A 4.1-magnitude earthquake occurred with its epicenter near Isleton, California, setting off a widespread alert across the Bay Area, startling many. The alert warned residents to grab their shoes, check for gas leaks, and evacuate, if necessary. For those in San Francisco, Hoodline has yet to speak with an individual who said they felt the tremor, though this sizable quake did put the efficacy of the ShakeAlert system to test. Closer to Bethel Island, Isleton, or Sacramento County, officials have yet to release any information about injuries or damage to the area.
Source: USGS
The earthquake.usgs.gov reports that ShakeAlert issued its initial earthquake warning within 5 seconds from the time it began, then continued to deliver regular updates about the earthquake's magnitude and exact location.
The ShakeAlert system was developed in 2019 in California to relay advance warnings to those situated in areas expected to be hit by an earthquake. Despite its initial challenges – long delays and budget constraints reported by SFist – the system has been expanded and proves to be a crucial tool in preventing major casualties following earthquakes in California.
In the latest case in Isleton, initial notifications from ShakeAlert wrongly estimated the magnitude as 5.7; however, the figure was first corrected to 4.5, then against corrected to 4.1.
Similarly, the original reported epicenter was 2 km (1 mi) north from the actual one, which was clarified in the following updates. The situations underscored ShakeAlert’s capability to provide timely and accurate alerts to the public affected by earthquakes.
The ShakeAlert system is designed to pick up the initial, weaker waves of an earthquake and instantly send alerts to residents' smartphones, allowing them a few moments to brace themselves before the stronger S- or surface waves make landfall. These alerts are transmitted through the MyShake app and can be pushed to smartphones without the app, as was the case today.
According to SFist, while ShakeAlert transmits notifications for any earthquake at or over 3.0 magnitude, Amber Alert-style text alerts are reserved for shocks of 4.0 magnitude or above. This is primarily because MyShake is configured to warn about quakes likely to be felt by people indoors.
