Repair of Earthquake-Damaged Masonry Fireplace Chimneys, South Napa Earthquake Recovery Advisory [open pdf - 2MB]
"The August 24, 2014 South Napa Earthquake has again served as a reminder that masonry chimneys in wood‐frame dwellings are extremely vulnerable to earthquake shaking. FEMA assessment teams observed over 100 brick masonry chimneys damaged in the South Napa Earthquake (Figures 1 and 2). Older, unreinforced masonry chimneys with degraded mortar are most vulnerable, but even masonry chimneys constructed according to modern standards are susceptible to significant damage. Collapses of previously damaged and reconstructed chimneys were also observed. This Recovery Advisory recommends best practices for reconstruction of earthquake-damaged masonry chimneys in one- and two-family dwellings to minimize risk of damage in future earthquakes."
Federal Emergency Management Agency: http://www.fema.gov/