Southern CA, Northern CA, Pacific Northwest
 
OVERVIEW

Southern California


Southern California is in the process of developing and implementing seismic retrofit programs to reduce the risk of earthquake-related damage to buildings and promote life safety by addressing the problems that make specific building types vulnerable to seismic events. Vulnerable buildings in Southern California include Soft Story buildings, Non-ductile Concrete Buildings, Unreinforced Masonry Buildings, and Pre-Northridge Steel Moment Frames. These building types are proven to be vulnerable to severe damage or collapse during an earthquake, so retrofitting can improve the safety of building occupants during an earthquake.


Why is retrofitting important in Southern California? Southern California is home to a vast, interconnected fault system. Far from smooth, this system is locked in a tectonic battle over which areas will give way. Tectonic forces are continually tightening the springs of fault systems such as the San Andreas, making large and moderate sized earthquakes inevitable. Retrofitting is important because it can reduce earthquake-induced building damage and aims to allow occupants to safely exit the building during an earthquake.

 


Map of Known Faults in Southern California:

 


Map Source: USGS

 

 

Map of Previous Earthquakes in Southern California (Magnitude 5 and greater):

 

Map Source: USGS

 

 

USGS Earthquake Forecast for Southern California:

 


Source: USGS UCERF3

 

Cities in Southern California are at different stages of reducing earthquake-related risk. Some cities have passed ordinances addressing all four vulnerable building types, and many others are currently developing ordinances to reduce risk associated with vulnerable building types.

 

 

 

Northern California

 

Northern California is also in the process of developing and implementing seismic retrofit programs to reduce the risk of earthquake-related damage to buildings and promote life safety by addressing the problems that make specific building types vulnerable to seismic events. Cities enact seismic retrofit programs by passing seismic ordinances, laws requiring the assessment, and retrofit of these specific building types. Ordinances specify minimum requirements for mandatory structural improvements intended to promote public welfare and reduce the risk of death or injury that may result from the effects of earthquakes on vulnerable buildings. The structural improvements, or retrofits, reduce earthquake-induced damage to the building and ensure that occupants are able to exit the building safely during an earthquake. Vulnerable buildings in Northern California include Soft Story buildings, Non-ductile Concrete Buildings, Unreinforced Masonry Buildings, and Pre-Northridge Steel Moment Frames. These building types are proven to be vulnerable to severe damage or collapse during earthquakes, so retrofitting can improve the safety of building occupants during an earthquake.

 

Why is retrofitting important in Northern California? Northern California is home to a vast, interconnected fault system. Far from smooth, this system is locked in a tectonic battle over which areas will give way. Tectonic forces are continually tightening the springs of fault systems such as the San Andreas, making large and moderate sized earthquakes inevitable. Retrofitting is important because it can reduce earthquake-induced building damage and aims to allow occupants to safely exit buildings during an earthquake.

 

 

Map of Known Faults in Northern California:

 


Source: USGS

 

 

USGS Earthquake Forecast for Nothern Califronia:

 


Source: USGS UCERF3

 

 

Cities in Northern California are at different stages of reducing earthquake-related risk. Some cities have passed ordinances addressing all four vulnerable building types, and many others are currently developing ordinances to reduce risk associated with vulnerable building types.

 


Certain Information Compiled from: SF, Alameda, Fremont, Oakland

 

 

Pacific Northwest

 

Portland, OR
Portland is in the process of developing a retrofit ordinance for Unreinforced Masonry (URM) buildings. Currently there are approximately 1,800 URM buildings in the City of Portland.

 

Seattle, WA
Seattle has completed a URM building inventory list and mailed notifications to building owners. Seattle is in the process of developing a retrofit ordinance for URM buildings.