Expecting the subsidence to be minute, AFAIK burying the sensors is not an option:

• Accelerometer signals would be minute. In addition, monitoring an accelerometer would have to be continuous - quickly draining any battery.
• Burying the sensor will shield any "waves" - rendering wireless communication unreliable to impossible.
• Burying will as well shield the sensor from any surface reference "signals".

I know of such supervisional measurements using laser triangulation or DGPS. The former could eliminate the need for wireless communication (the "sensor" just being a laser reflector on some mount), the latter might be a wireless sensor but would require a DGPS ground station transmitting the "correction signal".

Both methods are only applicable if the subsidence affects the surface as well. The "pro" is that these methods can be applied with a sensor that is only intermittently active, as they register the actual amount of subsidence and do not have to get the exact moment of soil movement.

Does this help?

Greeting.........

first, if you did not find wirless sensor, there is no problem, It can be.

About sensor, may be any sensor detect motion can be suitable if not try to test Piezo sensors. It is not wireless but as I said it will work wirelessly as you wanna

How large is the distance of the motion and its time duration? you can use microwave transmitter buried in the soil and multiple receive antennas at small distances. By measuring the output of the receive antennas one can estimate the distance of movement. one can calibrate the receivers to measure the movement distance. I think there are some solutions to this problems. As the frequency of the wireless system increases and antennas gets directive one can resolve the motion in better way.

Best wishes

Thank you so much U. Dreher , Abdelhalim Zekry , & Mohsen El-bendary for your precious answers and time.

What about if i use thermal image camera instead of sensors, or may i use both sensors and thermal image camera at the same time.

Actually my objective is to monitor and detect the changes or subsidence in soil due to any leakage in water pipelines or rain or any other cause.

I am still confused which way to go.

You suggestions will be appreciated.

Thanks in advance.

"... detect the changes or subsidence in soil due to any leakage ..."

This might prove difficult anyway considering the size of the area you seemingly want to monitor.

If it were "only" about the influence of water, you might consider measuring the conductivity of the soil (a relatively simple measurement although I'd recommend to use AC to minimize effects of electrolysis). This might not work for "... any other cause(s)."

Beyond that: considering the size (length) of water pipelines and the areas rain might affect, I cannot really imagine a reliable method to monitor an equivalent area without massive efforts.