Image of ship washed ashore during the Japan earthquake and tsunami

The new wave: Swiss Re provides direct access to its Japan tsunami model via CatNet

First fully fledged tsunami model output available now via CatNet®.

The March 2011 Tohoku earthquake that struck northeastern Japan measured a magnitude of 9.0 and was followed by a devastating tsunami. Remarkably, the bulk of economic losses were caused by the effects of the tsunami rather than by the tremors. The tsunami affected a 2000-kilometre stretch of the Pacific Coast and reached more than 5 kilometres inland. It is estimated that almost 535 square kilometres of land were inundated with a wave that reached a height of up to more than 40 metres.

The Japan example serves as a reminder that tsunamis can be a crucial loss driver in an earthquake event. Despite the lingering memory of the colossal tsunami damage caused by the Sumatra earthquake in 2004, tsunami risk has so far been a largely underestimated peril in the insurance industry. For other natural hazards such as storms, floods, or earthquake shaking the insurance industry usually uses models that simulate huge numbers of probable catastrophe events, such as earthquakes. Even though tsunami models are widely used in scientific and engineering communities, they have until now never been integrated by the insurance industry in their earthquake models.

A screenshot of CatNet®, Swiss Re's online natural hazard information and mapping system

Our tsunami model: an industry first

In response to this obvious shortcoming in current catastrophe modelling, Swiss Re began refining its model to measure tsunami probability. In 2011, a team of Swiss Re experts was able to simulate tsunami wave formation in the open ocean and measure the resulting inundation once tsunami waves hit the coast. Offshore tsunami wave heights were calculated using different combinations of pre-computed model runs. Meanwhile, for onshore tsunami inundation, the energy saved between the offshore tsunami and the frictional energy lost during inundation was taken into account. Using this methodology, the impact of the 11 March event in Japan could be very closely replicated. Beyond that, the model can estimate the impact of potential future tsunamis affecting the Japanese coast.

Having the first fully fledged tsunami model in the insurance industry, Swiss Re has been able to rigorously assess insurance risk due to tsunami since January 2012. In an effort to contribute to the industry's understanding and assessment of tsunami risk, the Japan tsunami model output is now available via CatNet® as a high resolution hazard map.

Expanding our outlook

Swiss Re's natural catastrophe experts are currently working to extend the Swiss Re model globally to forecast tsunami risk in Chile, Peru, New Zealand, Indonesia, and other tsunami-prone areas around the Pacific- and Indian Oceans. These models will be available also as high resolution hazard maps.

Published 24 September 2012

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