Thread by @USGS_ShakeAlert

Why “Drop, Cover, and Hold On” when you get a #ShakeAlert-powered alert📱? How do we know this is the best action to take? Check out this social science research! library.seg.org/doi/10.1190/ge…. Let’s dive in 🧵. @Cal_OES @ShakeOut @waEMD @OregonOEM @CAGeoSurvey @RocketRules1 @ECA

For a successful #EEW system to reduce injuries, 3 things should be considered: 1) the people who are alerted and the building types they occupy, 2) demographic variables such as gender, age, as well as quake experience & 3) types of quakes and performance of the EEW system.

The #ShakeAlert team analyzed earthquake injuries and deaths, focusing on quakes from the 1970s to now. Several studies from CA (Loma Prieta & Northridge) and WA (Nisqually) showed that people who move during shaking are twice as likely to be injured than those who don’t. @fema

So what does that mean? To reduce injuries, you’ve got to stop moving and get into a safer position, like under a table or chair, to ride out the heavy shaking. Otherwise, it would be a lot more difficult to protect yourself during heavy shaking.

We also know what kind of quakes we can expect on the West Coast. For these quakes only a few seconds of warning from #ShakeAlert is possible. Even for a Cascadia subduction zone quake only about a minute warning might be possible. More here: .

#EEW systems are popping up and each nation decides what to do for their EEW system. For example, although evacuation works for México City, they tend to have longer warning times. #ShakeAlert probably won’t provide time to evacuate without risking injury. @waDNR

Researchers also consider the region’s social and cultural environment. West Coasters in the U.S. are generally familiar with the annual @ShakeOut drill and Drop, Cover, and Hold On. The best actions are the ones you know to do already and practice makes survival happen.

See this video from the M7.1 Anchorage quake in 2018. This kind of action is possible because students practiced what to do. #ShakeAlert ultimately helps you do what you are already doing (Drop, Cover, and Hold On), just…faster and before shaking starts.

Protective actions for earthquakes vary country to country. We did this research so more information is available to determine the best protective action advice. Thanks to the #ShakeAlert team from @USGS_Quakes @IRIS_EPO @uoregon @UWEvanschool @HazCenter @NZJCDR @csuf