Higher earthquake risk for eastern US
A new US geological survey indicates that some parts of the US are at an increased risk of earthquakes, especially along the east coast.
New seismic hazard maps updated for the first time since 2008 show highest risk west but also increased risk east.
"The eastern US has the potential for larger and more damaging earthquakes than considered in previous maps and assessments," the report states.
The East Coast experienced one of its largest quakes for 100 years in 2011.
The 5.8 magnitude quake was centred on rural Virginia but was felt by hundreds of thousands of people, including in Washington DC.
Parts of states including Alaska, Hawaii, Oregon and California remain at the highest risk of seismic activity.
Major fault lines exist along the entire US West Coast, as well as in the Midwest near Illinois and Missouri.
"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 50 years," the new report finds.
"The hazard is especially high along the West Coast, intermountain west, and in several active regions of the central and eastern US."
The 16 states at highest risk are: Alaska, Arkansas, California, Hawaii, Idaho, Illinois, Kentucky, Missouri, Montana, Nevada, Oregon, South Carolina, Tennessee, Utah, Washington, and Wyoming.
Meanwhile, several states saw their risk of seismic activity lower, including Texas, Oregon, Utah and New York.
Earthquakes caused by fracking - utilising a mixture of water, sand and chemicals pumped underground at high pressure to crack open sedimentary rocks and release the fuels within - were not included in the analysis.
Several hundred earthquakes have hit Oklahoma so far this year, with fracking named a primary culprit, although the impact of fracking on earthquake risks is disputed.