The prevailing theory for centuries has been that the human mind is a blank slate at birth.
It was generally believed that neural connections are created from scratch with the accumulation of sensory information and experience. But doubts began to arise from George Dragoi of Yale University after spending more than a decade studying activity in the hippocampus, the brain region responsible for memory.
In his study of the rodent hippocampus, the scientist discovered that at an early age, individual functional groups of cells appear in this part of the brain, and after a short period of time, short sequences of cells appear. Within a few days after birth, these cells, groups and short sequences become the basis for increasingly complex connections that provide opportunities for the formation of memories.
Dragoi explains in new research that the human brain also has a cellular matrix shortly after birth. The scientist called it the “generative rules” of the brain.
The network of cells is activated sequentially. With the use of a “grammatical standard,” the hippocampus even in the first days of life contains letters and short words, but is unable to organize them into meaningful sentences or paragraphs that can be stored as memories. The scientist believes this helps explain why people do not remember the first years of life because neural activity improves over time.
New study reveals factors affecting "induced earthquakes"
Man-made earthquakes, or so-called induced earthquakes, have become a growing concern, as some can be strong enough to cause serious damage.
Better understanding the underlying physical processes of these events is key to avoiding large, unruly, systematically induced earthquakes. Therefore, a new study delved into the mechanisms of man-made earthquakes, focusing on the role of fault roughness and stress heterogeneity.
Researchers at the German Research Center for Geosciences (GFZ) published a study explaining the factors affecting human-caused earthquakes.
Their study enabled them to shed light on earthquakes induced during activities, such as fluid injection or extraction as in oil or gas reservoirs, wastewater disposal, or geothermal reservoirs.
The study explores the interplay between fault roughness and stress heterogeneity in the formation of seismic events and provides a roadmap to better understand and potentially prevent such events.
Dr. Li Wang and his team at the Department of Geomechanics and Scientific Drilling at the German Research Center for Geosciences collaborated with researchers from the University of Oslo to conduct pioneering fluid injection experiments under acoustic monitoring in the Geomechanics Laboratory at the German Research Center for Geosciences (GFZ).
By compressing rock samples equipped with sensors to detect acoustic emissions (micro-earthquakes), the team simulated conditions similar to those found in geological reservoirs during fluid injection.
The study revealed that rough and smooth cracks in rocks interact differently during laboratory experiments.
“We demonstrated the gradual localization of small seismic activity indicating stress transfer before large events induced during fluid injection,” emphasizes Dr. Wang.
In contrast to smooth faults, injection-induced slip on rough faults results in spatially localized clusters of acoustic emissions, especially around extreme stresses.
This phenomenon leads to higher rates of local induced slip and a relatively greater number of large seismic events.
Laboratory observations and real-world implications
To understand the importance of laboratory experiments for real-world earthquakes, scientists have compiled data sets from various studies of induced earthquakes.
Seismic injection efficiency, which represents the ratio of energy released in earthquakes to hydraulic energy input, helped distinguish between pressure-controlled ruptures and unruly ruptures.
“Our laboratory observations bear similarities to those field-scale induced earthquakes consistent with pressure-controlled ruptures,” said Dr. Wang. “The study suggests that monitoring fluid injection into geological reservoirs in real time could help identify localization processes prior to larger induced events.” "This provides a way to avoid it."
This research is part of an ongoing initiative to predict earthquakes induced in geological reservoirs and mitigate seismic risks. By bringing processes from the field scale into the laboratory, scientists aim to control and understand the factors that lead to seismic events in more detail.
Professor Marco Bonhoff, Head of the Department of Geomechanics and Scientific Drilling at the German Research Center for Geosciences, highlights the possibility of conducting such studies to mitigate human-caused seismic risks. He points out that “understanding rock deformation processes in more detail is a prerequisite for reaching general acceptance when using the geological subsurface to store and extract energy.”