Earthquake precursors are events that precede an earthquake, and are known to begin days, months, or even years before an earthquake occurs.
Some of the known seismic precursors include animal behavior, changes in groundwater levels, certain radio waves, and seismic light, but it has not yet been scientifically proven that these events are directly related to earthquakes.
Even if a known seismic precursor event occurs, it is difficult for current science to predict when and where an earthquake will occur. For this reason, developed countries are scrambling to create systems to detect and disseminate earthquake events as early as possible.
For example, Japan, which is prone to earthquakes, has a system in place to disseminate warnings within 10 seconds of an earthquake.
Strange animal behavior?
It is widely believed that animal behavior is a precursor to earthquakes.
Pre-earthquake migrations of birds and amphibians, as well as strange behavior of dogs and cats, have been observed in actual earthquakes.
For example, during the 2004 South Asia earthquake and the 2005 Pakistan earthquake, wildlife was seen moving to higher ground, and there were reports of toads running away in droves before the 2008 Sichuan earthquake.
There have also been cases of animals dying in large numbers, such as the 2011 Great East Japan Earthquake, where the carcasses of more than 50 dolphins washed up on the shores of Ibaraki Prefecture five days before the quake, leading many to believe that it was a precursor to a major earthquake.
In 2011, 107 whales were found dead on a beach in southern New Zealand two days before the Christchurch earthquake.
There are two schools of thought on whether these animal behaviors are earthquake precursors: some argue that the plates that make up the earth’s crust are under strong pressure before an earthquake, creating an electric field that can affect animal perception, while others argue that there are irregularities between animal precognition and geomagnetic phenomena that make it difficult to make a connection.
However, most experts agree that animals with superior senses may be able to detect earthquakes before humans, but they are not suitable for earthquake prediction technology.
Mysterious seismic light and an unusual rainbow?
Earthquake light, a luminous phenomenon observed in the atmosphere, is also considered a possible precursor to an earthquake.
Earthquake light is a flash of light in the sky that lasts for seconds to tens of minutes and has been observed in Nagano, Japan in 1965, Sichuan, China in 2008, and Chile in 2010.
In 2012, researchers at the Quebec Department of Natural Resources in Canada discovered that seismic light is caused by electrons bouncing off rocks and hitting a layer of air.
There have also been reports of seismic rainbows, which appear as long horizontal streaks or vertical lines just before an earthquake.
Rainbows have been seen in the days leading up to the 2010 Chilean earthquake, and unusual rainbows have been recorded in the days leading up to the April 2008 earthquake in Sichuan, China.
These reports of rainbows and flashes preceding earthquakes have led to claims of a strong correlation between the two phenomena.
However, this claim lacks scientific consistency, as flashes of light or unusual rainbows do not necessarily lead to earthquakes.
Clouds Speak, Earthquake Clouds?
The theory of seismic clouds was coined by Hiroharu Sasaki, head of the Japan Earthquake Prediction Association.
Sasaki argued that powerful electromagnetic waves from the ground rise into the sky before an earthquake to form seismic clouds, which can take on different shapes depending on the time of year leading up to an earthquake, including long, thin strips, waves, stretches into the sky, tornadoes, and rainbow-colored clouds.
In fact, before the 2008 Sichuan earthquake, the same cloud shape as Sasaki’s claim was observed.
There have also been claims of seismic clouds before the 2009 Wenan earthquake in China, the 2010 Haiti earthquake, and the 2011 Great East Japan Earthquake.
However, the general consensus in the academic community is that there is no significant correlation between seismic clouds and earthquakes.
A The academic community also denies the existence of seismic clouds, saying, “Clouds are formed by water vapor condensing into droplets as the air rises, and electromagnetic waves cannot affect the cloud formation process.
In particular, the periodicity and consistency of precursor phenomena are important, and it is unreliable to predict them based on the movement or appearance of simple clouds.
Microquakes and the full moon?
A micro-earthquake is when a portion of a fault fails to withstand the stress and shakes, before the massive fault ruptures all at once.
The method of predicting earthquakes by observing microquakes has only been successful once before, in 1975, when a microquake was detected in Haicheng, a city near Dalian, China, leading to the evacuation of one million people, reducing the damage of a magnitude 7.5 quake.
In 2016, a team of researchers from the University of Tokyo in Japan published a study in Nature Geoscience that found that large earthquakes are more likely to occur during full or new moons.
In fact, the team analyzed large earthquakes over the past 20 years, including the 2004 Sumatra and 2011 Great East Japan Earthquakes, and found that tidal differences peaked about two weeks before the quakes.
The team speculated that the change in gravity between the Earth and the Moon affected the Earth’s fault lines.