The recent devastating earthquake in China has led to discussion about whether earthquakes can be predicted. USGS scientist Mike Blanpied sets the truth about what science is capable of.
Hello and welcome to the USGS CORECAST.
'm Jessica Robertson. Today I would like to welcome and introduce our guest, the USGS scientist, Michael Blampied.
He will talk to us about earthquake prediction.
Thanks for joining us today, Mike.
Jessica
First I would like to know
can the USGS, or other organisms to predict earthquakes?
Jessica Mike, there is currently no organization, government or scientist can predict correct time and the occurrence of an earthquake. However, scientists are very good to say more general things about the risks of an earthquake. For example, we see the flaws and patterns of earthquakes for many years and we can do a good job of saying that as the "landscape" it is likely that earthquakes occur on faults, such as large earthquakes tend to be.
Using this information, we can improve building codes, we can make planning land use, we avoid the failures close to buildings that are dangerous and so on. So you can predict long term, where the earthquake hazard is likely to be.
Jessica
I know that after a major earthquake, it is likely that aftershocks may occur.
Can you predict the size and timing of these replicas?
Mike
Following a large earthquake, there are a number of replicas. After a big earthquake, there may be many aftershocks can last for months or even years. However, decrease in frequency and generally decrease in size over time. Scientists can say about the frequency and number of replicas to be produced, but not exactly when or where.
Scientists do another thing after a major earthquake, is to calculate the amount of "stress" that moved on the failures close to the area increasing the risk of major earthquakes.
Jessica
"The USGS has conducted experiments to predict earthquakes?
Mike
Yes USGS has done and has sponsored much research over several decades in the prediction of earthquakes, both specific prediction experiments and also more generally to understand the predictability of earthquakes.
For example, is there something that happened on earth before an earthquake that allows it to be detected on the surface?
The USGS and the state of California engaged in a careful experiment in earthquake prediction. In central California, there is a section of the San Andreas Fault that runs through the small town of Parkfield and back in the 80's it was noted that there had been a pattern of earthquakes of magnitude 6, a number of these earthquakes were spaced every 20 to 25 years, the last was in 1966. Based on that model, the USGS has predicted that there would be another one coming probably in the mid 80's. And that led to a very intense experience to try to capture all possible information on the earthquake with a variety of instruments and also to predict if possible. It turned out that the earthquake was not in the 80's and was not included in the 90's. In fact, he waited until 2004.
We have made the capture of wonderful information about the earthquake using a variety of sensors, however, there is nothing we can say that it was foreseeable by the earthquake. Land gave no indication of a "foreshock" or an electrical signal or a signal of water or anything else that tells us the possibility of the onset of an earthquake. Just shows what we have learned over several years and decades on earthquake prediction, if possible at all is very hard. Jessica
So can you give an example of what can predict about a particular fault?
Mike
Well, the Hayward Fault on the east side of the bay of San Francisco is a great example. The Hayward Fault has a long history of earthquakes and Geologists have dug into the fault zone and look at the rocks to determine that earthquakes occur on the Hayward fault every 140 years with some variations. It's been 140 years since the 1868 earthquake did great damage in the San Francisco Bay and therefore the Hayward fault is one that could tell us something about the maturity of an earthquake.
Now there is great variability in the regularly of the earthquakes and we can not say whether the next earthquake will happen tomorrow or 10 years or even 20 years. But we do know that this earthquake is very likely, we think it probable that an earthquake of magnitude 6.8 and therefore very dangerous. And we can take action now to protect the Bay Area against the earthquake we're pretty sure to come. "
Jessica
Now I have learned that animal behavior can predict earthquakes. Is that true?
Mike has been a good deal of research on this subject in various places and what I have understood there has been no demonstration that earthquakes are predictable, especially for animals, however, research continues on this issue. One thing that is clear is that some animals are very sensitive to different vibrations coming from the ground interior.
And so many times an animal senses early arrival of the first emerging weak waves of an earthquake, and this allows us to realize that the earth trembles before that captures the human being and so, an earthquake can cause animals to react in a few seconds or even a minute before the closest human beings.
Jessica
So can the USGS, or any other do the same and early detection of these waves?
Mike
Yes, indeed, there is a job in that area and his listeners may be aware of wave detectors, simple devices that one can, for example, connecting up the gas line in your home. This device basically felt by gentle shaking and if detected, turn off the gas before the arrival of the shocks that follow. The other way we can make an early warning is to place seismographs in the vicinity of where it will be an epicenter of an earthquake in high risk areas. When an earthquake's seismic network takes steps on the earthquake and computers can determine that an earthquake has begun and that the information was radioed ahead to areas that have not yet received a strong jolt. We call this earthquake
system, early warning, and there are operating systems in Mexico and Japan and the USGS and partner organizations in California are doing research to understand what benefits an early warning system could have earthquake in California or anywhere in the world "
Jessica
What exactly is the role of USGS science and earthquake prediction?
Mike
The USGS actually has a unique role in earthquake prediction research. USGS is a federal agency which is responsible for issuing warnings of geological disasters such as earthquakes, landslides land and volcanoes. This includes federal responsibility for issuing earthquake predictions.
Jessica
Is there anything else you want to share with us today?
Mike
just want to make clear that we have no way to predict earthquakes as discussed. There is no reason for optimism. There is a greater amount of data, new theories and computer programs are powerful and scientists are using to explore the ways in which one could predict earthquakes in the future.
certainly hope that one day we're in a world where an earthquake can anticipate and predict before it happens.
Jessica
Well thanks for joining us today Mike.
Mike was very nice talking to you.
Jessica
And thanks to all our listeners who joined us on this episode of CORECAST. If you want real-time and historical information about earthquakes around the world or to learn more about science the earthquake, visit www.earthquake.usgs.gov. If you feel an earthquake, please report your experience on the site didyoufeelit located on the USGS Web site.
