Using Semiconductor Physics to Forecast Earthquakes | Friedemann Freund | TEDxChristchurch
Earthquakes are the deadliest of all recurring natural disasters, disruptive and enormously costly.
They are feared because
they seem to strike without possibility of prior warning.
Earthquake disasters affect about 1/3rd of the world population.
For decades seismologists have tried to find ways to predict earthquakes using the established cientific tools of their discipline, namely mechanical physics. Yet, their efforts have failed and earthquakes remain unpredictable today as ever – except in terms of statistical probabilities with wide uncertainty windows, years to decades, or in terms of seconds of warning, when a major earthquake is already in progress. The reason for this deeply dissatisfactory situation is that the pre-earthquake processes, which can produce precursory signals, were never properly understood.
Vision of the GeoCosmo is to provide an actionable earthquake forecast system based on insight gained over decades of work to decipher the processes that take place deep in the Earth’s crust as tectonic stresses build up prior to earthquakes.
The GC vision is based on progress in understanding (1) solid state and semiconductor physics, (2) electrochemistry, and (3) chemistry as related to observations that can be made at the Earth surface, in groundwater, well and spring water, in the atmosphere all the way up to the ionosphere, and on observations made by satellite remote sensing. The vision is to demonstrate that it is possible to forecast major earthquakes days before they strike.
Objective of GeoCosmo is to establish and maintain ground stations, ground station networks, and satellite data streams to collect extremely diverse data and to use state-of-the-art artificial Intelligence to recognize patterns and trends.
Expected Results are to demonstrate the feasibility of actionable forecasts giving PLACE-DATE-MAGNITUDE of impending major earthquakes within reasonable limits (<200 km uncertainty, within a 1-3 days of the actual occurrence, and within 1 unit of magnitude on the Richter scale).
The Exploitable Results will carry far into the future, as the forecast methodology to be developed here will be refined and applied to different seismically active regions around the world as their ground station networks come on-line.
To improve today’s current observational capabilities, the GC is building regional networks of ground stations with multiple sensors in covering areas several hundred kilometers across. Wherever possible, we are updating existing seismic ground stations. The GC also uses satellite images to augment observational capabilities. Thus, the target regions are monitored from the ground and from satellites, adding to multi-parameter observations from complementary scientific disciplines to the science of seismology
Most earthquakes, large ones, are caused by tectonic processes deep in the Earth’s crust and upper mantle.
Lesser-magnitude seismic events can also be caused by the withdrawal of gas and oil from the subsurface, or by the injection of water during fracking or geothermal energy recovery. Those so-called “induced earthquakes” are typically of small to moderate magnitude. However, they create major concerns, among the public in populated areas. Since induced earthquakes tend to occur at shallow depth, 3-5 km, sometimes as deep as 5-7 km, shaking at the surface can be intense. For this reason, in many regions, the public is greatly concerned and often tries to block commercial activity of any kind that can cause induced seismicity.
Earthquakes are unpredictable, say seismologists, even major events and huge disasters. The reason is that the seismologists take a mechanistic approach to earthquake forecasting –primarily relying on rock rupture analysis to identify foreshocks. However, this approach has been shown to be ill-suited to predict when and where an earthquake may occur, except with wide statistical uncertainty margins given in years or decades.
Thousands of lives and billions of dollars could be saved annually, if it were possible to derive actionable information about the build-up of stresses deep below, in the “seismogenic zone”, which reaches down to about 35-45 km, sometimes deeper. The challenge is to identify and properly interpret the signals that the Earth produces prior to major earthquakes. Strategies could then be developed to use such pre-earthquake signals to take steps that can reduce the losses. However, to reach this goal, a better understanding of how these pre-earthquake signals are generated is needed.
Scientists from different disciplines in different countries have tried to interpret different pre-earthquake signals that have been reported. Many hypotheses have been presented. Some may properly account this or that observation, but none has led to an overarching insight. Disappointed by this general lack of success, famous seismologists in the USA and other countries insist that pre-earthquake signals are a myth. They say it would be a waste of time and resources to even study them. Some have declared categorically that earthquakes cannot be predicted
The situation changed dramatically with the discovery that rocks contain dormant electronic charge carriers which can be awakened by stress. Stress is what the Earth applies generously to the rocks deep below, at ever increasing levels, up to the point where rocks can undergo catastrophic rupture leading to an earthquake.
The electronic charge carriers that are awakened in rock deep below have a special name: positive holes. They have some outstanding properties. For instance, once the positive holes are activated, they can flow out of the stressed rock volume, travel through kilometers of rocks and arrive at the surface of the Earth. In a theoretical paper published in 1984 in one of the leading physics journals, the Physical Review, it was shown that, when positive holes arrive at the surface, they build up microscopic but very steep electric fields. Those E fields easily reach a million volt per centimeter or more, predicted to be capable of ionizing the air by a well-known process, called "field ionization". In this process air molecules that come close to the ground surface loose an electron to the ground and flies away as an airborne positive ion.
For years this idea remained an interesting theory but was not tested. Eventually, in 2007-2008, experiments were set up at the NASA Ames Research Park to measure the field-ionization of air in contact with the surface of a large chunk of rock stressed at one end. Here is what these experiments told us: During the early phase of stress application a positive surface potential was seen building up, in full agreement with the theory, leading to microscopic but steep electric fields at the rock surface. Those E fields then caused massive air ionization, producing exclusively positive airborne ions at the tune of some 10,000,000 per second and centimeter square. Subsequently, during even higher stresses, another process was found to abruptly set in: the generation of corona discharges, which manifested themselves by tiny light flashes and the production of positive and negative airborne ions at the tune of some 100,000,000 to 1,000,000,000 ions per second and centimeter square.
What does this mean? Well, it means unusually large ion concentrations in the ambient air. Normally there are between 100 and 10,000 ions per cubic centimeter of air depending on whether they are measured in a natural environment, a forest or on a lake or in an unnatural environment such as a city.
High air ion concentrations have consequences. For one, every ion can act as a nucleus attracting water molecules so that they condense into a tiny droplet. Billions of tiny droplets make for a fog or haze. In addition, during water condensation heat is released. This heat warms the air and can create an updraft that carries the water droplets upward, where they can grow and form clouds. If there is an active fault along which massive air ionization continues to take place at the ground level, it can cause a stationary cloud to form, which is continuously fed by airborne ions rising upward and causing moisture condensation. Though the wind may blow, such a cloud stays “anchored” for hours, even days, along the fault line.
This, however, is not yet the end of the story. Positive airborne ions will continue to move upward, pulled and even accelerated by the global electric field, some 250,000 Volts that exist between the Earth’s surface and the ionosphere. As the positive air ions drift up towards the ionosphere, which begins around 100 km altitude, they perturb the ionospheric plasma by pulling its electrons down. This leads to distinct changes in the Total Electron Content (TEC) of the ionosphere, which can be derived from GPS satellite data. Ionospheric TEC anomalies have been widely observed prior to major earthquakes and are considered a possible precursory sign.
Back, down on Earth, the generation of massive amounts of airborne ions at ground level has potentially far-reaching consequences for humans and animals alike. The medical community has known for over 50 years that positive airborne ions cause anxiety, headaches, nausea, and other ill feelings, probably due to increased levels of the stress hormone serotonin in the blood stream. Understanding the interplay between positive airborne ions and living things may help us understand why, for instance, animals in the wild have been shown to disappear from their normal habitat and why, for centuries, domestic animals have often been reported to be restless and even panic days to hours before major earthquakes.
Dr Friedemann Freund
Chairman of GeoCosmo TM