Hi Shan,

It appears to me that you are measuring ground tilt with your sun shadow based method. And that is exactly what Pavel is doing. However, his sensors are usually in abandoned coal mines etc. rather than on the surface like yours. So they are less subject to daily surface variations.

If the two of you were to compare notes regarding when you detected signals I expect that you would learn that both methods often detect signals around the same time.

Your method might be better for specifically identifying the fault zone where an earthquake is going to occur as it covers a larger area. His focuses more on individual fault zones and generates better long term data. He can follow the buildup of strain in a fault zone for months before the earthquake occurs.

These are personal opinions that are based on my interpretations of both methods.