A whole lot less shaking going on

More aftershocks are expected, but intensity and frequency are down

Aftershocks from the recent earthquakes near Ridgecrest, Calif., are decreasing in both frequency and magnitude, and seismologists say they expect the pattern to continue.

The earthquakes on July 4 and 5 — one a magnitude 6.4 and the other a 7.1 — were the strongest to hit the area in 20 years. Thousands of aftershocks have been reported, and scientists have said they expect thousands more — about 34,000 over the next six months.

But since an initial cluster quakes of magnitude 5 and above that struck in the hours following the 7.1 temblor, the aftershocks have been subsiding in intensity and striking less often, an analysis of seismological data shows.

Caltech seismologist Egill Hauksson said late Monday the earthquake sequence seemed to be quieting down faster than was initially thought.

One possible reason: The quakes are occurring in an area of Earth’s crust that is relatively warm. Aftershock sequences in those areas can be particularly intense but

also fade more quickly — as has been seen in relatively hotter rock in the Imperial Valley.

Scientists had earlier said the probability of another earthquake of magnitude 7 or greater resulting from the July 5 quake was less than 1%.

“Now it’s probably quite a bit less than that,” Hauksson said. “It’s extremely unlikely by now to have another magnitude 7” quake resulting from that sequence.

The U.S. Geological Survey said Tuesday that the aftershocks would continue to taper off in the coming days and weeks, and that the probability of another large quake — magnitude 4 or higher — also will decrease.

Aside from one death in Nevada attributed late Tuesday to one of the quakes, no major injuries were reported. But the temblors damaged homes and roads and sparked anxiety, causing many to question their quake preparedness.

On Tuesday, the Trump administration declared a federal emergency for Southland areas devastated by the Ridgecrest quakes.

The declaration, which was requested by Gov. Gavin Newsom, authorizes the Federal Emergency Management Agency and the Department of Homeland Security to assist with disaster relief in Kern and San Bernardino counties.

“California is grateful for President Trump’s approval of our request and the ongoing efforts of local, state and federal emergency responders to protect communities across the region,” Newsom said in a statement.

Genaro Molina Los Angeles Times ALEX VASQUEZ and son Joaquin clean up their home’s garage in Ridgecrest, Calif., on Tuesday.

Genaro Molina Los Angeles Times MARK STOCKMYER walks away from a neighbor’s red-tagged home in Ridgecrest, Calif. A Caltech seismologist says a major aftershock is now unlikely.