Ionospheric Anomalies Detected Before 2016 Kumamoto Quakes (News)

Science Technology

Kyoto, Feb. 28 (Jiji Press)—A Japanese research team said Tuesday that it detected preseismic ionospheric anomalies above the Kyūshū region just before the main shock in a series of powerful earthquakes in and near Kumamoto Prefecture last year.

Similar anomalies in the ionosphere, a layer of the atmosphere some 300 kilometers above the surface that reflects radio waves, were detected just before the March 2011 temblor occurred off northeastern Japan, unleashing a massive tsunami.

But no such anomalies had been observed before an inland quake.

The team, whose members include Kyoto University Professor Umeno Ken, analyzed Global Positioning System observation data before the main shock of the 2016 Kumamoto quakes, according to an article published in the US Journal of Geophysical Research.

It found that sharp increases in electrons occurred over Kyūshū in southwestern Japan from about one hour before the main quake struck at 1:25 am on April 16 (4:25 pm on April 15 GMT).

Umeno stated that the research may reveal more about how these ionospheric anomalies work and even help to predict earthquakes. He hopes to conduct further tests together with government and other organizations.

[Copyright The Jiji Press, Ltd. Content edited by the editorial team.]

Kumamoto Castle in April 2016, after it was damaged by the earthquakes. (Photograph by Hashino Yukinori of

Kyūshū earthquake Jiji Press