The pilot reported that during the preflight inspection, the fuel gauges indicated that each tank was half-full. The pilot did not visually inspect the fuel tanks to verify the fuel gauge's indicated reading. After a 40-minute local flight, the engine lost power during the right turn to the base leg of the airport traffic pattern. The pilot recalled that airplane's fuel gauge indicated that ¼ of the fuel capacity remained. He forced landed in a "flat" attitude on the desert. The nose landing gear dug into the soft, dry surface and the airplane nosed over. The airplane sustained substantial damage to horizontal stabilizer and the rudder. Additionally, the pilot reported that the accident could have been prevented by visually inspecting the fuel tanks using a fuel stick to assess the airplane's fuel quantity. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.