Global positioning system aka GPS is used in our everyday life very frequently. Whether you are in an area or you are trying to find something in your own area GPS is an essential tool. It is also used in monitoring faults and detecting earthquakes.
How Does GPS Work?
GPS works using the satellites that orbit the earth. There are about 30 active satellites and some backup satellites that are orbiting the earth which is in case of a replacement of the active ones. These are what make the GPS workable.
These 30 satellites orbit the earth and make a circle so that the GPS can be used from any location on earth. Each time someone tries to see a location, the GPS sends a signal to these satellites.
Three satellites from different directions receive the signal and send the distance of those satellites from the GPS. After cross sectioning all three distance data, the GPS can tell the exact location within a few mm distance. It can also detect how high or the location is from the sea level using the same method.
That is the basic principle of the GPS. But there are a lot more that happens in the background. The 30 satellites are also divided into a few groups that follow different paths to cover the whole globe. While cross sectioning they use spherical models to do that. It gets a lot more technical on that side.
GPS in Monitoring Faults
A fault is a fracture between two blocks of rock that allows the block to move relative to each other. This movement is often the cause of an earthquake. Not all the faults are always active. Some faults are always slowly shifting and some stay still.
How Does Earthquake Work?
These faults whether moving or not build up stress over time. Most of the time the still ones are responsible for building stress in them but the moving ones can also have sudden unpredictable movement because of stress.
The still faults stay still because 2 or more block gets close and causes friction rendering them unable to move. When the stress reaches a certain level when it can overcome this friction, the fault slip happens.
Fault slip is when the blocks start to move. This sends a shockwave of energy throughout the earth’s crust causing the earth to shake which we call an earthquake.
How Does GPS Come in Work?
GPS can be used to monitor the faults and check for shifts in faults. In an area that is prone to earthquakes, these GPS stations can be set to monitor the displacement of the faults. The data frequency can be changed to update per sec, min, hr or even year to monitor how much the faults shift in a certain time.
One big problem when it comes to earthquake research using a seismometer is it can measure the earthquake but there is no additional data to add to the research. GPS can take care of this additional data.
GPS stations can be set to measure how much the faults are shifting if shifting at all to provide a baseline for safety. While currently, this is not something that is capable of predicting earthquakes but in the future with enough data from pre and post earthquake it may even be possible to predict one earthquake using GPS.
Right now these GPS stations are used with a frequency of a year to check the movement of the fault. In the past scientists have used a post earthquake data to determine that the movement of the faults is directly connected to how strong the earthquake will be.
How Do You Monitor the Faults?
In an earthquake prone area, several GPS stations are set up. That is because normal GPSs are not strong enough to calculate the precise location that is needed for the study. These GPS stations monitor and update the fault movement at a certain frequency.
This frequency is usually once every year. But if an area is due to an earthquake then the frequency can be lowered down as much as one second. Adding a stress meter to it, scientists can check the movement and stress of the fault. That way there is enough data pre-earthquake to process the behavior of the faults in that certain area.
Then if an earthquake hits, the area with the station gets displaced. Not all the stations always stay functional after the earthquake but those that are functional can be used to gather data as soon as possible. This has to be done quickly otherwise the faults will move to a position that will no longer is useful for the study.
This along with the pressure gauge is possible to determine how much pressure and movement has been caused before the earthquake or if there was a fault that used to move a certain distance then how much extra movement has caused the earthquake.
Q: Is it possible to predict earthquakes by monitoring faults?
Ans: It is debatable in the scientific community. Some believe that with enough data it is possible to predict it while others believe it will not be possible to predict with an interval that will help us get to prepare.
Q: What is the benefit of using GPS in monitoring plate movements?
Ans: GPS helps to gather data on the plate pre and post earthquake which will help us to map an early earthquake warning sign.
Q: How is GPS used to measure earthquakes?
Ans: By measuring the displacement of the plates it is possible to tell the strength of the earthquake.
GPS and earthquake research still have a long way to go but it is already revolutionizing the earthquake research sector with its precise location telling ability. With enough data, we may be able to predict an earthquake in advance and act according to the warning. GPS is the tool that will be leading this data to us.