4.8 Quake One of Mammoth Swarm’s Strongest

One of the strongest earthquakes yet in the Mammoth Lakes volcanic earthquake swarm, a magnitude 4.8, struck Wednesday at 12:36 p.m., as the resort filled with 25,000 skiers and other tourists at the start of the New Year’s holiday.

There was no damage in the Mammoth area from the temblor and eight quakes in the range of magnitude 3 that followed over the next 4 1/2 hours. In all, more than 520 quakes occurred Wednesday by 9:30 p.m.

Coming when they did, the quakes--centered near the airport six miles southeast of the town and nine miles from the Mammoth Mountain Ski Area--prompted some defensive reactions by townspeople.

Calls to several bars and hotels were met with chilly responses.

At Grumpy’s, for instance, an employee who refused to give his name said bluntly: “I really don’t want to perpetuate this story. We just want to stay out of it.”

At the Dry Creek bar in the Mammoth Mountain Inn, a man who identified himself as Steve agreed to ask skiers whether anyone had felt the quake.

There was a chorus of no’s evident over the line, and Steve said, “We’re way up on the mountain. These things are all down in town. Try down there.”

Two ski-boarders said they had noticed the quake while out on the slopes of Mammoth Mountain.

Lee Grassini, 17, of Woodland Hills said, “It felt like one of the aftershocks from the Northridge quake. I was standing on the snow, and the trees were shaking back and forth. It shook up and down. It pushed up and dropped down again.”

Chad McConneghy of Agoura Hills remarked, “It was a quick jolt, and that was the end of it. The mountain started to rumble and snow started falling from some of the rocks and trees.”

A resident reached at home, Helen Warren, said Wednesday’s quake was “felt no more than any other one.”

“We have had no damage whatsoever,” she said. “This town is crawling with skiers, so I don’t think anyone is worried about anything.”

The marketing director at the Mammoth Mountain Ski Area, Pam Murphy, said town reaction against all the attention being paid to the quake swarm had intensified in the wake of what she characterized as an alarmist report on CBS national news last week on the chances of a volcanic eruption near Mammoth.

After the program, Murphy said, more calls questioning conditions came in than ever. But she said most were from Easterners, often relatives of Mammoth employees.

Some, she said, asked, “What does an earthquake feel like?”

The ski area is sending out a question-and-answer sheet and a newspaper report stressing scientific evaluations that an eruption is unlikely in Mammoth in the near future and that, if one does occur, it will be comparatively small.

As for business, Murphy said, “We are currently 22% above skier visits from last year. We have had about 220,000 skiers since we opened Nov. 7. We’re seeing 15,000 on the slopes every day this holiday, and there are 10,000 more accompanying them in town.”

Mammoth Lakes Mayor Kathy Cage said her guess is that despite all the attention the latest quakes have received, “By the time we get our next series of storms this weekend, people will forget about it. . . . Once the snow is refreshed, we’ll see the concerns dissipate.”

The chief U.S. Geological Survey monitor of the situation, David P. Hill, on Wednesday was a little less sanguine. He said that ground deformation in the Mammoth area--a sign of volcanic unrest--is about commensurate with the level of early November, before 4.8 and 4.9 temblors sparked a surge of quakes in late November that numbered 2,300 in one week.

“As long as we see deformation continue, we can probably expect to see continued earthquake activity with earthquakes in the range of 3 to perhaps 4, 4.5,” he said.

Wednesday’s quakes--including the 4.8 at 12:36 p.m. and eight quakes ranging from magnitude 3 to 3.6 in the next 4 1/2 hours--were centered on the west side of the airport, six to seven miles southeast of Mammoth Lakes.

Airport director Bill Manning said that there was no damage at the facility and that planes continued to land. He said, with the holiday, he expected the airport to reach its capacity of 80 planes on the ground by this morning, even with the weekend storm expected.

The new quakes have been centered a few miles farther outside town than most of the ones in late November.

The Mammoth area has not had a volcanic eruption for about 250 years, but scientists have said the odds of one increase in times of seismic unrest and ground deformation.

Although most of the quakes have been close to U.S. 395, authorities completed a bypass road from the ski area to a part of the highway not affected, allowing traffic in an emergency to get out to the north of town.

Elsewhere Wednesday, a quake series continued near the Imperial County town of Niland, with 4.1 and 3.5 jolts northwest of town in the early morning.

Times correspondent Martin Forstenzer contributed to this report.