New research may help experts predict large earthquakes before they occur, thanks to the discovery of patterns in the earth’s movement.
A study into fault activity around earthquakes in Japan shows a correlation between a relatively small movement in the earth known as a ‘slow-slip’, and the timing of earthquakes of magnitude five or more.
Experts hope this information will assist in predicting large-scale earthquake events around the world.
A slow-slip refers to the slow movement of rocks caused by a fault, which doesn’t result in an earthquake — that is, the earth moves without creating seismic waves.
While it was understood that slow-slips caused stress on earthquake prone areas, and in some cases foreshocks ahead of larger quakes, further information has been difficult to gather because slow-slips can be hard to detect, and large earthquakes are not frequent occurrences.
In this study, Naoki Uchida, Assistant Professor at the Research Centre for Prediction of Earthquakes and Volcanic Eruptions at Tohoku University in Sendai, Japan, analysed data around over 6,000 seismic moments in northeastern Japan over 28 years.
The results show that slow-slip rates clearly increase following a major earthquake. However, Uchida’s detailed analysis suggests this increase actually begins a few days before the event.
According to the paper, this finding may also suggest that slow-slips accelerate stress on the earth, and in turn contribute to major earthquakes. More importantly, slow-slip occurrence may act as a signal for larger quake events, if their presence can be accurately monitored.