On May 10, 2018, the geologic beasts of the tiny island of Mayotte began to stir. Thousands of earthquakes rattled the French island, which is sandwiched between Africa and Madagascar. Most were minor shakes, but they included a magnitude 5.8 event that struck on May 15, the largest yet recorded in the region’s history.
In the midst of this seismic swarm, a strange low-frequency rumble rippled around the world, ringing sensors nearly 11,000 miles away—and baffling scientists.
Now, researchers may have at last found the source of the unexpected activity: the birth of a submarine volcano some 31 miles off Mayotte’s eastern shore. Sitting about two miles underwater, the baby volcano stretches nearly half a mile high and extends up to three miles across.
The observations came after French scientists launched a multi-pronged mission to get a better grip on the origin of the ongoing seismic swarm. Coordinated by France’s National Center for Scientific Research (CNRS), the work includes surveys from the ship Marion Dufresne co-led by Nathalie Feuillet from the Institut de Physique du Globe de Paris and Stephan Jorry of the French research institute IFREMER.
The data are still preliminary, and many questions remain unanswered as the scientists work to analyze their findings and publish the research in a peer-reviewed journal. In the meantime, the team has issued a joint press release announcing the new volcano and its probable link to the odd throng of earthquakes.
“In light of this discovery, the government is fully mobilized to pursue and deepen our understanding of this exceptional phenomenon and take necessary measures to categorize and prevent any risks it represents,” the agencies say in the release.
Stephen Hicks, a seismologist at Imperial College who previously analyzed Mayotte’s strange seismic happenings, adds that the announcement offers some much needed clarity for the island’s inhabitants, who have been thoroughly shaken after months of unexplained tremors.