A 3.5-magnitude quake hit the Ontario area just after 1 a.m. Wednesday. About an hour later, there was a 3.7-magnitude temblor in Lytle Creek.
There were also reports of a small earthquake in the Redlands area, but that one hasn't been confirmed by the USGS.
There have been no immediate reports of significant damage or injuries.
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The overnight shaking comes after a 3.5-magnitude quake struck near the nearby Fontana area and rattled other parts of the Inland Empire Tuesday afternoon.
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