The Bermuda Triangle is well known as an urban legend haven: shipwrecks, ghosts, and strange disappearances populate stories about the area. But in 1817, a real disaster occurred in the legendary location: an earthquake with an epicenter in the Bermuda Triangle caused an East Coast tsunami. A newspaper at the time termed the occurrence a simple “tidal wave,” but a new study conducted by U. S. Geological Survey research geophysicist Susan Hough and colleagues determined the truth behind the occurrence, pinning down the size and location of the 1817 earthquake behind the 800-mile wave more closely than ever before.
On January 8, 1817, ships docked south of Philadelphia on the Delaware River were rocked by what contemporary reporters considered a rogue tidal wave. Hough and her team were able to link that strange Atlantic activity to a known earthquake that took place on the same day. First-hand accounts had led geologists to estimate the size of the quake at 4.8 to 6 magnitude. Hough used a new computer model and geologic data to revise that estimate – discovering that the earthquake was a magnitude 7.4 earthquake, which “releases almost 8,000 times more energy than a magnitude-4.8 quake,” Becky Oskin reported on Live Science in her September 9, 2013 article “Bermuda Triangle earthquake triggered 1817 tsunami.”
Hough and her team were able to use the model to narrow down the epicenter of the earthquake, and then conclusively show that the 4:30 a.m. earthquake could have caused the tsunami that hit Delaware Bay at 11 a.m. The wave that rocked boats was a foot high – and traveled 800 miles from off the coast of South Carolina to Delaware Bay.
“When we started to say, ‘OK, it’s the Bermuda Triangle Fault,’ that did not go over well,” Hough said in the Live Science article. “Some of our colleagues didn’t want us to get into all this hooey.” But while the urban legends might be false, the tremors of the Bermuda Triangle Fault have been supported multiple times: ships felt earthquake tremors in 1858, 1877, and 1879.
Bermuda Triangle: Not that dangerous
But despite the 1817 earthquake and the variety of urban legends that have sprung up around the Bermuda Triangle, its waters are not that dangerous, according to the World Wildlife Foundation. As Elizabeth Barber reported in the June 1, 2013 Christian Science Monitor article “Bermuda Triangle doesn’t make the cut on list of world’s most dangerous oceans,” the Caribbean and the Bermuda Triangle, despite their reputation for shipwrecks and disappearances, did not hold water against the South China Sea – which “has had more shipping accidents than any other water body,” Barber said.
The top most dangerous waters for shipwrecks include:
- The South China Sea and the East Indies
- The east Mediterranean Sea
- The Black Sea
- The North Sea and British Isles
One of the goals of Hough’s study was to gather more information about East Coast earthquakes. The only other East Coast offshore earthquake that has been studied took place in 1929 off of Newfoundland. The April 2012 earthquakes 170 miles east of Boston – a swarm of 15 events, the largest of which had a 4.0 magnitude – has encouraged several scientists to look into the phenomenon more seriously. And other tsunami-like waves have hit the East Coast in recent years, including a 2008 meteotsunami – a tsunami caused by weather – that hit Bothbay, Maine; and a June 28, 2013 surge that stretched from Puerto Rico to the northeastern coast of the U. S. Some scientists blamed weather effects for the 2013 surge, but others posited that an underwater landslide could have been the cause.
John Ebel of Boston College was inspired to look into the threat of East Coast tsunamis by the 2012 earthquake swarm. In an April 2013 article covering Ebel’s research, “East Coast cities at risk in future tsunamis,” posted on The Atlantic Cities, writer John Metcalfe explained that the Pacific has a higher rate of tsunamis because of greater occurrences of volcanic explosions and shifting tectonic plates. Ebel theorizes that the northeast is at risk because the current seismological activity is similar to the earthquake of 1929. According to Metcalfe, “That temblor triggered an underseas landslide that swamped Newfoundland with towering waves, crushing homes and killing 29 people.” Though the population is much higher now than it was in 1929, thankfully, modern monitoring systems would give residents much greater warning than their 20th century peers.
What tsunamis go on record as the worst? An Australian Geographic listing of “The 10 most destructive tsunamis in history” by Campbell Phillips considered these among them:
- The 2004 tsunami in Sumatra, Indonesia, caused by a 9.1 magnitude earthquake
- The 2011 Japanese tsunami, which killed more than 18,000 people with 10 meter high waves
- The 1755 Atlantic tsunami that hit Lisbon, Portugal with waves up to 30 meters high
- The 1883 tsunami caused by the explosion of Krakatau volcano
Are you worried about an Atlantic tsunami?