Answer:
Because the amplitude of the surface waves diminishes less rapidly with distance than the amplitude of P or S waves, surface waves are often the most important component of ground shaking far from the EARTHQUAKE source, thus can be the most destructive.
I’m not sure exactly what you’re looking for, but the US spent $15m dollars and gained 54% of Mexico’s pre-1836 territory. There’s a nice article on Wikipedia called ‘Mexican Cession’ that seems helpful. Hope this is helpful :)
