Do Electromagnetic Anomalies In Atmosphere Herald Earthquakes?

Science Magazine ^ | 12/21/2015 | Julia Rosen

[Patriot777]

Scientists have detected electromagnetic anomalies before major earthquakes, like the magnitude 9.0 event that struck Japan in 2011, triggering a massive tsunami that wiped out coastal communities like Ōfunato, shown above.

Can electric signals in Earth’s atmosphere predict earthquakes?

By Julia RosenDec. 21, 2015 , 1:45 PM

SAN FRANCISCO, CALIFORNIA—Ask seismologists when they’ll be able to predict earthquakes, and the answer is generally: sometime between the distant future and never. Although there have been some promising leads over the years, the history of earthquake forecasting is littered with false starts and pseudoscience. However, some scientists think that Earth’s crust may give hints before it ruptures, in the form of electromagnetic anomalies in the ground and atmosphere that occur minutes to days before an earthquake. Last week, here at the fall meeting of the American Geophysical Union, researchers shared their evolving understanding of these phenomena—and how they might be used to predict deadly quakes.

Kosuke Heki, a geophysicist at Hokkaido University in Sapporo, Japan, first got interested in the subject when he spotted an increase in the total electron content of the ionosphere—the charged outermost layer of the atmosphere—above Tohoku about 40 minutes before the magnitude 9.0 earthquake struck in 2011. Heki had long used GPS data to study ionospheric responses to earthquakes, which occur when the sudden movement of Earth’s crust reverberates through the atmosphere. Ionospheric disturbances interfere with the communication between GPS satellites and receivers, leaving a fingerprint at specific radio frequencies that researchers can tease out.

In 2011, Heki was skeptical of electromagnetic precursors. But since then, he has used the world’s growing array of GPS stations to identify similar signals before nine other major earthquakes, he explained at the meeting. In addition, Heki has found that earlier anomalies precede stronger earthquakes, potentially reflecting the longer time needed to initiate rupture along larger segments of a fault.

[SunkenCiv]

;^)

[Fai Mao]

There was a 7+ earthquake here three years ago. I heard it before I felt it.

[Windflier]

I know of the '91 Sylmar quake, having been in Northridge when it happened, but didn't know there had also been one in '71.

Yes, it was a real good shaker. Even though we lived forty miles from the epicenter, I recall folks in my neighborhood getting new driveways, afterwards.