Southern California Hit by Dozens of Earthquakes Over 18 Hours as Swarm Unfolds Near Lennox and Westmont

LENNOX, Calif. — Parts of Southern California experienced a burst of earthquake activity from Friday night into Saturday, as dozens of small earthquakes struck within a relatively short period around Lennox and Westmont.

The series of tremors unfolded between about 8 p.m. Friday and 2:30 p.m. Saturday local time, according to U.S. Geological Survey data. The earthquakes varied in strength, with recorded magnitudes ranging from 1.0 to 2.7.

While the earthquakes were relatively small, the repeated shaking was noticeable enough for residents in several South Los Angeles communities to report feeling light tremors.

The activity was concentrated in a relatively small area, fitting the description of what scientists call an earthquake swarm.

What Is an Earthquake Swarm?

The U.S. Geological Survey defines an earthquake swarm as a series of earthquakes that occur within a relatively small geographic area over a period of time.

Unlike a more typical earthquake sequence, an earthquake swarm does not necessarily feature one clearly defined main earthquake followed by a series of aftershocks.

Instead, multiple earthquakes can occur in succession, sometimes over hours, days or even longer periods.

That distinction is important when looking at the recent Southern California activity. The dozens of earthquakes recorded between Friday evening and Saturday afternoon were not described as one major earthquake followed by conventional aftershocks.

Earthquake swarms can occur along faults and can continue for varying lengths of time, according to the USGS.

Dozens of Small Quakes Recorded Near Lennox

The strongest earthquakes in this particular swarm reached magnitude 2.7, while several others were considerably smaller.

Although earthquakes of these magnitudes generally produce limited shaking, repeated activity in a populated region can still attract attention, particularly when residents feel multiple tremors within a short period.

The swarm’s location also put it close to communities in the South Los Angeles area.

Lennox and Westmont were among the areas around which the earthquake activity was concentrated, while local reports indicated that people in surrounding communities noticed light shaking.

There were no reports in the provided information of major damage or significant injuries connected to the swarm.

Activity Occurred Near Newport-Inglewood Fault Zone

Data shows that the earthquake activity occurred near the Newport-Inglewood Fault Zone, a fault system that runs through part of Southern California.

The region is no stranger to earthquake activity, with numerous faults crossing or affecting communities throughout Southern California.

The presence of a fault zone provides important geological context for the swarm, but the occurrence of a series of small earthquakes does not by itself establish what will happen next.

Earthquake swarms can behave differently from one event to another, and their duration and intensity can vary.

For residents who felt the shaking, however, the repeated tremors served as another reminder that Southern California remains an active earthquake region.

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Residents Feel Light Shaking as Activity Continues

The earthquake sequence stretched across more than 18 hours, beginning Friday evening and continuing into Saturday afternoon.

That extended period of activity made the swarm notable even though the individual earthquakes were relatively small.

Scientists continue to distinguish earthquake swarms from sequences dominated by a single mainshock because the pattern of activity can provide different information about what is happening underground.

For now, the reported earthquakes around Lennox and Westmont remain characterized by their small magnitudes and clustered activity.

Residents who experienced the shaking reported light movement, while USGS data documented the series of events.

The recent swarm highlights how quickly earthquake activity can develop in Southern California and how even relatively small tremors can be felt across populated communities.

Did you feel any of these earthquakes in Southern California? Share where you experienced the shaking in the comments.