How can you predict it???

Question

Im doing an essay on earthquakes, and need to know if its possible to predict them. I know theres one supposed to happen in San Francisco between 2010-2030, but how do they know??

Answer 1

In the example you're thinking of, the prediction is based on the frequency of occurence of earthquakes in that area in history (human history as well as recorded in the geologic record), and also based on geologic measurements of strain on portions of the moving fault.

The predictions are given probabilities, because simply put we really don't know when an earthquake might happen or even if it will. However, we do try to give a level of confidence that it might happen with a percentage. I don't have the numbers in front of me, but I believe the likelihood of a large (>6.5) earthquake on the Hayward Fault in the SF Bay Area is something like 60-70% in the next 30 years. In other words, it's getting overdue!

Aside from these types of predictions, there really aren't any other meaningful or reliable methods. You may come across things like "dogs bark more right before a quake" or "we get very hot weather before a quake" and stuff like that. Unfortunately, statements like that are often incorrect and therefore meaningless as ways of predicting earthquakes.

Answer 2

So far, they can only give estimates on how many occur over a given period of time at a certain level. So, if an area averages a 7.0 every 150 years on average, and it's been 140 years, they can say there's a high probability of one occuring in the next 10-40 years. There are interesting theories emerging about infra-sound vibrations (sub sonic very low pitches) being emitted days or hours before quakes and thinking that some animals may be able to sense those. No definitive proof, but there is a guy in San Francisco that predicted the "World Series" quake a few years ago using that idea.

Answer 3

From the USGS website:

No. Neither the USGS nor Caltech nor any other scientists have ever predicted a major earthquake. They do not know how, and they do not expect to know how any time in the foreseeable future. However based on scientific data, probabilities can be calculated for potential future earthquakes. For example, scientists estimate that over the next 30 years the probability of a major EQ occurring in the San Francisco Bay area is 67% and 60% in Southern California.

The USGS focuses their efforts on the long-term mitigation of earthquake hazards by helping to improve the safety of structures, rather than by trying to accomplish short-term predictions.

For further information, see: Earthquake Prediction discussions

But I do know they are still working on theories that MAY help narrow the time frame & increase the possibility of prediction, since a friend of mine is one of the lead researchers.

Answer 4

I don't know if you know about P and S waves. However, research shows that there is a slight slowing of the speed of P and S waves that travel underground prior to an earthquake. There also may be a slight drop in the level of well water.
With that being said, I can predict an earthquake. I predict that there will be a mag 5 earthquake in California along the San Andreas fault within the next 50 years.
The problem does not lie in being able to predict earthquakes but rather in being precise about the time of the earthquake.
Sorry, I just couldn't resist!

Answer 5

Methods for prediction of earthquakes & Tsunami
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1. Seismic gape: - The earthquake at a particular place may occur for every fixed gape of time. By knowing the past records of the quakes affected at that place may help to decide when the earthquake is next due.

2. Planet position.: - When the stress is accumulated at the tectonic plate boundary and the same time if the position of more than 2 planets comes in a straight line this may help to accelerate the earthquakes. There fore the full moon days and new moon days are more vulnerable days for earthquakes. Some time this method fails why? Think of a sick patient. New moon and full moon days are dangerous for only sick patents. These days will not affect the healthy people. The same way if there is no accumulated stress at the tectonic plate boundaries no need to worry about the planet positions.

3. Sun rays falling method: - If you observe the position of the sun rays falling on our wall at a particular time on all days it should form an angular infinity symbol. If there is any deviation in its path it means that there is some difference in height of the earth. That means some strain noticed at that place. Somebody claims that they can predict the place of epicenter by observing this. The laser beam measuring method of earth height from satellite also will help.

4. MCDB:- Chinese scientist claims that they can predict up to 60 % accuracy by sensing electro magnetic rays.

5. Cloud forming: - Few hours to a few days before the occurrence of earthquakes a cloud reader claims that he has noticed a peculiar mosaic type of formation .We may also notice some lightening in the sky.

6. By sound :- A professor from Ajmeer University claims that he was able to hear a low frequency noise under 125 meter depth in a bore well. The same thing was reported by one Mr. Nair that he heard some roaring noise under the earth one week before the occurrence of earthquake in Gujarat.

7. By frequency of waves :- Mr Richter Allen of Berkley University claims that he can decide the magnitude of earthquake just 4 seconds after observing the frequency of the primary wave. Present method needs the full seismographic picture to find the real magnitude that too from as many places as possible to have fairly accurate results. His claim has got some truth because when there is a slip of bigger tectonic plate the frequency of quake will be less. If a small tectonic plate slips the frequency of the waves will be more.
8. There are several changes in nature and in the behaviors of animals and birds can be observed before an earthquake and Tsunami. I wrote several articles on these subjects..






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Answer 6

Based on historical frequency.