By Theresa Pinto, M.S, Contributing Reporter
MIAMI BEACH, FLORIDA – According to a study published by the Journal of Geophysical Research Solid Earth in April, an earthquake that struck in 2009 near the Samoan islands may have exacerbated the extent of sea level rise affecting the islands today.
The researchers anticipate the Samoa-Tonga earthquake will cause approximately 12-16 inches more of sea level rise, over and above the level expected from global climate change, in just a few decades.
They calculated the post-seismic activity of the 8.1 magnitude earthquake, causing subsidence – or settling caused by movement under the ground’s surface – was increasing the effective rate of sea level rise to five times the global average.
The Samoan islands are an archipelago located in the South Pacific where most of the quarter million inhabitants reside on one of three large islands. Like Florida, flooding and saltwater intrusion into freshwater drinking aquifers caused by sea level rise are also dual concerns for the Samoans.
The study‘s authors make clear that more than climate change can determine overall amounts of sea level rise. For instance, the sea around Louisiana is 24 inches higher in some places than it was in 1950 but mostly due to sinking land – caused by subsidence.
Another study published in May on sea level impacts of the Sumatra-Andaman earthquake of 2004 shows a significant increase in sea level due to post-seismic deformations. However, the researchers make a positive correlation between the rising seas and the contemporaneous recovery of the shallow coral reef in the area.
For Florida, this could mean sea level rise does not bring only bad news, and with innovative thinking but pragmatic planning, coastal regions can make resiliency just a fact of life.
However, Florida is also considering oil and gas extraction techniques, such as fracking, which could disrupt its unique limestone foundation but also has implications for earthquakes. In March, the Florida panhandle saw five minor earthquakes in just three weeks.
Earthquakes in Florida are rare, in fact, none had been reported prior to March (with the exception of a 3.6 magnitude earthquake near Daytona Beach in 2016 triggered by naval testing nearby). In April, the U.S. Geological Survey sent scientists to the Florida panhandle to determine whether the quakes were caused by oil and gas exploration in the area.
According to Jorge Aquilar, the southern regional director for Food and Water Watch, “The area itself does not actually have naturally occurring earthquakes. And so, what the geologists have said is that it is likely due to oil and gas operations.” Supporters of fracking say it does not cause earthquakes, no more than other deep-well injection processes such as for wastewater disposal.
Neither of two bills to ban fracking statewide recently passed in this year’s legislative session. One of the bills even failed to mention the ban of matrix acidizing fracking, which is the only method that can occur in Florida.
Regardless of whether fracking and other methods of getting at fossil fuels cause earthquakes that impact Florida’s sea level, the extraction and use of fossil fuels do cause greenhouse gas emissions that are unusually warming the oceans and melting Arctic ice – and impacting rising seas in Florida.