Old age and earthquakes are believed to be responsible for a chimney fire in Yucca Valley early Monday morning. According to County Fire Captain Rick Denison, the mortar and bricks of a chimney in a home in the 56000 block of Sunset Avenue were cracked, probably from earthquakes and old age, allowing heat and fire to escape from the chimney into the walls surrounding it, and last night, the walls caught fire. Firefighters responded to the home just after midnight this morning to find the house filled with smoke and the fire had burned completely through the wall above the fireplace. The resident was using a garden hose to spray down the walls. Fire fighters tore down the wall and ceiling around the fireplace to find that the studs inside the wall had been charred over the years until last night, when the residents stoked the fire before bed, the studs started burning. Captain Denison reminds residents to have their chimneys inspected and cleaned regularly, and to install working smoke detectors in their homes.