The New York Times March 28, 1988, Monday, Late City Final Edition An Irish Songwriter Shows Her Volatility By JON PARELES Passion is volatile in Sinead O'Connor's songs; within a verse, it can become love, anger, lust, vulnerability, defiance or religious fervor. The songs on her debut album, ''The Lion and the Cobra,'' carefully channel those raw emotions, shifting unpredictably from plea to accusation or from meditation to rock stomp; her voice can be sweet or lacerating, delivering endearments in a bitter rasp or breaking into wordless ululation. On Saturday, with ''The Lion and the Cobra'' now in the Top 50, the Irish songwriter gave her first New York City concert at the World, which sold out weeks in advance. Miss O'Connor, who is in her early 20's, looked like a post-apocalyptic waif on stage with her head shaved and wearing a black outfit - abbreviated leather jacket (quickly doffed for a halter top), tutulike skirt, tights and shoes - that brought out her pale complexion. But beyond her striking appearance, she's just learning how to project her songs to a concert audience. She stands nearly still, gripping the microphone stand with both hands, sometimes swaying or doing a side-to-side, heel-and-toe shuffle; as she concentrates on her singing, the song's beat seems to leave her unmoved. For the first part of the set Ms. O'Connor and her band re-created the songs from the album, barely changing arrangements or vocal inflections; the sudden snarls in ''Jerusalem'' and the tenderness in ''Just Like U Said It Would B'' arrived on cue, whereas the album sounds daring and spontaneous. Although the performance lasted barely an hour, Miss O'Connor introduced three unrecorded songs, two rockers about lovers locked in battle and a lullaby with religious overtones. As with her other songs, they are odd combinations of clicheed images (kisses tasting like wine, for instance) and fierce, blunt statements whose conviction is unassailable. By the end of the concert, Miss O'Connor seemed less diffident. Her encore, ''Troy,'' was an fierce solo; she accompanied herself on 12-string guitar, spat out the song's bitter questions (''Do you love her? Does she hold you like I do?'') and raked the audience with a baleful gaze. It is possible that Miss O'Connor is simply adjusting from folky solo performing to leading a rock band, and that she hasn't yet found her own theatrical equivalent of the rock beat. While she learns, though, her voice and her songs will carry her. She is scheduled to appear April 25 at the Ritz, 119 East 11th Street.