: INCOIS, InaTEWS and TDMRC (Tsunami and Disaster

Mitigation Research Centre, Banda Aceh) for their support during the various stages of publication.

ContactsAdityam KrovvidiHead of Impact Forecasting Asia Pacific Singapore +65 6239 7651 [email protected]

Sastry DharaDirector, Impact Forecasting Singapore +65 6645 0137 [email protected]

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