site.btaSystematic Antarctic Research Vital for Understanding Long-Term Glacier Trends, Says Seismologist

Systematic research in regions such as Antarctica is extremely important because it reveals the long-term condition of glaciers and the direction of their development, seismologist Gergana Georgieva said in a BTA interview.

Georgieva is a chief assistant professor at the Faculty of Physics of Sofia University. Her main research focus is the structure of the Earth and the propagation of seismic waves from strong earthquakes. For the past ten years, she has been studying glacier seismicity. The 34th Bulgarian Antarctic Expedition is her eighth mission to the Bulgarian Antarctic Base St. Kliment Ohridski.

“In 2015, under our first project, we installed a seismic station with the same equipment as the stations in Bulgaria. Initially, it operated only when there were people at the base, and we removed it for the Antarctic winter,” she said.

She added that after the first year this approach proved unsustainable and risky for the equipment. As a result, the team began leaving the instruments in place, with seasonal installation and removal.

“In 2020, we relocated the station to a more sheltered site and left it to record year-round. From a partially operating station, it became a permanent one and is now among the few seismic stations in Antarctica that, in theory, record data continuously throughout the year,” Georgieva explained.

At present, the Bulgarian Antarctic base cannot fully support such equipment year-round. During the Antarctic winter months, August and September, there is about a one-month interruption due to lack of power, as the station is located one kilometre from the base and relies on solar energy and batteries.

“Over the past ten years, we have recorded more than 1,000 earthquakes and tens of thousands of seismic events – signals caused by ground movement that are not earthquakes. In Antarctica, these seismic events are actually icequakes resulting from glacier movement,” the seismologist explained.

According to her, these are not earthquakes that people feel strongly. The reason is that base buildings are designed to withstand wind and shake much more during strong winds than during an earthquake of magnitude 5.

“In the past ten years, there were three earthquakes in the South Shetland Islands region with magnitudes of around 6.8, but they were farther from the Bulgarian base and were not felt by us,” she added.

“When the project for the new laboratory was being prepared, I was asked to assess the seismicity of the area. Before the seismic station was installed, this was very difficult because no one knew what kind of earthquakes occurred there. Now that we are present on site, we can observe the local seismicity,” Georgieva said.

She explained that her task this year is to monitor the seismic station, download the data and check that everything is functioning properly.

“My main task is to carry out glacier measurements. We have 16 markers placed at specific points on the glacier surface, and another eight on the Kontel Glacier from last year,” she said. “We can measure the coordinates of these markers to track glacier movement—not only how fast it moves and in which direction, but also whether the speed changes over time. This is interesting and useful information. Studies show that glaciers that are melting and shrinking tend to slow down. At the same time, in the lower part of a glacier, where summer melting predominates, warming can increase the speed because meltwater begins to flow and accelerates the glacier.”

The seismologist noted that these processes remain poorly studied, especially in Antarctica. Existing studies are largely based on satellite data, which are most reliable when combined with ground-based observations.

“Our work is important because of the ground measurements. In recent years, our efforts have focused on systematic monitoring. Over a period of 10 to 15 years, we need to accumulate consistent data. Systematic research in a region such as Antarctica is crucial because it shows the long-term condition of glaciers and the prevailing trends,” Georgieva said.

She added that sufficiently long-term studies currently exist for fewer than 20 glaciers worldwide, most of them in the Alps and the Himalayas.

“I would not say that Antarctic glaciers are disappearing, because we do not yet have the data to support that. We need systematic research over at least 15 years, which is half of the 30-year climate cycle,” she explained.

According to Georgieva, research in a specific area and the presence of seismic stations in Antarctica are important not only for understanding local seismicity but also for studying global seismicity, as each station contributes to the worldwide seismic network. Such research is also essential for understanding the structure of the Earth.

“Processes in one place are linked to broader processes. Every local study is a small grain of knowledge that will be important in the future,” she concluded.