Natural disaster seismic waves. At the Earth's surface, earthquakes manifest themselves by vibration, shaking, and sometimes displacement of the ground. Earthquakes are caused by slippage within geological faults. The underground point of origin of the earthquake is called the "seismic focus". The point directly above the focus on the surface is called the "epicenter". Earthquakes by themselves rarely kill people or wildlife. It is usually the secondary events that they trigger such as building collapse, fires, tsunamis (seismic sea waves) and volcanoes. Many of these could possibly be avoided by better construction, safety systems, early warning and planning. When natural erosion, human
The Superstar Effect The Superstar Effect The Superstar Effect or "Tiger Woods effect" refers to the change in performance caused by the presence of a highly ranked player - a superstar - in a rank-order competition. The phenomenon was first described in a study titled ""Quitters Never Win: The (Adverse) Incentive Effects of Competing with Superstars"" by Jennifer Brown, which examined the performance of golfers at events with and without Tiger Woods. In contradiction to what intuition would suggest (namely that increased rivalry encourages better performance), Brown finds that the presence of a superstar is in fact associated with reduced competitor’s efforts in