San Luis Obispo County supports plans to conduct high-energy seismic surveys offshore of Diablo Canyon nuclear power plant but wants to make sure the best technology is used and fishermen are adequately compensated.

That’s the crux of a letter the Board of Supervisors on Tuesday will consider sending to state officials a week before a crucial hearing in Sacramento. Supervisor Bruce Gibson, who has a doctorate in geophysics, has publicly questioned whether PG&E plans to use the best available technology when it conducts the three-dimensional surveys late this year.

The letter, written by Gibson, would ask the state to have an independent panel of industry experts such as petroleum geologists review PG&E’s plans. Gibson said he believes that larger survey equipment used by private industry could yield better results than the academic research technology proposed by PG&E.

“Given the significant environmental and economic impacts, we realistically have only one opportunity to do a survey of this magnitude — this survey must be done right,” the proposed letter concludes.

Consideration of the letter is scheduled for the supervisors’ afternoon session Tuesday. The State Lands Commission will hold a hearing Aug. 14 in Sacramento to decide whether to approve the seismic surveys.

Gibson and three local environmental groups unsuccessfully petitioned the commission to hold the hearing in San Luis Obispo. “We believe the growing public interest would be well served if the meeting were held close to where the most potentially affected individuals reside,” Gibson said in a letter to the commission.

Curtis Fossum, the commission’s executive officer, said the state’s budget deficit prevents moving the meeting to San Luis Obispo. “For those unable to attend, the commission meetings are webcast at www.cal-span.org,” he said.

PG&E plans to use the research vessel Langseth to tow an array of 18 air guns through the water in grid patterns from approximately Cambria to Guadalupe. The surveying would take 41 days. The air guns would emit loud sounds into the ocean that penetrate Earth’s crust. Echoes would be picked up by hydrophones towed by the vessel as well as by stationary underwater and onshore receivers.

The resulting three-dimensional images of the earthquake faults near Diablo Canyon are intended to give seismologists a better picture of the seismic danger facing the nuclear power plant.

Jearl Strickland, director of nuclear projects at Diablo Canyon, will give a presentation to supervisors Tuesday outlining the qualifications of the scientists who designed the seismic surveys. He will also argue that the surveys should go forward as planned.

One of the main environmental concerns of the surveys is the harm they could do to marine wildlife, sea otters and fisheries in particular. The loud sounds emitted by the air guns could injure wildlife or drive it away from the area, and fishermen will not be allowed to fish in the areas where the surveys are being conducted.

PG&E has offered local fishermen $1.2 million in compensation for lost catches based on recent landing records, Strickland said. The fishermen have not accepted the offer, and negotiations continue.

In addition to the State Lands Commission, the National Science Foundation is preparing an environmental analysis of the surveys. It will cover the environmental impacts of the surveys on federal waters, which begin three miles from shore.

The foundation will hold a public hearing from 7 to 9 p.m. Wednesday in the Board of Supervisors chamber in the County Government Center, 1055 Monterey St. in San Luis Obispo.