Sounds like the damage was trivial, perhaps akin to plucking cactus spines from your rear end. I guess the commander "got even" in a very true sense.
>>"An ad hoc pow-wow is convened in officers' quarters to choose a suitable target, using a list of West Coast locations drafted prior to the aborted Christmas Eve shelling last year. The waterfront of San Francisco and the town of Castroville are among the rejected objectives. Lt Yamazaki Atsuo, engineering officer of I-17, finally suggests they bombard Ellwood's oilfields off Santa Barbara. His suggestion is approved, since it provides an easy access and escape route."<<
http://www.combinedfleet.com/I-17.htm
Edit: I also found this:
>>"Local legends, according to Hough, maintain that Nashino targeted Goleta because oil workers mocked him after he allegedly tripped and fell into a patch of cactuses in front of an off-duty working crew. After this humiliation and mockery, Nashino, an oil tanker captain at the time, swore revenge.
Hough said he disputes this legend entirely.
“He was a career naval officer and, thus, had never worked as a farmhand in Goleta,” Ken said. “The story of him being a captain of an oil tanker that stopped at Ellwood where he came ashore and fell into a cactus patch is not true. It’s a long told Santa Barbara legend, which may have happened to someone, but not to Captain Nishino.”"<<
http://dailynexus.com/2013-02-28/goleta-remembers-oil-field-...
San Diego, Los Angeles - Long Beach. Malibu. Ventura. Santa Barbara. Pismo Beach. Big Sur. Carmel. Monterey. Castroville. Santa Cruz. Pacifica. San Francisco. Eureka-Arcata.
And that's along some 800 miles of coastline. Only the starred cities are of any particular size now, and most would have been far smaller during WWII. The Japanese may have chosen to avoid cities as they were more likely to be effectively defended.
Santa Barbara's oilfields would have been a modestly significant strategic target, though US oil facilities elsewhere, particularly in Texas, were vastly larger. California also had major inland fields near Bakersfield, Taft, and throughout the Los Angeles basin.