USGS ShakeAlert

ShakeAlert EEW System public safety information, news, and updates. ShakeAlert: for a Hazard Ready Nation (HRN). Posts & "likes" are not endorsements.

[USGS ShakeAlert @USGS_ShakeAlert]

We hope everyone is safe! Did you know that anyone in CA, OR, & WA can have the power of ShakeAlert Earthquake Early Warning in the palm of their hand? Remember to Drop, Cover, and Hold On if you feel shaking or get an alert.

Learn more how to be ShakeAlert Ready here: https://t.co/J6xW2Qmt1k

@FEMARegion10 @UOHazardsLab @OregonOEM @PNSN1

📷Anyone can have the power of ShakeAlert Earthquake Early Warning in the palm of their hands.

[USGS ShakeAlert @USGS_ShakeAlert]

Good evening northeast Oregon! Did you feel the M 4.3 earthquake about 12 miles southeast of Joseph at 11:42 pm? The ShakeAlert Earthquake Early Warning system was activated.

Learn more about the quake here: https://t.co/Y3Uhne28wV

@OregonOEM @UOHazardsLab @PNSN1 @FEMARegion10 @USGS_Quakes

📷ShakeMap from this earthquake.

[USGS ShakeAlert @USGS_ShakeAlert]

The ShakeAlert system estimated this quake at less than magnitude 4.5. Alerts were *not* delivered to cell phones or other devices by our Alert Delivery Partners in Oregon through cell phone operating systems and mobile apps.

@USGS_Quakes

📷ShakeAlert EEW alerts are delivered to cell phones for earthquakes estimated by the USGS at magnitude 4.5 or larger.

[PNSN @PNSN1]

@USGS_ShakeAlert LEBA now has a new sensor, new vault, upgraded power system with backup batteries, and dual telemetry (Starlink and cell modem) to ensure real-time seismic data can be relayed back to PNSN, even during a power outage and/or loss of local cell signal.

[PNSN @PNSN1]

Happy #FieldworkFriday! LEBA underwent a full rebuild recently. This WA station, ~25 miles from the coast near Willapa Bay, plays an important role in coastal monitoring and contributing to @USGS_ShakeAlert earthquake early warning in the event of a Cascadia Subduction Zone EQ.

[USGS ShakeAlert @USGS_ShakeAlert]

Thanks to our session presenters Katrina, Dare and Puja!

@BerkeleySeismo @PNSN1 @UOHazardsLab @OregonOEM @Cal_OES @ListosCA @cascience @CAGeoSurvey @PPSConnect

📷ShakeAlert parters from Berkeley Seismology Lab, University of Oregon, and Portland, OR Public Schools present a ShakeAlert workshop.

[USGS ShakeAlert @USGS_ShakeAlert]

Workshop starting soon in Safe Credit Union Convention Center Room B3 in Sacramento, CA

Waves Move You: Middle School Seismology with ShakeAlert!

https://t.co/DeE0CP38iU

📷Check out ShakeAlert sessions at the California Science Education Conference

[Caltech Seismo Lab @CaltechSeismo]

#FieldPhotoFriday Even after it has passed, the summer heat can still take its toll on our equipment! One of the SCSN stations near Agua Caliente recently needed a new battery to replace one that was less than 2 years old. Surface temperatures over 150° F have been logged at this site! That kind of heat for months on end is brutal on tech. Great work as always keeping the seismic network running! #ShakeAlert #CalOES

[USGS ShakeAlert @USGS_ShakeAlert]

Check out all of the great resources from ShakeAlert Partner - the California Geological Survey - in booth 520.

@CAGeoSurvey @CalConservation @Cal_OES @ListosCA @FEMARegion9

Learn more about CGS Resources: https://t.co/qT2420IbuT

📷CGS team members share teaching resources that feature the wonders of California geology.

[USGS ShakeAlert @USGS_ShakeAlert]

Attending the 2026 California Science Education Conference in Sacramento? Did you know you’re in earthquake country? Learn how anyone can receive ShakeAlert earthquake early warning alerts on a cell phone in CA, OR, and WA:

https://t.co/Vc9QgS9l1N

Thank you to all of our science educators for your hard work and dedication!

Visit the ShakeAlert team in Booth T1.

@Cal_OES @cascience @FEMARegion9 @BerkeleySeismo @ListosCA @CAGeoSurvey @NSTA @CaltechSeismo @UOHazardsLab @PNSN1

📷Learn how you can be powered by ShakeAlert earthquake early warning.

[USGS ShakeAlert @USGS_ShakeAlert]

Welcome to the 2026 California Science Education Conference! Come by and visit ShakeAlert and EarthScope at Booth T1 in the exhibition hall.

Free educational resources: https://t.co/UbrV7himCi

📷Booth T1 - Learn more about ShakeAlert and EarthScope.

@cascience @PNSN1 @RocketRules1 @Cal_OES

[USGS ShakeAlert @USGS_ShakeAlert]

Thanks for your comment Rose. The USGS reports the measurements coming from the field as they come from the field. As the earthquake happens, more and more seismic stations (in all directions) see the quake and more measurements are made resulting in updated magnitudes. It's much like seeing an image in low resolution which can be very fuzzy but as pixels are added the image can sharpen providing greater detail.

[USGS ShakeAlert @USGS_ShakeAlert]

Good morning Southern California! Did you feel the magnitude 4.7 earthquake about 4 miles north of Delta, Baja California Mexico at 10:27 am? The ShakeAlert Earthquake Early Warning system was activated.

See: https://t.co/PRYYDZ1c6L

@ImperialCntyCA @SanDiegoCounty @Cal_OES @CAGeoSurvey @ListoSanDiego @ListosCA @FEMARegion9 @USGS_Quakes @CaltechSeismo

📷ShakeMap from this earthquake.

[USGS ShakeAlert @USGS_ShakeAlert]

Here is a description of the different shaking intensities on the Modified Mercalli Intensity (MMI) scale.

[USGS ShakeAlert @USGS_ShakeAlert]

The ShakeAlert system estimated that intensity (MMI) 3 [weak] shaking and greater reached California resulting in alert delivery to phones. See how the as MMI 3 (shown as MMI 2.5) polygon crossed the US/Mexico border?

Learn more here: https://t.co/qwNmavTNdW

📷The ShakeAlert EEW system estimates shaking from an earthquake in a matter of seconds after it begins. The estimated shaking levels are shown as polygons in the image below.

[USGS ShakeAlert @USGS_ShakeAlert]

Question: If the #ShakeAlert Earthquake Early System operates in CA,OR, & WA why could alerts be delivered to phones in CA by an earthquake in Mexico?

@Cal_OES @FEMARegion9 @CAGeoSurvey @ListoSanDiego @ListosCA

[USGS ShakeAlert @USGS_ShakeAlert]

We know that feeling the ground shake can be unsettling. Are you ShakeAlert Ready?

Learn how to receive #EEW alerts on your phone: https://t.co/J6xW2Qmt1k

@ImperialCntyCA @SanDiegoCounty @Cal_OES @CAStateParks

📷If you feel shaking or get an alert: Drop, Cover, and Hold On!

[USGS ShakeAlert @USGS_ShakeAlert]

Since the ShakeAlert system estimated this quake at magnitude 5.0 or greater alerts were delivered to cell phones or other devices by our Alert Delivery Partners in California through cell phone operating systems, mobile apps, and the Wireless Emergency Alert system (WEA) Did you receive an alert? Please share a screenshot if you like. Thanks!

📷Table showing the levels at which ShakeAlert-powered alerts are delivered.