A shaky afternoon in Southern California. Hope everyone is safe. Did you feel the M4.9 #earthquake near Westmorland at 5:31 pm PT? The #ShakeAlert system issued a message and passed it along to our delivery partners. If you received a message, share a screenshot with us!
.#ShakeAlert powered #earthquake alerts were delivered by the @MyShakeApp and @fema Wireless Emergency Alert System - WEA. You can find this map at: prod-earthquake.cr.usgs.gov/earthquakes/ev… Check out the map - if you are inside the MMI 3 (weak) polygon you might have received an alert.
If you are inside the MMI 4 (light shaking) polygon you might have gotten more than one alert. That's good since we want you to get alerts through every pathway possible. The WEA the message reads: "Earthquake Detected! Drop, Cover, Hold On. Protect Yourself. -USGS ShakeAlert"
Question: WEA alerts are only distributed for M 5.0+ earthquakes. Why was a WEA distributed for a M 4.9? Hint: Check out the Summary Report at: prod-earthquake.cr.usgs.gov/earthquakes/ev…
The final #ShakeAlert Message estimated the earthquake size at M 5.2 which qualifies for a WEA! The ShakeAlert system has to work very quickly but it still provides great estimates about the magnitude and shaking expected. You too can learn to interpret Post-Alert Summaries!
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