“Immerse the brick in water for two weeks. Then dry it in the sun. If it does not crack or effloresce, it is fit for foundation.”
In 2020, seismologists at IIT Roorkee compared Varahamihira’s descriptions to modern digital seismograph data. They verified that his "circular" earthquake corresponds to Rayleigh waves and his "jerking" type corresponds to primary (P) waves. He also correctly noted that earthquakes are more frequent at dawn and dusk (times of maximal tidal stress on fault lines). the brhat samhita of varaha mihira varahamihira verified