Isleton, California - A town that was built under the level of the Sacramento River got a wake-up call from Mother Nature Wednesday morning when a moderate, but highly noticeable earthquake struck right after stores opened.
People from Sacramento County to San Francisco received an earthquake alert on their phones around 9:30 a.m. Wednesday.
Residents of Isleton, a small town with 800 residents about 60 miles northeast of Oakland, were struck hardest. Reports for Isleton, which sits below a levee on the Sacramento River, originally identified the quake as a magnitude 5.7, but it was quickly revised down to a 4.1, according to the United States Geological Survey.
FILE - Old Seismograph that once recorded earthquake activity. Now replaced by computer applications.
Myriam Carbagal was tending DeJack's General Store when the quake hit. Video of the incident shows racks of liquor and wine bottles shaking.
"The whole shelves go like side to side and behind me there were some bottles that I just kind of heard them falling. We didn't know what was going on," Carbagal said.
Another resident was unconcerned.
"This one didn't seem strong to me at all," said Julianne Rile, who experienced the both big Napa and Tahoe quakes. She spoke of today’s quake saying. "It was more rolling, that's what I felt. Other people might say something different."
But others in Isleton were concerned.
Taqueria Mi Rancho staff ducked under tables.
"[It lasted] around 10 seconds and the building was shaking, and we saw a couple of things fall, some dishes, some knives," said Taqueria Mi Rancho employee Oswaldo Segoviano.
Chuch Bergson, Isleton City Manager, was also a little concerned.
"It was only three seconds, we rode it out. We were a little nervous afterwards," he said. "Then we started getting all those texts from USGS. They said take cover. It was about a minute after the fact."
KTVU asked the USGS scientist who helped develop the Shake Alert App why some folks got a delayed warning.
"Everything from the type of cell phone to the settings on the cell phone to the cell phone provider, there are these technological subtleties," said USGS Seismic scientist Robert DeGroot.
His best advice: Put every earthquake alert available on your devices to assure alerts get to you as soon as possible.
"Get everything you can, it's better than getting no alerts," Degroot added.
Perhaps the most important question for Isleton was how did the levees perform?
That's an important because the levees protect land, farms, people and homes. And the water in the river is often much higher than the land they're protecting.
A recent state evaluation of levees surrounding Isleton show the crucial riverside ones to be strong, but some of the levees behind the town need rehabilitation work.
Throughout the Sacramento-San Joaquin Delta, there are just over 1,100 miles of levees that need constant surveillance, maintenance and repairs, records show.