Stopping The Next Big One

The work of an earthquake. Can we prevent it?

A system that could predict earthquakes has long been the Holy Grail of scientists trying to prevent the next catastrophe. Now a small Israeli company, backed by experts, is not only claiming to have discovered a method for accurately predicting earthquakes well before they occur, but also for preventing some of them.

The history of earthquake prediction is long and at most, fruitless. In the 4th Century B.C. Aristotle proposed that earthquakes were caused by winds trapped in subterranean caves and ancient Chinese and Italians studied special clouds which were thought to be indicative of impending quakes. More recently a group of scientists at the University of California, Los Angeles claimed an earthquake approximately 6.5 on the Richter scale will occur in Southern California by September 2004. It didn't happen. The grim history of earthquake prediction led some seismologists like Robert J. Geller from Tokyo University to claim that it is practically impossible to predict earthquakes and that it seems unwise to invest heavily in monitoring possible precursors of upcoming earthquakes. Despite the long line of failed projects and the harsh criticism sprung each time a new earthquake prediction method was suggested, a small Israeli company named Terramoto has recently proposed a three stage method which its inventor, Meny Nachman, believes will not only help predict earthquakes with very high accuracy but also be able to stop some of them from occurring altogether.

The Earth's crust is broken into a mosaic of moving tectonic plates.
The Earth´s crust is broken into a mosaic of moving tectonic plates.

Why earthquakes occur?

In order to understand Terramoto's idea we first need to go deep underground in order to understand what causes earthquakes in the first place. According to the theory of plate tectonics developed in the 1960's the earth's interior is made up of two layers, the outer lithosphere and the inner asthenosphere. The lithosphere essentially "floats" on the asthenosphere and is broken-up into ten major plates. These plates are in constant motion relative to each other with a typical velocity of a few centimeters per year. Although the velocity in which the entire plate is moving is relatively constant, the velocity in which material is moving along intersections of plates, also known as fault lines, is not constant and is believed to be changing due to irregularities in the material composing these parts of the earth asthenosphere. These irregularities are attributed to rocks, sometimes kilometers in size, which are buried in the ground and can be found at times up to 20 kilometers below the surface. These rocks can locally stop the movement along a fault line and by doing so accumulate tremendous pressure which is released abruptly when the rock finally crushes. This instantaneous release of mechanical energy is what we call earthquake and the strength of the quake is dependent upon the amount of energy accumulated in the rock over the years. Relatively small quakes happen all the time near fault lines around the world and although we usually do not feel them, the system developed by Terramoto regards them as highly important signs that can reveal much about an impending big earthquake.

Terramoto's three stage method for detecting and preventing earthquakes:

Terramoto has developed a method based on existing equipment which will map, predict and if possible prevent major earthquakes from occurring along known fault lines.

Mapping – a number of measuring stations will be placed along the fault line equipped with special microphones called geophones (a standard seismological equipment) which will be buried in the ground. Each geophone will be capable of measuring the low frequency noise caused by faint earthquakes and using triangulation techniques will locate the points in the ground where pressure is building up. The idea behind this method is that if in a specific point along the fault line we measure a certain amount of energy release and in another point along the fault we measure a similar amount of energy release then we can assume the existence of a third point in the gap between these first two points were energy, at least at the same amount, is being accumulated.

Predicting – When a potentially hazardous point is located, a deep ultrasound survey is performed using equipment borrowed from the oil industry. The survey is performed in order to locate the specific rock where the pressure has accumulated. Using drilling equipment (again borrowed from the oil industry) extract a sample of the rock and evaluate its strength, and combined with the ultrasound scan determine its size and shape. This data is then used to create advanced mathematical models that can predict how much pressure the rock could endure before succumbing to the sheer force of the tectonic plate. The amount of pressure built up can be a good indication of the possible force of the earthquake that can be unleashed when the rock eventually shatters. In order to be able to give an accurate time prediction of an upcoming quake, two lasers will be placed each on a different tectonic plate and by measuring the interference pattern they create it is possible to evaluate the relative velocity in which the two plates are moving and thus the rate of the energy accumulation inside the rock.

Geophone is an instrument used to detect vibrations passing through the earth's crust.
Geophone is an instrument used to detect vibrations passing through the earth´s crust.

Preventing – When a high-magnitude earthquake has been predicted it is possible to drill up to 10 kilometers inside the ground and place explosives inside the rock in order to perform a series of controlled blasts to weaken the rock, gradually relieving the built-up energy accumulated over the years.

IsraCast approached Dr. Shmulik Marco, from the Department of Geophysics and Planetary Sciences at the Tel Aviv University, to get his professional opinion on the method developed by Terramoto. Dr. Marco explained that systems like the one suggested by Terramoto, are important tools for saving human lives and as such are worth much more than the amount of money that will be invested in them. The idea behind the system is not entirely new, and although there are some technological obstacles in the way, the main reason such systems have not been implemented in the past are more political then technological. According to Dr. Marco there is a real need for rethinking priorities and reallocation of funds to the field of seismology which suffered from heavy cutbacks in recent years especially in the U.S. As for the method suggested by Terramoto, the first stage (mapping) is definitely possible and partial experiments of this sort are currently taking place around the world. The second stage (predicting) is also possible although it will pose great technical difficulties due to the need to drill more than eight kilometers below the ground (there are currently a handful of drilling teams working below this depth around the world). The third stage (prevention) is the least feasible at this point mainly due to the need to find ways to detonate huge rocks deep inside the ground, in an extreme environment of intense heat and high pressure. But even if the third stage would not always be performed, advance warning can give countries time to prepare quick response teams, strengthen buildings and in some cases even evacuate people ahead of time.

Mr. Nachman, Terramoto CEO, told IsraCast that despite the difficulties involved with deep earth drilling, there are still many potentially devastating earthquakes which are caused by rocks less then 8 km inside the ground. These rocks can be reached using existing drilling equipment and the blast can be performed inside the rock using a relatively small charge that will create an initial crack in the rock, preventing it from accumulating dangerous pressures. According to Mr. Nachman Terramoto's system will be able to predict the center of an upcoming earthquake with precision of within about one meter, half a Richter scale in magnitude and a timeframe of between a week and a month of its occurrence. Based on the data collected it should be possible to predict earthquakes many years in advance and thus either prevent them by a series of controlled explosions or prepare for the event by strengthening buildings and evacuating people.

Terramoto was founded by Mr. Nachman in 2005 and its new method is currently patent pending in the U.S. and Israel. The development of the first stage of the system for which Terramoto is seeking investors should cost less than one million dollars, and the full system including six measuring stations should cost approximately one million dollars upon completion. When we factor these costs we should always consider that besides the horrific loss of life we attribute to many high magnitude earthquakes there is also a huge financial cost attached to them. The 1976 Northridge Los Angeles 6.9 magnitude earthquake demolished some 15,000 buildings resulting in a total loss of around $15bn; in Kobe Japan the 7.1 magnitude earthquake in 1995, cost $90bn to $147bn in repairs alone and resulted in 180,000 buildings destroyed or seriously damaged. An accurate reliable early warning system might have prevented these and other human and economic catastrophes.

by Iddo Genuth - IsraCast

The original story can be found here.
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© 2005 IsraCast. Published with permission of Iddo Genuth

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