Via Eurekalert: Researchers from the Universidad Pablo de Olavide (UPO) and the Universidad de Sevilla (US) have found patterns of behaviour that occur before an earthquake on the Iberian peninsula. The team used clustering techniques to forecast medium-large seismic movements when certain circumstances coincide.
“Using mathematical techniques, we have found patterns when medium-large earthquakes happen, that is, earthquakes greater than 4.4 on the Richter scale,” Francisco Martínez Álvarez, co-author of the study and a senior lecturer at the UPO revealed to SINC.
The research, which will be published this month by the journal Expert Systems with Applications, is based on the data compiled by the Instituto Geográfico Nacional on 4,017 earthquakes between 3 and 7 on the Richter scale that occurred on the Iberian Peninsula and in the surrounding waters between 1978 and 2007.
The scientists applied clustering techniques to the data, which allowed them to find similarities between them and discover patterns that will help to forecast earthquakes.
The team concentrated on the two seismogenic regions with the most data (The Alboran Sea and the Western Azores-Gibraltar fault region) analysing three attributes: the magnitude of the seismic movement, the time elapsed since the last earthquake and the change in a parameter called the b-value from one earthquake and the other. The b-value reflects the tectonics of the region under analysis.
A high b-value means earthquakes are predominantly small in size and, therefore, the land has a low level of resistance. In contrast, a low value indicates that there are a relatively similar number of large and small seismic movements, which implies the land is more resistant.
Successful Forecast Probability Greater than 80%
“We have discovered the strong relationship between earthquakes and the parameter b-value, recording accuracy rates of more than 80%,” Antonio Morales Esteban, another of the co-authors of the study and a senior lecturer at the US highlighted. “After the calculations had been performed, providing the circumstances and sequences we have determined to be forerunners occur, we obtain a significant success probability”.
The technique summarises the forecasts in two factors: sensitivity (probability of an earthquake occurring after the patterns detected occur) and specificity (probability of an earthquake not occurring when no patterns have occurred).
The results reflect a sensitivity of 90% and specificity of 82.56% for the Alboran Sea region and 79.31% and 90.38% respectively for the seismogenic region of the Western Azores-Gibraltar Fault.
That is, there is a high probability of an earthquake in these regions immediately after the patterns discovered occur (high sensitivity) and, moreover, on most of such occasions, they only occur after the patterns discovered (high specificity).
At present the team is analysing the same data using their own algorithms based on “association rules”, other mathematical techniques used to discover common events or those which fulfil specific conditions within a set of events.
“The results are promising, although I doubt we will ever be able to say that we are capable of forecasting an earthquake 100% accurately,” Martínez Álvarez conceded.
References:
A. Morales-Esteban, F. Martínez-Álvarez , A. Troncoso , J.L. Justo y C. Rubio-Escudero. “Pattern recognition to forecast seismic time series”. Expert Systems with Applications 37 (12): 8333�, diciembre de 2010. Doi: 10.1016/j.eswa.2010.05.050.
“”””” fhsiv says:
December 3, 2010 at 2:01 pm
Hey George E. Smith!
His name is Berkland not Berquist. “””””
The hell you say ! Well I do believe you are correct; well I’ll fess up and not try to blame it on my keyboard errors.
I cannot remember the names of every scientist that ever was; but I usually can get close.
Thanks for sorting that out for us, old Chap.
“”””” Gary Pearse says:
December 4, 2010 at 9:39 am
John Day, George Smith:
Some 40 years ago, upon hearing about anxiety among animals prior to an earthquake, I suggested to colleagues that early stress could possibly result in quartz in sandstones or granites to respond with build up of a peizoelectric charge (early radio). “””””
Gary, I believe you. How easily we (those of us that are lay geologically) can dismiss a pile of rocks as just that; when they really are complex systems of crystals, and compounds having all sorts of physical properties.
So I would certainly buy a Piezo or related strain effect that could produce radio waves. I’ve heard actual accoustic recordings of earthquakes reverberating aound inside the earth like thunder. The now unobtainable LP record, called “Out of This World” was recorded on mag tape running at 0.02 inches per second; and then played back at the then standard open reel speed of 7.5 inches per second to create the signal recorded on the LP.
The flip side of that 12 inch LP carried atmospheric radio noises like, Whistlers, Howlers, Dawn Chorus, and the like, which generally relate to lightning strikes that happen somewhere on earth and create audio frequency radio signals that propagate along the earth magnetic field lines.
I once worked at a DSIR Government lab in Wellingotn (lower (or upper) Hutt perhaps) NZ; and they were doing radio atmospheric research along with some satellite location in Norway or thereabouts; so we used to listen to Whistlers all the time.