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The Blind Zone of Earthquake Early Warning

June 1, 2020

One USGS scientist has sorted through the challenges, the claims, and the data to determine what the possibilities and limitations really are for EEW, and the results may surprise you.

Read the new Science for Everyone article: The Blind Zone of Earthquake Early Warning


map of Los Angeles area with different gradational colors
The 1994 M6.7 Northridge, CA Shakemap showing MMI (Modified Mercalli Intensity) levels of shaking, with the earthquake epicenter shown as a red star, and the fault shown as a rectangle. The innermost dotted circle doesn’t include the communication or reaction time latency (area labeled BZ); the next dash-dotted circle includes the 2-second communication latency (area labeled CZ), and the next dashed circle also includes the 5-second reaction time (labeled RZ). Most residents in the area of the strongest shaking (red area) did not receive any warning. The outermost blue dash-dotted circle shows the location of the P wave at the warning time, suggesting that most residents of the strongly shaken area would have been alerted by the P-wave itself before they received a warning from the EEW system. (Public domain.)

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