In addition to yesterday's shake near Yucaipa (4.9 magnitude), there was an earthquake on Sunday in Anza (5.2). Not only are those two temblors just 25 miles apart, but Anza is 25 miles from the San Andreas fault, and the Yucaipa shaker was just 8 miles from that fault. And, "The Big Quake Question: What Comes After Four?" informs us that "Some scientists believe one earthquake can shake loose, or trigger, another nearby or elsewhere in the world."

The Big One is coming.

Previously: "Tremor Watch 2005"

UPDATE: Holy Moley! From "Experts' Heads Shake After Quakes":

Lucy Jones, a seismologist with the U.S. Geological Survey, believes that the 5.2 Anza quake June 12 probably triggered the 4.9 Yucaipa quake four days later.

She noted that both quakes were within about 25 miles of each other and occurred on secondary faults — the Anza quake near the San Jacinto fault and the Yucaipa around the San Andreas...

[...her fellow seismologist husband disagrees...]

It has long been held that earthquakes relieve pressure on fault lines, potentially decreasing the threat of a massive quake.

But experts said it was not that simple...

Jones said modest earthquakes do relieve some stress and may redistribute it elsewhere, but not in a significant way.

"The net change is a decrease," she said. "But there are some locations where there is an increase."

Everyone must leave California immediately.