The Kenai Fire Department and Enstar Natural Gas are conducting separate reviews of the gas leaks, explosions and fires that destroyed four houses in Kenai following Sunday's 7.1-magnitude earthquake centered 60 miles west of Homer.

Enstar is conducting a standard review, said Lindsay Hobson, a spokeswoman for the company. The purpose of the effort is "to see if there's anything that can be learned or improved," she said. "That's just part of the process. We haven't drawn any conclusions at this point."

The company that delivers natural gas to about 140,000 customers across much of Southcentral Alaska is keeping regulatory agencies informed of its efforts, including the U.S. Pipeline and Hazardous Materials Safety Administration that regulates the transportation of hazardous materials.

A spokesperson with the agency said it is monitoring the situation in Alaska.

"Enstar reported to PHMSA that a portion of its distribution system was shut down as it investigated reports of a fire and explosion in Kenai, including whether it was related to (the) earthquake," said Damon Hill, with the agency's Office of Governmental, International and Public Affairs. "PHMSA has not received any other pipeline safety concerns in Alaska at this time."

Hilcorp Alaska, the dominant oil and gas producer in Cook Inlet, reported no injuries or major damage to any of its facilities.

"We immediately initiated onsite inspections of our facilities in the area and did an aerial inspection as early as possible on Sunday morning of all pipelines and facilities," said Lori Nelson, external affairs manager at Hilcorp Alaska.

"Swanson River operations were without power temporarily, only resulting in minor process upsets," she said. "We also experienced temporary outage of some compressors in the system but we were able to still meet the demands of local utilities without interruption."

Enstar is conducting a leak survey over its entire system from Homer to north of Houston to detect natural-gas leaks. It will take about a week to complete, Hobson said.

"We do this on annual basis routinely and then after a major earthquake," she said.

The earthquake led to a surge in calls to the company from homeowners worried about gas leaks.

The company responded to about 80 calls on Sunday and early Monday morning, repairing about 60 leaks across its distribution area after callers sought checks of gas meters and appliances. The company usually receives about 60 calls a week.

It's unknown how many of the leaks, if any, were caused by the 1:30 a.m. earthquake. Hobson said most of the calls were "routine, above-ground gas leaks."

Enstar urged the public through its Facebook page at 3:16 a.m. on Sunday to look for natural-gas leaks. That warning, and the increased concern related to the earthquake, may have prompted more calls.

"The leaks could have been caused by the earthquake or they might not have been, but the important thing is we have fewer leaks today, and we repair every leak," Hobson said.

Only one leak was below ground, in a distribution line in the Mountain View neighborhood in northeast Anchorage.

"Any underground gas leak is considered an emergency, but this was set back in an alleyway away from homes and residents, so there was a very, very low risk associated with it," she said. "And it's no longer leaking. It's fully repaired."

Jeff Tucker, Kenai Fire Department chief, said the department suspects there were two separate gas leaks at the Lilac Lane fire associated with two different homes that led to the explosions and fires. He said the fire marshal and an investigator are looking into the incident.

"We have nothing to suspect it's anything beyond the earthquake" that caused the explosions, Tucker said.