How alerts work
Earthquake notification vs earthquake early warning
The terms sound similar, but they describe systems with different timing, technology and purposes.
In one sentence: an early warning may tell you that shaking is approaching; a notification tells you about an earthquake that has already occurred and been reported.
What is an earthquake notification?
An earthquake notification is sent after a monitoring network has detected, located and published an earthquake. It usually includes an estimated magnitude, location, depth and origin time. These values can change as scientists analyze additional observations.
Notifications are useful when you want to monitor a region, check on family or property, follow significant global earthquakes, or learn what caused shaking you just felt. Delivery can be quick, but it is still post-event information.
What is earthquake early warning?
An earthquake early-warning system detects an earthquake after it begins and attempts to send a warning before the strongest shaking reaches locations farther from the epicenter. It is not a prediction: the earthquake is already underway.
The potential warning time depends on distance, detection speed and communications. People close to the epicenter may receive little or no warning. In the United States, the USGS-operated ShakeAlert system covers California, Oregon and Washington and distributes messages through partner systems.
Why the difference matters
A post-event notification should never be presented as a promise of advance warning. If an app reads a published earthquake catalog such as the standard USGS GeoJSON feed, its alerts normally happen after the earthquake has been detected and published. That can still be valuable—just for a different purpose.
Where SeismoWatch fits
SeismoWatch monitors the USGS global earthquake feed and sends matching events based on a chosen area and magnitude threshold. It is a near-real-time earthquake notification service, not an early-warning system. Alerts are sent after an event appears in the USGS feed.
For advance-warning coverage, use the official or supported emergency-warning options available in your location. Do not rely on SeismoWatch as an emergency or life-safety service.