Hi All. Predicting earthquakes has been one of the most interesting and difficult challenges a scientist can attempt. For many decades, San Francisco had waited for the "big one" to hit. Then in the fall of 1989, as thousands of people drove home from work on bustling freeways, the earth began to rumble. Within minutes a city of several million people was shaken nearly to disaster. Destroyed homes...collapsed bridges...fires...ambulances.... Was this the quake they had waited for? Could somebody have accurately predicted it?

When we talk about predicting quakes we tend to mean the accurate prediction of earthquakes that will happen soon, rather than at some vague time during the next ten, fifty or hundred years.

Looking at the earthquake history of an area can make long term and general predictions. We can say for certain that there will be a minor earthquake in California this week, possibly even today, because we've looked at the records for the last few decades and seen that there are hundreds of tremors every year; thousands if we include the minor ones. We cannot say when the next major one will occur.
We can say that there is a good chance that there will be a major earthquake in Mexico during the next 50 years, and that Britain is most unlikely to be hit by a damaging quake in the next two or three hundred years. Such information is useful on a long term scale but of no help when trying to predict the immediate future and save lives and property.

To date most of the prediction research is centered around the theory of Dilatancy. It has been noticed that when a rock is stressed it begins to expand; to dilate. This is caused by micro-cracks and fractures in the rock opening up and becoming larger. This only seems to start when a rock is roughly half way toward its breaking point.

Visually monitoring the size of a rock sample underground is not possible, but there are several indirect ways to gather the information. When a rock becomes stressed it begins to change physically. It transmits seismic waves at changing speeds, its magnetic properties can alter and its electrical resistance will also vary. The physical change in rock size may lead to a general uplifting of the ground surface or a change in the groundwater pressure and levels. Scientists monitor all these factors and are beginning to find generalized patterns of activity.

The Chinese have claimed considerable success with a totally different approach to the problem. It has long been known that animals, birds and insects seem to change their behavior patterns before an earthquake.

In December 1974 Chinese scientists began to receive reports of snakes coming out of hibernation and freezing to death on the cold ground. This activity was followed by a series of minor tremors at the end of the month.

During January 1975 they received even more reports of strange animal behavior. Much of these concerned larger animals such as cattle and horses, which had become restless, refused to enter buildings or seemed frightened for no obvious reason.

In February that year a major earthquake struck. The epicenter was in Haicheng, the area from which most of the animal reports had been received.

This question must be asked, do we really want accurate predictions?

The obvious answer may seem to be 'Yes, we do'. Sufficient warning would allow for the safe evacuation (if that was a viable option) of the population, gas and water supplies could be cut before pipes were ruptured, and emergency services need never be caught by surprise again.

What about the other side effects though? It is unlikely that general predictions will ever be more accurate than within a year or two, perhaps ten. This time scale serves no purpose when it comes to evacuation and similar precautions. A city cannot be left deserted for years whilst the populace waits for a possible disaster. During that wait though, what would happen to the development of the area. Would business want to invest in something, which might be destroyed? Would it be possible to get earthquake insurance when the insurance companies know they will have to pay out, and how many people would want to take out a mortgage on a home likely to be destroyed?

It is because of problems like these, and the fear of false alarms making the whole warning system a waste of time, that some people have suggested that warnings should never be released until a totally fail proof system has been developed.

Scientist for the most part have a fairly good idea as to where and when the next major quake in California is going to strike. The data I was receiving for more then 3 years was fairly accurate in the when and where in that it allowed me to use a 5 day window with a radius of 25 miles in my predictions, but never the less it had one obstacle that stood in the way of making the prediction more useful then what it was. I was never really sure as to what the magnitude of the quake was going to be. No matter how close I came to getting the location and time correct it didn’t make any difference if the magnitude wasn’t correct, or was unknown before the quake occurred.

The magnitude of a quake is determined by the amount of stress at a given point. Without knowing how much stress has accumulated at a given point and how much more is needed to break the obstacle that is preventing movement there will never be a successful quake prediction program. If one knew how much stress has accumulated and how much more is required you would indirectly know the time and location of the next major quake. All that is required is time and money and those with the convictions that earthquake prediction can become reality. The path to a successful earthquake prediction program is filled with many obstacles and hazards, which at times must seem insurmountable. However it can be done. It will be done. Take Care…Don in creepy town

Reference
EssayBank.Co.Uk
Geography Resources for Teachers and Students
The Regents of the University of California
The United State Geological Survey
The University of California Berkeley