Why L.A. is laughing at ''Volcano''

In Volcano, Wilshire Boulevard becomes a toxic fondue, and all that volcanic ash in the air means one very-bad-hair day. So why have Angelenos been yukking it up at preview screenings? Because the movie is packed with geographical references, local celebrities, and mordant in-jokes. A quick tour:

· The molten rock cascading into an L.A. subway stop alludes to problems with the city’s controversial fledgling subway system, which has endured fires, sinkholes, and charges of poor engineering since its construction began in 1986.

· A seismologist named Rachel (Laurie Lathem) sports the same close-cropped hairdo worn by Cal Tech’s Dr. Kate Hutton, a calming presence on L.A. TV, where she frequently offers the first official word on a quake’s magnitude.

· The garish station wagon plastered with ads pleading for work and sucked into the lava flow is an exact copy of an actual self-promotional vehicle owned by local would-be actor Dennis Woodruff.

· KCBS reporter Harvey Levin, always an enthusiastic participant in disaster coverage, is one of the 45 media folks who make cameos as themselves in the movie.

· One of the city’s ubiquitous billboards for the pneumatic, self-proclaimed celebrity Angelyne bursts into Sodom-and- Gomorrah-esque flames.

· The Ballona Wetlands, which figure in the crisis’ resolution, have become famous as the habitat that determined environmentalists are trying to save from the Playa Vista/DreamWorks development.

· A subway conductor is seen reading a book…on how to write a screenplay.