Verisk’s AIR Worldwide Enhances Extreme Event Models for Japan With Release of Updated Earthquake and Typhoon Models

BOSTON, July 27, 2021 (GLOBE NEWSWIRE) -- Catastrophe risk modeling firm AIR Worldwide has announced the release of significantly updated AIR Earthquake and Typhoon Models for Japan. The past several years has reaffirmed the vulnerability of Japan to typhoons and earthquakes and prompted updates to AIR's Industry Exposure Database, earthquake hazard and both earthquake and typhoon vulnerability including building, contents and business interruption damage. These updated models provide insurance and reinsurance companies with a comprehensive view of risk and account for insurance policy conditions specific to Japan. AIR Worldwide is a Verisk (Nasdaq:VRSK) business.

“Ten years ago the M9.0 megathrust Tohoku earthquake became the most widely instrumented earthquake in history, generating copious ground motion data, damage observations, and detailed insurance claims data,” said Dr. Kazuya Fujimura, vice president and managing director, Verisk. “The Tohoku earthquake not only informed the view of risk associated with megathrust earthquakes in Japan but also globally, e.g., the Hikurangi subduction zone in New Zealand and the Lesser Antilles subduction zone in the Caribbean, where, with limited historical data, the possibility of mega (M9.0 or larger) earthquakes cannot be ruled out.”

The AIR Earthquake Model for Japan is a fully stochastic model that captures the complex seismicity of Japan by generating events along known crustal faults, along and within subduction zones, and within different regions and zones with little to no historical earthquake activity through smoothed background seismicity.

Our updated Japan earthquake model is informed by the Headquarters for Earthquake Research Promotion (HERP’s) most recent seismicity model but with modifications to the time-dependent rupture possibilities (TDRP) estimates for earthquakes on the Nankai Trough and some crustal faults to better reflect uncertainties in the HERP 2019 TDRP model and parameters.

In the updated AIR Earthquake Model for Japan, numerically simulated tsunamis generated by all M>7.0 tsunamigenic earthquakes from our time-dependent, stochastic earthquake catalog were used to determine coastal inundation and flow velocities. The stochastic catalog reflects AIR’s view on time-dependent rupture probabilities for different sources, including tsunamigenic ones such as those along the Nankai Trough. Our model incorporates the latest data sets, including detailed three-dimensional subduction interface/fault geometries, high-resolution bathymetry/elevation data with coastal levees, dikes and sea walls, regional tidal solutions to account for the effect of astronomical tides, and land use/land cover (LULC) data to capture land friction characteristics that impact runup extent.

AIR’s updated Japan earthquake model also incorporates insights into ground motion prediction equations, including the weighting of two produced after the Tohoku earthquake and three produced before, to provide more accurate ground motion calculations for megathrust earthquakes, magnitude saturation, and new magnitude scaling. In addition, our insights into buildings’ seismic response gained from damage observations, detailed claims data, and changes to design and construction practice as it relates to tsunami risk inform our damage functions. With the updated seismicity and ground motion modules as well as the latest understanding of the vulnerability of the built environment, AIR’s model presents the most realistic view of the earthquake risk in Japan.

“While no model can predict when or if the next large tsunamigenic earthquake in Japan will occur, using the updated AIR Earthquake Model for Japan, can help prepare for tsunami losses by providing a detailed and accurate view of tsunami risk in Japan, said Dr. Bingming Shen-Tu, vice president of research, AIR Worldwide.”

“In 2018 and 2019, four powerful typhoons struck Japan, incurring total insured losses of approximately USD 30 billion from wind and flood damage,” said Dr. Boyko Dodov, vice president of research, AIR Worldwide. “As is the case after any major storm or severe storm season, we have been analyzing and reanalyzing a plethora of meteorological data, market exposure and company claims data sets from these and previous historical storms.”

The AIR Typhoon Model for Japan is part of the AIR Northwest Pacific Basinwide Typhoon Model. Japan’s location in the Pacific Northwest Basin combined with its unique topography puts it at risk from typhoon winds, precipitation, and storm surge. The model is a fully stochastic, event-based model that shares a catalog with other AIR-modeled countries in the region, including mainland China, Southeast Asia, and South Korea. The Japan typhoon model captures the effects of tropical storm and typhoon winds, precipitation-induced flooding, and storm surge on insured properties in Japan.

Wind intensity computations are based on a storm’s intensity, size, location, forward speed, and direction, as well as the underlying terrain and land use in the region. The effect of extratropical transitioning is also included to accurately assess the full impact on properties due to precipitation from a tropical cyclone. Flood intensity computations are based on total accumulated precipitation both on-plain and off-plain, soil type, land use/land cover data, and topography. The model includes separate damage functions for wind, precipitation-induced flood, and storm surge perils. Additionally, the model explicitly accounts for the regional variability in wind vulnerability due to differences in regional construction practices. The model also considers the effects of existing flood mitigation measures and lessons learned from the 2018 and 2019 typhoon season.

The AIR Earthquake and AIR Typhoon Models for Japan are available in the 2021 releases of Touchstone^® and Touchstone Re catastrophe risk management systems.

About AIR Worldwide
AIR Worldwide (AIR) provides risk modeling solutions that make individuals, businesses, and society more resilient to extreme events. In 1987, AIR Worldwide founded the catastrophe modeling industry and today models the risk from natural catastrophes, terrorism, pandemics, casualty catastrophes, and cyber incidents. Insurance, reinsurance, financial, corporate, and government clients rely on AIR’s advanced science, software, and consulting services for catastrophe risk management, insurance-linked securities, longevity modeling, site-specific engineering analyses, and agricultural risk management. AIR Worldwide, a Verisk (Nasdaq:VRSK) business, is headquartered in Boston, with additional offices in North America, Europe, and Asia. For more information, please visit www.air-worldwide.com.

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