For years, "the big one" has been used colloquially by Southern Calif. residents to describe an earthquake that could devastate the region.
With yesterday's 4.4 magnitude earthquake serving as a reminder of the spontaneity of these rumbles, people across the region are reassessing their level of preparedness.
Alex Hernandez with earthquakestore.com, which is based in Burbank, Calif., said his company has seen a huge jump in sales - something they haven't experienced since 2011's 9.0 magnitude earthquake in Japan.
"Usually we sell about 30 items - that's spiked up to 300 today," Hernandez said.
Water, food and blankets are in the kits provided by the company. In addition, the kits include "potable aqua," pills that kill bacteria when dissolved in water that provide for clean drinking water when in a pinch.
Earthquakestore.com kits can run as high as $200 with beginner kits starting at around $25.
Other items in a typical earthquake survival kit include knives, ponchos, flashlights and a portable radio.
The Southern California Earthquake Center, whose partners include USC, Caltech and the California Office of Emergency Services, has an extended list of recommended supplies here.
Greg Renick with the California Office of Emergency Services said to ABCNews.com that earthquakes are survivable, especially if you prepare for them.
"Identify things in your home or workspace that could fall or injure you, and take time to secure those items," he said.
Yesterday's quake was called a minor event by seismologists. The last major quake to hit the region was a 6.7 in 1994.