OVER ROTATION CAUSES A TAIL STRIKE.

Narrative

ON TKOF FROM SNA; WE FELT A 'THUMP' DURING ROTATION. WE SUSPECTED A POSSIBLE TAIL STRIKE -- A SUSPICION FURTHER STRENGTHENED WHEN THE FLT ATTENDANTS CALLED AND SAID IT FELT LIKE WE WENT OVER A SPD BUMP. WE CONTINUED THE DEP AND 'WENT TO THE BOOK' AFTER GETTING TURNED OVER THE ZLA. THE CAPT; WHO MADE THE TKOF AND HAD BEEN FLYING; TURNED THE CTLS AND CTR OVER TO ME WHILE HE GATHERED INFO AND READ THE ABNORMAL CHKLIST. WE TOLD CTR WE WISHED TO START A DSCNT (ABOUT 20000 FT) FOR THE PURPOSE OF PRESSURIZATION. EVENTUALLY WE GOT DOWN TO 8000 FT AND OPENED THE OUTFLOW VALVE PER THE CHKLIST. THE CAPT WAS WORKING WITH DISPATCH; LAX OPS AND MAINT CTL TO DETERMINE THE BEST COURSE OF ACTION. THERE WERE NO ADVERSE INDICATIONS IN THE ACFT OTHER THAN THE INITIAL THUMP. AFTER CONSIDERING FUEL; WE ELECTED TO LAND AT OAKLAND; OUR ORIGINAL DEST. A VERY GRADUAL DSCNT WAS MADE OUT OF 8000 FT TO TRY NOT TO EXCEED 500 FPM. AN UNEVENTFUL LNDG WAS MADE IN OAK. MAINT INSPECTED THE ACFT AND FOUND THE TAILSKID WAS NOT COMPRESSED AND THE SHOE WAS SCRAPED BUT WITH LIMITS. THEY SIGNED OFF THE ACFT AND WE PROCEEDED WITH OUR NEXT FLT. SUPPLEMENTAL INFO FROM ACN 312117: I HAVE BEEN FLYING THE B737-400 FOR ABOUT A YR AND A HALF; DURING WHICH TIME I HAVE MADE NUMEROUS SNA NOISE ABATEMENT DEPS. I HAD MADE 5 SNA NOISE DEPS DURING THE PREVIOUS MONTH. THIS ROTATION DID NOT FEEL ANY DIFFERENT THAN ALL THE REST I HAVE MADE; AND I AM STILL UNSURE OF WHY I HAD A TAIL STRIKE.