PAHOA, Hawaii - The U.S. Geological Survey's 35-year-old maps of lava danger zones in this southern corner of the Big Island are a tableau of earthy colors and odd shapes originally meant for scientific and planning purposes.

The maps have also long been used by the home insurance industry to assess lava hazard risks. But in the last year or two, the maps have become a source of contention as insurers have hiked rates or completely abandoned areas that are deemed to be the most dangerous.

Fannie Mae, the huge backer of home mortgages, recently declared it would no longer do so in the two most hazardous zones. That has residents pointing fingers of blame at the charts that even the Geological Survey acknowledges are outdated.

''Now that it has become the bible, so to speak, there's no way to get rid of it,'' local real estate agent John Dirgo said of the maps. ''It's being used for purposes it was never intended for.''

Wendy Ford's home is located in the zone deemed most at risk, and until this year, she's paid less than $425 a year for insurance. But her premiums are skyrocketing now even though her neighborhood hasn't seen new lava since 1790.

''I just keep looking and looking at these maps and (they don't) make any sense,'' she said.

But for insurance companies, which essentially have to predict the future when assessing risk, the maps are a valuable tool when deciding to offer coverage in a given area and how much it will cost, said state Insurance Commissioner J.P. Schmidt.

The maps ''provide an objective, scientific standard that they can use to help determine the risk that they are facing,'' he said.

The Geological Survey last revised the lava hazard maps for the entire Big Island and the Puna district in 1987. The 500-square-mile district encompasses Kilauea, one of the world's most active volcanoes.

The agency produces similar maps in Washington, Oregon and Alaska, but volcanoes there are located farther from populated areas and are not as active.

The map of the Puna district shows the five most dangerous zones. The highest risk is in Zone 1, a narrow band extending the district's length where vulcanologists say lava can appear in any spot with little warning. More than 25 percent of the land there has been covered with lava since 1800. In the somewhat less dangerous Zone 2, lava has covered 15 to 25 percent of the land since 1800; no lava has flowed since 1800 in Zones 5 through 9.

Ford's 2-acre property is in the Leilani Estates subdivision, a 45-year-old tract where homes are separated by green foliage dotted with old-growth ohia trees. It sits more than 10 miles from the the closest active lava flow, yet it's in Zone 1. The land underneath a nearby development, Nanawale Estates, was inundated in 1840 but is in Zone 2.

Liberty Mutual insured Ford's 2,200-square foot, three-bedroom home that was assessed at $231,000 for $424 last year. The company had wanted to cancel her policy last year after it decided to no longer cover homes in Zones 1 and 2, but relented for one year after Ford complained to state regulators.

But the coverage has now lapsed, and Ford's separate hurricane policy also jumped much higher.

That left her stuck with only two choices: Lloyd's of London or the state-created Hawaii Property Insurance Association. Both quoted her rates of more than $3,000 annually. She chose Lloyds, which includes hurricane coverage, at $3,147 a year.

The 17-year-old HPIA, the insurer of last resort for Hawaii homeowners, covers 2,400 properties on the Big Island. It has hiked rates almost 60 percent in the last two years because of higher coverage limits and reinsurance costs, said Schmidt.

In 2005, natural catastrophes in the United States cost insurers $62 billion, several times the annual average of $10 billion to $12 billion, said Robert Hartwig, president of the Insurance Information Institute. Last year's $26 billion in payouts was the third highest ever.

With such losses, Hartwig added, the cost of providing coverage in disaster-prone areas has prodded some insurers to reduce their exposure.