MUSICAL TRENDS come and go, but heavy metal blares on. To many rock fans, H.M. seems like rock's eternal dinosaur, slogging on unperturbed by changing styles, tastes or times. In fact, though, heavy metal continues to evolve within its formal constraints and is healthier than ever, thanks to burgeoning scenes in Los Angeles, Germany and Japan. Here are a few of the heavier recent releases.

ACCEPT -- "Metal Heart" (Portrait BFR 39974). This is the heavy metal album to beat in 1985. Accept plays heavy metal the way it's meant to be -- hard, fast and hook-heavy. Like the best of AC/DC or Judas Priest, Accept structures its songs with the brevity and precision of pop singles, but deliver its melodies with skull-crushing intensity. Add deafeningly vivid production by Dieter Dierks, and you've got an album destined to bust speakers and break leases.

RATT -- "Ratt" (Time Coast 90245-1-Y). Before Ratt's "Out of the Cellar" made it the biggest band to have emerged from L.A.'s metal underground, its independently produced EP was the hottest H.M. record on the West Coast. This is an updated version of that EP, and while it lacks the slick assurance of "Out of the Cellar," it makes up for it with added speed and bite, particularly on the bracing guitar solo on "Walkin' the Dog."

ROUGH CUTT -- "Rough Cutt" (Warner Brothers 25286-1). As the spelling suggests, these five Los Angelenos are hoping to grab the same market that boosted Ratt into the top ten. But the group plays too safely to satisfy the hard-core metal maniac. Where Ratt relies on brute force to drive its hooks home, Rough Cutt slathers on harmony vocals, trading drive for gloss.

CELTIC FROST -- "Celtic Frost" (Enigma 72016-1). Instead of hard and fast, this L.A. trio goes in for slow and spooky, sounding like Black Sabbath "Paranoid" pushed to the nth degree. The murk gets a little thick at times, but there's enough power behind Celtic Frost's droning, groaning dirges to make it invigorating in small doses. Careful, though -- prolonged exposure may lead to an overwhelming urge to burn incense.

METALLICA -- "Ride the Lightning" (Electra 9 60396-1). From San Francisco, this quartet plumbs similar Gothic depths, but with more energy than Celtic Frost. Favoring throbbing, dirge-like ravers that owe a lot to later Black Sabbath, its only weakness is for overblown instrumentals like "The Call of Ktulu."

METAL CHURCH -- "Metal Church" (Ground Zero GZ 002). Metal Church sounds like what Iron Maiden might have become had that band continued to rely on its music instead of its special effects. With an approach solidly based on classic early '70s metal, but brought up to contemporary speed and intensity, this Seattle quintet delivers the best of both worlds, particularly through its fiery, blues-based guitar work. One of the best of the American Indies.

LOUDNESS -- "Thunder in the East" (Atco 90246-1). Leave it to the Japanese to come up with a generic heavy metal band name. Loudness is fairly typical of Japanese metal, favoring complex arangements and lots of flash, here provided by Akira Takasaki, Japan's answer to Eddie Van Halen. But Loudness is chronically short on originality, making this album a second-hand thrill at best.