Earthquakes: Scientists struggle with predictions
Tuesday 13 January 1998
On its own, that is a statement of the blindingly obvious, but earthquakes have financial and social implications. China had earthquake detectors long before the Western world, because they could be critical in so large a country with limited grain stocks.
Predicting when an earthquake will strike is only half the problem; the other half is saying how big it will be. Seismologists willingly admit they are not terribly good at either, although there is a growing body of evidence that an earthquake is preceded by electromagnetic disturbance (which, intriguingly, animals seem to be sensitive to).
This is because most significant quakes are the result of "slips" between two colliding pieces of the Earth's crust. The San Andreas fault in California, for example, consists of a northward-moving piece of coastline and a southward- moving land mass. Because the crust contains magnetised minerals, the strain that builds up before they move can show up with very sensitive instruments.
The latest evidence comes from a researcher who appears to have correctly predicted three events along previously dormant faults in Greece. According to New Scientist magazine, Panayiotis Varotsos, a physicist at the University of Athens, strung wire across the landscape to detect electrical signals and found brief currents before the earthquakes.
The currents were tiny - a few nanoamperes, or billions of times less than that in household items. And Mr Varotsos is not sure how the finding could be used for larger-scale faults: "Seismic electric signals will only be detectable at selected sites," he said, perhaps hundreds of miles away from the quake's epicentre. Predicting anything more than the likelihood of a seismic event will remain - as the Japanese team said in their understated way - "difficult".
- Charles Arthur,
- 1 I'm A Celebrity 2014: Jungle security stepped up after murder and 'suspicious death' near to camp
- 2 To help fuel their propaganda machine against the poor, our government has now decided to redefine the word 'welfare'
- 3 Jeremy Hunt: 'I took my children to A&E because I didn't want to wait for GP appointment'
- 4 Girl, 7, gets Tesco to remove 'stupid' sign suggesting superheroes are 'for boys'
- 5 This letter from a reader explains why women can’t play football
Rochester by-election: Ukip gains second MP as Tory defector Mark Reckless holds seat
'Beast of Bolsover' Dennis Skinner takes Ukip MP Mark Reckless to task moments after he is sworn in
Ukip says babies born to immigrants in the UK should be classed as migrants – which would include Nigel Farage’s own children
The young are the new poor: Sharp increase in number of under-25s living in poverty, while over-65s are better off than ever
Tamir Rice: 12-year-old boy playing with fake gun dies after being shot by Ohio police
Exclusive: UK approved £7m Israeli arms sales in six months before Gaza conflict
£35000 per annum: Ashdown Group: Required skills include SQL querying, SSRS, u...
£30000 - £35000 per annum: Ashdown Group: C#.Net Developer - C#, ASP.Net, HTML...
Negotiable: Argyll Scott International: Senior Business Analyst - Insurance ...
£25000 - £29000 per annum: Recruitment Genius: This independent, growing Sales...