If you are at the beach and you feel strong earthquake shaking, leave the beach.
Earthquake experts are warning people that a large tsunami could have a significant impact on Southern California's coastal areas.
Lucy Jones, who studies earthquakes and tsunamis for the United States Geological Survey, warns that while rare, a tsunami could trigger a sudden 10-foot increase in sea level that would put low-lying areas such as Venice Beach and Huntington Beach at risk.
She adds that nearly 100,000 people could live in a tsunami's inundation zone if the wave were to strike California during the day.
"If they all just walk out of the zone, we won't have any casualties," Jones said.
Jones says that unlike earthquakes, officials can usually give plenty of advanced warning of an approaching tsunami.