IntroductionHazards pose a risk to everyone. Our acceptance of the risks associated with dangers dictates where and how we live. As human beings, we accept a certain amount of risk when we choose to live our daily lives. From time to time, a danger becomes an emergent situation. Tornadoes in the Midwest, hurricanes along the Gulf Coast, or earthquakes in California are all dangers that people in these regions accept and live with. This article will examine a hazard that has caused a disaster requiring response by emergency management personnel. Specifically, the risk examined most closely here is an earthquake. With the recent twentieth anniversary covered by many media outlets, the January 17, 1994 Northridge, California earthquake is the costliest earthquake in American history to date. Earthquakes Before examining the Northridge event, understanding the natural hazard of an earthquake will help to better understand exactly what happened and why it was such a significant geologic event. With four distinct layers, two layers, the crust and the upper mantle, make up the skin which constitutes the surface layer of the Earth. The crust is not a single, continuous piece. It's actually several different pieces, or plates, that fit together to form the puzzle that makes up the Earth's surface. These plates are in constant motion and rub against each other. These areas, called fault lines, where plates rub against each other, feature places where one plate "gets stuck while the rest of the plate continues to move." When the plate has moved enough, the edges peel off and this is how most of the world's earthquakes occur” (Wald, 2012). The energy stored thanks to the friction of the two plates...... middle of paper ......earthquake: the 1994 earthquake still fresh in the minds of Los Angeles after 20 years. Retrieved from http://www.dailynews.com/general-news/20140111/northridge-earthquake-1994-disaster-still-fresh-in-los-angeles-minds-after-20-yearsCrisan, B. (2010). Disaster Case Study: The 1994 Northridge Earthquake. Retrieved from http://www.academia.edu/684114/Disaster_Case_Study_The_Northridge_Earthquake_of_1994 Gordon, K. and Emerson, J. (2010). Governing through Disaster: Lessons from the 1994 Northridge Earthquake. Retrieved from http://thinkprogress.org/climate/2010/08/07/206563/governing-through-a-disaster/Oskin, B. (2013 ). Pre-earthquakes announce future earthquakes on certain faults. Retrieved from http://www.livescience.com/28134-earthquake-slow-slip-foreshocks-found.htmlWald, L. (2012). The science of earthquakes. Retrieved from http://earthquake.usgs.gov/learn/kids/eqscience.php