The resounding thump of Doc Marten boots has become a familiar and terrifying sound as menacing and murderous bands of Skinheads migrate into the smaller cities of the Pacific Northwest.

Their march into this moderately populated region has been accompanied by an outbreak of violent and largely random assaults, vandalism and the widespread distribution of neo-Nazi literature and hate slogans.Authorities say the movement is engaged in an energetic recruitment drive in high schools and on street corners to provide youthful shock troops for a network of white racist organizations.

They have signaled their presence in many neighborhoods in Portland with stickers bearing such legends as "Get Out Filthy Jew Pigs" and "This is Our Land, Get Out Now."

But the word of their exploits also has been written in blood. Bat-wielding members of a Skinhead faction called East Side White Pride were charged with murder in the beating death of a 28-year-old Ethiopian bus driver in Portland last month.

And in Spokane, Wash., another Skinhead is standing trial for attempted murder in a knife attack on a black man.

Those recent incidents - along with a string of reported Skinhead assaults against Asians, Jews and homosexuals - have galvanized public attention on the unconventional and loosely knit group of stubble-haired and tattooed thugs who once were visible only in such cities as Chicago, Detroit and Los Angeles.

Law enforcement officials monitoring the movement voice mounting concern that the Skinheads are establishing a new beachhead in Oregon and Washington, where they are forging close alliances with white supremacist leaders in the area.

"The Northwest has a small minority population, and I assume they (the Skinheads) think it's ripe for them to take over," said Portland's central precinct crime information officer, Loren Christensen.

"I guess the theory is that it's easier to move 30,000 blacks out of Portland than to move 3 million out of New York."

Marvin Stern, the Seattle-based director of the Pacific Northwest regional office of the Anti-Defamation League of B'nai B'rith, contended that the Skinheads have responded to the "stereotyping and scapegoating scenario passed to them from adult rabble-rousers."

A national Anti-Defamation League report on the Skinhead phenomenon, published in October, estimated there are only about 2,000 adherents scattered in 21 states. But, the report said, the Skinheads' influence might outstrip their numbers.

"It is now clear that Skinheads can no longer be ignored as `kids' who are simply acting out their frustrations in an antisocial manner," the report said.

"The Skinhead movement is growing in intensity, if not in size," added Christensen. "It seems like when we arrest one of their leaders here, five more come up from L.A. to take his place."

Portland harbors about 200 Skinheads - 50 of whom are described by police as "hard-core" - while Seattle authorities report about 20 Skinheads in that city.

But Tom Metzger, leader of the White Aryan Resistance in Fallbrook, Calif., has announced plans to begin recruiting in Seattle.

Metzger, a television repairman who earlier was a major figure in the Ku Klux Klan, flatly acknowledged in a published interview this month that he is trying to "inject some ideology" into the Skinheads in order to use them as "front-line warriors" in his organization.

The Skinheads also have ties to Richard Butler, leader of the Aryan Nations/Church of Jesus Christ Christian compound in Hayden Lake, Idaho. Butler will be host for a National Skinhead Seminar next April.

"These kids have added vitality to those old-line organizations," Christensen said. "In turn, these organizations are giving the kids a cause, a philosophy.

"When we bring them in, they all deny being white supremacists or Nazis, but there they are in these boots and with swastikas tattooed all over their faces and necks."

Howard Klink, public affairs director for Portland's Juvenile Court system, agreed that the Skinheads appear to regard the Northwest as "especially fertile ground - but the community is digging in to let them know that this is not a racist town."

Portland police have been alerted to pay keen attention to the Skinheads, but Christensen noted that vigilance is about the only measure authorities can use to counter the threat.

"It's not illegal to be a Skinhead or to have a philosophy that's a bunch of crud," he said. "We have to let them look stupid and wait for them to commit a crime."