An 18-year-old man suffered head and chest injuries Saturday night after a 100- to 200-pound boulder struck him during a partial cave-in at More Mesa east of Austin Road, according to Captain David Sadecki of County Fire. Four UCSB students — including the injured man, whose name and condition aren’t being released — were in the five-person-capacity cave at the time when a section detached overhead that the victim was holding onto, Sadecki said. Firefighters used ropes and a hard stretcher to rescue the student, which took about 30 minutes; he was taken to Cottage Hospital. According to Sheriff’s Office spokesperson Kelly Hoover, this incident marked the third cave-in in 10 years; in 1989, a cave-in at More Mesa Beach killed a 17-year-old. The caves have sparked concerns among nearby homeowners, who worry bonfires could spread to the bluffs. Hoover said the Sheriff’s Office, County Fire, and the Austin Road Homeowners Association have monitored the caves for two years and have informed the property owner — who lives out of town — of the concerns.