Large earthquakes may broadcast warnings, but is anyone tuning in to listen?

Dec 12, 2007

Like geological ninjas, earthquakes can strike without warning. But there may be a way to detect the footfalls of large earthquakes before they strike, alerting their potential victims a week or more in advance. A Stanford professor thinks a method to provide just such warnings may have been buried in the scientific literature for over 40 years.

In October, Japan instituted a nationwide earthquake warning system that heralds the advance of a big earthquake; its sophisticated machinery senses the shaking deep in the earth and transmits a warning signal that can beat the tremors to the surface by seconds.

Antony Fraser-Smith, professor emeritus of electrical engineering and of geophysics, has evidence that big temblors emit a burst of ultra-low-frequency electromagnetic radio waves days or even weeks before they hit. The problem is that nobody is paying enough attention.

Fraser-Smith has been interested in electromagnetic signals for decades. Most of these waves come from space, he said, generated in the upper atmosphere by the sun and then beamed down to Earth.

In 1989, Fraser-Smith and his research team were monitoring ultra-low-frequency radio waves in a remote location in the Santa Cruz Mountains as part of a long-term study of the signals reaching Earth from space. On Oct. 5, 1989, their equipment suddenly reported a large signal, and the signal stayed up for the next 12 days. At 2:00 p.m. on Oct. 17, 1989, the signal jumped even higher, about 20 to 30 times higher than what the instruments would normally ever measure, Fraser-Smith said. At 5:04 p.m. the 7.1 magnitude Loma Prieta earthquake hit the Monterey Bay and San Francisco Bay areas, killing 63 people and causing severe damage across the region.

Fraser-Smith originally thought there was something wrong with the equipment. After ruling out the possibility of technical malfunctions, he and his research team started to think the Loma Prieta quake had quietly announced its impending arrival, and that their equipment just happened to be in the right place at the right time to pick up the message.

"Most scientists necessarily make measurements on small earthquakes because that's what occurs all the time," Fraser-Smith said. "To make a measurement on a large earthquake you have to be lucky, which we were."

Along with Stephen Park, earth sciences professor at the University of California-Riverside, and Frank Morrison, professor emeritus of earth and planetary science at UC-Berkeley, Fraser-Smith continued to study the phenomenon of earthquakes emitting electromagnetic waves through a study funded by the U.S. Geological Survey (USGS).

When the USGS terminated the funding in 1999, he decided to move on to other things. But he was recently drawn back into this issue by a local private company that wanted to use his methods to develop earthquake warning systems.

"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, just as he had found at the Loma Prieta site. The earliest report was from the Great Alaska earthquake (M9.2) in 1964. Up until now, most of the focus for earthquake warnings and predictions has been on seismological studies, but no seismic measurements have ever shown this kind of warning before a big quake, Fraser-Smith said.

This technique will probably only yield results for earthquakes of approximately magnitude 7 or higher, because background waves from the atmosphere will tend to mask any smaller signals. But these are the quakes people are most concerned about anyway, from a safety and damage point of view.

Some seismologists are suspicious that these results are real, Fraser-Smith said. But it would take little effort to verify or disprove them. He is calling for federal funding for a mission-oriented study that would place approximately 30 of the ultra-low-frequency-detecting instruments around the world at hotspots for big quakes. It would cost around $3 million to buy 30 of these machines, he said, which is cheap compared to the cost of many other large studies.

Every year, there are on average 10 earthquakes of magnitude 7 or higher around the world. So within just a few years, he said, you could potentially have 10 new measurements of electromagnetic waves before big quakes-surely enough to determine whether the previous four findings were real.

Source: Stanford University

Explore further: Magnitude-7.2 earthquake shakes Mexican capital

add to favorites email to friend print save as pdf

Related Stories

Egypt archaeologists find ancient writer's tomb

2 hours ago

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

Ex-Apple chief plans mobile phone for India

2 hours ago

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

NASA's space station Robonaut finally getting legs

2 hours ago

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Health care site flagged in Heartbleed review

15 hours ago

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...

Airbnb rental site raises $450 mn

15 hours ago

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.

Recommended for you

Magnitude-7.2 earthquake shakes Mexican capital

Apr 18, 2014

A powerful magnitude-7.2 earthquake shook central and southern Mexico on Friday, sending panicked people into the streets. Some walls cracked and fell, but there were no reports of major damage or casualties.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

out7x
2.7 / 5 (3) Dec 13, 2007
piezoelectric properties of minerals, such as quartz, have been well known.

More news stories

China says massive area of its soil polluted

A huge area of China's soil covering more than twice the size of Spain is estimated to be polluted, the government said Thursday, announcing findings of a survey previously kept secret.

UN weather agency warns of 'El Nino' this year

The UN weather agency Tuesday warned there was a good chance of an "El Nino" climate phenomenon in the Pacific Ocean this year, bringing droughts and heavy rainfall to the rest of the world.

Making graphene in your kitchen

Graphene has been touted as a wonder material—the world's thinnest substance, but super-strong. Now scientists say it is so easy to make you could produce some in your kitchen.

Low tolerance for pain? The reason may be in your genes

Researchers may have identified key genes linked to why some people have a higher tolerance for pain than others, according to a study released today that will be presented at the American Academy of Neurology's 66th Annual ...