Scientists say they have identified signals of ground motion that could predict earthquakes up to two hours before they strike. The signals were recorded or detected by GPS acquisition devices. The facilities were located in areas where large earthquakes have struck in the past.
However, the researchers noted that there is currently no proper equipment to use the data to predict earthquakes. But if the sensitivity of current GPS measuring devices can be improved, researchers say a new earthquake warning system could be possible.
Earthquakes are caused by movements or landslides in existing faults beneath the earth’s surface, the US Geological Survey (USGS) explains. A fault is a long break in rock attached to the Earth’s crust. When stress builds up along a fault, energy waves are released and travel through the crust. This causes the ground to shake.
The technology for predicting earthquakes is currently very limited. But the USGS has equipment that can capture seismic data when an earthquake is just starting. The term seismic refers to earthquake activity.
The USGS method allows people to be warned in areas where seismic activity is expected. But this method can generally provide a warning only a few seconds before an earthquake. The USGS system is called ShakeAlert. It was already deployed along the west coast of the US. That is where most of the country’s earthquakes occur.
But a new detection method could produce warnings up to two hours before an earthquake’s devastating effects are felt. Such a system could save lives by giving people a chance to get out of buildings that could collapse in an earthquake.
Two scientists from France’s National Research Institute for Sustainable Development conducted a study that described the latest results. The finding recently appeared in the journal Science.
For this study, the researchers examined GPS data collected before and after past earthquakes around the world. Data was collected on 90 earthquakes greater than 7 on the Richter scale. The study period covered the last 20 years.
The team identified a pattern of fault movements when they examined data collected from different areas. Motion signals were recorded within two hours of the earthquake. The researchers said the study shows that faults generally start moving about two hours before a large earthquake.
Scientists have identified such signals before a single earthquake in the past. Until now, however, researchers have been unable to link these signals to all seismic events.
While the data identified this pattern, the researchers said tools that could capture real-time GPS data do not currently exist.
The National Research Institute for Sustainable Development issued a statement on the development. She said that in order to make predictions, researchers “would have to measure signals at least 10 times smaller than what we can currently do.”
Another way to possibly build a better earthquake prediction system would be to develop “dense measuring networks” that are located very close to faults. But such an effort would require major technological advances, the institute said.
Quentin Bletery is a geophysicist at the University of the Côte d’Azur in Nice. Bletery collaborated on the study with Jean-Mathieu Nocquet, another researcher at the university.
Bletery told Science that the study found that no observable movement was identified in the first 46 hours leading up to the earthquake. But about two hours before the earthquake, GPS signals recording movement began to increase.
To confirm their findings, the team compared this data with more than 100,000 random time periods recorded when no earthquakes were reported. This experiment found that similar patterns occurred only 0.03 percent of the time in earthquake-free regions.
“This tells us that earthquakes are predictable in nature,” Bletery told Science.
The researchers note that more research is needed to support their findings. Much of the information used in the latest study, for example, relied heavily on data from GPS stations near major earthquake sites.
Read Now:West African leaders plan military intervention to reverse coup in Niger: ECOWAS intervention
