Earthquake Rocks Ontario: A 3.9-Magnitude Event and Its Aftermath
Significant Earthquake Activity Reported
A 3.9-magnitude earthquake struck near Ontario Saturday morning about 30 minutes after another smaller quake hit the area, according to the U.S. Geological Survey. The first temblor was just three miles southwest of the city in San Bernardino County and was reported by USGS at 10:05 a.m. Soon after, at 10:34 a.m., a 3.9-magnitude earthquake shook the same area.
Aftershocks and Historical Context
Less than an hour later, at 11:20 a.m., a dozen aftershocks had followed—ranging from a magnitude of 2.1 to 1.0 and all reported within 4 miles of Ontario. This year has been the most seismically active since 1988, seismologists said last month following a string of earthquakes in the Southern California region.
- In June, an area of Los Angeles County near Pasadena was struck by a 3.5-magnitude earthquake.
- In August, another 4.4-magnitude tremblor was felt across a larger distance.
- Earlier in August, a 5.5-magnitude quake with an epicenter in Central California rattled widely.
These incidents illustrate the heightened seismic activity in Southern California, reminding residents of the constant geological shifts beneath their feet.
This article was prepared using information from open sources in accordance with the principles of Ethical Policy. The editorial team is not responsible for absolute accuracy, as it relies on data from the sources referenced.