RIVERSIDE, Calif. -

The average price of a gallon of self-serve regular gasoline in the Inland Empire today recorded its largest daily increase since Oct. 7, rising nearly two cents to $3.676.

The 1.9-cent increase is the result of crucial equipment at the BP refinery in Carson being de-activated for unplanned maintenance and the catalytic cracker at the Chevron refinery in El Segundo being shut down as well, cutting supplies, according to industry analyst Bob van der Valk.

Catalytic cracking is a critical step in turning petroleum into gasoline.

The average price in Riverside and San Bernardino counties is now 4.6 cents more than one week ago and 8 cents higher than one month ago but 4 cents less than one year ago, according to figures from the AAA and Oil Price Information Service.

The average price has increased 18 times in the past 20 days, rising 13.2 cents over that span, after falling to its lowest amount in exactly one year, $3.544, on Dec. 27.