The crater at Vera Cruz grows nearly 4 m and reaches 89.5 m long; cause of erosion still unknown | Bahia

In the last disclosure of the crater size last November, it was 86 meters long and 36 meters wide. Already, the updated data point has a length of 89.5 m and a width of 40.9 m.

As in the last measure, only the depth decreased because of the accumulation of debris that falls with the growth of the hole. With this, the depth has gone from 40 to 36.4 meters.

Dow reported that there were still no details of the causes of the crater and was continuing his studies to determine how the gulf, a geological phenomenon known as the "underground void", had appeared in Matarandiba. The first part of the results of the badessments has a deadline for the completion of the works in the second quarter of 2019.

The company indicated that the increase in the length of the crater was expected until the end of the year. the complete stabilization of the ground, because, from a technical point of view, the edges of the erosion are generally the same size as the bottom of the erosion. According to the company, when the upper edges are on the same perimeter as the bottom, there should be a stabilization.

Dow noted that the community of Matarandiba was confident, according to the results of the geomechanical study published in late November, conducted by the independent German consulting firm Institute for Geomechanics (IFG), a worldwide reference in the field.

However, as a precaution, technologies offering real-time information on subsoil movements in the region have been installed, including a high-precision satellite that tracks and restores the movement history. of soil in the insular region. Micro-sensors have also been installed to monitor any movement and the possibility of new occurrences. Since the start of monitoring, no geological variation has been identified, the company said.

] The erosion was discovered by Dow Chemical, which operates in the area where the hole appeared at the end of June this year, when routine work, and was 69 meters long. The crater is in the middle of a native forest in the locality of Matarandiba and is about 1 km from where the locals live, what they fear.

Access to the area where the hole is formed is difficult because of the closed forest, but the whole area is isolated and has been monitored to avoid the presence of curious.

In September, the State Attorney's Office of Bahia (MP-BA) opened an investigation to determine the causes of the opening of the crater. The lawsuit was filed by prosecutors Eduvirges Tavares and Ubirajara Fadigas, who work in the field of the environment. The MP also said that the purpose of the action was to preserve people's lives and protect the environment.

Dow Química has been present in Bahia since the 1960s and has not reported any damage to the environment due to its exploitation. The company said that the crater was more than 200 meters from a well that has been out of operation since 1985 and that for more than 30 years no activity has occurred on the site. .

The company also said that since June, after the discovery of the crater, periodic meetings had been held with islanders to keep them informed about studies, arrangements and clarify doubts, activity that will continue over the next few months. The line of direct communication, according to the company, is via WhatsApp.