The shutdowns, which were taken as a precaution, were not expected to disrupt Hawai'i gasoline supplies.

"Due to the fact that (the shutdown) was triggered by an earthquake we do have more robust procedures to go through to make sure the integrity of our plant is not compromised," said Chevron spokesman Al Chee.

Tesoro's Kapolei refinery is expected to resume gasoline production tomorrow, said company spokesman Nathan Hokama.

"The startup process is underway. There are no short-term supply issues," he said.

The refinery, which had power restored at about 6 p.m. yesterday, plans to bring various units back on line over the next several days, Hokama added.

Tesoro officials conducted "safety assessments" following the outage and detected no damage to the refinery. In addition, all Tesoro gas stations are open for business, Hokama said. The stations experienced a surge in gas purchases following the resumption of power, he added.

Tesoro's Kapolei refinery handles 94,000 gallons of oil per day and produces a range of products, including gasoline, jet fuel, diesel, heavy fuel oils, liquefied petroleum gas and asphalt.

Sunday's earthquakes were not expected to have any noticeable impact for most drivers. However, temporary supply disruptions were expected in Kona following the closing of Kawaihae Harbor, the only facility for unloading heavy cargo vessels in West Hawai'i. The harbor was closed because of possible structural damage to the harbor pier.