AIR updates Japan earthquake model using data from 2011 disaster

AIR Worldwide has updated its earthquake model for Japan to include information gained after the March, 2011 earthquake and tsunami, which killed more than 16,000 and caused about US$217 billion in economic losses and US$36 billion in insured losses.

Boston-based AIR Worldwide stated Monday in a press release that its updated Earthquake Model for Japan is available in its Touchstone, CLASIC/2 and CATRADER products.

On March 11, 2011, the magnitude 9.0 earthquake occurred near the northeast coast of Honshu, Japan, according to the United States Geological Survey.

As of January 2013 it was the catastrophe with the highest economic loss (at US$217 billion) since 1950, according to Aon Benfield’s Annual Global Climate and Catastrophe report released earlier this year.

AIR Worldwide’s new model for Japan uses claims data from the March 2011 Sendai tragedy, including personal accident, marine hull and cargo, as well as industrial facilities. AIR Worldwide, a unit of Verisk Analytics Inc.’s makes simulation software designed to predict the behaviour of catastrophes.

“Separate damage functions for all four earthquake perils (shake, tsunami, liquefaction, fire following) have been validated against a substantial amount of individual claims from the Tohoku event,” AIR Worldwide stated. “Most notably, these claims data revealed wood construction to be more vulnerable than previously considered. Because a vast majority of residential structures are wood, this insight has a significant impact on Japan’s risk profile.”

The disaster, which affected the Tohoku region, “yielded a vast amount of ground motion data, damage observations, and detailed claims data,” AIR Worldwide said. Its new model also includes the effects of liquefaction.

“Although eclipsed by the tsunami and shake damage, the liquefaction damage produced by the Tohoku event was severe,” AIR Worldwide stated. “Widespread areas of the Kanto Plain, especially around Tokyo Bay and along the Tone River, exhibited deformed streets, sidewalks, and train tracks as well as damage to underground pipes.

AIR’s new liquefaction module incorporates recent studies on the surface geology, geomorphology, and shear wave velocity of soils in regions prone to liquefaction and leverages recommendations from the Japan government and findings from the Christchurch, New Zealand, earthquake.”

AIR was referring to a magnitude 7.0 earthquake in September 2010 and numerous aftershocks that have hit New Zealand.

AIR Worldwide’s new model for Japan “reflects a more thorough understanding of subduction zone segmentation and the possibility of multisegment ruptures as well as a new formulation of plate geometry where the Pacific and Philippine plates interface beneath the Kanto Plain.”

USGS states the Sendai quake “resulted from thrust faulting on or near the subduction zone plate boundary between the Pacific and North America plates.” The Pacific plate, according to USGS, moves westward relative to the North America plate at a rate of 83 millimetres per year at the latitude of Sendai “and begins its westward descent beneath Japan at the Japan Trench.”