Why do US earthquake warnings sometimes go wrong?
Author: Huizhong Chen
The U.S. Geological Survey (USGS) issued a warning on March 4th about a 5.9 magnitude earthquake in Nevada, but later withdrew the warning, stating it was a false alarm.

Earlier that day, the USGS's Shake Alert system issued a warning that a 5.9 magnitude earthquake had occurred at 4:06 PM GMT on March 4th, 6 kilometers east of Dayton, Nevada.
The earthquake alarm immediately alarmed the public, but the USGS quickly realized it was a false alarm; no earthquake had occurred. The USGS withdrew the warning and announced an investigation into the cause of the false alarm, promising to release updates to the public.
A geophysicist at the USGS stated that this may be the first time the agency has issued a completely false earthquake warning.

