No doubt some law of physics about the nature of too-long-compressed energy can explain the nuclear power of Etta James’ “Burnin’ Down the House,” the explosive blues matriarch’s first live recording in more than 20 years.

Fueled partially by her blaring backup band, the dynamo shouts out bluesy odes to the joy of sex with her opening anthem, “Come to Mama.” On Willie Dixon’s “I Just Want To Make Love to You,” there are even steamier shouts and cries celebrating the sensual as James struts her stuff like a one-woman blues roots band.

But don’t think James is just a one-note or one-mood diva of earthiness. She’s also capable of evoking a rich variety of emotions and expressions in the grand manner of such legendary powerhouse singers as Dinah Washington, Ruth Brown and Big Maybelle.

At the heart of her great talent are her gospel roots, which come shining through with true grit, heat and vitality on “I’d Rather Go Blind.” Her voice, even for all its rough-hewn power and glory, can be warm, soulful and sometimes even delicate as hallelujah gospel keyboard licks wail away behind her.

Basically, every song James sings becomes her own property. “All the Way Down,” for example, may be out of the disco era, but she gives it a street-smart edge, an all-knowing New York state of mind.

“At Last,” one of her many big hits, has long been her own form of expression, sometimes tender, from the heart but always hip and laced with original, beautiful, edgy twists and turns.

Richard Rodgers might not have approved of the inventive liberties she takes with his classic melody. Nonetheless, these earthy, expressive Jamesian passages, both here and throughout the disc, cry out for more live recording sessions.