Starting in the 20th century , the use of brickwork declined in some areas due to concerns with earthquakes . Earthquakes such as the San Francisco earthquake of 1906 and the 1933 Long Beach earthquake revealed the weaknesses of unreinforced brick masonry in earthquake-prone areas . During seismic events , the mortar cracks and crumbles , and the bricks are no longer held together . Brick masonry with steel reinforcement , which helps hold the masonry together during earthquakes , was used to replace many of the unreinforced masonry buildings . Retrofitting older unreinforced masonry structures has been mandated in many jurisdictions
San Francisco earthquake of 1906
1906 San Francisco earthquake
Brick