On August 14, 2021, a magnitude 7.2 earthquake struck western Haiti, causing massive damage and significant loss of life. With relief efforts for the Haiti earthquake underway, the country is slowly digging out and moving on, but the scale and impact of the disaster are raising questions about how we can better prepare for and respond to these events. One potential solution is before-and-after satellite images.
A Country in Crisis
Haiti has seen more than its fair share of hard times. In 2010, the country endured a magnitude 7.0 earthquake, and it’s spent the last decade trying to rebuild. Ongoing political instability has made difficult economic conditions even worse, and immediately after the earthquake, the nation was battered by Tropical Storm Grace. The country is also facing a substantial doctor shortage, with only a handful of physicians available for the millions of people in the Les Cayes region alone.
As of September 24, 2021, Haiti has reported more than 2,200 deaths and over 12,000 earthquake-related injuries. Hardest hit were the areas of Les Cayes and Jérémie, with some 50,000 homes destroyed and 77,000 damaged. Also damaged or destroyed were 20 schools, 25 health centers and 60 places of worship. This most recent Haiti earthquake likely occurred along the same fault line as the 2010 quake, and its impacts were felt as far away as Jamaica.
Assessing the Impact
Satellite images of affected areas before and after the quake show the full extent of the damage. As Space notes, images captured in January 2020 and again on August 15, 2021 show hotels, cathedrals and hospitals before and after, and while some are now partially collapsed, others have been reduced entirely to rubble.
Imagery from NASA’s Jet Propulsion Laboratory (JPL) offers a different look at the impact. Using interferometric synthetic aperture radar images from the ESA’s Copernicus Sentinal-1A Satellite, teams from JPL and the California Institute of Technology created a deformation map of the Earth’s surface.
The false-color map shows permanent surface movement caused by the quake. Areas in blue moved toward the satellite (upward and eastward), while those in red moved away (downward and westward). The star represents the epicenter of the quake, which traveled west along the existing fault line. Areas of dark blue and red represent the most movement in the Earth’s surface. Near the epicenter, the Earth moved 16 inches (40.64 cm) toward the satellite, while farther west, movement away reached up to eight inches (20.32 cm).
Ongoing analysis of this data also paves the way for better understanding of specific fault characteristics, such as depth and direction, which may provide more accurate earthquake modeling over time.
Evaluating the Risk
The use of satellite imaging in disaster response isn’t new, and as the Humanitarian Practice Network (HPN) points out, imagery can have a significant impact on both tsunami and earthquake response. Increased satellite image resolution and GPS accuracy can make these space-based solutions invaluable in efforts to evaluate both pre-quake and post-quake risk.
When it comes to pre-quake preparation, images could be used to identify areas of higher risk, especially around known fault lines. Regular evaluation of existing infrastructure and support structures offers the potential for proactive response that could help countries better prepare for potential impacts. Long-term image analysis could also reveal trends in quake behavior along common fault lines (such as direction and severity), allowing governments to better focus any preemptive response.
On the post-quake side, these images offer a way to asses areas of increased risk. For example, continual imaging may reveal ongoing surface movement that could indicate aftershocks or a potential second quake, in turn helping first responders prioritize people in those areas. Analysis may also show damage to buildings or roadway infrastructure that could pose problems for rescue crews. Large buildings on the verge of collapse could be avoided in route planning, and detours could be mapped out to limit the chance of teams getting stuck and needing rescue themselves.
Preparing for the Worst
One of the most pressing problems in disaster recovery efforts is empowering first responder teams with accurate and up-to-date information about where they’re going and what challenges they may face. With typical communications channels often out-of-service, radio and cellular frequencies can get overwhelmed, leaving aide efforts with limited ability to connect in real-time.
High resolution satellite imaging offers a way for teams to see what they may encounter before they start their journey from relief camps. For example, post-earthquake analysis could show blocked roads or collapsed bridges, helping first responders pinpoint specific areas that have suffered major damage. Equipped with these images, workers can make informed choices about which vehicles to drive and what supplies to bring, and they can also more accurately judge how long trips may take based on current conditions.
Eyes in the Sky
Despite advancements in seismic sensor and satellite technologies, predicting and responding to earthquakes isn’t an exact science. Quakes can occur without warning and cause widespread destruction that puts both residents and rescuers at risk. The use of satellite imagery, however, can help teams reduce their risk on the ground and increase their ability to quickly reach those who need their help.
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