One for Fetzer & Wood devotees to mull over...

[Thermate911]

Evidence Mounts for Electromagnetic Earthquake Precursors

Keay Davidson
Wired
Mon, 17 Dec 2007 03:26 EST
http://www.wired.com/science/discoveries/news/2007/12/earthquake_alarm

Scientists revealed data Thursday that an electromagnetic alarm might have preceded a 2007 earthquake in Northern California. The evidence could offer support to a controversial theory that mysterious and little-understood signals might offer fair warning for imminent catastrophic earthquakes.

Scientists detected the signal Oct. 30 near Milpitas, California, 19 hours before a medium-size quake -- with its epicenter in the Alum Rock neighborhood of San Jose -- shook the region, scientists told Wired News Thursday.

"Alum Rock saw a signal that didn't happen at any other site: It was a series of electromagnetic pulses that were drawn out over eight minutes," said Tom Bleier, a researcher with QuakeFinder, a Palo Alto firm. He cautioned, however, that further study is needed to determine if the electromagnetic signal has "some other cause" besides the quake.

The new data, reported here at the American Geophysical Union annual meeting, was met with some skepticism. But the evidence could be a watershed moment in earthquake detection, a field that has a long and perpetually disappointing history. The discovery could strengthen the case of scientists who suggest that big quakes are preceded by strange signals, including one that may have come before the catastrophic 1989 Loma Prieta earthquake in the San Francisco Bay Area.

"There are at least a dozen theories that predict these (electromagnetic precursors) should occur," said Jacob Bortnik, a UCLA space physicist and a consultant for QuakeFinder.

To test the theory that quakes emit advance warning signals, a small team of California scientists funded by the satellite company QuakeFinder, has installed some 70 electromagnetic sensors across California, including some in high schools, in exchange for satellite internet access. The device is a white box, 4 feet tall, which contains an instrument called a search-coil magnetometer, designed to detect the type of signal that researchers theorize acts as a quake alarm.

At about 1:30 a.m. on the day before Halloween, one of the sensors -- located on the property of a plumber near Milpitas -- detected a puzzling series of electromagnetic pulses. Late that same day, a 5.6-magnitude quake occurred nearby, with its epicenter at Alum Rock, just south of the Calaveras earthquake fault.

QuakeFinder engineers are now analyzing data from the sensor, trying to determine whether it gave advance warning of the Alum Rock quake, said Bleier, who is trained in electrical engineering. He cautioned that the data analysis is only 30 percent finished, and it's premature to say whether the signal emanated from the quake or is due to some other cause.

Skeptics believe the electromagnetic signals might not be due to quakes at all. Rather, they could be caused by sources ranging from the natural to the artificial -- say, from solar activity or from electromagnetic fields generated by auto engines.

Scientists at the AGU meeting Thursday argued whether a particularly dramatic electromagnetic alarm preceded the 7.1-magnitude Loma Prieta earthquake of October 1989, which devastated parts of the San Francisco Bay Area. Antony Fraser-Smith, now an emeritus professor of electrical engineering at Stanford University, detected the signal.

According to Fraser-Smith, the 1989 signal began from an unknown source up to two weeks before the Loma Prieta quake. The signal peaked sharply a few hours before the quake struck.

But critics point out that Fraser-Smith's records don't include evidence of natural, day-and-night variations in the Earth's electromagnetic field, which are normally present in such records, said Malcolm Johnston, a geophysicist at the U.S. Geological Survey office in Menlo Park, California.

Fraser-Smith also had some supporters at the conference. David Culp, a Stanford graduate student in electrical engineering, presented evidence supporting Fraser-Smith's 1989 detection. He emphasized the dramatic spike in electromagnetic intensity hours before the quake. Efforts to explain the signal via nonquake mechanisms are "entirely implausible," Culp said.

A long-time proponent of the earthquake-alarm theory, Friedemann T. Freund, a scientist at NASA Ames Research Center in Mountain View, California, also presented data on the possible mechanism underlying the electromagnetic signals.

He reported the result of a lab experiment in which he subjected rock to high pressures, modeling pre-earthquake conditions. It caused the rocks to develop electrical currents, he said. After relieving pressure on the rock, the electrical current slowly faded out -- just like the electromagnetic measurements after quakes.

"Either there is a big devil down there moving magnets back and forth, or there is some kind of physical effect causing (these signals)," Freund said.

Johnston, however, said Freund's electrical currents would be "short-circuited" by the abundant groundwater in underground rock.

Still, with evidence mounting that the signals might be real, some scientists are calling on the federal government to develop a network of electromagnetic sensors to detect such signals before quakes. Even skeptics agree more detection is necessary.

"We need a much more comprehensive (electromagnetism-monitoring) network," Johnston said.

But Bill Ellsworth, a prominent Geological Survey geophysicist, said that in the absence of an infinite amount of federal funding, first priority should go to the development of more seismic-detection networks that -- unlike earthquake alarms -- are based on well-understood physical principles.