Bricks and boards shattered by America's most destructive earthquake in four years littered the streets of this little town today as rescue workers attempted to clean up after a disaster that left 47 injured, every brick building downtown destroyed and houses on nearly every block knocked askew.

After Monday afternoon's strong quake, half of Coalinga's 7,000 residents were homeless and bulldozers were knocking down many of the shattered buildings the temblor did not quite topple. Gray-white brick dust covered nearly everything and aftershocks coming at the rate of two or three an hour shook broken windows and caused residents to dash back outside continually.

The 4:42 p.m. PDT quake registered between 6.1 and 6.5 on the Richter scale, in which each ascending number measures a 60-fold increase in strength. The ground rolled up and down like a wave at sea for 15 to 20 seconds and left residents here to survive a night of scattered fires and escaping gas.

Many were still sifting through the wreckage early this morning after sleeping in their cars or in the city's small parks overnight.

"It is absolutely remarkable no one was killed," said city manager Glenn Marcussen, standing near an old rooming house where the second-story brick walls had collapsed to reveal a bed and mattress.

The sudden quake, which emitted no preshocks to warn scientists, appeared to state officials today to foreshadow a colossal disaster for California's larger cities located in earthquake-prone regions. According to a federal report, Los Angeles, the nation's third largest city, has more than a 50 percent chance of a quake in the next 30 years strong enough to kill 3,000 to 13,000 people.

Nearly every unreinforced brick building in Coalinga collapsed yesterday. Los Angeles officials said today they have at least 8,000 similar structures in their city, and most of them are much larger than those here. A city ordinance passed two years ago allows another eight to 15 years before those buildings must be removed or reinforced. San Francisco, which also has thousands of unreinforced brick buildings, has yet to even survey such structures.

James Slosson, former California state geologist and a seismic consultant, said today a quake similar to the Coalinga temblor would cause "thousands" of casualties if it hit Los Angeles.

Franklin Lew, assistant superintendent of building inspections in San Francisco, said replacing the old structures there poses serious political and economic problems, because they house lower-income families now desperately short of space.

At least six of the aftershocks sweeping this small town 200 miles north of Los Angeles registered a Richter magnitude of 4, enough for a separate mention in the newspapers on normal days. City officials estimated downtown damage in this San Joaquin Valley area of oil fields and cotton, wheat and vegetable farms at about $25 million. They expected that figure to climb.

Like a blind snake making one wild bite, an earthquake usually does its serious damage very near its epicenter--in this case about five miles northeast of Coalinga. People as far away as San Francisco and Las Vegas said they felt the quake, but Coalinga was the only town near enough to feel the full force.

A U.S. Geological Survey spokesman said the quake appeared to occur on a small, relatively unknown fault 20 to 30 miles north of the long San Andreas Fault that threatens much of the California coast.

Deni Delano, 30, a teacher, was standing in the kitchen of her one-bedroom wooden house when the earthquake knocked it off its foundation. The floor buckled and dishes rained down on her.

Taken to the local hospital with a leg gash, she found a chaotic scene, with nurses in civilian clothing rushing in to help treat wounds and direct the most serious patients to outlying facilities that still had electricity. "Everybody was so covered with the dust from the bricks, they are such a horrible color, I thought one of them was gone, but then I saw he had hold of his little health insurance application in one finger," Delano said.

Her landlord promised to return the rent and told her to move out quickly since the house would soon be bulldozed with other damaged structures. For most Coalinga residents, earthquake insurance "is just too expensive," Delano said.

The country's last major destructive quake hit California's Imperial Valley in 1979, causing 100 injuries and $50 million in damage. A 1971 earthquake in the San Fernando Valley caused 65 deaths.

Stan Allen, news director at tiny KOLI-AM radio, said he found an eerie calm in the shattered downtown area when he walked out to take a look. The gas in the kitchen of the Coalinga Inn restaurant had ignited, eventually gutting the restaurant and Petty's jewelry store next door. But few if any people were panicking as they searched for friends and relatives, he said.

"If you had told me no one was going to be killed in this thing," said county sheriff sergeant Jerry Schmidt, "I would have called you every kind of liar."