Chile Prepared for Tsunamis
By Carolina Contreras/Diálogo January 18, 2017
The Hydrographic and Oceanic Service of the Chilean Navy (SHOA, per its Spanish acronym), installed on December 7th a new, next-generation buoy for tsunami detection in northeastern Valparaíso, off the coast of Pichidangui, Chile. The buoy is part of the Deep-ocean Assessment and Reporting of Tsunamis System (DART), which was developed by the U.S. National Oceanic and Atmospheric Administration (NOAA). Known as DART 4G, the system consists of a sensor installed on the ocean floor and connected to a buoy on the surface of the water, which constantly generates information that provides tsunami alerts after an earthquake or high-intensity seismic event, when a tsunami is still far from shore. The DART-4G buoy was installed per the July 2015 memorandum of understanding between NOAA and SHOA. The first two systems went into operation in 2015. The first system is located off the northern coast of Mejillones and the second to the south of the city of Constitución. This new prototype “ has been set up to cover a coastal sector that was devoid of monitoring; as such, we are now going to have better forecasting,” said Rear Admiral Patricio Carrasco, director of SHOA. Because of its history of seismic activity, Chile is the only South American country to have three of the five DART-4G buoys in operation around the world. The other two prototypes of this modern monitoring technology are located off the Pacific and Atlantic coasts of the United States. “We rely on people who have been trained by NOAA and have visited our facilities and certified our work processes,” said Rear Adm. Carrasco. After an earthquake registering a magnitude 8.8 on the Richter scale and a tsunami struck off the coast of south-central Chile on February 27, 2010, the Chilean Navy initiated a change process, creating new technological capabilities within its National Alerts and Sea Quakes System. The DART buoys are part of these new tools and a source of relevant information that allows authorities to better manage the threat of a seaquake and prevent harm to the population. Next-generation technology Five DART buoys monitor 5,000 kilometers of the Chilean coastline - two second-generation models (DART II) located off the coast of Iquique and Caldera in the north of the country, one that SHOA already had in operation and three new, next-generation DART 4G buoys deployed in Chile’s central and southern zones, which are notable for innovations that improve the prediction of these natural events. The DART-4G model includes a new bottom pressure recorder and software capable of distinguishing between a tsunami signal and the “noise” produced by an earthquake. The 4G system also features advances in energy optimization. Autonomous battery life for the tsunami sensor has been increased to five years, and two years for the surface buoys. The power in the DART II buoys last only two years. In addition, data reception during events also has been improved. This includes standard weather sensors for wind, temperature, relative air humidity, surface temperature of the ocean, and barometric pressure. “Now larger event histories on tsunami behavior can be obtained,” said Sergio Barrientos, director of the National Seismology Center. Nationwide coverage In November 2016 a team of NOAA professionals traveled to Chile to conduct the final phase of training for SHOA and Chilean Navy teams in charge of installing the buoy and putting it into operation. Aided by the scientific research ship AGS Cabo de Hornos, on December 7th they were able to lower the equipment down to 4,223 meters, at a distance of 220 kilometers from the coast. “It was an important event for this institution, upon independently carrying out this whole process,” said Rear Adm. Carrasco. “We have earned NOAA certification not only in the area of installation, but also in the areas of electronics and ship capabilities.” The buoy must be located close to where tsunami-triggering quakes occur. That is why the central-northern region of the country was chosen; the area was lacking this type of measurement coverage and an increase in seismic activity has been forecast there. “It is more likely that large earthquakes will happen in those areas where these kinds of natural events have not been caused in the last 10 or 100 years,” Barrientos said. The DART system’s range covers not only the entire coast of Chile but the rest of the Pacific Rim countries as well. It provides monitoring and alerts not only in the event of a Chilean earthquake but also when quakes happen in other countries and the tsunami waves may reach Chilean shores. “That was the case with the earthquake and tsunami in Papua New Guinea on December 17th, when the buoys were activated and they measured waves that could have reached Chile. Or take the earthquake that happened in the south of Chile on December 25th, on Isla Grande de Chiloé, where the monitoring information was also sent to international centers,” Barrientos said. For SHOA and the Chilean Navy, the prevention effort for this kind of natural disaster demands revising and improving their procedures on an ongoing basis. Meetings between NOAA and SHOA are already scheduled for this year, both in the United States and in Chile, for the purpose of making new advances. “We are working from the basis of ongoing improvement, and we are evaluating and learning about systems that may help us transmit the information to the community rapidly and with greater precision,” Rear Adm. Carrasco concluded.
