One of the most attractive features of Shan's forecasting method is its extremely low cost. You basically just trace the sun's shadow on a wall and then I expect use the results with some special calculations.

Even if it were accurate only 30% of the time it could be used effectively by people in both wealthy and impoverished countries around the world. And that might enable them to detect the approach of at least some of their own destructive earthquakes. Every village could run its own program. Residents wouldn't need a strong central government or large buildings filled with electronic equipment.