Remove author archive

I would filter template_redirect, with an is_author() conditional, e.g.:

function theme_slug_redirect_author_archive() {
    if ( is_author() ) {
        // Put your redirect code here;
        // Redirect to home_url(), or 
        // return a 404, or whatever
    }
}
add_action( 'template_redirect', 'theme_slug_redirect_author_archive' );