On June 26, 1996, about 1330 hours Pacific daylight time, a Cessna R172K, N1133V, was substantially damaged after colliding with terrain near Oroville, California. The pilot was seriously injured. The flight originated from Nevada City, California, on the day of the accident at an undetermined time. Visual meteorological conditions prevailed for the personal flight and no flight plan was filed. A Butte County Sheriff's helicopter was passing the accident area and spotted the downed aircraft. The helicopter landed near the accident site and transported the injured pilot to a hospital. The aircraft was moved to a secure storage area where it was examined by representatives from the airframe and the engine manufacturer under the guidance of an FAA inspector. Neither the pilot's logbook nor the aircraft logbooks were recovered. The damaged propeller was replaced with a serviceable propeller and the engine was started and ground run for several minutes. The examination of the damaged propeller blades revealed chordwise striations, gouging and bending. Both VHF communication radios were set for a common traffic advisory frequency of 123.00 MHz with both nav receivers set to Marysville VOR, and the ATC transponder was set for a VFR 1200 code. According to participants in the investigation, the aircraft landed with excess speed without flaps, 90 degrees from a suitable landing direction. According to family members, on the day of the accident it was the pilot's 47th wedding anniversary. The pilot was involved in a divorce and had visited his attorney on the morning prior to the accident. He had also just completed radiation therapy for prostate cancer.