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When a magnitude 7.0 earthquake struck Haiti in 2010 and an estimated 200,000 people died, there was only one seismometer in the country. The shaking quickly overwhelmed the seismometer, an educational tool installed in a high school, recording little useful data.
It was weeks before foreign seismic experts could travel to the disaster area, and then months before the portable seismometers they installed recorded enough aftershocks to shine a light on the faults that broke.
last August, A 7.2 magnitude earthquake struck Haiti.. Conventional seismometers installed after the 2010 earthquake were not working at the time. But a few small, inexpensive instruments run by citizen scientists have succeeded in capturing seismic waves, giving researchers a much faster view of where Earth is breaking deep down, and demonstrating the value of joining the enthusiasm of curious, non-specialist scientists. (The earthquake’s death toll was about 2,200, much lower than in 2010, largely because its epicenter was in a more rural part of the country.)
“In 2021, we got this information in real time,” said Eric Calais, a geophysicist who has been working on Caribbean tectonics for more than 30 years at the École Normale Supérieure in Paris. “So that’s a big difference.”
writing In an article published Thursday in the journal Science, Dr. Calais and colleagues talked about 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. Dr. The data also reveal some surprises, Calais said: At the eastern end of this segment, the fault was not vertical, where two tectonic plates were crossing each other. Instead, the two plates were being pushed against each other as the north plate slipped over the south plate.
Dr. “If we didn’t have the aftershock distribution, then we wouldn’t be able to put the exact geometry into our models,” Calais said. “Then our assessment of what was going on would have been wrong.”
The Caribbean is a region of sometimes 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. “Like the Pacific Rim on a smaller scale.”
But tectonic plates are colliding at a slower rate, and large earthquakes are less frequent. The second half of the 20th century passed quite calmly in the region. Dr. “People have been a little indifferent about it,” Hough said. “The 2010 earthquake did not surprise any earthquake professional in the world, but it did surprise many people who were unaware of its scientific implications.”
Dr. Hough and Dr. Calais were two of the earthquake experts who traveled to Haiti in 2010. Following that year’s earthquake, international organizations provided funding to install conventional seismometers in Haiti, costing tens of thousands of dollars each. . When the 7.2 magnitude earthquake struck on August 14, none of Haiti’s conventional seismometers were working, although a seismometer at the US Embassy was collecting data.
Dr. “It seems difficult, if not impossible, to operate a traditional kind of state-of-the-art seismic network in Haiti,” said Hough. “For example, they don’t even have a functioning power grid, let alone reliable internet everywhere.”
Haiti is politically unstable, suffering from widespread poverty and vulnerable to natural disasters. President Jovenel Moïse was killed a month before the August earthquake. A few days after the earthquake, a tropical storm, Grace, passed over the island.
At a seismology conference in Malta in 2018, Dr. Calais met Branden Christensen, a company based in Panama that put together a small, inexpensive computer called the Raspberry Shake. a Raspberry Pi He creates a seismometer, a small, inexpensive device commonly used by the oil and gas industries to measure small ground motions, costing several hundred dollars instead of tens of thousands of dollars.
Smaller than a bread box, Raspberry Shake devices can measure minute ground movements, although in a smaller frequency range than modern conventional seismometers. But they don’t need to be fixed to the ground and only require a power outlet and internet connection.
Dr. “I immediately thought that the simplicity of the device would have a better chance of long-term survival in Haiti, meaning it would be maintenance-free,” Calais said. He used some of the remaining grant money to purchase five of them and began looking for volunteers who could put one in their home or office with colleagues in Haiti. The network has since expanded to around 15 devices.
Dr. Calais said the Haitian data show that Raspberry Shakes make scientifically valuable measurements, although not as capable as traditional seismometers. “They can do the job when it comes to recording even minor aftershocks,” he said.
But Raspberry Shakes are not immune to Haiti’s infrastructure limitations. When the main earthquake struck last August, only one in three near the epicenter was operational.
The device closest to the epicenter was offline because the host had allowed internet service to be interrupted. But when he felt the jolt, he immediately renewed it. Dr. “We have to acknowledge this kind of problem,” Calais said. “Internet and power are never given in Haiti.”
The researchers were also able to add three Raspberry Shakes to the area, measuring more than a thousand aftershocks, six of which followed in the weeks that followed.
seismic data, posted online, Dr. It’s just part of Calais’ motivation to build the Raspberry Shake network. It also aims to spread knowledge about earthquake hazards among volunteers hosting the Raspberry Shakes and other people in Haiti.
“We want to force some people in society to behave differently,” said Steeve J. Symithe, a geophysicist at Haiti State University and author of the Science paper.
Born in Haiti, Dr. Symithe was studying to become a civil engineer, but changed fields after the 2010 earthquake and Dr. He did his PhD with Calais.
Born out of a Kickstarter project in 2016, Raspberry Shakes is now installed worldwide, with networks similar to Haiti’s networks in France, Oklahoma, and Nepal. More than 1,600 device data company website. “They’re popping up everywhere,” said Mr. Christensen.
With enough devices deployed, “you can start doing magic things like earthquake early warning,” said Mr. Christensen. “You can start mapping and detecting earthquakes where people think they are seismic, or you can start mapping faults.”
In some studies, there is not even an earthquake. Inside An article published in Science in July 2020scientists used data from 300 seismic stations, including 65 Raspberry Shakes to observe the reduction of noise from trains, airplanes, factories and other man-made vibrations globally As a result of the Covid-19 pandemic.
“Without the Raspberry Shake, that would be a very difficult question to answer,” said Mr. Christensen. “The reason is that most professional-grade seismographs are installed in mountains and places that are really quiet, away from people.”
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