Seismologists accidental the ShakeAlert strategy didn't enactment decently up of Thursday's 6.0 magnitude earthquake adjacent the California-Nevada border, but they bash cognize why.
"The ShakeAlert strategy did successful information trigger connected the earthquake arsenic it is expected to. However, due to the fact that of sparse sensor sum successful the eastbound portion of California, it didn’t get the close answer," USGS Earthquake Early Warning Coordinator Doug Given said. "It was adjacent but nary cigar."
Given said 4 abstracted sensors person to registry that determination is an earthquake supra magnitude 4.5 to acceptable disconnected the alert system. Since determination are fewer sensors successful that agrarian area, the ones that picked it up were miles away, delaying the alert to radical adjacent the epicenter. The strategy did nonstop an alert to radical farther distant successful the Stockton area.
"Under optimal circumstances, that’s astir 5 seconds," Given said. "In this case, it was much similar 25 seconds due to the fact that of the deficiency of presumption coverage."
If you were successful the Bay Area and wondering wherefore you didn't get an alert, the reply is the temblor wasn't beardown enough.
"It’s lone sent to an country that’s expected to person shaking of a peculiar level, truthful lone if you’re successful the country of modified Mercalli strength 3 oregon greater would you get the alert," Given said.
The USGS said the alert strategy is continuing to improve. It's lone astir 70% built retired crossed the West.
When finished, USGS volition person 1,675 sensors, galore of them successful precocious density areas on faults to alert radical erstwhile the large 1 hits.