Verisk Typhoon Model for South Korea

Enhancements to the Verisk Typhoon Model for South Korea

Scope

Comprehensive model update that includes an additional peril, new data, and new modeling processes.

General model updates

Peril(s)
  • Storm surge peril added
Model resolution

  • Updated flood hazard (precipitation flood and storm surge) resolution to 30 m

Hazard

  • Additional quantile mapping step around typhoon minimum central pressure over South Korea. This approach is used to better reflect the updated 1951-2021 historical storm intensities.

  • The distribution of maximum intensities of stochastic storms reflects historical intensities.

  • Precipitation is based on a stochastic model trained on dynamically downscaled reanalysis, conducted separately for non-typhoon and typhoon precipitation and merged into a precipitation product covering the model domain.

  • New precipitation flooding module integrates flooding from typhoons with flooding from other sources, ensuring representation of various spatio-temporal interactions in a scientifically sound manner. Flooding instances are included in a typhoon event based on the spatial and temporal extent of typhoons.

  • The hydrological model includes all rivers draining 10 km2 or more, using updated Digital Surface Model corrected for buildings and tree canopy to represent bare earth elevation.

  • The off-floodplain/pluvial model uses a 2D shallow water wave model.

  • Flood defense return periods are estimated based on levee database, population, land use, and exposure data.

  • Updated 1-minute surface wind (10-m height) leverages 30-m resolution elevation data from the Japan Aerospace Exploration Agency from 2021 and 10-m resolution Land Use Land Cover data from the European Space Agency from 2020.

  • Updated resolution of the physical properties from 1-km to 10-m grid

  • New state-of-the-art storm surge hazard that represents near-present climate conditions; the surge hazard module is based on shallow water wave equations on a flexible mesh and uses digital terrain, bathymetry, land cover, tide, and flood defenses.

Vulnerability
  • Damage functions take into consideration mitigation efforts such as first flood elevation, water barriers, pumps, and design-level considerations.

  • Updated height bands.

  • Low-rise, mid-rise, high-rise, and tall buildings have separate damage functions based on regionally-dependent performance after typhoons.
  • Regional vulnerability distributions are based on regional building codes.

  • New primary characteristic supported for wind: Year-built (in addition to occupancy, construction, and height).

  • The wind vulnerability module accounts for the evolution, adoption, and enforcement of building codes. Year band and design wind speed zones reflect the evolution of South Korean building codes.
Catalogs and event sets
  • Stochastic catalog(s)
    • Updated 10,000-year catalog
    • No change to event IDs
  • Historical event set
    • Five new events
      • 2010 Kompasu
      • 2012 Sanba
      • 2020 Maysak
      • 2020 Haishen
      • 2022 Hinnamnor

Touchstone-specific updates

  • Support for additional risk types
    • Auto
    • Infrastructure
    • Large industrial facilities
    • Marine
  • Support for additional construction and occupancy codes
    • Construction: Updated to 135 classes total (including marine asset classes)
    • Occupancy: Updated to 129 classes total (including large industrial facility and marine storage classes)
  • Support is now available for 12 secondary risk characteristics for flood and surge perils
    • Backwater valve protection
    • Base flood elevation
    • Basement finish type
    • Basement level count
    • Content vulnerability
    • Custom elevation
    • Custom flood standard of protection
    • First floor height
    • Floor of interest
    • Foundation type
    • Service equipment protection
    • Wet flood-proofing
  • Support for flood hazard maps/geospatial layers (20-, 50-, 100-, 200-, 250-, and 500-year return periods)
  • Support for Location-Level Event Intensities (LLEI) for all perils.

Touchstone Re-specific updates

  • Updated Industry Exposure Database
    • Vintage updated to 2024
    • Resolution updated to 1 km grid cells
    • Large industrial facilities and high-rise locations were manually located and valued.
    • Revised exposures for single family home masonry and concrete construction, commercial and apartment mid-rise quantity and quality
  • New support for Auto line of business.
  • Updates to the supported CRESTA zones
  • Legacy exposure and loss sets will be upgraded during Touchstone Re upgrade or import to match the supported geography scheme.