Amoco Corp. has reported a 69 percent increase in earnings in the fourth quarter, based largely on oil prices that soared because of the Persian Gulf crisis.

The Chicago-based oil giant said it earned $538 million, or $1.07 a share, compared with $319 million, or 62 cents a share, in the final three months of 1989. Revenues for the period were $9.2 billion, compared with $6.8 billion in 1989.Amoco had also racked up third-quarter profits that were 57.7 percent higher, and it said the year's earnings amounted to $1.913 billion, or $3.77 a share. That was 19 percent higher than 1989's figures of $1.610 billion, or $3.12 a share.

Revenues for 1990 totaled $31.6 billion, compared with $26.8 billion in 1989.

Amoco became the first major oil company to release earnings for a quarter in which the petroleum industry was expected to reap huge profits, as companies raked in a higher price for oil they produced at the same time they saw improved profit margins for refined products.

Chevron Corp. had recently predicted its fourth-quarter earnings would be so big that it anticipated a political attack from oil's critics.