Provadia is a town that connects the words “earthquakes” and “salt,” often referred to as “white gold.” The extraction of this mineral has been happening since ancient times, becoming industrialized about a century ago. Earthquakes are frequent in the area, and there is a common belief that the disturbance of the earth’s layers is linked to these seismic activities, though this connection is not conclusively proven. The knowledge surrounding it is often quoted, as science tends to approach such matters cautiously—extraction carries risks, but without it, life would be unsustainable. Thus, the risk is never officially recognized.
The intersection of human needs for production and consumption with the equally significant need for safety should be thoroughly explored. A current case brings several questions to the forefront.
Two New Drilling Projects
The company “Provadsal,” part of the chemical giant “Solvay,” has a concession until 2030 for the extraction of salt from the Mirovo salt deposit. They plan to develop two new drilling sites, in addition to the 24 currently in operation. The procedure is nearing completion and has received the necessary permits, including from the Regional Inspectorate of Environment and Water (RIOSV) in Varna. The two new wells will be drilled to a depth of 2000 meters, while the extraction of rock salt occurs at depths of 1000, 1250, 1750, and 2000 meters. Despite seismic and other risks, the Environmental Impact Assessment (EIA) report has been approved. Solvay claims that the new wells will replace depleted ones, ensuring that overall production capacity does not increase. Essentially, they guarantee that no greater amounts will be extracted, indicating that there will be no increase compared to the approved annual extraction plan and concession agreement.
Skepticism from Local Residents
Engineer Kadriya Mehmed from Provadiya is among those who are not satisfied with the assurances of safety provided. While she understands that the extraction industry cannot be halted, she raises valid concerns. “In 2022, Solvay announced an annual increase of 200,000 tons in the production of calcined soda. Şişecam also reported increased capacity. How is that possible if extraction isn’t increasing? We are talking about companies within the same group that use rock salt as a primary raw material,” she commented in a podcast with “EcoVarna.”
There are other objections to the project, but the primary concern revolves around the risk of earthquakes.
Frequent Earthquakes
Earthquakes in Provadiya are frequent, though fortunately not severe. Their mild intensity might be why the broader Bulgarian public is unaware of the area’s seismic vulnerability. Nonetheless, tremors do occur; the most recent one happened in June, measuring 2 on the Richter scale. Damage such as displaced roof tiles, fallen furniture, and cracked walls is not uncommon in Provadiya and surrounding villages.
Amidst these concerns, Mehmed asserts that the local community has not received adequate guarantees. In the EIA, she notes, and during public discussions, data on seismic activity is primarily based on old reports from 1980 to 1996. “People expected to see research covering the last five to ten years,” she says. Furthermore, seismologists point out that the most significant earthquake in Bulgaria in 2022 measured 4.5 on the Richter scale, with one occurring in Provadiya on April 4 of the same year. This places the area high on the list of concerning seismic zones.
In spring 2024, an interesting development occurred in Parliament. Deputy Stela Nikolova inquired whether there were plans to relocate the railway line from Varna to Sofia near Provadiya. The EIA for the two wells proposed moving the railway as a precautionary measure. The response was that the Ministry of Transport and the National Railway Infrastructure Company (NKJI) had not received such proposals, and the investor denied any intention to undertake such measures. However, it is noteworthy that the railway line has been unstable due to earth movements, with subsidence observed for decades.
Concerns Over Railway Safety
The risk of incidents on the deforming railway line, which trains traverse at speeds of 100 kilometers per hour, is one of the reasons why RIOSV has mandated an impact assessment. The Provadiya to Bozveliysko road, which is also of national significance, is similarly affected, with the risk of complete closure due to deformation. Other concerns are expressed as follows: “The area falls within a seismic zone with induced (anthropogenic) seismicity and slow ground deformation, likely due to the extraction of brine. The Provadiya River flows through the deposit area, and given the critical deformations of the terrain, there is a risk of significant disruption and destruction of protective embankments, leading to water seepage.”
The EIA does acknowledge the seismic situation but asserts that there is no risk to people from the activities.
Scientific Backing and Controversy
The project has received approval following the EIA. Regarding the seismic aspect, the decision is based on a statement dated March 18, 2024, signed by Prof. Nikolai Miloshev, director of the Institute of Geophysics, Geodesy, and Geography at the Bulgarian Academy of Sciences (BAS). It states, “there is no data to conclude that the exploitation of the salt body near Provadiya increases seismic activity in the area.”
The position from BAS is intriguing. It cites a report indicating that over a ten-year period, 535 earthquakes have been registered within 30 kilometers of the salt body. Most of these—390—are minor, imperceptible to people, with magnitudes not exceeding 1.5. However, the frequency is undeniable. BAS attributes this to increased monitoring stations in the area, suggesting that the higher numbers reflect improved measurement capabilities.
The report also states that 17 earthquakes of magnitude between 2.5 and 3.5 occurred over ten years, with three exceeding 3.5. This may seem innocuous to outsiders, but not to residents.
Minimal Impact Claims
“The natural seismic processes in the Provadiya area are outlined in Bulgaria’s seismic zoning map. The implementation of the investment proposal cannot trigger more significant impacts than natural ones, as the volume of salt extracted will comprise only 0.026% of the approved reserves. In terms of area, this represents merely 0.09% of the deposit. Even cumulatively accounting for all other wells, they cannot generate maximum impact in the examined area. Monitoring is ongoing, with reports on seismic events provided every four months, and annual statistics compiled for the period from January to December of the current year.”
This is part of Solvay’s response to inquiries from EcoVarna. It cites BAS’s position and adds that there are no plans to relocate the railway line. “The investment proposal has followed all necessary legal procedures for publicity—notifications, consultations, etc. The investment proposal is not new and does not negatively impact the environment or the local population, and it is vital for the region’s economy,” concludes the statement.
A Call for Accountability
“The previous impact assessment was conducted in 2000. The current one, therefore, comes almost 25 years later. The deposit has been under extraction throughout this period… The next assessment will likely occur in another 25 years. We owe it to our children to act, ask questions, and not leave them with our problems,” concludes Kadriya Mehmed, who has appealed RIOSV’s approval.
