DUBLIN - It's been a month now, and Iceland's volcano shows no sign it will stop belching ash across Europe anytime soon. The rolling eruptions threaten more havoc for summer vacation plans and higher costs for struggling airlines.

Although the global disruption of last month's massive eruption has faded, smaller ash plumes snarled air services intermittently over the last week all the way to Turkey - more than 2,500 miles (4,100 kilometers) from the Eyjafjallajokul (pronounced ay-yah-FYAH-lah-yer-kuhl) volcano.

Air-control authorities and geologists agree that the continent must be braced indefinitely for rapid shutdowns of air services as computerized projections try to pinpoint where the ash clouds will float next at the whim of shifting winds.

"We do not pretend to be psychics," said Einar Kjartansson, a geophysicist at the Icelandic Meteorological Office, who often has been asked to guess the volcano's next move since it began spitting lava and ash March 20.

Huge volumes of ash, which can clog jet engines, forced most of northern Europe to shut its air services April 15-20, grounding an estimated 10 million travelers worldwide.

Since then the ash plume has thinned and spread out, shifting shape by the hour, rising into North Atlantic air routes and imposing awkward detours on hundreds of trans-Atlantic flights daily.

Some insurers are offering travel coverage for flights delayed because of volcanic ash, though in many cases reimbursement would not be large enough to cover major expenses such as hotel charges. One major British insurer, Direct Line, announced on April 20 that it would not cover ash disruption in future policies because travelers "are buying cover in the knowledge that there is a problem."

The costs to airlines associated with an ash cloud can add up quickly. Consider that two hours of jet fuel to divert to another airport can cost $5,000 to $10,000 depending on the size of aircraft involved.

This weekend, Lufthansa couldn't land in Munich so diverted planes to other German airports and bussed passengers the rest of the way.

Lufthansa spokesman Thomas Jachnow said the airline hadn't calculated yet how much extra costs it was suffering because of the sporadic diversions and grounding of aircraft over the past week. Dozens of European airlines have suffered similar extra costs and are already lobbying their national governments to help foot the bill, which includes paying the hotel and food bills of stranded customers.

Jose Luis Barrera, deputy president of Spain's College of Geologists, said Europe should get ready for ash-covered inconvenience at least through the summer - and perhaps longer. He noted that the volcano's last eruption ran from 1821 to 1823.

"We're going to have to learn to live with the volcano," Barrera said. "Just as in California, people learn to live with the earthquake that may be waiting for them. ... This is the same. Preventive measures will have to be taken for if and when the mass of ash gets worse."

Irish tourism centers dependent on Europeans and Americans arriving by air say their summer will be bleak if the volcano doesn't stop. Ireland's government has called in tourism industry officials emphasizing they must woo more Irish to compensate for the missing foreigners.

"Pre-volcano we were having a great year. Then all hell broke loose, thanks to your man (the volcano)," said Debbie Walsh, manager of a heritage museum in the County Cork port of Cobh.

She said this summer, the key to financial survival would be the approximately 50 cruise liners expected to disgorge tourists in Cobh. "We're lucky in that we can fall back on the cruise liners. Nothing is going to stop them from coming in."

One of Ireland's top attractions, the Guinness brewery in Dublin, provides a living barometer for when the city's air links are closed.

"About 90 percent of our visitors come through Dublin Airport, so when the ash threat shuts it down, it's like turning off a tap at the Guinness Storehouse," said managing director Paul Carty.

Lufthansa, one of Europe's most financially secure airlines, said its bookings are on target with what they would expect this time of year. But analysts warned that most carriers are on shakier financial ground, depend on summer holidaymakers for the bulk of their profits - and are particularly vulnerable to a drop-off in bookings now.

"That is why all airlines are monitoring closely what affect it (the ash worries) will have on their bookings," said John Strickland, director of JLS Consulting, a London-based aviation consultancy firm. Airlines in fact are trying to get some relief from the European Union for the hotel costs they absorbed during the Europe-wide shutdown.

Airline, business and tourism leaders also increasingly have questioned Europe's competence to measure the true threat.

Criticism has been sharpest in Ireland and Britain, Iceland's southeast neighbors and fellow islands heavily dependent on air links for their economic health.

Ireland's two major airlines, Aer Lingus and Ryanair, this week accused the existing authorities - the Volcanic Ash Advisory Center in England and the Eurocontrol air safety agency in Brussels - of not knowing enough about the ash to make informed decisions to shut down air services.

Both airlines appealed for the European Union to source and fund new measures based on American practice before the summer high season for travel arrives. They complained that Europe had been too slow to adopt measures long observed by the U.S. Federal Aviation Administration.

Aer Lingus chief executive Christoph Mueller said Europe's Volcanic Ash Advisory Center "has been proven inaccurate several times and we have lost confidence in its reliability."

He proposed that specialized aircraft should be deployed around the Atlantic to identify ash clouds and measure their density, something the current early-warning systems usually fail to do.

Many individual travelers, however, appear to be taking the continuing ash threat in stride.

In prosperous Norway, one of the countries most in the volcano's firing line, travel industry officials say nothing will deter most of the nation's 4.9 million people from booking flights to the Mediterranean this summer. They say Norwegians wouldn't even mind getting stuck on the beach for a few extra days if the ash demands it.

"People are not so concerned about being stranded, but they are concerned about money. What will happen to my booking if I have to cancel a flight? Will I get my money back?" said Helen Begby, a spokeswoman for Apollo, one of Norway's largest charter travel agencies.

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