Introduction The mission of the Spatial Data on the Web Working Groupas described in its charteris to clarify and to formalize standards on spatial data on the Web. This document describes the results of the first steps of working towards these goals. Members of the Working Group and other stakeholders have come up with a number of use cases that describe how spatial data on the Web could work. From these use cases, a number of requirements for further work are derived.
The predictions are then evaluated by testing whether they correlate with actual earthquakes better than the null hypothesis. Clustering occurs in both space and time.
As the purpose of short-term prediction is to enable emergency measures to reduce death and destruction, failure to give warning of a major earthquake, that does occur, or at least an adequate evaluation of the hazard, can result in legal liability, or even political purging.
For example, it has been reported that members of the Chinese Academy of Sciences were purged for "having ignored scientific predictions of the disastrous Tangshan earthquake of summer Following the L'Aquila earthquake ofseven scientists and technicians in Italy were convicted of manslaughter, but not so much for failing to predict the L'Aquila Earthquake where some people died as for giving undue assurance to the populace — one victim called it "anaesthetizing" — that there would not be a serious earthquake, and therefore no need to take precautions.
The rate of occurrence of both must be considered when evaluating any prediction method. Therefore, Stiros stated that it would be much more cost-effective to focus efforts on identifying and upgrading unsafe buildings.
Since the death toll on Greek highways is more than per year on average, he argued that more lives would also be saved if Greece's entire budget for earthquake prediction had been used for street and highway safety instead.
Research into methods of prediction therefore focus on empirical analysis, with two general approaches: Forty nominations were made, of which five were selected as possible significant precursors, with two of those based on a single observation each.
Published results are biased towards positive results, and so the rate of false negatives earthquake but no precursory signal is unclear. In cases where animals display unusual behavior some tens of seconds prior to a quake, it has been suggested they are responding to the P-wave.
It has also been suggested that unusual behavior hours or even days beforehand could be triggered by foreshock activity at magnitudes that most people do not notice. It was believed this happened in a 'preparatory phase' just prior to the earthquake, and that suitable monitoring could therefore warn of an impending quake.
Subsequent study showed it "failed for several reasons, largely associated with the validity of the assumptions on which it was based", including the assumption that laboratory results can be scaled up to the real world.
In the s it was considered a likely breakthrough when Russian seismologists reported observing such changes later discounted.
Radon emissions[ edit ] Most rock contains small amounts of gases that can be isotopically distinguished from the normal atmospheric gases. There are reports of spikes in the concentrations of such gases prior to a major earthquake; this has been attributed to release due to pre-seismic stress or fracturing of the rock.
One of these gases is radonproduced by radioactive decay of the trace amounts of uranium present in most rock. A review  found reports of changes in radon emissions prior to 86 earthquakes since But as the ICEF found in its review, the earthquakes with which these changes are supposedly linked were up to a thousand kilometers away, months later, and at all magnitudes.
In some cases the anomalies were observed at a distant site, but not at closer sites. The ICEF found "no significant correlation". A review  found the "most convincing" electromagnetic precursors to be ULF magnetic anomalies, such as the Corralitos event discussed below recorded before the Loma Prieta earthquake.
However, it is now believed that observation was a system malfunction. Study of the closely monitored Parkfield earthquake found no evidence of precursory electromagnetic signals of any type; further study showed that earthquakes with magnitudes less than 5 do not produce significant transient signals.
In a paper  they claimed that by measuring geoelectric voltages — what they called "seismic electric signals" SES — they could predict earthquakes of magnitude larger than 2.
As proof of their method they claimed a series of successful predictions. Additional criticism was raised the same year in a public debate between some of the principals.
Just three hours before the quake the measurements soared to about thirty times greater than normal, with amplitudes tapering off after the quake.
To many people such apparent locality in time and space suggested an association with the earthquake. More recent studies have cast doubt on the connection, attributing the Corralitos signals to either unrelated magnetic disturbance  or, even more simply, to sensor-system malfunction.
The resulting charge carriers can generate battery currents under certain conditions.Figure 2. How relative dating of events and radiometric (numeric) dates are combined to produce a calibrated geological time scale.
In this example, the data demonstrates that "fossil B time" was somewhere between and million years ago, and that "fossil A . A large pile of sand accumulates in front of the sledge when this is pulled over dry sand (left).
On the wet sand (right) this does not happen. Presents analysis and interpretation techniques to aid scientists in conducting fieldwork and research Provides the latest information on geodynamic concepts, from isostasy over continental collision, to more recently, feedback mechanisms between tectonics and climate.
3. Methodology. In order to find out the requirements for the deliverables of the Working Group, use cases were collected. For the purpose of the Working Group, a use case is a story that describes challenges with respect to spatial data on the Web for existing or envisaged information systems.
Earthquake prediction is a branch of the science of seismology concerned with the specification of the time, location, and magnitude of future earthquakes within stated limits, and particularly "the determination of parameters for the next strong earthquake to occur in a region.
Earthquake prediction is sometimes distinguished from earthquake forecasting, which can be defined as the. Though this example may seem simplistic, it reflects the way scientists pursue data collection, analysis, and interpretation.
Data (the plural form of the word datum) are scientific observations and measurements that, once analyzed and interpreted, can be developed into evidence to address a .