MADISON COUNTY, Miss. (WLBT) - The United States Geological Survey reports minor seismographic activity Thursday morning in Madison County. However, you likely didn’t even know it happened.

But how are earthquakes currently measured? According to the United States Geological Survey (USGS), earthquakes are recorded by a seismographic network which measures the movement of the ground ...

Two years later, the observatory added the first seismographic equipment deployed by the University of California, and in 1891 a glass conservatory was built on the hill as part of the original campus ...