The Parkfield section of the San Andreas fault in California, known for its regular earthquakes, may help predict the imminence of a major earthquake.
Although there are signs that this area might soon experience another earthquake, the signals are not yet clear, and the next earthquake could differ from the one in 2004.
Researchers are focusing on this part of the fault, which experiences earthquakes approximately every 22 years, with the last one occurring in 2004. This section, located between two zones of different tectonic behaviors, is in a transitional phase. South of Parkfield, the fault is locked, preventing the plates from moving against each other, while to the north, the plates are constantly slipping.
According to a new study published on March 22 in the journal
Frontiers in Earth Science, monitoring Parkfield could help predict future earthquakes.
Variations in the measurement of seismic wave attenuation, observed before the 2004 earthquake, have not yet been detected. Seismic attenuation, which reflects the loss of energy of sound waves as they travel through the Earth's crust, is related to the permeability of rocks.
Just before an earthquake, the accumulated stress opens long cracks while closing shorter ones, which affects the energy of seismic waves at different frequencies. These measurements are valuable indicators to anticipate earthquakes and save lives.
For now, Luca Malagnini, research director at the National Institute of Geophysics and Volcanology in Italy and lead author of the study, is not trying to predict the exact day of the next earthquake but remains attentive to signals that could indicate its imminence.