Unlike some natural disasters, earthquakes are difficult to predict (though not impossible to try to map with seismic activity data, fault lines and historical precedent). But recent tremors around the Salton Sea prompted scientists to release a warning to Southern California.

t's not just initial earthquakes (which shook the area around the Salton Sea this week) that are concerning but also the aftermath of a patch of seismic activity, because of the impact it could have on larger faults, or that the current quakes might be a precursor of something larger.

This seems to be the concern now:

The California Office of Emergency Services released an advisory warning for much of Southern California, explaining that there is a greater possibility of an earthquake with a magnitude of 7 or higher until October 4. The agency’s warning comes after over 140 seismic events — or a "swarm" of activity — since September 26 under the Salton Sea near Bombay Beach, California.

This is only the third time since 1932 that an earthquake swarm has been recorded in this area.

These small to moderate earthquakes are feared to be foreshocks for a larger event, due to their proximity to an area that connects the southernmost end of the San Andreas fault with the Imperial fault.

Current calculations put the chances of a major earthquake at as likely as 1 in 500 until October 7 with the likelihood decreasing each day. This is slightly less than previous predictions that placed it at as likely as 1 in 100.

"According to the U.S. Geological Survey, as of Tuesday, the chances of a magnitude 7 or greater earthquake being triggered on the southern San Andreas fault over the next seven days were as high as 1 in 100 and as low as 1 in 3,000," the Los Angeles Times reported. "Without the swarm, the average chance for such an earthquake striking on any given week is 1 in 6,000."

Forecasts of extremely destructive earthquakes are nothing new to the West Coast. In fact, the San Andreas fault itself has become increasingly famous for such doomsday scenarios due to its depictions in movies like San Andreas

The southern San Andreas fault is actually generally quiet; scientists estimate that there has not been a large rupture since 1680. However, this could be cause for concern because many scientists believe that a rupture is long overdue given that a major earthquake hasn’t appeared along this stretch in recorded history.

“Any time there is significant seismic activity in the vicinity of the San Andreas fault, we seismologists get nervous, because we recognize that the probability of having a large earthquake goes up,” Thomas H. Jordan, director of the Southern California Earthquake Center, told the Los Angeles Times.

Based on previous scenarios simulated by scientists, a major event could have catastrophic effects. A 2008 report from the U.S. Geological Survey said that an earthquake with a magnitude of 7.8 in Southern California would kill around 1,800 people, injure 50,000, and cause more than $200 billion in damages.