USGS PAGER Explained: Earthquake Loss Estimates Are Not Confirmed Counts
Understand PAGER earthquake alert colors, estimated losses and uncertainty. Use a reporting checklist to avoid presenting modeled impacts as confirmed casualties.
PAGER estimates potential impact after an earthquake
USGS PAGER is an automated impact-assessment system. It combines estimated shaking and population exposure with loss models informed by past earthquakes and regional building vulnerability. Its purpose differs from simply reporting magnitude: it helps responders and readers assess potential consequences. A loss estimate is a model output, not a count established by rescue teams.
Read both loss panels before quoting the summary color
The onePAGER summary includes separate fatality and economic-loss assessments. The higher alert level determines the summary color. Probability bars show uncertainty across loss ranges; a colored banner is not a precise toll. Look at which panel drives the summary before writing that an earthquake is expected to be deadly or economically damaging.
Why the estimate can change
Additional shaking information can change the estimated exposure and losses. The version and creation time therefore matter when comparing reports. A changed PAGER assessment for the same earthquake is not evidence of another earthquake. Save the event identifier with your notes so that later versions remain attached to the right event.
Do not turn exposure into casualties
The population-exposure table groups people by estimated shaking intensity. It is not a list of injured or deceased people. The USGS documentation also cautions that actual impacts can differ from the automated estimates and that not every uncertainty is captured. Keep estimated exposure, modeled losses and independently confirmed impacts in separate fields.
A newsroom exercise: preserve the uncertainty
Imagine a fictional report whose economic-loss alert is higher than its fatality alert. The sound summary identifies the economic assessment as the reason for the overall color. It does not select the upper end of a fatality range and present that number as deaths. The comparison below is our editorial reading aid, not a USGS product or a report about an actual earthquake.
What to collect before sharing a PAGER screenshot
Our checklist is: keep the original event link; record the product version and timestamp; name the panel you are describing; preserve the range and uncertainty; and leave confirmed impacts blank until a reliable report supplies them. Blank means unconfirmed, not zero. Link readers to the full product instead of circulating a cropped color label. For protective action, follow local officials and the relevant official warning service.
Put it into practice
| What you see | Useful wording | Avoid |
|---|---|---|
| Estimated loss range | “USGS models a range of potential losses.” | “This many people have died.” |
| Population exposed to shaking | “The model estimates exposure to this shaking level.” | “Everyone in the exposure table was injured.” |
| A revised product | “The assessment was updated; check its version.” | “The changed estimate proves a new quake occurred.” |
| No confirmed impact report | “Confirmed impacts are not available in the sources checked.” | “There was no damage.” |
Official sources
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For an active emergency, follow the issuing agency and local authorities. Read our editorial policy.