Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

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

14.12.2007
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.

Louis Bergeron | EurekAlert!
Further information:
http://www.stanford.edu

More articles from Earth Sciences:

nachricht Atmospheric scientists reveal the effect of sea-ice loss on Arctic warming
11.03.2019 | Institute of Atmospheric Physics, Chinese Academy of Sciences

nachricht Sensing shakes
11.03.2019 | University of Tokyo

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

Im Focus: Revealing the secret of the vacuum for the first time

New research group at the University of Jena combines theory and experiment to demonstrate for the first time certain physical processes in a quantum vacuum

For most people, a vacuum is an empty space. Quantum physics, on the other hand, assumes that even in this lowest-energy state, particles and antiparticles...

Im Focus: Sussex scientists one step closer to a clock that could replace GPS and Galileo

Physicists in the EPic Lab at University of Sussex make crucial development in global race to develop a portable atomic clock

Scientists in the Emergent Photonics Lab (EPic Lab) at the University of Sussex have made a breakthrough to a crucial element of an atomic clock - devices...

Im Focus: Sensing shakes

A new way to sense earthquakes could help improve early warning systems

Every year earthquakes worldwide claim hundreds or even thousands of lives. Forewarning allows people to head for safety and a matter of seconds could spell...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Levitating objects with light

19.03.2019 | Physics and Astronomy

New technique for in-cell distance determination

19.03.2019 | Life Sciences

Stellar cartography

19.03.2019 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>