Keep On Stompin’ : Those Aussies in Silverchair have a debut hit album, are touring the United States for the fourth time--and they’re only 16.

If Bill and Ted were real-life Australian teenagers with a bass-playing buddy, they would be Silverchair, a trio of schoolboys whose first album, “Frogstomp,” has abruptly launched them into rock stardom.

Powered by the singles “Tomorrow” (a Top 10 hit), “Pure Massacre” and the new “Israel’s Son,” “Frogstomp” has sold 1.5 million in the United States since its release last summer and is still going at the rate of about 20,000 a week. It spent three weeks in the Top 10 of the national sales charts, sending the group onto the tour circuit in such prestigious positions as the opening slot on the Red Hot Chili Peppers’ upcoming East Coast swing.

Daniel Johns, Ben Gillies and Chris Joannou’s excellent adventure began in high school in Newcastle, a blue-collar town two hours north of Sydney, where singer-guitarist Johns and drummer Gillies spent a fair portion of their adolescence jamming in their parents’ living rooms and garages.

When the two decided to get serious and take the next step in their rock ‘n’ roll quest, they enlisted Joannou to play bass and dubbed themselves the Innocent Criminals. By June 1994, they’d renamed themselves Silverchair and submitted a song to a demo tape contest sponsored by an Australian video show.

Their prize was some studio time, and they used it to re-record “Tomorrow.” The record became an alternative radio hit and caught the attention of Murmur, a Sony-affiliated Australian label that signed the band and released “Frogstomp” in Australia in June 1994. Epic Records in the U.S. then signed Silverchair and released the album here last June.

The three 16-year-olds have managed to fit four trips to the United States into their equivalent of our junior year of high school, and their single-minded pursuit of rock ‘n’ roll nirvana remains unencumbered by record industry rigmarole, the international dateline, occasional physical injuries--and, on a recent afternoon during a tour stop in L.A., an appendicitis scare that has sent drummer Gillies to Cedars-Sinai to have some mysterious abdominal pains checked out.

Johns and Joannou have just returned to their West Hollywood hotel after dropping Gillies at the hospital, and they settle into the cushy lobby furniture as if it were home.

Johns, whose streaky blond hair seems to be in the formative stages of dreadlocks, munches on a lettuce-and-tomato sub sandwich and sips apple juice. The pensive Joannou, deeply tan from the Australian summer sun, is an intent observer who listens carefully to Johns and inserts an occasional aside. When he starts to explain the rationale behind his new buzz-cut, Johns suddenly cuts him off.

“He’s rebelling against metal,” Johns says with a smirk. “So he’s shaven his head to avoid a metal kind of image.”

“He’s just being stupid,” Joannou says of his bandmate. “I just got sick of [having long hair].”

“We’re just joking,” Johns chimes in. “It looked crappy long.”

Welcome to the world of Silverchair--a realm where nuances, implications and inferences don’t exist. People, places and things fall into basically two categories--the good and the bad.

On the eve of their fourth American tour, where they’ll open for the Chili Peppers, and with their album still going strong, things are pretty good. The band just had six weeks off, which was also good, but its only warmup gig before tonight’s headlining show at the Hollywood Palladium was, according to Joannou, pretty bad.

Tied to this sense of good and bad is an equally unshakable perception of right and wrong that underlies the appeal of Silverchair’s music. The songs don’t dwell on the gray areas of the real world or the subjectivity of adult life, but neither do they offer the usual “I Just Want to Be Your Everything” sentiments.

“You say that money isn’t everything, but I’d like to see you live without it,” Johns sings in “Tomorrow.” Though some might chalk up the statement to youthful idealism, it’s also about actions speaking louder than words, a concept that has resonance with adults too.

“I find it incredibly refreshing,” says David Massey, the vice president of artists & repertoire at Epic Records who signed the band.

“When you get to know them, they very much speak their minds. It’s not complicated for them. It’s just black and white. They know what feels right. They’ve got a lot to say, but it’s a no-bull---- zone.”

Having polished off their Subway fare and exhausted their store of observations for the afternoon, Johns and Joannou dart off to the elevators as soon as Gillies returns from the hospital, still a little uncomfortable but feeling well enough to down a sandwich. He’s every bit as no-nonsense as his bandmates, though more inclined to talk about things than simply talk.

Silverchair might be undergoing an accelerated growth rate, but the members haven’t left hero-worship behind. Recently, Gillies recalls, the group rescheduled a performance time and drove for four hours from New Jersey to Washington to catch their favorite “hell-band,” Helmet. In spite of their valiant effort, they missed the show.

“We got to meet them, though,” Gillies recalls. “We basically talked about instruments, touring, stuff like that. But [drummer] John Stanier”--a tone of deep respect creeps into his voice--”he’s a machine. He’s like a brick wall.”

Though he’s just offered the afternoon’s first and only full-fledged simile, he denies that his propensity for conversation is any greater than that of his bandmates. But he can understand that impression.

“I don’t know. Daniel, because we’re good friends, we just act like total idiots together. But when he’s got to do interviews, or he meets someone new or something like that, he can be kind of shy. That’s just the kind of person he is, but because I’ve known him 10 years, he just seems normal to me.”

At 4 in the afternoon, a line of concert-goers--mostly female--stretches for a half-block along the sidewalk outside the Palladium. When the Silverchair tour bus pulls up, the girls who have been patrolling the parking lot move toward it, hoping for a glimpse.

As the band’s entourage--which includes a road crew made up of the three stars’ fathers--disembarks, a stricken girl shouts, “Daniel!” Johns looks toward her, momentarily making eye contact. Reeling from the effects, she screams, “I love you!”

John Watson, the group’s manager, takes a pragmatic view of Silverchair’s following.

“They do draw a younger audience--the younger female audience as well as the older male, mosher kind of crowd,” he says. “The younger girls will probably move on to other things sooner or later, whereas the older, more rock-oriented crowd tends to hang with acts for a longer period of time. That’s why they’ve studiously avoided any kind of teen press. They don’t do posters, they don’t do color pinups precisely to minimize that following.”

The crowd at the sold-out Palladium that evening is indeed an odd combination of surfer urchins, grungy rockers and starry-eyed girls. By the time Silverchair launches into its third number, the spry, grinding “Findaway,” the moshing and screaming are at full force, and the band is thriving on the energy.

The most telling moment of the night comes during “Madman.” One minute Johns is surveying the seething pit as he wails on his guitar, and the next moment he’s mute--silenced by a blown fuse. Without missing a beat, he raises both hands in the air and beams as he makes the universal hang-loose gesture that means “rock on.”

It’s that ability to make even the most cliched rock ‘n’ roll gestures totally their own that gives Silverchair an edge. Its music, after all, isn’t strikingly distinctive. Its heritage is a venerable one that began more than a decade before the members were born, with Black Sabbath and Deep Purple, and stretches up to their current favorites Helmet, Soundgarden and the Jesus Lizard.

What caught the ear of Epic’s Massey was the gutsy, heartfelt way the band tackled the idiom.

“People kept telling me they’re derivative,” Massey says. “Yes, they were 14-year-olds when they wrote that album. Any 14-year-olds would be influenced by the bands they love, and to me that was completely healthy. I felt that the delivery, the execution of what they did showed huge promise.

“Now, as they are maturing, they are very much finding their own voice. . . . They are a band who are evolving so rapidly that I have no concerns about the future.”

With 10 Chili Peppers dates ahead of them and eight new songs being fine-tuned for the next album, neither does the band. Gillies says the album will be a much darker affair than “Frogstomp,” though he’s not entirely sure why. And the band isn’t concerned with how this newfound darkness will go over with fans.

“If people don’t like it, they don’t like it,” Joannou says with a shrug. “They’ll probably like it if it’s good.”

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