Ever since the Great Tohoku Earthquake, the frequency of earthquakes occurring worldwide has risen. Recently, a 6.1 earthquake has hit around the border of China and Tajikistan. Now, scientists have found that by detecting gravity signals instead of seismic waves to predict the occurrence of earthquakes can vastly improve the Earthquake Early Warning Systems currently used.
Earthquake Early Warning Systems depend on the detection of seismic waves to predict how strong an earthquake will be. The magnitude of an earthquake has a corresponding level of warning that will be publicly shared. The stronger the magnitude of the earthquake, the direr the warning. However, the problem of using seismic waves in the Earthquake Early Warning Systems is that it can only detect the seismic waves as the earthquake is currently occurring.
A study led by seismologist expert Professor Jean-Paul Montagner at Institut de Physique du Globe de Paris examined gravity data collected during the Great Tohoku Earthquake that happened in Japan last 2011. The group was looking for a signal that preceded the arrival of the earthquake. Fortunately, they were able to find this small static signal and thus opened the door for further studies regarding the correlation of gravity signals and earthquakes.
According to Professor Montagner, gravity signals occur due to the shifting of Earth's mass on either side of the fault line during an earthquake. The shifting of the Earth changes the gravitational field of the area hit by an earthquake. Gravity signals travel at the speed of light and can be detected 40,000 times faster than seismic waves.
The faster the gravity signals can be detected, the more time for an improved Earthquake Early Warning System to warn the public of an incoming earthquake. There is still no definite calculation on how much time the detection of gravity signals can give people but extra minutes are enough to prevent a huge number of casualties in the event of an earthquake.
Further studies are still needed regarding gravity signals as they are almost too small to be detected. The use of extremely sensitive and specific tools to detect gravity signals are needed to accurately predict the occurrence of an earthquake.
There is still a long way to go but Professor Montagner and his team are optimistic regarding the correlation of gravity signals and earthquakes. Hopefully, improved versions of the Earthquake Early Warning System would include the detection of gravity signals.
