Looking down on the endless maze of Los Angeles sprawl just before landing, after having observed the sparely populated, visually soothing Plains and Rockies. I asked myself.

Why would anyone subject himself to living in such an endless, claustrophobic jungle of cement?

My answer was only moments away at the end of the runway. It's the beaches.

East Coast beaches like Daytona, Sea Island, Myrtle, Nags Head, Virginia, Ocean City, Rehoboth, Atlantic City, Coney Island and Hyannisport may have earned your affection over the years. But beaches like Venice, Marina del Rey, Playa de Rey, Manhattan, Hermosa and Redondo - all within six miles of the Los Angeles airport - will win your love at a glance.

Pristine sand (natives insist with tongue in cheek that some of this sand was transported to Waikiki to form its beach, rolling waves, sweet salt air you are reluctant to exhale. And the people . . . they're beautiful. Golden-bodied, sunshine-haired, and firm.

EVEryone appeats so healthy. Middle-aged men ride skateboards and surf-boards with their sons and daughters. The older people jog. The kids ride skates. Everybody rides bicycles. Not to get - or stay - in shape. For fun.

Two days on the beach and I found myself jogging, riding a skateboard . . . doing pullups, yet. IN Washington, I ride an elevator one flight down and drive to the store two blocks away.

The rapidity of the transformation is amazing. In places like the Virgin Islands or Hawaii, you can feel the stress slowly draining from your body, After a week or so you grow relaxed, mellow and a bit lethargic.

But on THESE beaches it's like a magic elixir has banished all the bad blood, anxiety and tension. The adrenalin-like mixture makes you reluctant to release the sights and smells, and the emotions they engender, and go to sleep.

It starts just after dawn when the suffers converge in their wetsuits - average water temperature is 60 degrees, ranging from a summer high of 68 to a winter low of 50, while air temperatures average about five degrees warmer - former an irregular black dotted line just beyond the breakers.

Already on the scene when they arrive are the all-night pier fishermen; the few remaining blanket-wrapped lovers, reluctant or unable to quit their previous night's embrace, and the gulls.

They are followed by the treasure hunters, arriving between 8 and 9 a.m. with metal detectors to sift the sands for items of value misplaced by yesterday's beautiful people in their frolic.

The wide sidewalk beside the beach becomes crowded with joggers, bike riders and skateboarders - mostly in the middle and upper age groups - while younger adults straggle into the neighborhood restaurants to wipe away the cobwebs of last night's party with coffee before heading for work.

Now the first blankets and picnic baskets start dotting the beach, brought by mothers and their children. These are followed by teenagers who set up camp in prearranged spots to await this season's mates or alight at random to wait a new adventure. By late morning the last group, the young adults, ambles cat-like across the sands to absorb the best of the sun's tanning rays.

The first sunbathers begin to wander off around 4:30 p.m. to eat, meet mates returning from work, or prepare for early evening parties. Except for dwindling handfuls of children by the swings and a few handholding couples beside the water, the sand is barren by 5:30 p.m. Sufers now once more line the water on their boards where they will remain until dusk.

Older joggers and bke riders again crowd the sidewalk - replacing the teen-agers who occupied it in the heat of the day. Must - reflecting the mood of the crowd within - begins pouring from the bars and houses as darkness descends.

Through the evening, intermittent laughter and occasional surprised or delighted squeals eminate from the beach where groups or couples have once more wandered. The final laughter dies about 3 a.m. - and hour after the bars close - as (or because) you yourself fall asleep. Then you're up again at 7 a.m., because you don't want to waste any portion of the approaching day.

A few days here and you can understand why they don't seem to worry about earthquarkes. Given six months or so, I suspect I would not worry either.

Little niceties add to the scene.

Trucks sift the sands of the beaches each morning, cleaning whatever debris was left by the previous days picnickers.

The piers are free, unlike the East Coast ones you pay to go out on. And they're clean, nicely kept cement.

They have benches on them to sit and sinks for cleaning the fish you catch.

The beaches have exercise bars and swings, and restrooms, and showers for washing the sand off when you leave - all free. There are free buses!

Exorbitant taxes and prices are apparently not the things with which these accoutrements are purchased. Property taxes were reduced recently at one of the beaches.

Prices for food, housing and clothes appear to be somewhat lower than in the Washington area and, while the purchase price of housing is high - as at any beach - rents are not outrageous and utilities are ridiculously low. One landlord said the electricity cost for his main and rental house, combined, was $24 per month. The gas bill was $14.

My base has been a motel room over-looking Hermosa Beach, between Manhattan and Redondo. It was the only direct beachfront motel I could find after driving along all three. While there, I was told by several people that Hermosa was the least desirable beach in the area . . . that I should go north, toward Santa Monica . . . that I should go south, down to La Jolla or San Diego. These may well be nicer, but if they are, I'm not ready for them.