What did the chinese people invent during the han dynasty to predict or deal with natural disasters?

The Chinese people invented the Seismometer during the Han dynasty to help predict natural disasters. The Seismometer measured the motion of the ground, and  things included of seismic waves such as, earthquakes, volcanoes, and other things that involve explosions that are generated by seismic waves. 

the map that was shown mostly had eastern asia highlighted. the answer would mostly likely be "the spread of communism into eastern asia set the stage for the korean war."

hopefully this .