3.9-magnitude earthquake strikes Ontario, Inland Empire on Saturday

On Saturday morning, a 3.9-magnitude earthquake struck the Inland Empire near Ontario, following a smaller 3.5-magnitude quake that occurred just 30 minutes earlier. The first tremor was recorded at 10:05 a.m. with its epicenter located approximately three miles southwest of Ontario. This seismic activity was part of a series of 32 smaller quakes that took place within three hours, including aftershocks and minor tremors, all occurring within a two-square-mile area. Seismologist Dr. Lucy Jones characterized the sequence of tremors as a "small swarm" within the Fontana Seismicity Lineation. This event marked the largest earthquake in San Bernardino County since 1953, highlighting the area's seismic activity. Brian Olson, a geologist, noted that the initial 3.5-magnitude quake could be seen as a foreshock, given the significance of the subsequent quake. This year has been particularly active for seismic events in Southern California, with experts noting it as the most seismically active year since 1988. Earlier in the summer, the region experienced a series of earthquakes, including a 3.5-magnitude quake in June and a 4.4-magnitude quake in August. While these magnitudes typically do not cause severe damage, they have been felt widely across the region. In the aftermath of the 3.9-magnitude quake, more than a dozen aftershocks were recorded, raising concerns about future seismic activity. Experts indicated that the high number of aftershocks could increase the likelihood of additional earthquakes in the area, emphasizing the need for preparedness among residents.