João Câmara, 'Land of Shakes': largest earthquake in RN turns 40 years old and changed the seismolog When a magnitude 1.7 tremor was recorded in João Câmara at 8:26 pm, on February 19th this year, a few minutes were enough for the information to reach the computers at the UFRN Seismological Laboratory, in Natal. The signal traveled through the network of dozens of stations spread across the Northeast, was processed by digital systems, reviewed by experts and transformed into a bulletin, which can be accessed by Civil Defense and the National Center for Natural Disaster Monitoring and Alerts (Cemaden), for example. Today, this process is almost automatic. 40 years ago, when the 5.1 earthquake, the largest in the history of Rio Grande do Norte, hit João Câmara, none of this existed. ?? "João Câmara, Terra dos Abalos" is a special series from g1 that remembers the 40th anniversary of the biggest earthquake ever recorded in Rio Grande do Norte and one of the biggest in Brazil. In this second report, we show how the seismic sequence transformed João Câmara into a natural laboratory and changed the direction of Brazilian seismology. The third and final article will be published this Monday (21). READ ALSO: João Câmara, 'Land of Abalos': largest earthquake in RN turns 40 and changed seismology in Brazil ? Click here to follow the g1 RN channel on WhatsApp Old equipment used to measure earthquakes LabSis/UFRN At the time, records were made on analog equipment, printed on smoked paper. The team consisted of just three teachers. There were no mobile stations to install in affected areas nor a national seismic monitoring network. It was precisely that sequence of earthquakes that began in 1986 that changed this scenario and transformed Brazilian seismology. "I would say that there was a before and after João Câmara in seismology in Brazil. From this point on, seismology centers and groups were consolidated, there was investment and training", highlights Aderson Nascimento, coordinator of LabSis. Before JC One of the seismographic stations operated by LabSis LabSis/UFRN When the first tremors began to be felt in June 1986, the UFRN seismology group had already been studying the region's seismic activity since the beginning of the decade. Although Brazil already recorded earthquakes, few were studied continuously. Events that caused such significant impacts on an urban population were also rare. Biggest earthquakes in Brazil g1 Retired professor Joaquim Mendes Ferreira had visited João Câmara for the first time in 1983, after a tremor recorded in the region. "At the time, Mayor Ribamar already had this concern and invited me to go there", he says. Three years later, in 1986, he returned accompanied by professors João da Mata and Mário Takeya and then scholarship holder Francisco Hilário to follow a sequence that still seemed small. "We went to the field at the beginning of June. But the activity increased, the magnitudes began to grow and we realized that we were facing something completely different", he recalls. LabSis researchers in João Câmara, in 1986 LabSis/UFRN Archive Until then, explains Joaquim, the available structure was quite limited. "We didn't have field equipment. There was only one permanent station and the work was basically visiting the areas, collecting information and sending the records to research centers abroad", he recalls. As the tremors intensified, the university's small team began monitoring the evolution of the crisis on a daily basis. The challenge, however, went far beyond science. "What really shook people wasn't just the physical damage. It was the tremors and then the aftershocks, one after the other. Psychologically, it was devastating", recalls Joaquim. The then mayor Ribamar Leite says that he became interested in the topic when he was still at the Science faculty and, therefore, had invited professor Joaquim Ferreira to visit the city. "There was no predictability. At the time there was a thesis in the city that with a sequence of hundreds of smaller earthquakes, a big one would come. Another thesis said that with the dispersion of energy in the smaller ones, there wouldn't be enough strength for a big one, but nothing was scientifically proven", he says. City became laboratory As the earthquakes attracted the country's attention, João Câmara began to attract experts from different parts of the world. Researchers from the University of São Paulo (USP), University of Brasília (UnB), as well as scientists from Japan, the United States, England, Greece and Venezuela arrived in the city to monitor an unprecedented phenomenon in Brazil. "President José Sarney ordered technical teams to come. Scientists from all over the world came to João Câmara, cutting-edge scientists", recalls former mayor José Ribamar Leite. The reason for such interest was simple. The country had never experienced a seismic sequence of that size. House deteriorated by earthquakes Archive LabSis/UFRN More than recording an earthquake of magnitude 5.1, the researchers began to observe an activity that would last for more than a decade and exceed the mark of 50 thousand recorded tremors. "João Câmara's seismic evolution opened new paths of knowledge in this area and helped train many researchers, in addition to attracting international partnerships with UFRN", summarizes seismology specialist Eduardo Alexandre. It was during this period that the Fern Fault began to reveal features to researchers that were still unknown. "Monitoring showed that it was a structure approximately 38 kilometers long and made it possible to accurately map areas that were previously unknown", explains LabSis coordinator, Aderson Nascimento. After JC Four decades later, Joaquim summarizes the importance of that period in a phrase that has become well-known among researchers in the field. "History is divided between before and after Christ. Seismology in Brazil, in a way, also