A deeper focus affects a small area. An earthquake may have various effects on a region. Land slides as well as changes in the level of water in lakes may also occur. Rivers have been known to overflow, dry up completely, or even change directions as the result of an earthquake. These effects are why California takes earthquake preparation seriously.
Scientists analyze specific warning signs in order to make earthquake predictions.
A higher frequency of tremors as well as minor eruptions and abnormal animal behavior are also symptoms of an impending quake. Almost a century before the infamous earthquake that destroyed most of San Francisco, another destructive quake left its horrendous mark not on California but on the central United States. Picture yourself in the early 1800's. You are snuggled warmly in your bed as the mantel clock chimes two o'clock on a December morning. You pull the covers more tightly around you to keep out the cold.