Ultra-Low-Frequency RF Emissions May Provide Earthquake Warnings

December 14, 2007
Scientists have long searched for a way to predict damaging earthquakes in advance. A Stanford University researcher may have found the answer—ultra-low-frequency RF emissions from the deep in the Earth.

Antony Fraser-Smith, professor emeritus of electrical engineering and geophysics at Stanford, found evidence that big earthquakes emit a burst of ultra-low-frequency (ULF) electromagnetic radio waves days or even weeks before they hit. Fraser-Smith and his team were monitoring ULF emissions in the Santa Cruz Mountains as part of a long-term study of signals reaching Earth from space. On Oct. 5, 1989, their equipment suddenly reported a large signal, which stayed up for the next 12 days. At 2 p.m. on Oct. 17, 1989, the signal increased by 20 to 30 times what the instruments would normally measure. At 5:04 p.m., the 7.1 magnitude Loma Prieta earthquake hit the Monterey and San Francisco Bay areas, causing death and destruction.

When these signals were received, Fraser-Smith thought something was wrong with the equipment. After determining the equipment was working normally, he and his research team realized their equipment may have been in the right place at the right time to catch early signals of the Loma Prieta earthquake. “Most scientists necessarily make measurements on small earthquakes because that’s what occurs all the time,” he said. “To make a measurement on a large earthquake you have to be lucky; which we were.”

The study continued, even after USGS terminated funding in 1999.

“I took a new look at the measurements, concentrating entirely on large earthquakes,” Fraser-Smith said, “And all of a sudden I could see the forest through the trees.”

He found three other studies describing electromagnetic surges before large earthquakes, including one from the Great Alaska earthquake in 1964.

Most research has focused on seismological studies to predict earthquakes. Fraser-Smith acknowledged some seismologists are suspicious of his study’s results. He counters that it would take little effort to verify or disprove them. He asked for federal funding for a mission-oriented study that would place approximately 30 ULF detecting instruments in hot spots for big quakes around the world. He said it would cost about $3,000,000 to buy 30 of the instruments. This is cheap when compared to other studies.

An abstract titled “Ultra-low-frequency Electromagnetic Monitoring within PBO” by Simon Klemperer, Tony Fraser-Smith, Greg Beroza, and Darcy Karakelian at the Department of Geophysics at Sanford University, provides technical details on the emissions and the equipment to detect them. ULF frequencies range from 0.01 to 10 Hz. The abstract says the monitoring equipment includes three orthogonal magnetometers and two orthogonal electric dipoles. To detect ULF emissions, the equipment takes samples at a 40 Hz rate. Interference from power lines or electric railways is an issue.

Amateur seismologists at locations around the world have set up sensitive equipment to monitor earthquakes as they happen. I can’t help but wonder if hobbyists with some knowledge of electronics and a little help from Fraser-Smith’s team might get together, build and set up their own network of ULF monitoring stations, connected using the Internet, in active earthquake areas, even if the government doesn’t come up with the funding.

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