What Would Happen If Earth Rotated Faster?

An increase in Earths rotational speed could have various impacts on life: ranging from increased earthquakes and tsunamis to a shortening of the length of the day. People could be floating in central Africa while the polar ice might melt extremely fast, submerging most parts of the world. As the rotation of the planet principally determines the length of the day, a faster rotation speed would mean a shorter day. So, the number of days in a year would increase (provided that Earth still revolves at the same rate).