SAN FRANCISCO (Reuters)- A massive underground shelter to shield business executlves and their records frum nuclear bomb attacks or civil insürrections Ís being planned in central California. Bekins Moving & Storage Co. , architect of the plan, said it haa bought land for a shelter capable of housing 1, 000 executives and office personnel 40 feet underground for up to 30 days. A brochure the firm is using to promote the bunker among large U. S. corporations calis it a corporate survival center. lts main purpose will be to protect such firms in the event of nuclear war, but Bekins officials here said it would help offset increasing fears within the business world over rioting, bombing attacks, and destruction of files. The shelter, which will be topped by a jet landing strip for quick cess, will house a computer center, a Communications center, a large records storage unit, offices, living quarters, a morgue, and a cafetería able to serve 1, 000 persons in 90 minutes. The space put aside for offices can serve as alternative headquarters for a limited number of business firms during any emergency, the brochure said. Bekins officials said construction of the bunker was tentatively scheduled to begin next year on a 200acre ranchland site in the Diablo Mountains near Coalinga, midway between San Francisco and Los Angeles. Soma firms, the officials said, were thinking of moving into the underground complex as soon as it was ready and setting up alternative headquarters there. Banks, oil companies, construction and manufacturing firms are among those said to be interested. Space inside the shelter would be leased to them at $100, 000 a year each on a 10-year lease.