Residents rattled in Reno

MOGUL, Nevada – It's not the chips of drywall littering their carpets or nails popping from their walls that are wearing people down in the hilly suburbs west of Reno.

It's the relentlessness of two, three, 20 little rumbling earthquakes day after day, frightening their children awake.

"It breaks my heart," said Teresa Fleck, whose 8-year-old son, Curtis, climbs into bed with her when the earth starts moving.

Fleck remembers tiles falling from her dorm's ceiling during the magnitude 6.7 Northridge quake in 1994. But the hundreds of quakes now plaguing Mogul are more nerve-racking than anything she experienced growing up in California.

"It's horrible. It just seems to keep going," she said.

Mogul and neighboring Somersett, where luxury homes nestle on ridges and ravines, have been shaken since Feb. 28 by a swarm of earthquakes so shallow that people feel even the little ones. There have been nearly 600 quakes of magnitude 1 or over, many packed into the last eight days.

Walls crack, pictures break, and the ground pops and groans.

"It's like 'Jurassic Park,' " said Somersett resident Wayne Kerr. "You can hear them rumbling."

Some parents are taking their kids to relatives' or neighbors' homes across town, just to give them a break, said Trish Dolan, who teaches at Rollan Melton Elementary School in the quake zone.

Many of her second-graders are anxious, sad and sleep- deprived, Dolan said.

At her own home, chicken wire shows through a crack that snakes more than 30 feet along two exterior walls. Dozens of smaller cracks zigzag from arches and corners inside.

No buildings have fallen during the swarm, whose largest quake so far measured 4.7. Nothing is red-tagged as uninhabitable. The structural damage lies in people's hearts.

"It's scary," said Trish Dolan's daughter Jordyn, 11, who just wants the swarm to end. "It's not like a fire – you can't see it coming."

By late this week, bigger tremors were coming a little farther apart, but seismologists said that has happened before during the Mogul swarm, and then the pace picked up again.

No one is sure what caused an otherwise quiet area to erupt into a string of grumbling. One theory focuses on deep stresses below the quake zone.

Geoff Blewitt, a University of Nevada physicist who focuses on measuring minute earth movements with GPS, believes that since the swarm began, a 20-square-mile area has shifted eastward one centimeter – just under a half-inch.

The shift is too great to be caused by the swarm itself and hints that a deeper, underground creep is straining the region above it, Blewitt said. The swarm could be partially releasing that strain.

More work is needed, though, before that idea can be proven or discounted, he and others at the Nevada Seismological Laboratory emphasized.

Blewitt inferred the creep from measurements at just one GPS site, mounted on a library and more typically used to aid county surveyors. He hasn't gone through enough records yet to completely rule out settling or groundwater movement below the library as a cause for the shift.

Still, he thinks he's on to something significant, because the movement eastward began on Feb. 28, the same day the swarm started, and the change appears inconsistent with seasonal pumping of groundwater.

He's hoping to learn more as he monitors two additional GPS sites that a colleague set up last week east of the swarm and directly on top of it.

The area is starting to bristle with equipment. Thursday and Friday, other teams began digging holes to install portable seismic stations borrowed from an instrument center in New Mexico.

Meanwhile, other University of Nevada, Reno, researchers are trying to map what's beneath the swarm, as well as collect video and first-person reports from the few thousand people who live in Mogul and Somersett.

"In one sense, I'm interested in everything," said John Anderson, director of the Seismological Laboratory, whose research includes an Internet survey asking people if they've experienced unusual tremors, sounds or other phenomena.

He is eager to delve more deeply into data showing when the swarm picked up speed and intensity. Lately, though, much of his time has been devoted to briefing the governor, sharing reports with other scientists and advising the university on its own quake safety programs.

The campus, an oasis of green lawns and red brick not far from the casinos, has a dozen unreinforced masonry buildings, including one that houses the president's office.

Amid press conferences and TV appearances, Anderson tries to put updates online and take quick, hungry looks at the data he'll study more thoroughly later.

While earthquake swarms aren't unusual, it's a little less common to have one right under a populated area that can be quickly and easily studded with monitoring equipment.

Before it's over, "We're certainly going to know more about swarms," Blewitt said.

So will the residents of Mogul and Somersett.

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