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A shaky Friday evening in Southern California. Hope everyone is safe. Did you feel the M4.6 #earthquake about 2 miles west of El Monte just before 11:39 pm PT? The #ShakeAlert system issued a message and passed it along to our delivery partners. More info: earthquake.usgs.gov/earthquakes/ev… 
Let us know if you got an alert and share screen shots if you want. At this magnitude apps that are Powered by #ShakeAlert can deliver alerts to people who could feel MMI III (weak shaking) or greater. Check out how big the MMI III+ region is on this map. @Cal_OES
Check out the #ShakeAlert post-alert summary at: earthquake.usgs.gov/earthquakes/ev…. The first ShakeAlert Message was issued by @USGS 4.5s after the quake started. The quake was about 11 miles deep and it took about 3s for the first waves to reach the surface where they could be detected.
Hi everyone! It’s #ResearchFriday! #ShakeAlert is constantly looking for ways to improve the System. One way we learn is to ask “What if?” questions. Today let’s ask: What if the ShakeAlert System had been operating with 2020’s technology during the 1994 Northridge earthquake?
At 4:30 am on 1/17/94 a M6.7 earthquake occurred near Northridge, CA. The shaking it generated caused damage throughout Los Angeles County, including the San Fernando Valley. There were 57 deaths, over 9000 injuries, and billions of dollars in property damage.
Our goal in studying this is to have a better idea how #ShakeAlert could perform for a moderate earthquake impacting a major urban area.
We want to update you on yesterday’s M5.8 earthquake 11mi SSE of Lone Pine, CA. The #ShakeAlert-powered Apps and @fema WEA delivered alerts to thousands of people in Southern California. #QuakeAlertUSA @MyShakeApp @Cal_OES @EarlyWarningLab
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Since October of 2019 the Wireless Emergency Alert (WEA) system and Apps have been undergoing the testing of public alerting in California. One advantage of WEA is that it can broadcast a single message to many people without overwhelming the cellular system. (2/6)
#ShakeAlert works very quickly and the first estimate of the earthquake’s size was M5.0, big enough to alert people by WEA and Apps. As the earthquake grew in size #ShakeAlert issued updates to a growing area. (3/6) earthquake.usgs.gov/earthquakes/ev…
Learn more about the ShakeAlert message issued for the M 4.9 earthquake - 10.5 mi ESE of Anza, CA at 6:53 pm PT. earthquake.usgs.gov/earthquakes/ev… @Cal_OES @CaltechSeismo @BerkeleySeismo
An @fema WEA Alert was distributed for this earthquake. Currently WEA alerts are only delivered for earthquakes M5 and greater and only to those who could feel light shaking (MMI 4) or greater. If this quake was only M 4.9 why was a WEA delivered?
Check out the ShakeAlert Post-Alert Summary at:earthquake.usgs.gov/earthquakes/ev… and look for the final ShakeAlert message.
Learn more about the M4.4 earthquake 13km WNW of Toms Place, CA at 10:36 am on 2/1. A #ShakeAlert was issued. See: earthquake.usgs.gov/earthquakes/ev…
Take a look at the #ShakeAlert Post-Alert Summary.
earthquake.usgs.gov/earthquakes/ev…
Would have Apps like #QuakeAlertUSA or @MyShakeApp delivered an alert to cell phones? Look at previous tweets for clues. @Cal_OES @BerkeleySeismo @EarlyWarningLab
earthquake.usgs.gov/earthquakes/ev…
Would have Apps like #QuakeAlertUSA or @MyShakeApp delivered an alert to cell phones? Look at previous tweets for clues. @Cal_OES @BerkeleySeismo @EarlyWarningLab
Learn more about the M 4.6 earthquake - 23km NNE of Barstow, CA at 6:03 pm Pacific time. The USGS issued a #ShakeAlert. earthquake.usgs.gov/earthquakes/ev….
For earthquakes M4.5+ Apps being tested in CA such as @MyShakeApp from @BerkeleySeismo and #QuakeAlertUSA from @EarlyWarningLab can distribute alerts to users in the MMI 3 (weak) shaking or greater.
More about the alert:
earthquake.usgs.gov/earthquakes/ev…
More about the alert:
earthquake.usgs.gov/earthquakes/ev…
@MyShakeApp @BerkeleySeismo @EarlyWarningLab The ShakeAlertLA App from @LACity is also being tested but only in Los Angeles County. Check out the map to see what the shaking intensities were like in @CountyofLA. Let us know if you have any questions.
