These small, inexpensive devices help monitor earthquakes in Haiti

When a 7.0 magnitude earthquake struck Haiti in 2010, killing an estimated 200,000 people, there was only one functioning seismometer in the country. The shaking quickly overwhelmed the seismometer, an educational tool installed at a high school, and it recorded little useful data.

Weeks passed before foreign seismic operators could travel to the disaster area, and then months passed before the portable seismometers they installed recorded enough of the fading aftershocks to shed light on the fault that had erupted.

Last August, Haiti was hit by a 7.2 magnitude earthquake. Conventional seismometers installed after the 2010 quake were not working at the time. But several small, inexpensive instruments operated by citizen scientists managed to capture the seismic waves, giving researchers a much faster view of where the earth had fractured deep underground and demonstrating the value of the To arouse the enthusiasm of curious non-experts for science. (The earthquake’s death toll was about 2,200 people, much fewer than in 2010, largely because the epicenter was in a more rural part of the country.)

“In 2021 we had this information in real time,” said Eric Calais, a geophysicist at the École Normale Supérieure in Paris who has studied Caribbean tectonics for more than 30 years. “So that’s a big difference.”

In an article published Thursday in the journal Science, Dr. Calais and his colleagues what the 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 non-vertical where two tectonic plates slide past one another. Instead, the two plates were also pushed together, with the northern one sliding onto the southern one.

“If we didn’t have the aftershock distribution, we wouldn’t have been able to fit our models with the right full geometry,” said Dr. Calais. “Then our assessment of what happened would have been wrong.”

The Caribbean is a sometimes overlooked seismic hazard zone with active volcanoes and earthquake faults. “The Caribbean is its own little 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 colliding more slowly, and larger earthquakes are less frequent. The second half of the 20th century was fairly quiet in the region. “People got kind of complacent,” said Dr. Hough. “The 2010 earthquake didn’t surprise earthquake experts around the world, but it did surprise many people who didn’t know the scientific results.”

dr Hough and Dr. Calais were two of the earthquake experts who traveled to Haiti in 2010. After that year’s quake, international organizations funded the installation of conventional seismometers in Haiti, each costing tens of thousands of dollars. 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.

“It is proving difficult, if not impossible, to operate a conventional, state-of-the-art seismic network in Haiti,” said Dr. Hough. “They don’t have a working power grid, for example, let alone reliable internet everywhere.”

Haiti remains politically unstable, suffers from widespread poverty and is prone to natural disasters. The President, Jovenel Moïse, was assassinated a month before the August tremor. A few days after the earthquake, a tropical storm, Grace, hit the island.

In 2018, Dr. Calais at a seismology conference in Malta Branden Christensen, the CEO of Raspberry Shake, a Panama-based company that combines a small, cheap computer called the Raspberry Pi with a small, cheap device that’s widely used in the oil and gas industry, to measure tiny ground movements and create a seismometer that costs a few hundred dollars instead of tens of thousands of dollars.

Smaller than a breadbox, the Raspberry Shake devices can measure tiny ground movements, albeit over a smaller frequency range than modern conventional seismometers. However, they do not need to be anchored to the ground and only require an electrical outlet and an internet connection.

“I immediately thought that the simplicity of the device is so simple that it has a better long-term chance of surviving in Haiti, which means no maintenance is required,” recalled Dr. Calais. He used some leftover scholarship money to buy five of these and, along with colleagues in Haiti, began looking for volunteers who would be willing to set one up in their home or office. The network has now grown to about 15 devices.

dr Calais said the Haiti data showed that while the Raspberry Shakes weren’t as powerful as traditional seismometers, they were still making scientifically valuable measurements. “They are able to record even small aftershocks,” he said.

However, the raspberry shakes are not immune to Haiti’s infrastructure restrictions. Only one of the three near the epicenter was operational when the main quake struck last August.

The instrument closest to the epicenter was offline because the host lost its internet service. But he renewed it right after he felt the tremor. “We have to accept these kinds of problems,” said Dr. Calais. “Internet and electricity are never a matter of course 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 the motivation of Dr. Calais to build the Raspberry Shake network. It is also intended to spread knowledge about earthquake hazards among the volunteers hosting 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 the State University of Haiti and author of the Science paper.

dr Born in Haiti, Symithe studied civil engineering but changed majors after the 2010 earthquake and received his PhD from Purdue University with Dr. Calais, who worked there as a professor.

Born out of a Kickstarter project in 2016, Raspberry Shakes is now being installed around the world, with networks similar to those in Haiti, France, Oklahoma and Nepal. More than 1,600 devices report their data to the company’s website. “They’re popping up everywhere,” said Mr. Christensen.

With enough equipment in place, “you can start doing magical things in terms of earthquake early warning,” Mr. Christensen said. “You can start mapping and detecting earthquakes in places that people thought were aseismic, or you can start mapping faults.”

Some of the research doesn’t even relate to earthquakes. In a July 2020 article published in Science, scientists used data from 300 seismic stations, including 65 Raspberry Shakes, to observe a global reduction in noise from trains, planes, factories and other man-made vibrations as a result of the Covid19 pandemic.

“Without Raspberry Shake, that question would have been very difficult to answer,” said Mr. Christensen. “The reason is that most professional seismographs are installed in the mountains and in really quiet places, away from people.”

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