export_ofoct.com

[00:00.40] Researchers say they have identified earth movement signals that could predict earthquakes up to two hours before they hit.

[00:12.35] The signals were recorded, or detected, by GPS collection devices.

[00:19.53] The devices were positioned in areas where major earthquakes had struck in the past.

[00:27.49] Scientists noted, however, that the right equipment does not currently exist to use the data to predict earthquakes.

[00:39.18] But if the sensitivity of current GPS measuring devices can be improved, the researchers say a new earthquake warning system could be possible.

[00:51.66] Earthquakes are caused by movements, or slips, in existing faults under Earth’s surface, the U.S. Geological Survey (USGS) explains. A fault is a long break in rock attached to Earth’s crust.

[01:12.38] When tension builds up along a fault, energy waves are released and travel through the crust. This causes the ground to shake.

[01:23.54] Technology for predicting earthquakes currently remains very limited.

[01:31.51] But the USGS does have equipment that can pick up seismic data when an earthquake is just starting.

[01:42.13] The term seismic relates to earthquake activity.

[01:46.91] The USGS method makes it possible to warn people in areas where seismic activity is expected.

[01:57.27] But this method generally can only provide a warning several seconds before an earthquake hits.

[02:05.77] The USGS system is called ShakeAlert.

[02:11.35] It has already been deployed along the U.S. West Coast.

[02:16.39] That is where the majority of earthquakes happen in the country.

[02:21.98] But the new detection method could produce warnings up to two hours before the damaging effects of an earthquake are felt.

[02:33.39] Such a system could save lives by giving people the chance to get out of buildings that might collapse in an earthquake.

[02:43.49] Two scientists from France’s National Research Institute for Sustainable Development carried out a study that described the latest results.

[02:55.71] The findings recently appeared in the publication Science.

[03:01.02] For the study, researchers examined GPS data collected before and after past earthquake events around the world.

[03:13.24] The data was collected on 90 earthquakes measuring larger than 7 on the Richter scale.

[03:22.00] The study period covered the past 20 years.

[03:26.79] The team identified a pattern of fault movements as they examined the data collected from different areas.

[03:36.61] The movement signals were recorded within two hours of an earthquake striking.

[03:43.25] The researchers said the study demonstrates that faults generally begin to move about two hours before a large earthquake.

[03:55.47] Scientists had identified such signals before single earthquakes in the past.

[04:03.18] But until now, researchers were not able to link those signals to all seismic events.

[04:12.20] While the data identified this pattern, the scientists said the instruments that could capture GPS data in real time do not currently exist.

[04:25.76] The National Research Institute for Sustainable Development issued a statement on the development.

[04:33.99] It said that in order to make predictions, researchers “would need to measure signals at least 10 times smaller than what we can presently do.”

[04:47.27] Another way to possibly build a better earthquake prediction system would be to develop “dense measurement networks” that sit very close to faults.