EarthquakesUpdating information about U.S. regional earthquake hazards
The USGS recently updated their U.S. National Seismic Hazard Maps, which reflect the best and most current understanding of where future earthquakes will occur, how often they will occur, and how hard the ground will likely shake as a result. While all states have some potential for earthquakes, 42 of the 50 states have a reasonable chance of experiencing damaging ground shaking from an earthquake in fifty years (the typical lifetime of a building). Scientists also conclude that sixteen states have a relatively high likelihood of experiencing damaging ground shaking. These states have historically experienced earthquakes with a magnitude 6 or greater. To help make the best decisions to protect communities from earthquakes, new USGS maps display how intense ground shaking could be across the nation.
The USGS recently updated their U.S. National Seismic Hazard Maps, which reflect the best and most current understanding of where future earthquakes will occur, how often they will occur, and how hard the ground will likely shake as a result.
42 states at risk; 16 states at high risk
While all states have some potential for earthquakes, 42 of the 50 states have a reasonable chance of experiencing damaging ground shaking from an earthquake in fifty years (the typical lifetime of a building). Scientists also conclude that sixteen states have a relatively high likelihood of experiencing damaging ground shaking. These states have historically experienced earthquakes with a magnitude 6 or greater.
A USGS reports that the hazard is especially high along the west coast, intermountain west, and in several active regions of the central and eastern U.S., such as near New Madrid, Missouri, and near Charleston, South Carolina. The sixteen states at highest risk are Alaska, Arkansas, California, Hawaii, Idaho, Illinois, Kentucky, Missouri, Montana, Nevada, Oregon, South Carolina, Tennessee, Utah, Washington, and Wyoming.
While these overarching conclusions of the national-level hazard are similar to those of the previous maps released in 2008, details and estimates differ for many cities and states. Several areas have been identified as being capable of having the potential for larger and more powerful earthquakes than previously thought due to more data and updated earthquake models. The most prominent changes are discussed below.
Informed decisions based on the maps
With an understanding of potential ground shaking levels, various risk analyses can be calculated by considering factors like population levels, building exposure, and building construction practices. This is used for establishing building codes, and in the analysis of seismic risk for key structures. This can also help in determining insurance rates, emergency preparedness plans, and private property decisions such as re-evaluating one’s home and making it more resilient.
