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Post Event Report: Mw 7.2 Haiti Earthquake: August 14, 2021

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Event Headlines

  • A large Mw 7.2 earthquake erupted Saturday August 14, 2021 on the Enriquillo-Plantain Garden Fault Zone in southwest Haiti, 78 miles west of the capital of Port-au-Prince, Haiti.
  • Significant damage is being reported across southwest Haiti, with recovery efforts hindered by heavy rainfall associated with Tropical Storm Grace and political instability.
  • Initial damage reports in the capital of Port-au-Prince are not as devastating as was seen in 2010 when 200,000-300,000 fatalities occurred. The 2010 event was only 15 miles west of Port-au-Prince. The 2021 earthquake was two times more powerful than the 2010 Mw 7.0 Haiti earthquake. Due to the convergence of the North America and Caribbean plates, Haiti and other northern Caribbean countries are susceptible to large earthquakes.

 

 

Shake Intensity Map of M7.2 Haiti Earthquake. Source: USGS.

Regional Impacts

As of Monday August 16th, the Haiti death toll stands at 1,297 people with at least 5,700 additional injuries. The US Geological Survey is estimating high levels of casualties and widespread disaster as a result of the earthquake, with a 35% likelihood of fatalities between 10,000 and 100,000 people and a more dire 37% likelihood of fatalities in excess of 100,000 people.  Economic losses will be significant as well, with a 36% likelihood of economic losses between $1.0bn to $10.0bn, with a 25% likelihood losses are in excess of $10bn. Outside of the capital of Port-au-Prince, insurance penetration for earthquakes is minimal, and thus the majority of the loss is likely to be uninsured.

 

 

Estimated Fatalities and Economic Losses. Source: USGS Pager Report.

Notable Impacts by Sector

Haiti is challenged to develop any building practices to endure strong earthquakes, as limited
construction practices only contemplate the implications from windstorm. The majority of construction on Haiti is performed without consideration of building codes, best practices, or code enforcement, resulting in low building quality compared to most of the world. Most multi-family or commercial risks are concrete construction that lack design to endure significant earthquakes. Thus, across southwest Haiti, reports of widespread devastation of nearly all structures is likely due to the significant vulnerability of the building stock. Nearly 7,000 homes have been reportedly destroyed with another 5,000 enduring significant damage. 82% of single family dwellings are made of sheet metal roofs with walls of brick, concrete or stone.

 

 

 Collapsed Building in Petite-Rivere-de-Nippes, Haiti. Source: Mercy Corps.
The most significant concern for Haiti is the humanitarian aspect of the event. Recent events across Haiti, including the assassination of the President last month has resulted in significant political instability.  The lack of COVID-19 vaccine supplies and difficulty with essential societal items such as clean water, electricity, communication and medical care will hamper response efforts. An international response effort to assist in search and recovery is underway.Steep topography results in severe landslide risk associated with ground movement while liquefaction in coastal areas also transpires in large Haitian earthquakes. Further ground failures are possible due to the recent heavy rainfall associated with Tropical Storm Fred last week and another round of heavy rainfall from Tropical Storm Grace in the next 72 hours.

 

 

Regions Most Susceptible to Landslide Risk in the M7.2 Haiti Earthquake.  Source: USGS.

 

Comparison to Historical Events

The island of Hispaniola is an area of frequent and strong seismic activity.  Four Mw 7.0 or higher earthquakes and an additional twelve events between Mw 6.0 and Mw 6.9 have transpired since 1900. Further back in history, the capital of Port-au-Prince was destroyed in earthquakes in both the 18th and 19th centuries. The most recent devastating earthquake in January 2010 has been widely studied due to the significant loss of life with best estimates of 200,000 to 300,000 people. The boundary between the North America and Caribbean plate stretches across Hispaniola, southern Cuba, Jamaica and around Puerto Rico, resulting in the elevated frequency of severe earthquakes in this portion of the Caribbean Sea.

 

 

Historical Caribbean Earthquakes and Plate Tectonics.  Source: USGS.

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