Only the Rialto events are aftershocks to the July 31 M4.3. The Lytle Creek events are near the San Andreas but not necessarily on it. We often see small events around the San Andreas but some analyses suggest they are on small faults not the main surface that will move in the big quakes.

I’m seeing lots of questions about whether the rate of great earthquakes is changing or whether climate change affects earthquakes. The answer is no. The long term rate of these big events is about 1/decade. But the distribution is random. The last one was 2011 in Japan

In addition to many M7+ earthquakes, this boundary has also hosted half a dozen M8+ earthquakes. Red circles mark the epicenter above the site where fault rupture began, and yellow shows the area on the megathrust fault that ruptured.

I once had a M2.7 directly under my house that felt so strong I went to work without waiting for a page (in pre-Internet days). It's a good reminder that how strong the shaking feels has much more to do with how close you are to the event. Duration of shaking is better for guessing magnitude.

The USGS produces a nice quantification of the risk of aftershocks. 7% chance of another M5 and less than 1% chance of being followed by a M6.