DATELINE: SEATTLE : Northwest Is Not Ready for the Big Ones : Warnings of a major quake, tsunami and volcanic mudflows are being ignored by most residents.

Floods, fires, earthquakes, hurricanes, brutal winter storms--the Pacific Northwest has escaped the worst of nature’s recent uprisings.

But--ah, yes, there is a very big BUT in this story--only the most fatalistic here can sleep easily, amid growing evidence of great dangers lurking below, beyond and above.

Add to that a pitiful lack of preparation and little experience with large-scale urban disasters, and you hear Northwesterners shrug uneasily among themselves and remark: “Boy, it’s going to be awful. Hope I’m away on vacation.”

The triple threat is for a colossal quake, a giant tsunami and rampaging mudflows from the volcano Mt. Rainier, 60 miles from Seattle. The picture is further darkened by unfavorable regional geography, suburban sprawl into volcanic danger zones, a plethora of old brick buildings, heavy reliance on bridges for transportation and a civic infrastructure already stretched thin.

This spring, scientists from Washington and Oregon issued the latest in a long string of eerie warnings: The region is ripe for a deep, giant jolt caused as the floor of the North Pacific thrusts itself under the North American continent--a subduction earthquake.

Among other things, the scientists measured unexpectedly rapid uplift of ground level along the Northwest coast, bulges rising 10 times as fast as elsewhere along the coast. The release of this pent-up energy could generate an earthquake of magnitude 8, the scientists figured. Other studies said a magnitude 9 quake could be expected from this bumping of tectonic plates.

Judging from the geologic record, such great quakes are infrequent. But their impact is huge: One point of land within sight of Seattle rose 23 feet during such a quake about 1,100 years ago. Scientists say there is evidence of a tsunami inundating Puget Sound, which is well inland from the ocean.

In modern times, a 7.1 quake shook Puget Sound south of Tacoma in 1949; and a 6.5 quake hit Seattle in 1965. Since then, Portland experienced a 5-plus earthquake, but Seattle has not moved.

Neither have government officials. The state commissioned an earthquake preparedness study in 1991, but few of its recommendations were accepted. For several years, Washington governors have requested appropriations to upgrade earthquake preparedness but were rebuffed by the state Legislature. This year, for the first time, $650,000 was approved. This may allow the state to hire its first earthquake planner.

Officials in Washington look at California with envy when it comes to readiness. “If California is a 10 on the scale, the most prepared, we are still a 1 or 2,” says Terry Simmons of the state Department of Transportation.

With all of its lakes, rivers and Puget Sound islands, the region is inordinately dependent on bridges. The state has begun strengthening these lifelines, but unless the pace is increased, it will take 71 years to complete work on all of the bridges.

After January’s 6.8 Northridge quake, experts here expressed frustration with the “so-what?” attitude of many here. “They’re going to have to be actually dragging bodies out before there’s a concerted effort in this state,” state geologist Steve Palmer said.

Seattle has undertaken a preparedness program, but only recently. In the process, officials discovered two public buildings--the police station, where the 911 emergency switchboard is located, and the Seattle City Light utility headquarters--are too unsound to retrofit and will have to be replaced.

Tsunamis, huge ocean waves, are often associated with coastal, subduction-type quakes. In 1992, scientists here began re-evaluating the Northwest’s vulnerability.

Sand berms were discovered on the Washington coast from what is believed to have been a tsunami 300 years ago. This is considered significant in view of the scant evidence remaining from the 9-plus earthquakes of the 1960s in Chile and Alaska.

Almost as worrisome is Mt. Rainier, which the Cascades Volcano Observatory in Vancouver, Wash., calls the most dangerous volcano in America. That’s because of its size (14,410 feet high), its massive mantle of stored ice and snow and its proximity to the dense population of Seattle-Tacoma.

The mountain has not sprung to life for 150 years, and has not seen a full-scale eruption in about 2,000 years, but Rainier has a history of generating giant mudflows, or lahars.

An estimated 156 billion cubic feet of ice and snow are stored on its unstable flanks, more than all the other Cascade volcanoes combined. Even a small quake or the everyday rotting of the mountain could trigger a stupendous, fast-moving mudflow.