May 19, 2020

Earthquake Safety: Retrofitting Homes and Planning for Multiple Risks in Puerto Rico and Communities at Risk

Earthquake-damaged building

Earthquake events can be sudden, frequent, and last for long periods of time – and when home structures fail, it is deadly. A 6.4 magnitude quake rocked the communities of southern Puerto Rico in early 2020, and thousands of aftershocks have continued to affect Puerto Rico’s southern communities. Approximately 33,000 homes have been damaged, and more than 6,000 families have been displaced. Some of them have yet to go home. 

On April 29 Enterprise hosted a webinar entitled, “Why is Puerto Rico Shaking? How to Keep Homes and Communities Safe from Earthquakes,” which was attended by more than 1,400 participants from throughout Puerto Rico and around the world. 

The webinar offered practical information on resilient housing design and construction, including: 

  • Why earthquakes occurring in Puerto Rico and the future risks
  • What happens to housing in an earthquake
  • How to assess the damage and stabilize housing
  • Best practices and methods for mitigating (and minimizing) earthquake damage and resilient rehabilitation

You can view the slides that accompany the recording of the training (Course number: 24478, Preferred Provider Program ID: 2067). 

Trainers included representatives from many organization across and outside Puerto Rico, including: 

Within a week of our session, another 5.5 magnitude earthquake struck the Peñuelas municipality, displacing an additional 50 families who were self-quarantining from Covid-19 in their homes. Additional seismic activity and upcoming risk from storm season threatens tens of thousands more households. 

Key Points: How to Keep Homes and Communities Safe From Earthquakes

  1. Understand house placards. It is important to consult with a building professional to identify the risk of housing after an earthquake before re-entering the structure. “The Applied Technology Council (ATC) explained the differences between three building earthquake assessment tags. If a placard is yellow or red, the house should not be reoccupied until it is repaired and certified for occupancy. In some cases, reevaluation may require an engineering evaluation by an engineer engaged by the owner.That engineer would provide a report, or a retrofit design, to the Authority Having Jurisdiction.” According to Miyamoto International, Guanica is the most earthquake-affected municipality in Puerto Rico. Out of approximately 8,000 homes, 1,300 were yellow-tagged, and 689 were red-tagged, 280 of which collapsed, resulting in a damage ratio of 25 percent.

Earthquake damage placards

  1. Consider and balance multiple risks when rebuilding homes. Earthquakes are a frequent risk to Puerto Rico’s southern communities, exposed to three fault lines. Particularly vulnerable are those communities in or near the flood plain. It is important to prioritize critical risks that could damage structure (earth movement and load) as well as impact the health and wellbeing of residents (mold, ventilation). See our Keep Safe Guide for information on balancing these risks.
  2. Rebuild to code. This will ensure housing is safe from structural failure. FEMA’s P-530, Earthquake Safety at Home, will help identify code compliant building strategies, information about evaluations and repair guidance. Always consult a certified engineering professional when fixing earthquake impacted homes. 
  3. Retrofit – don’t repair. According to Build Change, retrofitting should be the goal of post-earthquake housing work because: 
    • Repair addresses damages only, does not resolve structural deficiencies and it is unknown how these repairs will perform in a disaster. 
    • Retrofit evaluates the structure, adheres to a life-safety performance standard and has predictable performance in a disaster.
  4. Ensure community shelters support multiple needs. Communities should consider specific health and social needs of evacuees (including the need for physical distancing), systems to provide energy and spatial distance, as well as programming for occupants. Red Cross has provided guidance on shelter setup and many rules will reduce the number of individuals that can stay in a shelter. For additional information, check out Keep Safe | Communities Together, a guide for resilient community center design in island communities. 

Additional Resources 

Direct Assistance

  • Voluntary Engineers of Puerto Rico helping communities assess the damage of housing and identify repairs:  
  • Miyamoto International online resource center or earthquake relief support: https://www.facebook.com/MiyamotoPuertoRico/
  • ConPrometidos forms alliances among organizations and communities to deliver support
  • Recommended notification alert system: http://redsismica.uprm.edu/english/ and https://earthquake.usgs.gov/ens/
  • Heart 911, U.S.-based organization providing direct support on home repair
  • Direct Relief - Earthquake Strikes Puerto Rico, Direct Relief Mobilizes Response
  • Federal assistance: https://www.disasterassistance.gov/ or DisasterAssistance.gov/es in Spanish. Calling 1-800-621-3362, a hotline with multilingual Disaster Survivor Assistance operators. Visit www.FEMA.gov/DRC  to locate the nearest center, or text DRC and your zip code to 43362.
  • Puerto Rico for more information and assistance https://www.ddec.pr.gov/terremotos/ and https://levantatunegociopr.com/
  • PRoTechos is a non-profit corporation founded with the dual mission of rebuilding damaged roofs.
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