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Just before 9:00 a.m. local time on January 11, a magnitude 5.9 earthquake rattled Puerto Rico’s southwestern coast. The event comes after weeks of quakes have rumbled through the region—and odds are that the shaking is not over yet.
The series includes Puerto Rico’s most destructive quake in a century, a magnitude 6.4 earthquake that jolted residents awake in the predawn hours of January 7. Only a day before, a magnitude 5.8 quake also struck in the same region. Since late December, there have been 123 earthquakes of magnitude 3 or higher, which were strong enough for residents near the epicenters to feel, according to the U.S. Geological Survey (USGS). Six earthquakes of magnitude 5 or higher have also struck the island.
The events have wreaked havoc in a community still recovering from devastation in the wake of hurricanes Maria and Irma. The latest temblors collapsed homes and schools, knocked out power in some regions, triggered landslides, and toppled the natural rock arch Punta Ventana—a popular landmark that was long a draw for tourists. At least one death has been reported so far.
“These people have been through a lot,” says Wendy Bohon, an earthquake geologist at the Incorporated Research Institutions for Seismology (IRIS). “Buildings are damaged, people are afraid, of course, because it’s ongoing. They’ve been feeling earthquakes for days and days.”
What’s more, aftershocks will likely continue to rattle the region, and researchers are avidly studying the most recent events to better understand what might happen in the future.
“There’s just a lot of complicated tectonics happening in a really close area,” Bohon says.
Puerto Rico has a long history of earthquakes, although large events are rare. It sits at the edge of the Caribbean tectonic plate, where that plate is colliding with the North American plate. Such tectonic boundaries host the vast majority of the world’s quakes.
“The entire island is an active plate boundary zone, just like California—earthquakes are fair game everywhere,” Susan Hough of the USGS says via email. But Puerto Rico’s geology is even more complex than most, because the island is being squashed in a tectonic battle.
Under the island’s northern coast, the North American plate plunges under the Caribbean plate in a subduction zone. At the same time, a section of the Caribbean also seems to subduct south of the island at the Muertos trough, squeezing Puerto Rico in between them, according to the USGS. The result is earthquakes, and lots of them.
The island is particularly susceptible to what’s known as earthquake swarms, or series of events that are roughly the same magnitude, explains Elizabeth Vanacore, a seismologist with the Puerto Rico Seismic Network (PRSN) at the University of Puerto Rico at Mayagüez. Why, though, is an open scientific question, she says.
Some swarms seem to follow particular directional trends and zones of stress. One 2013 study even suggests that some swarms north of the island might be the result of a tear cutting through the subducting North American plate. However, there’s likely multiple causes for these events.
Vanacore says that this latest series of events seems to be more of a traditional earthquake sequence rather than a swarm, with a bigger temblor surrounded by its own entourage of smaller foreshocks and aftershocks. And as researchers continue to sort out the details of today’s event, she says one thing is certain: “There will be more earthquakes.”
The USGS estimates that there’s a 70-percent chance another earthquake of magnitude 5 or higher will strike in the coming week. The chance of a magnitude 6 or higher is currently 12 percent. While the latter percentage might seem low, it means that another large quake is not impossible. Researchers are still working to untangle the latest events, and as more information comes in, these forecasts may change.(Learn more about the pair of large earthquakes that struck California last year.)
Many of the quakes seem to trace to the Punta Montalva fault in southwest Puerto Rico, Vanacore notes, though geologists still have work to do to confirm this. The faults in this region are known to be the most active on the island, and while the Punta Montalva fault itself has largely remained quiet in the last few decades, since instrumental records began, this is a mere blip on geologic timescales, Vanacore says.
“When talking geologic times, you’re talking millions and billions of years,” she says. The next goal, Vanacore says, is to figure out how often this level of activity might occur along the Punta Montalva fault.
In the meantime, Vanacore cautions people to obtain information about the ongoing quakes from reliable sources, such as the USGS or the PRSN. Whenever possible, locals can also take steps to put themselves out of harm’s way in the near future.
“Stay in a safe location, away from power lines, or trees, or hill slopes—anything that can fall on you and hurt you,” Bohon says. “Be aware that more shaking is coming.”
This story has been updated with news of the January 11 earthquake; it originally published on January 7.
Brilliantly colored, noisy, and active during the day, many birds are easy to spot—and identify. In the past two decades, an average of fewer than six new bird species have been described every year in the entire world.
But 2020 will be different, as scientists have just announced 10 previously undescribed species and subspecies from three Indonesian islands east of Sulawesi.
This amazing avian haul was collected over six weeks in 2013 and 2014 to the mountainous islands of Taliabu, Peleng, and Batudaka, locations that were suspected to be hideouts for unknown birds, says study leader Frank Rheindt, an ornithologist at the National University of Singapore. One reason is that 19th-century explorers, such as British naturalist Alfred Russel Wallace, did not spend much time on these islands.
“We were also particularly intent on visiting islands surrounded by deep sea. Because they have not been connected to any other land mass during the ice ages, they are very promising places to discover species not found anywhere else,” says Rheindt, whose study appears in this week’s Science.
Many tropical forest birds shy away from open areas, so that “a stretch of ocean or even a highway can prevent their movement from one forested area to another,” he says. The few birds that do accidentally end up on isolated islands, for example after they are blown out to sea by a storm, may give rise to new species. (Read about a new species of flycatcher previously discovered in Sulawesi.)
Two of the newfound animals are leaf warblers that belong to a group of small, insect-eating songbirds that live across the Old World. Others include the Taliabu myzomela, a type of honeyeater that feeds on a wide array of nectar and fruit, and the Peleng fantail, a bird that does its name justice by fanning its tail feathers when it is upset or alarmed.
Field biologist Mochamad Indrawan of Universitas Indonesia was the first to collect and report the Peleng fantail but was not involved in the current publication.
“I really applaud the description of new species,” says Indrawan, who has worked with communities on the island to protect their forests for nearly 30 years. “They are very useful. But this is the age of extinction, the age of climate change, so I hope we can do more than that to protect these birds.”
During their expedition, Rheindt and colleagues relied on a tried-and-true method for tracking down birds: Their songs. Some were heard days before they were finally seen.
The first time Rheindt and colleagues hiked the mountains of Taliabu, they were hit with heavy rain and considered turning back. “Then I heard the typical insect-like chirping sound of a species of grasshopper warbler I had never heard before,” he recalls. (See beautiful pictures of songbirds.)
It would take a few more climbs to finally spot the tiny brown bird now named the Taliabu grasshopper warbler.
The team collected specimens of the birds, and back in the lab, carefully described their appearance and anatomy. The birds’ DNA and recorded songs were also analyzed to confirm the animals were different enough from any known species to be named a new species or a subspecies.
Since all these birds likely live nowhere else, they’re vulnerable to extinction, particularly due to wildfire and deforestation, which has been rampant on these islands, the authors say.
Rheindt is especially concerned about the grasshopper warbler.
“We’ve only found the bird in a small patch of dwarf vegetation high up in the mountains, in an area quite vulnerable to wildfire. As temperatures and drought increase, fire risk will too, and this bird has no higher place left to go.” (Read why birds matter, and are worth protecting.)
Study coauthor Dewi Prawiradilaga, a biologist at the Indonesian Institute of Sciences, adds that “we have to be optimistic that the publication of our discovery will help to keep the birds and their habitat safe,”
She hopes the Indonesian government will consider granting the newly discovered species and subspecies protected status.