In the aftermath of the massive Haitian earthquake on Jan. 12, officials have repeated the long-held opinion that “earthquakes cannot be predicted.”
That’s no longer true.
New electromagnetic techniques (EM) are detecting ominous signs of a killer earthquake’s approach. American and French satellites independently detected signs of danger over Haiti three and four days before the earthquake struck, killing an estimated 200,000 people.
But pre-seismic EM sensing is only funded in a limited research capacity. In France, the DEMETER satellite program, led by physicist Michel Parrot, lacks a forecasting component. Its data can only be analyzed after the fact. Likewise, a fledgling NASA research program is not staffed to provide forecasts; a scientist who interprets the data was away in the days before the quake.
IONISPHERE IS THE KEY
Designed for preliminary research into pre-seismic effects, DEMETER uses a single micro-satellite that takes about a week to pass over every point of the planet scanning for charged particles in the ionosphere, the topmost part of the atmosphere. In the 1990s, Japanese researcher Masashi Hayakawa demonstrated through ground-based radio-sounding that changes on the Earth’s surface before major earthquakes perturb the ionosphere.
Researchers believe the underside of the ionosphere, which is composed of negatively charged particles, is drawn downward as positive ions stream up from the Earth’s surface before a quake.
Looking at such data, scientists at Radio-Hydro-Physics, a private research company in West Virginia, analyzed subtle shifts in satellite and ground radio transmissions and mapped a disturbance in the Earth’s ionosphere over central Alaska before the Nenana Mountain earthquake of Oct. 23, 2002, now considered a fore-shock of the big Denali Fault quake which struck 11 days later. The Denali Fault event was the largest strike-slip earthquake to occur in North America during the past 150 years.
(This image is featured in a lecture on pre-earthquake effects by physicist Friedemann Freund that can be viewed on YouTube, www.youtube.com/watch?v=Y2ZwR9Dxbmo. The image is discussed 42 minutes into the video and appears again at one hour and 11 minutes.)
The NASA team uses a different technology based on satellite images familiar from weather forecasts. Such satellites measure the emission of invisible infrared light from the Earth’s surface. Decades ago Russian physicist Andrew Tronin noticed that strong quakes are preceded by marked infrared emissions.
NASA and university researchers have demonstrated with growing confidence their ability to detect signs of dangerous earthquakes days before they strike. They anticipated the 7.9 magnitude Wen Chuan quake, which struck China on May 12, 2008. Before this deadly quake, warning signs were so alarming that NASA researchers contacted their academic counterparts in China. However, the warning was not relayed to the people.
In Haiti, and many lesser-known quakes, DEMETER’s findings concur with NASA’s.
A TURF WAR
That these advances receive so little attention may stem from an academic and bureaucratic turf war that has been waged over the past three decades.
The largest player is the U.S. Geological Survey, whose earthquake research funding decisions are dominated by seismologists. Seismologists follow a mechanical model of earthquake hazard assessment.
Michael Blanpied, associate coordinator for the USGS Earthquake Hazards Program, says no electromagnetic research had been shown to be “predictive to the satisfaction of the USGS and the seismological community.”
Over the past 11 years, the agency has funded hundreds of projects, totaling about $6 million annually. Only one EM monitoring project was funded at, Parkfield, Calif., and it was deemed a failure.
EM researchers fault the way that seismologists conducted the Parkfield experiment, noting that sensors were placed in locations where electric currents were likely to be grounded out.
Magnetometers must be placed at points where readings are practical, said Anthony Fraser-Smith. “If you’re going to catch fish, you have to go where they live.”
Fraser Smith is a Stanford geophysicist credited with recording ultra-low frequency radio emissions before California’s deadly Loma Prieta quake in 1989. His detector was 4 miles from the epicenter.
Critics say the USGS, which has endured steep cutbacks, has a conflict of interest and that grants go to fund the agency’s existing seismic network.
Nobody denies that seismology is essential for studying the Earth. But seismologists themselves admit seismology can never produce practical forecasts.
At best it may state probabilities couched in terms of decades or centuries. Recent large quakes on presumably “quiet” faults have weakened that claim, however.
Researchers at NASA and in many other countries are placing bets on alternative approaches, including studying links between seismic activity and electro-magnetic waves.
Friedemann Freund, of NASA’s Ames Research Center, has developed what is widely regarded as the most comprehensive seismo-electromagnetic theory over the past 15 years. He’s confident further advances will make forecasts possible.
“We will be able to give practical forecasts for all strong quakes, certainly 7.0, perhaps even down to 6.0,” Freund says. “You will never know the exact day or the exact epicenter, just as you can never say exactly where lightning will strike. But you can say ‘The storm is coming!’ ”
Freund is a physicist and chemist who has made discoveries about how ordinary rock can act like a battery, unleashing currents of positive charges, whenever stressed by unequal pressures.
Tiny currents in the lab translate to huge currents in Nature, where thousands of cubic-kilometers of rock may be under severe stress during the run-up to a quake. On reaching the surface, these charges can cause the emission of infrared light. They can also ionize air, sending vast clouds of positive ions floating upward to perturb the negatively charged ionosphere. Freund’s theory has allowed him to account for and replicate all known EM precursors.
Recently there seems to be a thaw in relations between some conventional seismologists (including within the USGS) and the EM crowd more appreciated abroad. A year ago, after years of having his theories dismissed, Freund was invited to speak at the western headquarters of the USGS in Menlo Park, Calif. An invitation to speak at Berkeley soon followed.
MORE WORK TO DO
Parrot, of the DEMETER program, says EM researchers still have much work to do, but he is heartened by the sea change.
“Now the important point is that some seismologists start to discuss with us,” he wrote in an e-mail.
Meanwhile, business isn’t waiting on government. Tom Bleier of Quakefinder, based in Palo Alto, Calif., says his 55-station magnetometer network along California’s San Andreas Fault already has anticipated two earthquakes in the San Jose-Milpitas area.
Doug Rekenthaler, owner of Radio-Hydro-Physics, which analyzed the data pertaining to Alaska’s 2002 quake, is on the verge of launching an all-out tomography effort to image, in real time, 24-hours-a-day, the ionosphere over California.