WHY DO chrstian say that the cause of suffering and evil is men'sfault?

I lost my best friend after the erth quake that hit San Francisco in 1989. He suicide , he had severe burns all over his body . WHo caused the earthquake ? Obviosly if God created nature he created earthquakes too, and all the suffering that comes with it. Who are you supposed to pray when a loved one suffers and dies because of a natural disaster, how can you still have faith in GOD?