Global Assessment Report on Disaster Risk Reduction 2015
Making development sustainable: The future of disaster risk management

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Part I - Chapter 3
(Source: UNISDR with data from Global Risk Assessment.)
Figure 3.17 Top 15 countries: Tsunami AAL (excluding SIDS)
submarine landslide, which itself was triggered by an earthquake. In areas like eastern Indonesia (Lvholt et al., 2012 and 2014) and the Caribbean (Harbitz et al., 2012

Harbitz, C.B., S. Glimsdal, S. Bazin, N. Zamora, F. Løvholt, H. Bungum, H. Smebye, P. Gauer and O. Kjekstad. 2012,Tsunami hazard in the Caribbean: Regional exposure derived from credible worst case scenarios, Continental Shelf Research, Vol. 38, 15 April 2012: 1-23.. .
), tsunamis due to landslides and volcanic eruptions are more frequent and contribute to a significant portion of the risk in those regions.
In the open ocean, the speed of tsunami waves may exceed 970 km/h. Once tsunamis make landfall, wave heights may reach 30 metres above sea level or more. The speed and the distance that tsunami waves travel inland depends on the topography of the coastal area and land cover.21 The waves from the Tohoku tsunami of 2011 in Japan were as high as 10 metres and affected more than 400 km of coastline.22
Given that intense tsunamis completely destroy rather than damage physical assets in the proximity of the shore, tsunami risk is heavily influenced by exposure. This is reflected in the results
of the Global Risk Assessment, which show that tsunami risk is concentrated in a relatively small number of countries (Figure 3.17).
In terms of geographical regions, East Asia and the Pacific have the highest absolute tsunami AAL by far. Japan in particular has a far higher tsunami AAL than any other country.
As tsunami risk constitutes only a small portion of multi-hazard risk, it is not directly comparable to social expenditure or capital investment in either geographical regions or income groups.
However, the potential impact of tsunamis on the economy at the local, national, and even the global level cannot be ignored due to the cascading impacts that tsunamis can generate in countries where critical facilities such as nuclear power stations are located in coastal areas. This fact was highlighted by the Tohoku tsunami in 2011, which caused about US$130 billion in damage to buildings and total of US$210 billion in direct economic damage including infrastructure and the agriculture sector (GFDRR, 2012a

GFDRR (Global Facility for Disaster Reduction and Recovery). 2012a,The Great East Japan Earthquake: Learning From Megadisasters, Knowledge Notes. Executive Summary. The World Bank, Washington, D.C.. .
). There is a 10 per cent probability that a number of territories and countries will lose a significant proportion of their capital stock to tsunami risk over a 50-year period (PML500). This includes territories such as Macau and Hong Kong, where capital stock is heavily concentrated along the coastline, as well as larger countries such as the Philippines or New Zealand (Figure 3.18).
River floods
Floods affect more people worldwide than any other hazard. There are many different manifestations of flooding, including flash floods, coastal flooding, surface water and ponding floods. In this analysis, flood risk23 is calculated only considering river flooding, and the measure of intensity used is the depth of the water. For frequent small-scale floods, risks can be estimated statistically using historical data, but for major floods a probabilistic approach is required.
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