Earthquakes are seismic events where the Earth’s surface is moving due to a sudden release of energy in the lithosphere. They are commonly recorded around geological faults but can also be triggered by human activities.

The most relevant dimension to quantify seismic exposure at the earth’s surface is the Peak Ground Acceleration (PGA). The PGA does not only take the magnitude of the earthquake into account, but really focusses on the effects on the surface that cause the actual damage. Regional differences in geological properties are therefore accounted for.

Fluvial (river) flooding occurs when the water level in a river or stream increases and overflows, causing a temporary inundation of a normally dry land.

As such, river flooding can occur a long way from the original rainfall – and can remain for several days in large catchments.

Fluvial flooding for future years is provided for the following IPCC 5 scenarios:
• RCP 2.6 – aka. ‘Low Emissions’ assumes that CO2 emissions start declining in 2020.
• RCP 4.5 – aka. ’Medium’ or ‘Low-Medium Emissions’ assumes that CO2 emissions start declining around 2040.
• RCP 8.5 aka. ‘High Emissions’ assumes that Co2 emissions continue to risk throughout this century.

Heavy precipitation can cause damage both directly - through water damage / leakages – and indirectly by triggering pluvial floods or local land slides. The Precipitation Stress Index only relates to the rain intensity. Secondary effects like fluvial floods and landslides are captured in separate peril scores.

For the Precipitation Stress Index, we consider the current climate (based on the period 2000 – 2020), and several IPCC climate scenarios.

Tsunamis are large sea waves or wave series caused by earthquakes, volcanic eruptions, or other undersea movements in the Earth’s outer layer or on the coast.

Our model focusses on the risk from Earthquake generated Tsunamis – using the authoritative ‘Global Tsunami Model’ (GTM) which provides a ‘science-based understanding of tsunami hazard and risk’.

Surge/Tidal floods are inundations affecting land areas along the coast and caused by storm surge events which force seawater ashore.

Storm surges typically occur during low-pressure weather events (storms) where high-speed winds drive the phenomena.

In our model we combine the effects of coastal and estuarine storm surges.

Tornadoes are very local, and very severe weather events, with extreme wind speeds and devastating effects. It is impossible to forecast exactly where they will occur and what path they will take, but instead the circumstances that are required for tornadoes to develop can be modelled.

While even ‘light’ tornadoes can have devastating effects, the focus of the index translation is on probability of occurrence rather than in depth relations between tornado intensity and expected damage.

Global warming is one of the most tangible effects of climate change and resulting heat stress is expected to affect areas home to over one billion people by 2100.

Human health, biodiversity loss and agricultural damage are very direct effects of increasing heat stress, but also economic damage (for example through higher cooling costs in residential properties and industrial processes) are expected.

Fluvial/Surge
Flood defences are the structures and systems fit to mitigate or, ideally, avert the detrimental consequences of flooding.

We provide our Fluvial and Tidal flood models as both ‘undefended’ and ‘defended’ (i.e., taking account of defences) formats.

Where no flood defences are present – the models give equal results.

Sea level rise is an increase of the ocean’s levels due to global warming. This has been found to contribute to more damaging storm surges, coastal erosion, and flooding.

In addition, long term sea-level rise may render certain locations uninhabitable without significant intervention shoreline management. Our model incorporates present day flood defences.