Prior to major earthquakes, researchers have identified a movement of the ground that may potentially allow for advance warning of their occurrence. Published in Science, the study discusses the detection of a movement, called an aseismic slip, which can cause a small shift in the ground without any accompanying shaking. Says Quentin Bletery, study co-author and earth science researcher at the French National Research Institute for Sustainable Development (IRD) at the Cote d’Azur University, to Scientific American, “It’s solid evidence that there is something happening before large earthquakes. It’s solid evidence that there is something happening before large earthquakes.”
The study used information from a set of 3,026 GPS stations surrounding 90 earthquakes with magnitudes of 7.0 or greater. These stations were set up to record the exact location every 5 minutes, with the study examining the magnitude and direction of any displacement of these stations in the two days before a quake occurred. From the review, it was observed in the last two hours before the quake, an exponential acceleration in the horizontal movement of the sensors was observed, which was two as large at the maximum seen in the first 46 hours.
As to whether this information will be able to be used to develop a robust prediction model is unclear. Says Lucy Jones, seismologist and founder of the Dr. Lucy Jones Center for Science and Society, to Scientific American of the research, “It doesn’t give you a precursory, predictive ability because it’s a statement of how you’ve summed it rather than what’s going on at a particular earthquake. ‘I see this before main shocks’ and ‘I see this and know what’s coming’ are completely different questions.”
Source:
