(SFGate) - The wine industry suffered more than $83 million in damage from the magnitude 6.0 earthquake that rocked the southern part of Napa County on Aug. 24, according to a report released Tuesday by Silicon Valley Bank.

The report was commissioned by Napa County officials and the Napa Valley Vintners trade group to help winemakers seek federal assistance in rehabilitating the area's bedrock industry.

Rob McMillan, the bank's executive vice president, said the damage estimate was conservative and could rise as vintners hire contractors to come in and give estimates on needed repairs. Ultimately, the losses could fall between $70 million and $100 million, McMillan said.

"Bulk wine made up the majority of losses," he said. "But you also have to factor in that a lot of these people will be out of the market for a year and will have to rebuild their brand."

The report said roughly 60 percent of wineries in Napa County sustained some damage, with 25 percent suffering moderate or severe damage exceeding $50,000. The hardest-hit winery, which the report did not identify, had about $8 million in quake-related damage.

The majority of the damage was confined to the southern and western parts of the county, though there was less damage near the epicenter in American Canyon than expected. Wineries near Mount Veeder, Yountville, Oak Knoll and the Carneros region were said to suffer the biggest losses.