When a 7.0 magnitude earthquake hit Haiti in 2010, killing an estimated 200,000 people, there was only one working seismometer in the country. The shaking quickly overwhelmed the seismometer, an educational instrument installed in a high school, and it recorded little useful data.
Weeks passed before foreign seismic experts could travel to the disaster area, then months passed before the portable seismometers they installed registered enough of the fading aftershocks to shed light on the fracture that had ruptured.
Last August, a 7.2 magnitude earthquake hit Haiti. Conventional seismometers installed after the 2010 earthquake were not functioning at that time. But several small, inexpensive instruments from citizen scientists managed to capture the seismic waves, allowing researchers to see much faster where the Earth had breached deep underground and demonstrating the value of turning on the enthusiasm of curious non-experts for the science. (The earthquake death toll was about 2,200 people, much lower than in 2010, mainly because the epicenter was in a more rural part of the country.)
“By 2021 we had that information in real time,” said Eric Calais, a geophysicist at the École Normale Supérieure in Paris who has studied the tectonics of the Caribbean for more than 30 years. “So that’s a big difference.”
In a paper published Thursday in the journal Science, Dr. Calais and his colleagues what citizen science seismometers revealed about the August earthquake. About 40 miles of the same fault that caused the devastating 2010 earthquake ruptured, but further west. The data also revealed some surprises, said Dr. Calais: At the eastern end of this segment, the fault was not vertical, where two tectonic plates slide past each other. Instead, the two plates were also pressed together, with the northern one sliding on the southern.
“Had we not had the aftershock distribution, we would not have been able to give our models the correct full geometry,” said Dr. Calais. “Then our assessment of what happened would have been wrong.”
The Caribbean is sometimes a zone of overlooked seismic hazards with active volcanoes and earthquake faults. “The Caribbean is its own small-scale Ring of Fire,” said Susan E. Hough, a seismologist with the United States Geological Survey. “It’s like the Pacific Rim on a smaller scale.”
But the tectonic plates are collapsing at a slower rate and major earthquakes are less common. The second half of the 20th century was fairly quiet in the region. “People got a little complacent about it,” said Dr. hough. “The 2010 earthquake didn’t surprise earthquake professionals in the world, but it surprised many people who were unaware of the scientific results.”
dr. Hough and Dr. Calais were two of the earthquake experts who traveled to Haiti in 2010. In the wake of that year’s earthquake, international organizations provided funding to set up conventional seismometers, each costing tens of thousands of dollars, in Haiti. † When the 7.2 magnitude earthquake struck on Aug. 14, none of Haiti’s conventional seismometers were working, although a seismometer at the United States Embassy was collecting data.
“It just proves difficult, if not impossible, to run a conventional kind of state-of-the-art seismic network in Haiti,” said Dr. hough. “They don’t have a working electrical grid, for example, let alone reliable internet everywhere.”
Haiti remains politically unstable, suffers from widespread poverty and is vulnerable to natural disasters. The president, Jovenel Moïse, was assassinated the month before the August earthquake. A few days after the earthquake, a tropical storm, Grace, swept across the island.
In 2018, Dr. Calais at a seismology conference in Malta Branden Christensen, the chief executive of Raspberry Shake, a Panama-based company that combines a small, low-cost computer called a Raspberry Pi with a small, low-cost device widely used by the oil and natural gas industry to measure tiny ground motions, creating a seismometer that costs a few hundred dollars instead of tens of thousands of dollars.
The Raspberry Shake devices, smaller than a lunchbox, can measure minute ground motion, albeit over a narrower frequency range than modern conventional seismometers. But they don’t need to be anchored to the ground and just need a power outlet and internet connection.
“I immediately thought that the device was so simple that it would have a better long-term survival rate in Haiti, meaning no maintenance required,” recalls Dr. Calais itself. With some leftover scholarship money, he bought five and went with colleagues in Haiti to look for volunteers to place one in their home or office. The network has since expanded to about 15 devices.
dr. Calais said the Haiti data shows that while the Raspberry Shakes weren’t as capable as conventional seismometers, they still made scientifically valuable measurements. “They are capable of doing the job when it comes to absorbing even minor aftershocks,” he said.
However, the Raspberry Shakes are not immune to Haiti’s infrastructure limitations. Only one of the three near the epicenter was operational when the major earthquake struck last August.
The instrument closest to the epicenter was offline because the host had let its internet service expire. But he renewed it right after he felt the shaking. “We have to accept these kinds of problems,” said Dr. Calais. “Internet and electricity are never taken for granted in Haiti.”
The researchers were also able to add three Raspberry Shakes to the area, and all six measured more than a thousand aftershocks that followed in the weeks that followed.
The seismic data published online is only part of Dr. Calais for setting up the Raspberry Shake network. It also aims to spread knowledge about the dangers of earthquakes among the volunteers who organize the Raspberry Shakes and other people in Haiti.
“We want to get some people in the community to act differently,” said Steeve J. Symithe, a geophysicist at Haiti State University and author of the Science paper.
dr. Born in Haiti, Symithe studied to become a civil engineer but changed his field after the 2010 earthquake and received a PhD from Purdue University with Dr. Calais, who was a professor there at the time.
Raspberry Shakes, which emerged from a Kickstarter project in 2016, have now been installed around the world, with networks similar to Haiti’s in France, Oklahoma, and Nepal. More than 1,600 devices report their data to the company’s website. “They’re popping up everywhere,” Mr. Christensen said.
If enough devices are deployed, “you can start doing magical things in terms of earthquake early warning,” Mr. Christensen said. “You can start mapping and detect earthquakes in places that people thought were aseismic, or you can start mapping faults.”
Some of the research doesn’t even cover earthquakes. In a paper published in Science in July 2020, scientists used data from 300 seismic stations, including 65 Raspberry Shakes, to study a global reduction in noise from trains, planes, factories and other man-made vibrations. due to the Covid19 pandemic.
“Without Raspberry Shake, that would have been a very difficult question to answer,” said Mr. Christians. “The reason is that most professional seismographs are installed in the mountains and in places that are really quiet, far away from people.”