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Open
Letter to the scientific community, to the decision makers and to
the public
However, when it comes to earthquake prediction, the tools developed
by seismologists are blunt. They are blunt because the seismological
approach to earthquake risk is retrospective: look at past events
and calculate the probability of future events during, for instance,
the next 7 or next 30 years. Those who say that earthquakes are unpredictable do not face up to an inconvenient truth: Earthquake prediction depends not only on the history of past seismic events but also – and even more so – on the processes that unfold in real time deep in the Earth’s crust. It has been known for decades, even centuries, that the Earth sends out signals before major seismic events – a bewildering multitude of signals, sometimes distinct, more often subtle and patchy:
(i) Perturbations in the ionosphere 100-300 km above the ground, Until recently the scientific community had been unable to explain, not even in a broad brush, how the different types of signals may be generated. Nobody had been able to provide a physical basis for these signals and describe how they may be related or interconnected.
The last two years have brought major progress in our insight into
the processes deep in the Earth that seem to be responsible for the
generation of most, if not all of the pre-earthquake signals listed
above.
These currents can be quite strong. According to laboratory data,
every cubic kilometer of rock that is being stressed can deliver up
to 10,000 –100,000 Amps flowing for extended periods of time.
What is even more surprising, these currents can flow through thick
layers of rock. Their charge carriers pass through loose or consolidated
sand and soil. They are not stopped by water. They probably travel
over distances on the order of kilometers or tens of kilometers. The
same charge carriers cause the surface of the rocks studied in the
laboratory – and presumably the surface of the Earth –
to become positively charged. This charge may be strong enough to
affect the The same charge carriers generate microscopically small but very steep electric fields at the surface, sufficient to spontaneously ionize the air (Freund, 2003). If the water vapor pressure in the atmosphere is in the right range, the airborne ions can cause the condensation of water droplets and, hence, cloud formation. If the number of charge carriers streaming to the surface increases further, sparking and corona discharges can occur that lead to the emission of visible light and to the emission of broad-band radio noise (Freund, 2002).
When the same charge carriers recombine at the surface, they form
vibrationally highly excited, “hot” atoms that de-excite
by emitting a tell-tale spectrum of mid-infrared photons (Freund et
al., 2007). This newly discovered emission process may be responsible
for strange pre-earthquake “thermal anomalies” captured
in night-time infrared satellite images. Saying – as many in the seismological community have done in the past and continue to do – that preearthquake signals are untrustworthy or don’t even exist, is morally and scientifically irresponsible. ------------------------------------------------------------------------------------------- |
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