Loading…

Airbridge map

Gateway Alternative gateway Forward strip Likely knocked out Other airfield Epicenter Damage center Shuttle leg (straight line) Shaking intensity, USGS ShakeMap (yellow VI to red X)

Forward strip capacity

metric tons per day, after usability and road share

Airfield usability

the curve, with this event's airfields on it

All airfields

Backtest results

real earthquakes, compared with what happened

Event	Model flags as likely knocked out	What happened to airports	Model gateway	Relief gateway used	Match

Method

Full method and sources

1. Airfield usability

USGS ShakeMap gives shaking intensity (MMI) on a grid, with values up to X. The intensity at each airport is mapped to a probability that it can take relief flights in the first three days. The curve is a judgment call, set by hand while looking at the international backtests.

2. Need

USGS PAGER counts people at each intensity. Where PAGER was not run, exposure is rebuilt from US Census files. People at MMI VIII and above are the priority. Water is excluded; it is rarely flown at scale.

3. Airbridge

Heavy jets fly into a gateway airport. C-130s shuttle cargo on to airfields inside the damage zone. Throughput follows Air Force Pamphlet 10-1403. Cargo landing within 50 km of the damage center counts in full; the share falls to zero at the forward radius.

Limitations

A planning model, not an operational tool. Capacity is a ceiling for an assumed number of parking spots, not a forecast. Every limit the model leaves out can only lower it; the spot counts are guesses and can be wrong in either direction.
Forward strips are picked on runway length and width. Pavement strength and ownership are not checked, so private and turf strips appear.
The usability curve is judgment, and the international backtests use the same earthquakes it was set on.
Straight-line distances. No liquefaction, tsunami, fuel, customs, handling, weather, airspace or roads.
The airport table and Census population are current, including for replays of older events.
ShakeMap is revised repeatedly, sometimes years later. The version used is shown above.

Data

Earthquakes, ShakeMap and PAGER: U.S. Geological Survey. Population: U.S. Census Bureau, vintage 2023 estimates and 2023 Gazetteer. Airports: OurAirports. Base map: © OpenStreetMap contributors. Not affiliated with or endorsed by any of them.