A geological hazard is a geological condition, process or a potential event that poses a threat to the health, safety or welfare of a group of citizens, or the functions or economy of a community or larger governmental entity. The study of landforms affected by recent earth movements is called neotectonics or morphotectonics. It has been estimated that an average of 10,000 people a year are killed by earthquakes. Analysis of damage due to earthquakes in California and Mexico has shown that extent of ground-shaking and the resultant damage are critically dependent upon the nature and properties of rocks and soils at or near the ground surface. In case of the Mexico City earthquake of 1985, adjacent buildings with different geometries responded differently to ground motion, collided and destroyed each other. There is a close relationship in the distribution of the earthquakes and the volcanoes, for simple reason that both occur along plate margins and are related to plate movements.