You're reading: At least 7,500 earthquakes hit shattered New Zealand city (updated)

CHRISTCHURCH, New Zealand (AP) — It's been 10 months since the first big earthquake struck New Zealand's second-largest city. It's been nearly five months since a far more devastating one killed 181 people and crippled the downtown. But it's been just a few hours since yet another aftershock startled Christchurch residents during the night.

"I stop breathing," said Sheridan Cattermole, a bartender and a mom. "I get pins and needles all over. I either freeze or run. I just want things to be back to what they were like this time last year. I had my vege garden, and my sunflowers."

Seismologists have recorded 7,500 earthquakes in Christchurch since September — an average of more than 20 a day. The rumblings are rattling the psyche of the still-battered city.

They have left the land under thousands of homes unsafe to build on. Some people have left town entirely. Yet many have proven resilient, and some now see a reconstruction boom on the horizon.

Christchurch is the disaster that the world forgot. When the deadly quake toppled the iconic Cathedral spire and flattened buildings in this city of 390,000, people around the globe paid attention. But two weeks later, the massive earthquake and tsunami that killed more than 20,000 in Japan took center stage.

In New Zealand, the events in Christchurch continue to reverberate. In a country of 4 million, the cost of the quakes — estimated at more than $12 billion — amounts to eight percent of the country’s annual economic output.

Compare that to Hurricane Katrina, whose costs were less than 1 percent of U.S. gross domestic product. Christchurch will likely eclipse the Japan disaster in cost per person.

And nobody knows if the worst is over. Not even the experts.

When Kevin Furlong, a professor of geosciences at Penn State University, came to Christchurch on a sabbatical last year, he thought he would be studying earthquakes in the abstract — not living through them.

The quakes in the city have not followed the classic pattern, he said. Typically, a big quake hits and is followed by a series of ever-diminishing aftershocks.

In Christchurch, the initial Sept. 4 magnitude-7.0 quake didn’t cause widespread destruction because it was centered 30 miles (50 kilometers) west of the city, but it helped trigger at least two distinct new quakes on different fault lines, each with their own pattern of aftershocks.

First came a deadly magnitude 6.1 quake on Feb. 22, which was centered almost directly under a residential area and flattened buildings that had withstood the earlier quake.

Then a 6.0 magnitude quake struck on June 13. Though no one died, it was a psychological blow to people trying to rebuild.

Earthquakes are maddeningly difficult to predict, Furlong said. There’s no way of knowing whether there’s more to come, he said, though the odds improve with each day that passes without a major event.

New Zealand geologists estimated last week that there was a 23 percent chance another big quake would hit within a year, down from 30 percent last month.

"I’ve become much more attuned to what the public wants to know: ‘When will it stop and why are we having them,’" Furlong said. "To be honest, it’s really frustrating. You just can’t answer those very appropriate first-order questions."

That uncertainty is no comfort to people like Cattermole. She and her husband Pete, a cabinetmaker, and their three young children remained in their home in the working class suburb of Bexley long after most neighbors had left.

As recently as late June, they were sleeping in the living room to escape the muck creeping through the walls and floor at the sunken rear of their home. Their ruined possessions lay in a heap in the front yard, awaiting an insurance assessment.

All around, buckled homes sat abandoned atop a sea of mud and sand. A makeshift blue water pipe snaked along the sidewalk. The few who remained announced their presence with cardboard signs like the Cattermoles’: "3 Children & 2 Adults Still Here."

The problem: a phenomenon called liquefaction, when an earthquake forces underground water up through loose soil.

"It’s the same physics as quicksand," Furlong said. "Whole acres turn into something of a liquid. Houses sink. Water and mud jet up through the surface. You get cracks, sand volcanoes, flooding."

He said that geologists are reassessing the importance of liquefaction after the devastating impact it has had on Christchurch.

Cattermole and her family endured long stretches without fresh water and, with the sewer system broken, used a portable toilet on the street or a chemical toilet inside. "There’s so much stress around, you can just see it," she said.

They have since found a rental home and are moving out.

Their previous home was among more than 5,000 condemned by the New Zealand government last month because of liquefaction. Most are in the city’s low-income eastern suburbs.

Thousands more are likely to be condemned in what will force a major redesign of the suburbs.

The government has offered to pay homeowners for their losses, but many, Cattermole included, fear they will be priced out of new homes.

"There’s a plentiful supply of Rolls Royce-priced sections, but they’re not affordable for people on Toyota Corolla incomes," said Hugh Pavletich, a longtime Christchurch property developer and critic of the city’s land-use policies.

City officials say they’re working hard to ensure there’s plenty of affordable new land for displaced residents.

It’s hard to gauge what long-term effect the quakes will have. School enrollment is down about 7 percent — an indication of families leaving — and the economy is fragile.

Retail sales are down about 11 percent from pre-earthquake levels, and unemployment claims are up about 14 percent.

The center of the city remains off-limits behind chain-link fences and will stay that way for months, possibly years.

Demolition crews are planning to tear down about 1,000 hotels, office buildings and other unsafe structures. So far, they’ve taken down fewer than 150.

City officials estimate it will take nine months just to demolish the 26-story Hotel Grand Chancellor, which has been teetering since February. When the city center reopens, fewer than half the buildings will remain.

The new downtown is likely to be much lower. Christchurch residents appear to have little appetite for high-rises these days. "The magic number I’m hearing is three stories," said Connal Townsend, chief executive of the Property Council of New Zealand, which represents commercial property owners.

Around the country, building owners are bracing for big insurance premium increases, particularly for older structures, Townsend said. Homeowners are also likely to see earthquake insurance rates climb significantly.

The Port of Christchurch in Lyttelton, which handles almost all the region’s freight, has been unable to secure any earthquake insurance since June.

The port’s chief executive, Peter Davie, said he is essentially crossing his fingers, hoping that no more damaging quakes hit.

Even the Christchurch City Council has been unable to secure new earthquake insurance for much of its infrastructure.

Still, many are hoping that the billions of dollars flowing in from government and insurance payments will stoke a boom within a couple of years.

As the city looks to rebuild, Townsend said much will depend on the vision of city leaders: A bold reconstruction plan would inspire confidence and investment, while a second-rate one could scare away investors.

Attention is turning to Roger Sutton, a former energy executive who took a pay cut in June to become the first Christchurch earthquake czar, with broad planning powers.

Asked if he was worried whether new earthquakes could cause more damage, Sutton shook his head and said, "Hopefully, there’s not much more to break."