Some US geophysicists are going where few of their compatriots have gone before: to Cuba, Venezuela and other countries that are notoriously anti-American. But these countries are also notoriously plagued by natural disasters such as earthquakes, and so engineers are blanketing the Caribbean with a network of sensors to detect the crustal strains and brewing storms that threaten the region.
Early results from the US$6-million system, called the Continuously Operating Caribbean GPS Observational Network (COCONet) and funded by the US National Science Foundation (NSF), were presented in Cancún, Mexico, on 17 May at the American Geophysical Union Meeting of the Americas. COCONet is an offshoot of another NSF effort that, over the past decade, has sprinkled Global Positioning System (GPS) sensors across the western United States. That was child’s play compared with working across 31 separate national governments, many of which distrust the United States, says Glen Mattioli, a programme director at UNAVCO, a geodetic-survey organization based in Boulder, Colorado, that is managing the project.
Under COCONet, geoscientists across the Caribbean are gaining free access to data that will help them to understand and prepare for natural hazards such as earthquakes and hurricanes. But unless they adopt the network as the long-term backbone for observations in the region, the project could go down as just another well-meaning but failed effort to bridge national differences and develop scientific capacity. To most, it is worth the risk. “If you don’t bet, you don’t win,” says Franck Audemard, a geologist at the Venezuelan Foundation for Seismological Research in Caracas.
COCONet stations are being set up at sites as diverse as steep rainforest slopes and isolated coral-reef islands (see ‘A risky region’). Each station contains meteorological instruments, along with a GPS unit that constantly monitors ground movements and, in many cases, transmits those data in near real time. So far, UNAVCO has built or upgraded 38 of its planned 69 sites. At least 61 existing stations are also being incorporated into the network.
The project has made more progress than expected in acquiring the permits needed to set up stations, says Mattioli. That holds true even in Cuba, where officials have already approved the COCONet stations slated to arrive in June, even as US officials are still working through the permissions, Mattioli says.
Spurred on by the devastating 2010 Haiti quake, the network aims to fill out the currently patchy picture of the region’s geological turmoil. Off the Pacific coast of Costa Rica, for instance, a COCONet station on the isolated Isla del Coco is the only GPS station continuously tracking the Cocos plate as it dives beneath the Caribbean plate. The data show that the two plates are converging at a rate of 78 millimetres per year. Such information will help geophysicists to reconcile their ideas about plate motion in the region, says Marino Protti, a geologist at the National University of Costa Rica in Heredia, who presented his findings in Cancún.
Other COCONet stations dot Costa Rica’s Nicoya Peninsula, one of the few places on land that lie directly above a subduction zone. In September 2012, Nicoya shuddered from a magnitude-7.6 earthquake. “Having the network helped us see that it was not a whole-plate event,” Protti says. He thinks that remaining stress in the plate could trigger another large tremor.
Besides tracking movements in Earth’s crust, the GPS data allow atmospheric scientists to measure how much water vapour sits in the air between each station and the GPS satellites, based on the delay in the signal’s travel time. That information is a rare, real-time glimpse of how much water is available to power hurricanes, says meteorologist John Braun of the University Corporation for Atmospheric Research in Boulder.
COCONet is even yielding some unexpected societal benefits. In the Dominican Republic, land surveyors are eagerly using the nation’s nine stations to comply with a real-estate law that requires precise surveying of parcels of land for sale, says Alexander Holsteinson of the National University of Pedro Henríquez Ureña in Santo Domingo.
Yet funding for COCONet runs out in 2015, and no one knows what will happen then. Each country will have to find the money to keep its stations operating, says Guoquan Wang, a geophysicist at the University of Houston, Texas, and a COCONet member who developed a GPS network for Puerto Rico and the Virgin Islands. That means that host nations will have to find value in supporting the project, says Héctor Mora Páez, who heads the GPS network for the Colombian Geological Survey in Bogota. “You have to make the local people feel involved.”
- Journal name:
- Date published: