When the ground began shaking on the morning of August 14th, 2021, in southern Haiti, few of the already sparse permanent seismometers in the country were operational.
However, a small network of simple, tiny seismic stations — not much larger than a smartphone and hosted in volunteers' homes — recorded critical data about the earthquake, providing scientists and first responders real-time data about the main event and its aftershocks.
In a new study, published in the 11 March issue of Science, researchers describe how these citizen seismometers were the key to rapidly characterizing the magnitude 7.4 Nippes earthquake, which struck Haiti's southern peninsula, causing extensive damage and the loss of several thousand lives.
"Local seismiologists in Haiti are crucial, as seismic hazards are one of the main risks threatening the country," said Steeve Symithe, a geophysical researcher at the State University of Haiti and author of the study.
Hispaniola — an island shared between the nations of the Dominican Republic and Haiti — is sandwiched between two large and active seismic fault zones where the North American and Caribbean tectonic plates slowly converge.
As a result, much of the region is prone to frequent and destructive seismic events, including the catastrophic magnitude 7.0 earthquake that shook Haiti's capital, Port-au-Prince, in January 2010. The event devastated the city, leaving it and much of the surrounding area in ruin. In total, the earthquake — one of the most costly and deadly seismic disasters known — left 1.5 million people homeless and hundreds of thousands of dead.
However, despite the substantial seismic risk and a long history of damaging quakes, Haiti has only a handful of conventional, high-quality seismic stations and due to the country's limited infrastructure, building and maintaining a reliable seismic monitoring network remains a considerable challenge.
Tiny Seismometers to Fill the Gaps
Symithe was born in Haiti and experienced the 2010 earthquake firsthand. At the time, he was training to become a civil engineer.
"In 2010, I was the novice, who barely had any knowledge about this phenomenon, yet it was very easy to realize just how dangerous [earthquakes] can be," said Symithe.
After the quake, Symithe shifted gears to pursue geophysical research. When the Nippes earthquake hit a little more than a decade later, Symithe was once again in Haiti. This time, however, he was an early career scientist and a local leader in the effort to improve seismic monitoring and hazard maps throughout the country.
"In 2021, I was afraid and hesitant at first," said Symithe. "But after a few hours, I realized that this time, I was the one in charge of the scientific response. I went to the laboratory to gather the instruments that would be deployed in the vicinity of the earthquake epicenter."
Although the aftermath of the 2010 earthquake spurred the installation of new, conventional seismic stations, none were operational the morning the 2021 Nippes earthquake hit.
However, unlike earlier quakes, a budding network of portable citizen seismometers built using inexpensive and low-maintenance "Raspberry Shake" seismic stations distributed in 2019 allowed scientists to understand the mechanism of the Nippes quake and monitor its aftershocks in real-time.
In stark contrast to conventional seismic stations, which can cost tens of thousands of dollars to install and maintain and are often permanent fixtures, Raspberry Shake seismometers cost only several hundred dollars, are small, virtually maintenance-free and require only electricity and an internet connection to operate.
Based on widely available Raspberry Pi open-source computer hardware, Raspberry Shake devices have become commonly used teaching tools or low-cost ways to monitor seismic activity near volcanoes, oil and natural gas operations and other seismic sources. In one recent study published in Science, researchers used them to track the "global quieting" of human activity which resulted from COVID-19 lockdown measures.
A Future for Citizen Seismology in Haiti
To account for the lack of conventional seismic stations in Haiti, and the difficulties associated with keeping them running, Symithe and colleagues used the instruments to improve the capacity of the existing seismic network.
And the plan paid off. According to Symithe, it took weeks for different international scientific groups to travel to Haiti and deploy stations near the epicenter to gather data to study the fault that ruptured to cause the 2010 earthquake, and many months more to fully characterize the event and what ultimately caused it.
After the Nippes earthquake — and largely due to the citizen seismometers — Symithe and his colleagues had calculated the quake's strength, epicenter, rupture geometry and mechanism within mere hours.
According to Symithe, the 2010 and 2021 earthquakes are clear evidence that the country will undoubtedly face more serious seismic disasters in the future.
"We want to expand the network. The denser the network, the better it is," said Symithe. "Since the earthquake, we found that people in the country are more inclined to accept to host one of these instruments."
Since the Nippes earthquake, Symithe and his colleagues have installed 10 conventional large band seismic sensors and have placed several new Raspberry Shake devices with citizen seismologists throughout the region.
But barriers to this goal remain. Symithe said that one of the biggest challenges is finding potential citizen seismologists in remote areas of Haiti who have reliable access to electricity and internet. What's more, increased gang activity in the region makes trips into the field in some regions of the country a dangerous affair.